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Posts from the ‘3D’ Category

4
Jan

3D Stud Thermistor – MG Chemical Fix

Having toasted, and not that I mean that literally, more like broke, wore out, shorted, and just plain destroyed any number of those fifty cent hot end thermistors, I went in search of something a little more robust.

The keyword being robust. Except you can leave off the “ro”. Thus, bust.

Stud Thermistor

When I found was a bunch of these little guys. Essentially a typical brass standoff, with a thermistor (yeah one of the fifty cent glass bead marvels) glued inside.

Stud Therm

When I started using these, they seemed really handy, easy to change, didn’t break any wires. I was rather elated.

Within two months, I was deflated.

Whatever sort of epoxy or glue used to hold the glass bead into the brass fitting is designed like a tail light warranty. I.e. when they can’t see your tail lights your warranty is up.

Now if these cost fifty cents it’d be annoying but not a big deal. However, on average these are $5 USD. If one is going to shake loose every month or so, tis a bad omen.

Repair

To fix these, trying to get high temperature epoxy or some kind of car muffler goop that isn’t going to melt, stink, or be ugly to apply is a challenge.

And equally pricey. I tried some quick fixes, all failed, some far more spectacular than others.

High entertainment value, zero usable results.

MG Chemicals Solution

MG Chemicals has this magic silicon goop (and that’s my technical term) that is the weirdest stuff I’ve ever used. It’s called RTV106, comes in a tube, red goop, very strong silicon smell.

And. It. Never. Seems. To. Dry. Out. And. Harden. In. The. Tube.

Yeah, you got that right. I use it, screw the cap back on, go back in a month, uncap it, use it, screw the cap back on. I’ve done a few dozen times over the last year. Stuff is still the same as the day I cut the tube open. So, yeah. Weird.

According to the datasheet it will run all day at 260C with brief jumps to 315C. I primarily print PLA so I’m running 204C to 216C depending on the PLA.

RTV106

This stuff doesn’t burn, no odor, doesn’t flake off, sticks like, well like that “baby’s” brown stuff to a blanket. According to the data sheet it can corrode the brass so you wouldn’t use it on electrical circuits, but I’m using it on the OUTSIDE of the stand off.

I wouldn’t put any on the inside where the glass bead is.

Taint Purdy But It Works GREAT!

When the last stud thermistor popped out, I shoved it back in. Grabbed some RTV106, slathered up a toothpick, gooped it on. Wasn’t too neat about it either, as you can see…

Fullsizeoutput 2c49

And it’s been sitting like that for 5 months. Truthfully I have been waiting for it to fail. I think it’s going to be a long wait.

Side Effect

Something else I found was that after I, ah, “insulated” with the RTV106, the temperature held a little better. My guess is the thermal transfer of the RTV on the brass stud is shielding it from the fan right above it. That would be a win – win as far as I am concerned.

Summary

When you build a 3D printer, you don’t really think out of the box much.

You just build like everyone else and when something doesn’t work, you kind of look at what everyone else might have tried. I know I did in trying to fix the thermistors on these studs, but when I was talking with one of the MG guys they off handedly mentioned the temp range for the RTV106 a long time before there even was stud thermistors.

At any rate, my spongy brain absorbed that little nugget of info and I found that’s the easiest way to fix these things.

23
Dec

Marlin Firmware Fishing – Delta Bait

While it seems like only yesterday that I built my two delta printers, in reality it’s been almost three years. Or in “printer” years, just under 4,000 hrs.

I read that to be an expert it takes 10,000 hours of practice. Of course there’s a number of scientists who now will question that claim from 1993, my guess is they’ve probably spent more than the allotted 10,000 hrs disproving it, so maybe I’m further along than I think.

Or not.

Marlin 1.1.6

Having ripped the hood off Marlin 1.1.6 in the last month, I’ve learned a whole bunch about how it works, or more specifically why it does it does.

When you get down into the innards you find, that for a delta, at least, there’s a lot of trade off’s going on. Mostly due to the 8 bit processor that runs the whole thing.

For delta style printers, the LCD rotary button is hit and miss. When the printer is running. When the printer is idle, the control is very responsive. Why? Mostly it’s to do with the way Marlin figures out where in the world it’s supposed to go to. And we don’t help it any in this matter.

Marlin Planner

The bottleneck is the planner and our quest for quality output from these plastic droolers.

For example, let’s take a slow world example. We are printing a perimeter in slow motion, the long edge is 200mm long and we are moving 1mm per second.

Short math says this is going to take 200 seconds. I.e. 1mm/second, 200mm length.

With your stepper motor you have “steps per unit(mm)”, and in most of the printers (16x set stepping) it will be set to 80. So the move will be 80 * 200 = 16,000 steps long.

Good to this point, but now for the ultimately accuracy we have a setting in Marlin that looks like this:

DELTA_SEGMENTS_PER_SECOND = 200

So our original 200 seconds, gets expanded: 200 x DELTA_SEGMENTS_PER_SECOND = 40,000 segments total.

Each of the segments is 16,000 / 40,000 = .4 steps.

Marlin then feeds these segments to the planner. But the planner has a minimum number of steps it will use, anything shorter than that is handled differently. Way back in the early days it was set at 5 step minimum, with 1.02 and newer it’s set at 6.

So, the first segment is handed to the planner, but at .4 steps it’s too short, so it’s set aside, then the next, and so on until the total gets above the minimum. I.e. we have to hand it 15 steps to finally get it to move. Then that gets repeated all again until it can move again.

Should the planner get full, that’s when it actually goes out and checks the buttons on the LCD, updates the heater check (part of the watch dog timer), and a few other things. Which is why we find that on long straight slow runs the LCD seems unresponsive. But on fast cubic infill it’s the other way around. It’s all keyed off the planner.

So you can see, Marlin’s planner spends most of it’s time just reading and accumulating these little short steps until it gets to a point where it can plan a move.

This is why the majority of times where an end user complains about the LCD being somewhat unresponsive, the developers first retort is to “lower your DELTA_SEGMENTS_PER_SECOND”. The suggested number is 160. That results in a .5 step segment, we end up with 16,000 / 32000 = .5, and we’d have to feed the planner 12 segments before we hit the minimum and get a planned move.

Marlin Code Enhancements

The Marlin developers have gone to great lengths, considering it’s open source software, to ensure that not only everything that used to work, either works the same or better, but when they get handed a problem, they do their utmost to fix it.

In the planner “move” and “arc” routines there are now calls to the idle and watchdog timer to ensure everything keeps working. This means that generally the LCD and rotary encoder are fairly responsive even if you crank up the delta seconds. To a point.

Side Effects

It’s pretty easy to see just how much that DELTA_SEGMENTS_PER_SECOND number can affect the planner. When you’ll find as a side effect is the LCD becomes more responsive, and the printer will sudden print slightly faster on exactly the SAME print as it did previously.

During my tests, I changed values in the firmware, then run a worst case against it to see what damage I can do, I found a number of interesting things.

I found I could cause stutters in straight lines or on curves. Mind you it’s hard to see the printed results with the naked eye but with a microscope I have, it wasn’t hard to see the little blobs show up.

I also found that while straight lines worked for almost any setting, doing curves was more exacting. Stutters and pronounced lines in the curves were evident. Especially on high Delta settings at fast speeds.

Speed

Here is where things get interesting. Speed on a delta, set in your slicer, means, nothing. If you set the speed for a perimeter for 50mm/s, what you might get is, ah, well, who knows. I don’t. Not sure anyone does.

I’ve seen the YouTube video’s where the video is proclaiming some massive speed on a delta. Like 300mm/s. But really, it just means, fast. Again, no idea how fast. Just fast. Not sure how’d you even figure out how fast.

I know, the slicer sets the speed and the firmware should follow it. Yeah, nope.

On Delta printers the feedrate, jerk, acceleration, limits, etc. are applied at the steppers level and not to the Cartesian position. There’s only an indirect proportional relationship between the speed of the carriages and the speed of the effector.

Or, as you might surmise, two, very, different, things.

Smooth Sailing

The printer will always, and I mean always, print smoother from the SD card. A computer or print server like Octoprint/Astrobox tied to the USB of the Mega will never be as smooth. And by changing some of the firmware I can make it worse. A lot worse. Easily.

Looking at the LCD, if it’s updating fairly quickly, the planner is really working well. If not, it’s getting buried by math.

Stepper Motors/Drivers

Next up we get to stepper motors. All equal. Nah, probably more solid state than equal. Another foggy area. Seems the conventional thinking is use the biggest driver we can get. Like the DRV8825. Even with it’s built in bugs of missing steps. Add that to the stepper motor accuracy and suddenly you begin to see why 100 microns is the best you’ll ever get without major tweaking.

So you “hack” the 8825’s for fast decay, end up with a screaming chicken. Or you decide to use the TMC2100’s with their “silent chop” mode. And unless you crank the current on them, they tend to skip steps. But when you crank the current everything runs warmer. Trade offs.

Oddly enough, the best driver for the delta’s is the lowly A4988’s. Of which there are a number of versions (the versions being the values of the adjustment pot and the current sense resistors). The 4988’s are not great for heavy carriages like Cartesians are pushing around, hence the popularity of the 8825’s. But for a delta, even with a fan setup like mine, it can get quite interesting.

I set the current on my 4988’s to 400ma. Just because I could. I couldn’t hear the printer run from a nearby hallway. Turns out a lot of the noise we hear is the steppers being driven by heavy current. At any rate, I only got about 6 layers of a design when the hot end wandered off to sky print. I’ve been running them for almost 100 hours now with 800ma and never missed a beat. My guess is that 600ma or more of current is enough to hold the delta hot end in position.

Another oddity I found was that when I swapped out the 8825 for the 4988 at the extruder, I got more extrusion from the 4988. With the 8825 I got 99.7mm pretty consistent. With the 4988 swap and no other changes I was pushing 102.3mm. The 8825 does drop steps, as noted, and there is a 3 – 5% error rate on each rotation of the stepper motor. Still strange.

Just so I wasn’t going balmy, I did the same driver swap on a second delta. Same result. Had to re-level and drop the extruder steps.

4988’s are now all I’d recommend for the average delta.

Accuracy

Everything comes at a price, with delta printers, because of all the calculations, accuracy and speed are the prices. For example, if you never used the LCD for anything, disabling it in the firmware helps speed up a bunch of things because there’s nothing to do when Marlin would normally be busy updating the LCD.

Printing via USB from Octoprint, Astroprint, Repetier Host, Pronterface, really, what is the LCD doing? All the info is available from the printer server or the application on the computer.

If you want speed, drop the Delta Segments Per Second. But like they imply, speed does not always equal quality. Ever. Quality? Slow the printer down. Increasing the Delta Segments does this artificially because of the increased number of calculations.

I’d love to say there’s an easy way to get max speed, with max quality. Truth is, it’s all a trade off. You just have to find what works for you.

Currently I’m using Marlin 1.1.6, tweaked for a delta by me, and I’m using 120 Delta Segments Per Seconds and the printer has never been faster or printed as nicely. So I gained both some speed and quality mostly due to the minor software mods I have in Marlin.

Summary

Tinkering and doing “what if’s” has always fascinated me.

If it breaks, I can restore or fix it, no big deal. The amazing things you learn in the process is where the fun lies for me. So I’m well on my way to the 10,000 hour point…

17
Dec

Slic3r, Mercy Me

I’d seriously love to say that every 3D print I do comes out absolutely perfect. The actual truth is that some come out superb, and some come out sub-perb…

Which, as you might imagine teases me into holding my nose and diving into the 3D printing pool. Again.

A few days ago, while working on some modifications to the Marlin firmware that I’m currently testing, my 3D Benchy test prints were printing a little different. Specifically I had some gaps in the outside perimeter wall.

Ah…something new in the firmware to contend with.

Except, in this case, it wasn’t the firmware. Took me about 30 seconds to figure out but the give away is that the firmware controls the printer. It doesn’t tell the printer where to go and drool filament all by itself, the GCODE file does that. The firmware merely does what it’s told to do.

This is akin to writing computer software. For example, a software program will tell the CPU what to do. This can be completely different than what you want it to do. Thus two completely different things. Take a moment to emblazon that into your mind and you’ll be the better for it. Especially when you’re troubleshooting.

Slicers

There are any number of slicer programs for 3D printers currently on the market. Some are paid, free (as in open source) and proprietary. The only thing they share in common is they will slice an STL file into layers. Some will work better in some cases, some have better support abilities, and some will promote the early on set of baldness.

My poison is Slic3r that is being developed by PRUSA.

As of this writing they are up to 1.38.4 and with each release they manage to fix many bugs, add new features, and of course include the bugs they didn’t expect. The winner of course is the end user. If you’re travelling along this uncharted off road trail, the loser is also the end user.

When you’re slicing an STL, my strong suggestion is that you examine the layers, one at a time to preview any “problems” than might reward you with more recycle than cycle…

In Slic3r there is a LAYER tab. When you get a good design, it pays to just kind of glance through the layers to see what a good design looks like. Then when you print an example of “oh good grief”, you can look at it and compare the two…

Example

I’ll take the same Benchy STL, slice it in 1.34.1 and 1.38.4. I have exactly the same settings/option selected in both of the slicers.

The mind says they should be the same. Don’t listen to it…

First up, the slicer version 1.34.1 I normally use. Take a look at the outside wall of the boat. When you see a gap that big, that’s going to print exactly the same. With a big. Frigging. Gap. You might be able to fix it with an option, like “detect thin walls” or “ensure vertical shell thickness” or not. But if you don’t look at the layers, you’ll never know. Until it’s too late.

Slic3r1341 Benchy

Now we open the same STL, with the 1.38.4 version of Slicer and whoa. Something changed. Big time. Not only is the outside perimeter of the boat filled in, the honeycomb infill looks COMPLETELY different. And no, it’s not, it is the same 36% setting as the first one.

Slic3r1383 Benchy

The Ah Ha Moment. Not

Immediately I’m “assuming” that I should not use the older version because it messes up the walls. Keyword there? Assuming.

What you don’t see is that later on, the box behind the wheelhouse starts to get gaps in the wall for no apparent reason. So initially, it looked like the problem was “solved” when in reality it just moved someplace else.

And yes, every slicer I’ve used, between versions, will exhibit these odd, sometimes really odd, changes.

This confirms what I’ve found in working with the innards in Marlin. There are always trade-offs or compromises to be made. In Marlin this is particularly true with respect to Delta style printers because Marlin is trying to be the kitchen sink of 3D printer firmwares.

Summary

If your prints are coming out strange, or there is a design that isn’t working at all, don’t be too quick to blame the printer. It’s doing what the slicer told it to do.

This can be completely different what you expected (or wanted) it to do.

Trust me.

26
Nov

Octoprint vs SD

I’ll be the first to admit that being retired gives me way too much time to try out different things. Lately with the monsoon season upon us, golf is notably absent from my to do list, so I’ve been spending a fair bit (okay too much time) in the shop.

Which means I’ve been printing up 3D stuff doing tests to see “what if”. And some of it has been pretty darn eye opening. You know, the kind you don’t see coming.

Like new filaments on Amazon, stepper driver tests and the last one, Octoprint VS SD card prints. When it comes to 3D print quality, I tend to be a little OCD about it, and like most I have my brands of PLA that I go to, and others that I avoid. But the filaments I’ll leave for another day. Today, it’s my little shoot out between Octoprint and SD card printing.

3D Print Servers

I originally started out using Astrobox, but found out I’m not the target market for it.

I want more hands on with a printer controller than what Astroprint wants to do. Apart from my head not being in the “cloud”, when I print I want local control, I want complete slice control, I want it all. See, OCD.

Thus I’ve been using Octoprint for quite a while and haven’t had any issues with it at all. Til now. And I’m not sure why, but I have a suspicion….just no proof. So keep that in mind.

Essentially you send a GCODE file to the Octprint server running on a Raspberry PI3, then connect it via any computer on the LAN, away you go. I like the way it works, the connection, the information it gives me.

Then I happened to be reading that some people were saying that the SD card gave a better print quality. And in some cases faster…which, really doesn’t make a fat lot of sense…unless you dive in and look at some of the issues.

Curiosity got the best of me and I like to verify things I read about rather than just relying on Twinkles spouting off on some forum.

Print Test Setup

I found a design on the Thingiverse, Toms Simple Chunky Rocket…this is a picture of his print out.

Rocket

I used PRUSA’s 1.34.1 Slic3r, vase mode, .2 layer height, 30mm/s. The rocket is 200mm tall, diameter in the fat section is 80mm or more. So, tis a biggie. At the speed I chose, three hour print time.

I used Hatchbox Transparent Red so not a solid colour, easier to see print issues.

Marlin firmware 1.1.6 was used for both prints.

Octoprint Output

I was surprised when Octoprint was printing I could see the printer almost jog once in a while. Which didn’t make any sense since it’s going pretty darn slow. But when the print was complete, yeah. Wow.

Fullsizeoutput 2be8

One look at the surface and you can see the staggered looking tracks that oscillate all around the rocket body. When I saw the staggering, apparently I wasn’t dreaming. Those are lumps you can feel.

SD Card Output

I saved the SAME GCODE from the slicer onto the SD card and used the front control on the printer to select the rocket and print it. I did not use Octoprint so I could upload the GCODE to the SD card, nor did I use Octoprint to initiate the print. I did it all from the printers control panel.

In the middle (these are the front views of the prints), there is exactly one “pimple”. And that’s it. For all I know the SD card had a bit of a read problem at that one point.

Fullsizeoutput 2be7

Other Differences

For whatever reason, on the Octoprint print output there is a rather large seam right up the back. The camera washed it out but if you look at the top of the tail fin, you can see the start of it, and that wide streak goes right up to the top. Kind of a skunk stripe if you like…:-)

Fullsizeoutput 2be9

This is fascinating because in vase mode because the hot end never stops and just keeps going around and up. How it created the seam is beyond me.

But WHY?

Well that’s the $2 question isn’t.

I went looking for answers and all I can say is, I have a suspicion.

Octoprint sends the data through the USB connection to the Arduino MEGA that runs the RAMPS control board. There’s more than a few people who seem to have problems with communication like this. As in missed lines of GCODE, repeated sends of GCODE, or simply a failure to connect.

I put on my Tom Terrific thinking hat and looked at the MEGA I have in the printer. Then I tried connecting up Pronterface to the printer and I noticed something right off. Pronterface had some issues connecting to the MEGA via USB. For grins I tried Repetier Host, same delay in connecting and then it seemed “ok”.

But it got me thinking. My other printer connects instantly. mmmm. What’s the difference?

The Arduino MEGA used on my test printer is an off shore knock off that uses the low cost CH340G chip to handle the USB to serial connection. My other printer that just works, has an ATmega16U2 chip that performs the USB to serial.

I run at 250000 baud, 25 kilo bytes per second. This doesn’t seem like much, but I’m thinking that the low cost CH340G is fine in 90% of the cases it’s used in, but when it comes to 3D printing, the ATmega16U2 will blow the doors off it.

So yep, my plan is to remove that Arduino board and replace it with the better communication chipped one.

Will that fix it? My logic says it can’t make it any worse. Nothing to lose and from the printed samples, a lot to gain if it works.

[UPDATE] – So after swapping out the MEGA for a official one, the seam is still there, slightly less pronounced and the lumps are still there as well, but it more of a pattern. Which tends to make me think this is more of a firmware thing than anything else.

14
Nov

Marlin 1.1.6 – FVM Kossel

Apart from putting a lot of hours on both of my Kossel printers, as a software nerd I try to stay current with the latest, and sometimes not the greatest, firmware that’s running the printers.

Specifically the Fraser Valley Makerspace Kossel’s.

What seems like ages ago now, but a mere two plus years, I started out with 1.0, and quickly moved to 1.0.2 since it was easier to adjust the software for any mechanical build discrepancies. Eventually the Marlin developers included most of my hacks into the product so it was easier and at the same time, more difficult, to update.

To my mind the stumbling block is that when the primary market for 3D printers uses the Cartesian system, anything else warrants less than a cursory glance and testing. At least this has been my experience. Fortunately, there’s enough of us in that small percentage who can usually figure things out that went amiss.

When I started updating the first road block was looking at my old firmware and trying to figure out what they called it now, where they hid it and what delta configuration to use as a basis. For example, take a gander at the number of different printers than Marlin supports:

Marlin Printers

Now imagine each of those directories can hold a number of “variations” of said parent printer. Ah yeah. In the delta area there are a number of choices:

Marlin Delta

Just like fishing for real Marlin, the key to success is using the right bait. To be honest I haven’t gone through each of the iterations to see exactly what the difference is. Thus I was using “Generic” as the basis. Until I tried to use version 1.1.4 of Marlin. It didn’t work.

After a couple days of trying different configs, I ended up with the “kossel_mini” and that’s the closest to what the FVM Kossel has. When I got 1.1.6 working, I used the kossel_mini again and again, that’s the one I managed to get working.

It would be great to simply copy over your old delta configuration files, but alas, the rest of Marlin has changed so much that it’s not possible to do that.

I’d love to say that once you find the right config file, the hard part is over. Sadly, maybe an hour later it might be. But there are some bugs in Marlin that seem to only affect delta printers that even the developers have no idea why that might be. So, back to hacking the firmware to make it work. The way it should.

Firmware 1.1.6

Before I outline all the steps, let me say that make darn sure you have a current copy of the firmware used by your printer, a duplicate copy, on a flash drive or somewhere you won’t screw it up. In the event you foul something up, you’ll have the old version to put back and get the printer running again!

Secondly, if you’re under the impression that newer is “better”, forget that notion. I’ve run 1.0.2 thru 1.1.6 in side by side tests on my printers and I’ll be hornswoggled if I can see a difference in print quality with the same settings. I’ve read the notes on what has been “fixed”, “enhanced” or “new” and okay. If they say so, all I have noticed is the planner in firmware seems slightly faster. Ergo my Kossel’s have always just printed.

So as they say, if it’s not broken, you can’t fix it. Or as I sometimes am the living proof of, if it’s not broken, you’re not trying hard enough. YMMV.

Updating

Download Marlin from the GitHub link. Click on the download/clone button and download a “zip” of the archive.

You’ll have to move that into your Arduino sketch folder and unzip it. In the “example configurations folder” look for the two “kossel_mini” configuration files and copy those into the main Marlin directory. It will replace the two cartesian files of the same name.

Run the Arduino IDE and open your original firmware and the new Marlin (yeah, its name is just Marlin). I’d suggest you instantly save the plain Marlin you just opened as something like “Marlin 116-1” so you know it’s version 116 and “1” (to indicate sort of a first modification to it). Subsequent “mods” would be 116-2, 116-3 and so on. Thus you can always “rewind” to a prior version that worked before you fouled it up…;-)

Changes

The changes you are going to make are in 116 and in three files. The main is “Configuration.h”, bug fix is in “ultralcd_impl_HD44780.h” and the hack fix is “watchdog.cpp”.

The #xx is the LINE number in 1.1.6 and the first line is what you will find in the file. The line UNDER it is what you need to change it to. You will be using some values from your OLD Marlin 1.0 or 1.0.2 file. I have commented the second line as well in some cases, you don’t need to add my comments in.

Also keep in mind that the lines MAY look identical, but pay attention to any “//” marks which simply disable the line. There’s a bunch we don’t use.

Configuration.h

#77: #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes.
	#define STRING_CONFIG_H_AUTHOR "(YouWho, FVM_Printer)" // Who made the changes
#122 #define MOTHERBOARD BOARD_RAMPS_14_EFB
	#define MOTHERBOARD BOARD_RAMPS_13_EFB //33
#127 #define CUSTOM_MACHINE_NAME "Mini Kossel"
	#define CUSTOM_MACHINE_NAME “FVM_Delta”// your custom delta name
#226 #define POWER_SUPPLY 1
	#define POWER_SUPPLY 0

#286 #define TEMP_SENSOR_0 7
	#define TEMP_SENSOR_0 1// temperature sensor used by FVM

#325 #define HEATER_0_MAXTEMP 275
	#define HEATER_0_MAXTEMP 260

#330 #define BED_MAXTEMP 150
	#define BED_MAXTEMP 100// max EVER would probably be 110

#335 #define  DEFAULT_Kp 22.2
	#define  DEFAULT_Kp 20.03// look this up in your current configuration.h file

#336  #define  DEFAULT_Ki 1.08
	 #define  DEFAULT_Ki 1.25// look this up in your current configuration.h file

#337 #define  DEFAULT_Kd 114
	  #define  DEFAULT_Kd 80.01// look this up in your current configuration.h file

#442 #define THERMAL_PROTECTION_HOTENDS // Enable thermal protection for all extruders
	//#define THERMAL_PROTECTION_HOTENDS // disable thermal protection for all extruders

#443 #define THERMAL_PROTECTION_BED     // Enable thermal protection for the heated bed
	//#define THERMAL_PROTECTION_BED     // disable thermal protection for the heated bed

#493 #define DELTA_CALIBRATION_RADIUS 78.0 // mm
	#define DELTA_CALIBRATION_RADIUS 100.8 // mm

#499   #define DELTA_PRINTABLE_RADIUS 90.0 // mm
	  #define DELTA_PRINTABLE_RADIUS 108.0 // mm

#502   #define DELTA_DIAGONAL_ROD 215.0 // mm
	  #define DELTA_DIAGONAL_ROD 300.93 // mm// look this up in your current configuration.h file

#505   #define DELTA_HEIGHT 250.00 // get this value from auto calibrate
	  #define DELTA_HEIGHT 212.66 // look this up in your current configuration.h file

#510   #define DELTA_RADIUS 105.2 //mm  Get this value from auto calibrate
	  #define DELTA_RADIUS 145.86 //mm YOU HAVE TO CALCULATE THIS

In your old configuration.h file, there are 3 values that make up this the DELTA_RADIUS value.
For whatever reason the developers combined them in the 1.1.4 and newer to make it, ah, easier. For them I think.

The formula is: DELTA_RADIUS  = (DELTA_SMOOTH_ROD_OFFSET - DELTA_EFFECTOR_OFFSET - DELTA_CARRIAGE_OFFSET)

Pull out your calculator, look up the values for DELTA_SMOOTH_ROD_OFFSET, DELTA_EFFECTOR_OFFSET, and DELTA_CARRIAGE_OFFSET,
plug them in and figure out what the DELTA_RADIUS is and replace my 145.86 with your number.

#515 #define DELTA_TOWER_ANGLE_TRIM { 0.0, 0.0, 0.0 } // get these values from auto calibrate

If you have done a calibration for X, Y and Z, you can enter the correction numbers here.
I use a design and spreadsheet from Thingiverse for calibration and it’s how I ended up with the
numbers for the trim. If you haven't done it, leave them as 0.0, 0.0, 0.0...
https://www.thingiverse.com/thing:1274733

	#define DELTA_DIAGONAL_ROD_TRIM_TOWER { -0.49, 0.14, 0.35 }// these are MINE, use the above to link to find yours!

#561 #define Z_MIN_PROBE_ENDSTOP_INVERTING false // set to true to invert the logic of the probe.
	//#define Z_MIN_PROBE_ENDSTOP_INVERTING false // disable, we don’t have a probe

#593 #define DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 80, 760*1.1 }  // default steps per unit for Kossel (GT2, 20 tooth)
	#define DEFAULT_AXIS_STEPS_PER_UNIT   { 80, 80, 80, 145 } //look this up in your current configuration.h file

#600 #define DEFAULT_MAX_FEEDRATE          { 500, 500, 500, 25 }
	#define DEFAULT_MAX_FEEDRATE          { 500, 500, 500, 300 } //look this up in your current configuration.h file

#618 #define DEFAULT_ACCELERATION          3000    // X, Y, Z and E acceleration for printing moves
	#define DEFAULT_ACCELERATION          1400    // X, Y, Z and E acceleration for printing moves

Values higher can give ringing on outside perimeters/corners but print faster, values lower than this give clean corners but print slower.

#620 #define DEFAULT_TRAVEL_ACCELERATION   3000    // X, Y, Z acceleration for travel (non printing) moves
	#define DEFAULT_TRAVEL_ACCELERATION   2000    // X, Y, Z acceleration for travel (non printing) moves

If you have fans, or a hot end that has some mass/weight to it, lower values help reduce the shock of the move.

#630 - #633:
#define DEFAULT_XJERK                 20.0
#define DEFAULT_YJERK                 20.0
#define DEFAULT_ZJERK                 20.0 // Must be same as XY for delta
#define DEFAULT_EJERK                  5.0

Values lower make for smoother movement and print. Faster means more jerk and not as clean outside finish. I suggest the ones below:

#define DEFAULT_XJERK                 10.0
#define DEFAULT_YJERK                 10.0
#define DEFAULT_ZJERK                 10.0 // Must be same as XY for delta
#define DEFAULT_EJERK                 20.0

#649 #define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
	// #define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN // disable this

#767 #define Z_PROBE_ALLEN_KEY
	//#define Z_PROBE_ALLEN_KEY // disable this levelling option

#860 - 862
	#define INVERT_X_DIR false // DELTA does not invert
	#define INVERT_Y_DIR false
	#define INVERT_Z_DIR false

Change all to (make the false into true):

	#define INVERT_X_DIR true
	#define INVERT_Y_DIR true
	#define INVERT_Z_DIR true

#870 - #874
	#define INVERT_E0_DIR false
	#define INVERT_E1_DIR false
	#define INVERT_E2_DIR false
	#define INVERT_E3_DIR false
	#define INVERT_E4_DIR false

Change all to (make the false into true):

	#define INVERT_E0_DIR true
	#define INVERT_E1_DIR true
	#define INVERT_E2_DIR true
	#define INVERT_E3_DIR true
	#define INVERT_E4_DIR true

#1122 #define HOMING_FEEDRATE_Z  (200*60)// pretty fast!
#define HOMING_FEEDRATE_Z  (80*60)// more of a smooth speed

#1140 #define EEPROM_CHITCHAT   // Give feedback on EEPROM commands. Disable to save PROGMEM.
	//#define EEPROM_CHITCHAT   // Disable to save PROGMEM.

#1148 #define HOST_KEEPALIVE_FEATURE        // Disable this if your host doesn't like keepalive messages
	//#define HOST_KEEPALIVE_FEATURE        // Disable

#1149 #define DEFAULT_KEEPALIVE_INTERVAL 2  // Number of seconds between "busy" messages. Set with M113.
	//#define DEFAULT_KEEPALIVE_INTERVAL 2  // disable

#1150 #define BUSY_WHILE_HEATING            // Some hosts require "busy" messages even during heating
	//#define BUSY_WHILE_HEATING            // disable

#1170 - #1171
	#define PREHEAT_1_TEMP_HOTEND 180
	#define PREHEAT_1_TEMP_BED     70

Change this to what you normally print at (mine for example)

	#define PREHEAT_1_TEMP_HOTEND 200
	#define PREHEAT_1_TEMP_BED     60

#1174 - #1175
	#define PREHEAT_2_TEMP_HOTEND 240
	#define PREHEAT_2_TEMP_BED    100

Change this to an ABS setting (or a secondary filament for example):

	#define PREHEAT_2_TEMP_HOTEND 235
	#define PREHEAT_2_TEMP_BED    90

#1342 //#define ULTRA_LCD   // Character based
	#define ULTRA_LCD   // LCD 2004 (20x4)

#1352 //#define SDSUPPORT
	#define SDSUPPORT// our 2004 LCD’s have SD card slots

#1360 //#define SPI_SPEED SPI_HALF_SPEED
	#define SPI_SPEED SPI_HALF_SPEED// to help on some of the slower SD cards

#1400 //#define REVERSE_ENCODER_DIRECTION
	#define REVERSE_ENCODER_DIRECTION// rotation in a natural direction

#1456 #define PANEL_ONE
	//#define PANEL_ONE// disable this, wrong panel for 2004

#1490 //#define REPRAP_DISCOUNT_SMART_CONTROLLER
	#define REPRAP_DISCOUNT_SMART_CONTROLLER// display and controller used on the FVM Kossel

Now go back and check it. Twice if need be… Then SAVE IT.

watchdog.cpp

Next you are changing the time out. According to the dev’s, this shouldn’t affect our deltas. Except, it does.

So we have to fix it. Where it rears its ugly head is when you are doing a LONG STRAIGHT LINE with a high delta segments per minute count (like 200). If the line takes longer than 4 seconds to print, there is a “time out” and the Arduino Mega wanders off to never never land. I.e. it just crashes and the head sits exactly where it is and the heaters all shut off.

You have to reboot the printer to get some control back. The changes are done by changing the WDTO_4S (timeout in 4 seconds) to WDTO_8S to a time out in 8 seconds.

#36     _WD_CONTROL_REG = _BV(WDIE) | WDTO_4S;
	    _WD_CONTROL_REG = _BV(WDIE) | WDTO_8S;// we get time outs otherwise

#38	    wdt_enable(WDTO_4S);
   wdt_enable(WDTO_8S);// we get timeouts

ultralcd_impl_HD44780.h

On the current IDE, 1.8.4 I’m using it doesn’t like the word CHAR in caps, and in the ultraLCD file, sure enough, there are two lines in caps. Changed them to lowercase and it will compile.

#713 lcd.print((CHAR)LCD_STR_THERMOMETER[0]);
	lcd.print((char)LCD_STR_THERMOMETER[0]);// char should be lower case

#716	 lcd.print((CHAR)LCD_BEDTEMP_CHAR);
       lcd.print((char)LCD_BEDTEMP_CHAR);// char should be lower case

Summary

If I haven’t cured your insomnia by this point, you should have been able to upload the new code to your printer and be ready to go.

One last thing though, when ever I do a firmware change, I always check to make sure the bed is still level. Sometimes the math in the firmware is more or less accurate than what I was using so I just make sure. Don’t want the hot end smashing in the glass. Do we.

You know, for all the automation we have these days, you’d think someone would also come up with a program that would grab all our old configuration values, cram them into the new one, ask us specifics for old or updated items and we’d be done with it. To me, configuration should be seamless and painless. Please forgive me. I also believe in Santa Claus and the Easter Bunny.

22
Oct

Solutech PLA Filament

Having a couple of 3D printers means that for the care and feeding, I need to keep an eye on the mechanics and feed them, what seems like, endless amounts of filament.

Filaments I’ve obtained from our local makerspace who supply MG Chemical filaments, or via online. All dependent on what I’m looking for. While getting 1Kg for what I deem as a decent price is nice, there are times when that isn’t possible. If I want it, I get it. Simple enough.

Amazon seems to be trying to be one of the best sources of filament on the market, no doubt because of the free shipping. But their prices are up and down like a spasmodic yo-yo. One day a filament will be “on sale” for $14, the next day it will be $38. The day after $26. You have to watch the price roller coaster like a hawk if you’re using a lot of filament.

Still, I am always on the hunt for new filaments to test to see how they work for me. Therein lies the point. How they work for me. In my printer. For my models. I don’t assume for one second that everyone will experience the same results as I do. At best, might give you a heads up on what you might encounter.

I’m using my delta Kossel printers and those can work significantly different than others.

Standard Brands

My normal PLA filament brands are, in no particular order, Hatchbox, AMZ3D, and MG Chemicals. These are my goto filaments.

Why three different brands?

Simply put, while I’d like to say that all PLA flows, melts, and has the same finish after printing, my experience is that each of them is just different enough that they lend themselves well to specific types of print jobs. Or printed objects if you want to cut to the chase.

General purpose printing, MG Chemicals, and AMZ3D are fairly close. I do tend to use more of AMZ3D because for the same cost, I prefer the non-cardboard sided spools. Having said that, there are some colours in the MG PLA that are nicer than their counterpart in the AMZ3D line.

HatchBox Colour

Hatchbox has Pantone colours so when I need to use that, and I want a premium filament, out comes the Hatchbox. This used to be more true than now. Red PLA used to look more orange to my eye, but that has changed enough so red from most of the companies is actually red, not off-shore red or orange. Yep, they finally get it.

But while Hatchbox has a great filament, I’ve experienced something odd when printing their Red. The dye they use it vaporized coming out of the nozzle to a fine mist/fume and it has tint coated the front of my hot end heat sink. Least I think it’s the red, I also have some Hatchbox transparent red I was printing, but those are the only two red PLA filaments I have.

Fullsizeoutput 2bab

Before I took that photo, I’d used a Dremel with a brass brush to clean some of the red off. It was seriously coated.

Solutech PLA

Which brings me to a new brand I picked up from Amazon. Mainly because it was on sale, it’s advertised as “true colour” and I need some orange. No, not for printing Halloween pumpkins…

I ordered a spool of orange, and blue. Never did anything special in the printer, just loaded the orange filament and started a print job. At the same settings I’d use for my standard filaments.

In the photo you can see the filament looks sort of red on the spool but seems to print out in “early pumpkin”. It is getting near Halloween but really, it’s the digital camera doing the not so accurate colour rendition.

Fullsizeoutput 2ba3

First observation, Solutech PLA is “free flowing”. At my normal temp of 206C, I was getting some little blobs and whiskers which means the bowden was easily pushing the filament through the nozzle with little resistance. As I said, flowy.

Fullsizeoutput 2ba4

I found it flowed like hot butter. I ended up dropping the temp down to 202C. End of flow issues and whiskers. I didn’t bother testing to see how much lower I could go, but even at 202C it was flowing nicely. When the head moved it wasn’t leaving tails behind anymore.

Solutech – Hatchbox

There are some designs that just don’t lend themselves well to printing. Everyone has done the 3DBenchy to death but for my own tests I tend to print things with threads.

I’d designed a spool holder a while back so I printed one in Solutech Orange, the other in Hatchbox red. Printed at 50mm/s, 0.3mm layer height.

Fullsizeoutput 2ba7

As you can see the final prints look identical. And they are. But getting them to that point took some doing.

First Hatchbox PLA tends to cool quickly so doing the threads was easy. I had the cooling fans barely on and my standard temps were fine.

Solutech on the other hand, wow. With the same cooling fan speed, the PLA was holding heat like crazy, and the thread edge curling was nuts. Dropping the temp 8C from the Hatchbox setting and ramping the cooling fan speed up to 80% was required to curtail that.

Just to see what might happen, I re-printed them at 30mm/s (slow) and Hatchbox didn’t need a fan, Solutech did, although not as much.

This all reminded me of a bad golf shot where you hit a tree, cart part, and ball cleaning station but still end up beside the pin to tap in for a par. The results don’t indicate the means it took to get there.

Solutech Summary

Every filament out there brings its own little set of nuances to the table and 3D printing, to my mind is never going to be plug and play.

Solutech is not worse than any of my other filaments (wish I could say that for all the filaments I’ve tested), but it certainly requires different settings depending on what I might be printing. Thus I have to pay attention. Not a bad thing either.

24
Jul

3D Printer Power Supplies

Having built a dozen 3D printers, you get used to looking at parts that are top notch, some marginal, and some that you wonder why they were ever produced.

But there’s also some parts that you just take for granted. Case in point, the typical 12V, 20 or 30A (200-360 watt) power supplies.

Normal cost is in the $25 – $40 range (USD or CDN). Paying a premium for one, double or triple the cost, does not promise any higher quality than the budget ones in my experience.

The Tin Can

The typical tin can power supply takes 110-220 and drops it down to 12V (or whatever working voltage you need) that has a trim pot for fine adjustment. The majority of them look much like the one in the photo.

12V 30A Supply

The variation of these are ones that have a mesh covering and have no fan. Relying on convection to keep the wee beastie cool. For most of these types, 20A is usually the limit of their current rating, but I’ve seen a few 30A ones.

12V 30A Mesh

There’s a soldered fuse inside because using proper fuse clips would add cost and make no mistake about it, these things are cheaply made.

Cooling

The mesh covered ones are self cooling. Or as I found, when you fry one, they remain permanently cool. As you’ll eventually see this may not be a bad thing either.

The tin can versions all sport a fan. Considering the PCB’s in the ones I’ve looked at from various suppliers are all oddly similar, the fan voltages range from 12 to 16V. Or perhaps whatever is in the parts bins for that days assembly.

Paying a premium for one doesn’t ensure better quality but occasionally you’ll find a temperature controlled relay so the fan doesn’t run all the time. I blogged about this previously

For the MOSFET’s that do all the current handling, cooling is either them clamped to the case itself, or with an aluminum bar between the MOSFET’s and the case. Usually with some silicon material for insulation and goop for heat transfer.

IMG 1155

It’s not pretty, but it’s at least marginally functional.

Quality

Like most end users, I just wire them up and away I go. However, since I wrote the blog about adding a relay for fan control, I’ve modified half a dozen power supplies and that means I have to take them apart to do it.

What I found in TOO many is damned scary. Seriously. If you have one of these power supplies, my advice is disconnect it, take it apart and INSPECT THE THING! Yes, do it. If you get a new one before you put it into service, take it apart, INSPECT IT!

And don’t worry about the warranty sticker covering one of the screws, it’s a tail light warranty at best. I.e. when they can’t see your tail lights the warranty is up.

Disassembly

There will be a maximum of SIX screws on the top piece holding the fan. The “warranty” sticker might cover one. Don’t be surprised if some screws are missing, or stripped. I’ve found both. Standard M3 screws are what they use.

IMG 1151

Once you get the top screws off, you’ll see something like this, if not exactly the same if you’re disassembling a 12V 30A supply.

IMG 1153

Unplug the fan connector from the PCB and set it aside.

Remove the four or six screws holding the MOSFET’s to the case from the one side and end. Be careful not to rip the insulting gasket. If your supply has a metal bar between the MOSFETs and the case, wiggle it a little and slide it up out of the case. Set all those parts aside aside.

There are five holes in the PCB for holding it on to the case. I’ve yet to find a supply that uses five screws. Screws cost money, You’ll no doubt find four screws (one in each corner, one rarely in the centre) so remove them. Set them aside.

The whole PCB should now lift almost straight up and out of the case. And the fun begins.

Inspection

It doesn’t matter if you know zero about electronics or not. You’re not troubleshooting or doing component level repair.

What you’re looking for is potential hazards that will be pretty obvious once you know what to look for…

First, check the solder side of the PCB. You don’t want any untrimmed leads hanging down more than 1/8″ under the circuit board. On some of the supplies there is a plastic shield under the PCB, but I’ve also found a few that have nothing. If you see a long lead, don’t bend it over, trim it off. Use nail clippers if you don’t have wire nippers.

A reasonably good power supply PCB will look like below. All shiny, no dull solder joints, no leads poking out.

Good Supply

On the other hand, you can find something that looks like this one. See those BIG wire jumpers? That tells you SOMETHING is amiss with the PCB foil traces. Take a photo or two, put it back together, tell the seller it’s junk and don’t use it.

Not So Good

Moving on, flip the circuit board over so you’re looking at the component side. What you’re looking for is two things. Components that are bent over, shorting against other components and solder splashes.

I’ve only found one capacitor that was laying on top of a nearby resistor, which would have caused the supply to leak smoke when I powered it up.

On the other hand, solder splashes? LOTS..and LOTS. The trouble with solder is that it can stay fixed to where it settles, but at some point, heat, maybe a jar to the supply when you’re moving or transporting it and now it’s a shorting strip looking for a place to cause havoc.

Take a look at this photo…big thingie with coloured bands is a power resistor. But! What’s that “glint” of silver on the top of it? Solder splash. Get some tweezers and take it off. In some cases, you can flick it off with a finger nail. Just don’t flick it back on the circuit board.

Power Supply Solder Glob

Or look at this example on the last supply I checked…under the heavy jumper wires there is a piece of solder splash. Just. Sitting. There. I removed it with a pair of tweezers and it wasn’t attached to anything.

After which I thought I was done. Right….not! Take a look at the “400.”… that dot after the 400 silkscreen isn’t a dot, it’s a ball of solder. One touch and it moved.

Power Supply Glob 2

Tilt the board and look under any components you can. Loose solder loves to pin itself up against other component leads.

Summary

If you currently have a power supply in use and are under the impression that since you’ve been using it for “x” hours, it must be fine. Don’t assume, stop, check it.

The one I showed with the big jumpers on the PCB was one I’d used for over 400 hours. It worked fine. But every now and then the printer would do something odd and I blamed the firmware. So I took it apart. One of those jumpers wasn’t properly soldered. No, I didn’t fix it. I tossed it out.

I doubt these power supplies go through anything more than the briefest cursory glance for quality control. No doubt more about how fast they can be assembled, than can be they be assembled correctly. The old, time is money, problem.

Sadly, the end users, you and I, will end up the loser. Thus if you have one of these supplies, do yourself a favour and have a real good look at it. At least you’ll get a little piece of mind when you start one of those 33 hour print jobs.

17
Jul

3d Hot End Temperature Problem

Ever have one of those “problems” where you spend endless amounts of hours trying to solve it, doing everything thing you can, “By The Book”, only to be stumped at every turn?

Yeah, me neither.

Until 3 days ago.

In the Beginning

Last year we had a new fence put in, and over the winter and the heat this summer, the not so stellar post caps decided to split, curl and look more like pagoda roof lines than post caps.

IMG 1201

Which is not a big deal until you consider than the rain will end up on the post instead of being diverted by the cap.

I spent some time with Tinkercad designing a new post cap, hollow up inside, over hangs the edges of the post so there is no way the rain can land on the post.

IMG 1202

The Design

The design is pretty simple. I mean, it’s a post cap. How complex can it be…

IMG 1228

It prints upside down, top is about 86mm square, base is about 146mm square (when mounted on the post). The sides are 45 degrees so no support. But it is fairly big so it does take some time to print out.

The Ugly

When I started the first print, I was running the perimeters at 30mm/s, the infill (what little I used) was 50mm/s. After all nothing but a bunch of long straight runs.

And then I looked at the temp stability. Or more specifically the lack thereof. Crazy, 10C higher than set point, 12C lower, and oscillate like that for the entire print job. if it settled down it was only for two or three minutes. Then back to high and low sweeps.

I managed to get the print done, decided I’d use the other printer I have. Exact same symptoms. Large temp swings during the print.

Next I loaded up a different print as a test and printed it out. Temp was rock solid. Back to the fence cap. Wicked temp swings again. Do this enough and the result is male baldness.

The Solution Search

Off to the internet I go to see if anyone has the same problems. Only about 500,000 people do. Safety in numbers you know.

So I started reading about possible “solutions”…keyword, “Possible”…

Arduino AREF isn’t stable. Turns out if you have flaky 5V supply line this can happen. Mine is rock steady.

Shield thermistor leads. According to the theory, the PWM signal from the heater element can create “noise” on the thermistor leads. So I stuck my scope on it. My cables are all wrapped in a bundle so you’d think there’d be lots of “noise”. My conclusion after testing was the “noise” was caused by someone not knowing what the heck they’re talking about. In the one case it did fix, turned out it was a bad connection not noise. Moving on.

Heater damaged. As I happen to have spare parts for my printers, I replaced the heating element. No change.

Thermistor. Now we’re getting into the grey area. Damaged thermistor, loose wire, bad Dupont connector, RAMPS problem (should be using RAMBO or some other 32 bit control board), fan blowing on it, wrong setting(s) in firmware, not PID tuned, and broken leads. Except this does not explain why a different design prints with perfect temp and this stupid fence cap doesn’t. None the less, I tested three different thermistors. And got the same huge temp swings.

None the less I made a lot of adjustments to the firmware in the section that controls the PID, temp curve and heating variables. All to no better outcome.

Small design printed better. Fence cap, huge temps swings. No cure.

Then I thought, ah ha! Slic3r. Yeah, no. Made no difference. Sigh…

PLA! Yeah, something wrong with it. Change it! Yeah, did that, no change…ugh.

Nozzle! Yeah, no. Not that either.

Arduino! Swapped out an Arduino MEGA with a 16U2 for the el sleaze bucket ones with a CH340G. Nah. No change.

MUST BE THE RAMPS!!! Yeah, tried two different RAMPS boards. Same temp swings.

I pretty much gave up.

Two Heads, Better than None

I was ready to throw in the towel (along with the hot end and the rest of the printer) when the wife came in to see what I’d been mumbling to myself about.

I showed her the problem with the temp swings, told her about all the changes I’d made. She looked at the test prints, perfect, looked at the fence cap print, not so good.

Told me to start the fence cap print again and she watched the temps and called them out to me…

We let it run for about 3 layers and she said, “Cancel the print job”. I cancelled it, she said, “Okay, re-slice it and slow it down.”. I quickly said, “That won’t do anything, I can print far faster than I have it going anyway and the test prints were printing out fine at 50-60mm/s.

At this point I’d have peed on an electrical outlet if I’d thought it would help. So I set the speeds, infill, perimeter to 20mm/s. Or roughly half the speed of the last ice age.

Started the print, swing started the same and then…yeah. Stable. I was amazed.

So we did three quick tests. Speeds at 20, 25 and 30mm/s. You can see them in the graph below as test 1, 2, 3.

Fence Cap Temp

Time for a Guiness…

The Problem

When you look at a typical hot end, there’s a big chunk of aluminum with a heating element and thermistor in it. If and when you do some PID autotune, the head is stationary. All is right with the world.

When you print, the head moves, that big chunk of metal becomes a mobile heating element. Swing your arm, feel the wind rushing around your hand. Now pretend you’re the FLASH (oh go ahead you know you want to) and make your hand only vibrate. Very little air movement (if time starts to go backwards I suggest you stop…:-)

So the problem is simple. When the head is doing those LONG FAST lines, that heater block is dissipating heat like crazy, so much so the firmware can not maintain a control on it. Like tossing a stove top element around and trying to maintain a stable temp. Not. Going. To. Happen.

The Solution

The obvious solution is that if you’re going to print big stuff where the head is moving fast and long, plan on slowing it down. A lot. If you find big swings and you have a print job running, slow it down.

There are folks who say that a silicon boot on the heater block or wrapping the block in cotton/kapton will help, but I haven’t tried either of those to see if there is any merit there.

I suspect this is why a number of printers are enclosed in boxes so air in the box is warmer, thus easier heat control.

Insulating the head would be easier on a delta. Hence my thinking is it should be able to maintain a stable temp when the head is moving long distances fairly quickly.

Then again, if you read back through the initial problem “solving” list I had in the first place, you might just want to smile, and knowingly nod your head a little bit…

Later that same day…

Good thing I’m not a cat. My nine lives would have been used up years ago with my curiosity…

I decided to do a test by making a sock for the hot end. I used the cotton strips and some Kapton tape to make a boot..The print cooling fans were not used, the only fan on was for the heatsink tower.

IMG 1230

The hot end is wrapped all around except for the back where the wires for the heating element and thermistor are. Kapton tape is holding it all in place.

I loaded up the same fence post cap, set the speed for the perimeter to 30mm/s, infill to 50mm/s. And did three layers.

Insulated Hot End

if you look directly above the 7 min mark, you’ll see the temp drop and thats where the second layer starts. At the very right edge it looks as if the temp is coming under control. Except at that point I’d set the printer to 50% speed.

The cotton insulation does help, a bit. But certainly no where near what I imagined it might. The back of the heating element where the thermistor is no doubt very sensitive to air flowing past it. Thus if the whole end was wrapped up like a mummy, maybe it would be better. Or not.

For now, print at a slower speed, it works.

5
Jul

Gibson Robot Guitar – Revisited

I was in the studio the other day, went to tune up the Gibson Robot and…meh. Nothing. Plugged in the charger, and couple hours later. Nothing.

Swell. Just swell.

Back in 2014 I’d fixed it with a couple of El Cheapo rechargeable batteries I sourced off eBay. Fast forward three years and those batteries were toasted.

Of course this is pretty much standard for NiMH so…no big surprise. And those 2000 to 3000ma rated batteries off eBay, keep in mind those are just NUMBERS. For example I charged up some Eneloop’s, got 1.48V full charged. Did the same with some A3300 batteries (and some unmarked ones) off eBay and the best I got as 1.37V. Maybe you’re thinking 1/10th of a volt isn’t much, but trust me, in this case with a robot, it’s huge (for other reasons).

As it happened someone emailed me within the last week about that original blog post and since I had some time I decided to dive back into the Tronical murky waters.

The Examination

Instead of grabbing another set of junk batteries I decided that I needed to adjust my thinking for “long term”. If the batteries were going to be replaced every three years I might as well make it easier to do.

Next I didn’t want to use cheap batteries. My choice was to go with the Sanyo or Panasonic Eneloop batteries. The problem here is that the batteries don’t have solder tabs on them so one has to solder right on the battery terminal.

I started by looking for a dual AA battery holder than would fit in the confined area of the Gibson. I found a couple of these in my parts bin.

Bholdaa

The one I had fit, the second one was wider than the Gibson cut out so no go with it. I soldered up the wires, plugged it in and was rewarded with a flashing sequence of blue LED’s around the MCK ring. I have NO idea what that indicated. But there’s no way the thing would respond or tune. Cool flashy LED’s though….

In trying to figure out why, I originally thought the electronics might have fried itself, I came across the specs for these holders. Specifically 1 AMP output MAX! Any more than that the contacts/wire can heat up. Even with the connection I did have there was a large voltage drop. Mostly they want FAR less than 1 amp to be happy.

Last time I tried to power the Gibson with a bench power supply, it failed miserably. Apparently my new bench supply is of higher quality and it powered up the robot just fine. My goal was to measure the current used at idle and when tuning.

At idle the robot used around 340ma (one third of an amp). That surprised me, I didn’t think it would be that demanding.

Kicking the robot into tune mode, wow. Anywhere from 800ma to 1.6 Amps. Depending on how many tuners were running.

No wonder the batteries were soldered in.

The Options

I could either replace the batteries with some new soldered ones or find a battery holder that would fit.

According to what I could find, Eneloop does make tabbed batteries but I could find no source in North America for them. And really, I wanted to avoid soldering in new batteries if I could.

Which lead me to decide on a battery holder.

Armed with some electrical data, I started looking for “spring less” battery holders. Springless holders typically have large metal tabs that rub against the ends of the battery. The current through these connections can be far higher than the typical brass button and spring units in the previous photo.

Try as I might, all the holders I found weren’t going to fit into the Gibson’s battery area.

So you think that would be the end of it right? Nah.

Unleash the Maker

Back in 2014 I didn’t have a 3D printer. I do now. Couple of them as a matter of fact. I used Tinkercad and started designing a box that would fit in the area. A tray is what I finally found worked best.

But first, I needed some UBER springy metal to make battery tabs with. Off I went to eBay, Banggood, etc and found a few things, but not what I thought I could use. So I started to look around the shop for springy tin and presto. It darned near jumped out at me…

Jacks

When I was building guitar stomp box pedals, I was using a lot of these jacks on the PCB for connections. Nice springy tin connections. Yep. I cut the plastic off two of them to get four terminals. Bent them so they’d hold a battery.

Then it was off to add in the design to hold these. So the first couple of designs didn’t work but eventually I got a design that was going to work, at least good enough to test with.

IMG 1195

I couldn’t solder the wires on the tabs when they were in the battery housing I’d made or the PLA would melt. I decided to put the wiring on the bottom of the holder. Didn’t really matter any way.

IMG 1196

I used two terminals with a 16 gauge jumper wire. Took some wrangling to get it in but I got it.

IMG 1197

From the battery side it looks like this:

IMG 1198

Oddly enough, there is a LOT of tension in those little spring clips. So once the batteries are inserted you can see the force of them pressing against the ends.

IMG 1199

I finally put the whole thing back in the Gibson and it works absolutely perfect. As good as or better than the original Tronical design. When I plugged in the charger, it sync’d right up with the guitar and quickly charged the batteries to full.

IMG 1200

Summary

Is this perfect? Will it stand up? I don’t know.

I do know the batteries are wedged in the holder pretty darn good BUT, if they do come loose, I’ll put a zip tie around them and the holder so there’s no way they can budge.

Looking at the clips, I can also see another way to do this. A couple of M3 screws, some terminals, no spring clips needed. But then again, this might not work as good as the spring terminals…

All I know is that when the batteries go again in three years, I’ll be putting in another set of Panasonic Eneloop’s and it’s going to take me about two minutes to do it.

27
Jun

M.G. Chemicals PETG

After renovating the backyard last year, I installed some solar lighting.

The lights came with a plastic spike that pushed into the ground but I didn’t use them.

One reason was because that would have either put them in the planters where the solar cells would be blocked by the fence so no charge, or on the lawn where they would have to be moved every time the lawn was mowed.

On June 24th we had a scorcher of a day and Carol pointed out that the lights seemed to be listing. Some to starboard, others to port…and at a fair angle too!

Initially I thought the 3D printed mounts I’d made last year had come loose and to some point that was true.

Ultimately what had happened was that the screw holding in the mount had reached the PLA’s glass transition point, with the stress of the heavy weight of the solar light (they have a glass lens; not plastic), it was enough to start the topple syndrome.

IMG 1172

The outside temp was 30C. When I took the mount off the post rail, the screw felt a lot hotter than that.

Of course there was no use reprinting more mounts in PLA if they were only going to last a year.

Then I remembered I had some M.G. Chemicals new improved PETG.

IMG 1174

The glass transition point is 25C higher than PLA! I redesigned the mounts to make them taller and a thicker base for the screw to sit in.

IMG 1173

I started printing and replacing the mounts. After they were all done, it was time to sit back and wait.

IMG 1177

I only needed to wait until the next day. The temp outside climbed to 31.2C, and the solar lights stood like sentries without a movement.

The new mounts worked out perfectly.

One thing I should note if you try something like this, I used a fan on one print. PETG seems to cool off quick enough anyway so really the fan is more or less to stop stringing. I found the best way to print these small mounts is slow and no fan. Excellent adhesion between layers and almost no stringing in these small items.

26
Jun

3D Printer Noise – Not a Fan

One of the things that 3D printer reviews tend to gloss over is just how loud the popular Cartesian or Delta 3D printers can be. It doesn’t matter if the printer is a typical open frame type or closed up in a box, quiet is not a word that comes to my mind.

Given that the speed of the printer will affect the steppers, thereby transmitting said vibration through the printer frame itself, there’s not a whole lot you can do about some of it. Granted there are stepper dampers that are said to “lessen” the vibration transmission, or isolation feet so the printer doesn’t use the table/bench it’s sitting on as a “speaker”…

I tried the stepper dampers, ah, yeah. Didn’t seem to do as much as I’d thought. The budget dollar store rubber feet had a far greater impact though.

Fan Noise

However, what about when the printer is simply sitting idle? On a delta printer there is a fan on the hot end that needs to run continuously. Replacing that fan with a ball bearing low db fan is a good move. The original one that came with my printer sounded like a cement mixer.

Typical specs for the “cement” mixer would be as shown:

Noisy Fan

Considering the specs were from a ball bearing fan, it’s a noisy little brute. Basically, look for a 6,000 RPM, 0.15A max, and dB-A of 21 (lower is better). If you order these from eBay or some other equally sketchy source be aware that any specifications you see are going to be questionable. At best.

I picked up some Coolertec case fans OW4010DFS-2P hydro bearing, 15dB-A. You don’t more than 5 or 6 CFM. NASA wind tunnel fans not needed. The Coolertec fans? Wonderfully quiet, darned hard to get.

IMG 1175

Power Supply Fan

The second culprit, major source of annoying white noise is the power supply fan. On a typical 360 watt (12V 30A) switching supply I found that the fans on most of the ones I’ve worked on or bought, run all the time. Loud!

IMG 1151

I’d removed all the grating from one supply, replaced the fan with a quieter one and it’s still noisy.

By some sheer freak of nature I ordered a power supply from Amazon and when I installed it, the fan wasn’t running. I thought it was fried from the get go. I checked the voltage and it was fine. Once running for a while during a print job the fan would come on, run for a minute or two, shut off again.

I started to investigate why this happened.

The majority of these 12V 30A supplies “specify” a thermal controlled fan, so as the power supply heats up from current draw, the fan will cut in and cool it off. Oddly enough even though thermal control is stated, my experience is that the fans run all the time.

So….why? That’s the question.

Thermal Control

I took apart a power supply where the fan cycled and one where it didn’t. Started to look at what the differences were.

IMG 1153

It was surprising to find that the majority of the ones I have, from 4 different sources/companies, all use the same PCB. Or a minor variation thereof.

I tracked the difference down to a jumper of the “fan runs all the time”…see that jumper RT2? Yeah, there is supposed to be a thermal relay component there. But hey, that cost .97 so…jumper. Or as I found with a lot of offshore stuff, cost, not quality.

IMG 1154

The part that’s missing is a simple thermal relay, N.O. (normally open). It closes at 45C and opens at 33C.

KSD9700

To get the PCB out of the case is a little tricky. Remove the two screws that hold the heatsink bar on the MOSFET’s at the end and edge of the case.

IMG 1155

I found on my power supplies the screws were two different lengths. Thus, whatever comes out of the spare parts bins when they were assembled. There is an aluminum plate with some heat sink material on it, that needs to come off the side MOSFETs (where the thermal jumper wire is). You need the wiggle room to get the PCB out.

Next are the PCB screws. There should be five in total. One in each corner, one in the middle. Mine was built on a Friday at 3 minutes before quitting time, I only got four screws.

IMG 1156

To get the PCB out, slide it slightly forward (so the back edge of the PCB will clear the rear inset aluminum; about 1/8″). Notice on the side where there are no MOSFETS the PCB is notched so I just lifted that side up, but left the opposite edge with the MOSFETs where it was. Sort of rocked it back towards me. It’s a tight fit so don’t get heavy handed with it. It goes back in the same way.

Power Spply PCB

Once out, it’s easy to work on.

Thermal Relay

If you’re thinking the relay would attach to the case or the MOSFETS, ah, nope. It doesn’t. It actually goes inside the toroid coil on the PCB. And you glue it in there.

Start by bending the leads on the relay.

IMG 1159

Now you need some “glue”… but you want thermally conductive glue.

I found some on Banggood and eBay called “silicon thermal plaster”. It’s not inexpensive either and I decided that since I didn’t know what it was, couldn’t find any specs on it, and lastly didn’t feel like waiting for months to get it, I’d source somewhere else.

Which lead me to M.G. Chemicals. Who, oddly enough, seem to have a wonderful assortment of off beat items that fit exactly what I need.

One of which happens to be called, “Thermally Conductive Adhesive”.

IMG 1161

M.G. sells two kinds of this epoxy (it is a two part adhesive). One is called paste the other is flowable. I thought I would need the paste, but that was not available. I got the flowable instead.

I was hoping it was not as runny as five minute epoxy and I wasn’t disappointed! It’s about as “flowable” as silicon. I.e. you goop it, it stays gooped where you goop it. How’s that for technical terms…

As with the “silicon plaster”, 25ml isn’t inexpensive either. As in $31 CDN.

BUT, if you’re doing a couple of your own power supplies, a couple of friends as well, it cuts that cost down.

Seriously, and I do stress this point, when you buy something from a reputable company who supplies MSDS sheets, you know using it won’t cause a third eye to grow on your thorax three weeks later.

I got two mixing tubes with the adhesive and let me tell you, not only do they mix the epoxy PERFECTLY, you’re going to get a bonus hand work out shoving the mix through the tube…:-) The tubes are obviously a one time use but if you were doing a small restricted access and several of them, arrgghh matey, they be worth their weight in gold.

Otherwise, just put in a piece of paper and mix it like you do five minute epoxy.

Put the thermal glue on the edge of the toroid coil and don’t over use it. You don’t want to plug the air off from getting through the coil. Mine actually looks thicker than it really is. Maybe because I used a popsicle stick to put it in. I suggest a Q-Tip…

IMG 1162

The epoxy said it had a 45 minute working time and a 24 cure time. I left mine for about 6 hours to setup, then proceeded with the wiring. When I checked the joint 24 hours later, it was just like epoxy, hard as a rock.

Relay Wiring

Cut the jumper on the PCB and remove the two short wires.

IMG 1163

I used a solder sucker to clean out the holes…

IMG 1164

The relay is not polarized so there is no plus or minus to watch for. Simply solder in the two leads from the relay.

IMG 1165

Reassemble the PCB in the case, put the aluminum edge plates back in, PCB screws, case screws, etc.

IMG 1166

Make sure the relay wires are not chaffing on the heat sink clamp (yes, it’s a typical Mickey Mouse way the offshore guys do it) and button the case back up.

Rather than pop mine into a 3D printer I grabbed a bunch of LED strings and tested it.

IMG 1167

Kind of seasonal I must say, bright was the other thought…but sure enough, 10 minutes later I tested the heat of the edge MOSFETs, 45.6C, the fan came on, dropped the temp down to 33.2C and shut off. It works perfectly.

3
Jun

3D Printing Slicers

Having been down the somewhat unpaved road of 3D printer slicers over the past couple of years, I’m always on the look out for something that improves a 3D print without having to resort to sacrificing a spool of filament in an open fire pit on a full moon. At the stroke of midnight.

Let me preface this by stating I’m a delta printer guy. I’ve used cartesian’s but my go to printers are both Kossel styles. Built by me. So I know them well.

Slicing Software

There are those who seem to be able to make anything work, either right off because the software “works” like they do, or they stick with it long enough to learn all the nuances of it and master it.

I gave CURA a fair shake, kind of got it working, but while it felt pretty with it’s GUI, mining down to the settings I wanted to adjust with got annoying. I got the feeling it wasn’t designed for delta style printers in spite of the fact that many are using it on delta printers.

Venturing even further down the path, I bought Simplifry3D. Advertised as the be all and end all for slicing. Plug and play. Easy to use. Excellent documentation. Yeah, my experience dictates that would be four strikes against them. Make it five if you want to include the absolutely pathetic tech support.

Still, honestly, you have to try these things because what works fabulous for you may not work for others. Or vice versa.

After the roads I travelled down, it was nice to get back to Slic3r, even if there’s some pot holes in the road that need fixing. Or as someone said, “Better the devil you know than the one you don’t”. Thus I kept going back to Slic3r.

Slic3r

Slic3r hasn’t changed from the 1.2.9 version since June 2015. In software lifespans, two years is an eon. Mind you it is open source so you take what comes.

Slic3r is working on a 1.3.0 version and I suspect in time it will appear since they are pouring a lot of hours into it.

PRUSA Slic3r

Last year PRUSA forked Slic3r with the intention of making it work better with their own brand of printers. This got my attention since the work that PRUSA stated they’d be doing would be fixing up the various parts of Slic3r before adding in all their own bells and whistles to better suit their own printers.

With every release PRUSA has done, I’ve downloaded and run to see how it works with my Kossels. I’d be the first to admit this is not exactly what I would ever advise anyone to do. Me, I’m curious. Just a darn good thing I’m not a cat.

Some of the releases were, ah, how to put it, scary. The print head moving like a spasmodic hummingbird, or moving at the speed of the next ice age. Oh yeah, some issues for sure.

However, over time, each release got a little bit better. I’d check the forums to see what others would experiencing and see that would relate to anything I’d be doing and in most cases, nope. Delta printers are different.

Since the first week in April I’ve been using PRUSA’s 1.34.1 version exclusively. The quality that I am getting out it exceeds what I can get out of the 1.2.9 version of Slic3r. Admittedly some of the settings in the PRUSA version are different than the settings I used in Slic3r.

First off, the download link for the PRUSA 1.34.1 version.

Next the simple settings changes are in 3 areas, assuming you’re using the Expert settings in Slic3r like I am…

Preferences

Preferences

The USB serial connection is if you want to print from Slic3r via USB. I haven’t tried it, no idea if it works or not. I use Octoprint so everything is wireless here.

Layers

The only settings I needed to change here is in the “Quality” section. Specifically the “Avoid Crossing Perimeters”. Thin wall works sometimes, not others, much the same as vertical wall thickness. Normally I leave them unchecked and I’ll check the Plater–>Layers view to see how things look, maybe toggle them on or off and recheck.

A very nice edition is the SEAM position. If you want the seam hidden at the back of the print, just select REAR for the seam and it’s done. Works very nicely.

PS 1 Layers

Infill

For the infill, again, the only change I made was where it says, “Only retract when crossing perimeters”. I have it checked.

The rest are merely the stock settings I used all the time in the 1.2.9 version of Slic3r.

PS 2 Infill

Summary

One thing I would suggest if you want to travel this road, save your PRUSA settings with a unique name so you know they are specifically for PRUSA version not the 1.2.9 version of Slic3r.

I started to name mine like PRUSA_50403…shorthand for 50 infill speed, 40 perimeter speed, .3 layer height. Works well.

PRUSA has since released two more revisions but the current one is working so well, I haven’t felt the urge to try either of them out. Like they say, you can’t fix it if it’s not broken. Then again, maybe I’m just not trying hard enough…

27
May

Word Clock – revisited

Back in 2014 I built a word clock that consisted of a strip of 111 Neopixels (WS2812B), controlled by an Arduino.

I got all fancy with it, wrote a custom application for the Mac for all the settings and changed the time base more than just a few times. Everything from picking up the GPS RF transmission here, to a direct GPS module, and even a RTC (DS3231).

It has been running fairly well until the last few weeks when the “Twelve” word started to exhibit some odd colours and wouldn’t completely shut off. Of course then I noticed other things like the printed paper mask I was using for the words had started to fade a bit, allowing the square boxes to shine through. Lastly the colours didn’t look all that vibrant any more.

I tried a couple of bandaid fixes for it and Carol suggested I needed to redesign it.

Redesign – Rip apart

I think I spent the better part of a week going through all the permutations of controls when it finally dawned on me that I needed to come up with a new face design. I took the foam board, paper and ripped it all apart so the only part remaining was the backplane with the Neopixels on it.

IMG 1080

The next thing was to write a quick Arduino test routine to make sure the LED’s are all working. Oddly enough, even though the Twelve word was failing for the last couple of pixels, my test routine proved there was nothing wrong with those pixels…mmmm Odd…

New Cell Design

Guess who has a couple of 3D printers? I kind of balked at first because it’s not just a design small enough to print in one afternoon. It had to be done in pieces, the pieces put together somehow, and so on. Oddly enough as I used Tinkercad to design what I wanted, it started to go together easier.

Each of the words, like the original would be a box on their own. I thought about how to put the cells together to make the grid and realized the easiest way was to use some of those M3 screws I have.

IMG 1081

I did a row at a time, screwed end to end, then fit them between the side frame rails. More screws and I just kept printing and assembling.

For the “lens”, I printed two layers of white PLA. I tried thinner and thicker layers but two seemed to work the best. I also tested some transparent PLA but you could see the Neopixels behind the lens so that wasn’t going to do. The white diffused the LED’s perfectly.

IMG 1082

Eventually I got the whole display done and then had to work on the electronic control.

Clock Electronics

To control the Neopixels all that is required is an Arduino. But then I was back to a RTC, GPS or RF signal catcher and I really wanted something, ah, different.

I remembered I installed my own NTP time server on my OS X Mac Mini so…why not use it. I didn’t want to use an Ardunio with Wifi or ethernet, so I decided on an ESPduino D1. The ESPduino is nothing more than an Esp8266 with a CH340G uart connection. I have a couple of them in my parts bin thus if I blow one up, I have a spare.

I found a few sketches that showed how to do NTP, and then I came across a sketch that did it with an 8 digit seven segment display. I have the same display and wired it up for testing just to make sure it worked. It worked quite nicely with my ESPduino D1.

I used the sketch as a starting point for my word clock because my logic and control is significantly different. About an hour later I had a working clock.

IMG 1085

Clock Box

The original box was still in good condition and I used it again. Even managed to reuse the matte from the original in 2014.

IMG 1086

I was going to use a dc-dc buck converter to drop 12V down to 5V but decided to make it even more simple and just use an iPhone charger to supply the 5V everything was going to run off.

Plugged it all in, connected to the access point, set it to use my wireless network and it sprang to life…

IMG 1092

The Tweaks

The original clock had bluetooth for adjustments, colours, brightness, light levels for auto dim and so on. Honestly in the three years it’s been running, I never adjusted any of that. Instead I kept the new build simple with one of the original tweaks left in. The auto brightness.

There’s an LDR mounted in the top of the frame. When the light level in the room drops below a specific level, the clock brightness drops to it’s night time setting. That’s it. Simple.

I printed a ESPDuino D1 mounting plate I found on Thingiverse, stuck it to the back of the foam board, plugged in a USB cable from the iPhone charger and away it went.

IMG 1093

Six connections to the ESPduino and it’s wired.

For the Twelve issue, when I went back through the original sketch I wrote, I missed the number of Neopixels in the strip. By one. My math is better now…

4
May

Ole Mega Ain’t What She Used To Be

The Arduino Mega2560 has been around a long time, at least in the world of micro controllers. Since 2009 so it’s not the new kid on the block by any means. In that time we’ve moved through to R3, revision 3, and it has been a robust hard working reliable platform.

Right up to the point that someone with the IQ of a stump decided to dump the ATMEGA 16U2 and incorporate the cheaper CH340G USB to serial mangler. In most cases, this piece of digital cruft will work. But there is no comparison if you lift the hood or try kicking the tires.

ATMEGA 16U2 VS CH340G

It’s decidedly easy to spot the CH340G, at this point. Course if the same low life decides to change the packaging it’s going to be a little tougher. In the photo, and probably what you’ll see more of than anything else is the one on the left with the CH340. It’s a 16 pin DIP package.

ATMEGA CH

I feel the CH340 has but one goal in life. It pollutes Arduino boards, and it converts from USB to Serial and back.

On the other end of the spectrum, the ATMEGA16U2 is a microcontroller that firmware can be programmed into. Thus you can change the firmware and your computer will think it’s connected to a mouse, joystick, or keyboard. This is impossible to do with a CH340G.

An Arduino MEGA with a ATMEGA16U2 is plug and play for the most part. Most computers will recognize it in a few seconds after you plug it in.

The CH340G on the other hand, requires a driver to be downloaded and installed. Because of its brain dead nature, no computer is equipped to communicate with it unless that driver is there.

From what I can see, there is little price difference between the two but the ATMEGA16U2 is far superior. It might take a little more time to program the 16U2 to be a UART, so perhaps they are more intent on saving time than a users sanity.

The Sheep In The Closet

If you’re thinking, big deal, doesn’t matter to me, it might, depending on what you want to do with the MEGA.

For example, let’s say you want to do some blinky lights, Neopixels, TFT/LCD display, or some sensors. No big deal, it’ll work just fine because the 2560 chip is doing all the work. The 340G is just the way you program the 2560.

On the other hand, let’s shove a RAMPS board on it, upload some MARLIN firmware to it and then connect to it and run our 3D printer. At a high baud rate. Where a LOT of printers like to live. Specifically 250,000 baud. Don’t be surprised if you see messages from PrintRun like this:

Connecting...
Attempted to write invalid text to console, which could be due to an invalid baudrate
Attempted to write invalid text to console, which could be due to an invalid baudrate
Attempted to write invalid text to console, which could be due to an invalid baudrate

Say WHAT? You might not see that with Repetier Host, because it tends to filter out stuff it doesn’t understand so you don’t get junk in the monitor. But you can still see some “resends” because it didn’t understand the last thing it received.

The issue truly is the baud rate. According to the “data sheet” for the CH340H:

CH340 supports common baud rates: 50, 75, 100, 110, 134.5, 150, 300, 600, 900, 1200, 1800, 2400, 3600, 4800, 9600, 14400, 19200, 28800, 33600, 38400, 56000, 57600, 76800, 115200, 128000, 153600, 230400, 460800, 921600, 1500000, 2000000 baud.

Notice there is no “250,000” baud rate in that list? The closest is 230,400.

So many have tried to just code in the 230,400 and use it. And found themselves with errors that just don’t make sense…dropping to 115K baud doesn’t help much either. Marlin’s default with RAMPS is 250K.

I have tried different baud rates and met with poor results so I leave it at 250,000 and it works best on a ATMEGA16U2.

The reason for the 250K was the ATMEGA16U I suspect. The divider of the UART of the AVR (ATMEGA16U2) used in the Arduino can create 250000 without an error, while 230400 has a 3.5% error in clock. Even if 250000 is itself a non-standard baud rate, it just works.

CH340’s Arrggh.

Solution?

The biggest problem is places like Amazon and eBay. Type in Arduino MEGA2560 R3 and you’ll find correct images of an R3 board but a wrong description, images showing a CH340G but all the ad text describing the ATMEGA 16U2, and any combination thereof.

Asking the seller if it’s really a ATMEGA 16U2, I’ve found out (the hard way) is pointless. The mass majority have no clue as to the technical specifications of what they sell. Some will tell you what you want to hear and send you the wrong thing any way.

I don’t think it’s a case of bait and switch, it’s more just a case of blissful ignorance.

So you’re left with getting someone to take responsibility for what they sell. Or trying to find someone who actually knows what they sell. Either way, it’s a path that shouldn’t have be ventured down. Sadly, it’s turning out to be a path all to common.

7
Apr

Octoprint WIFI Hotspot

Having extensively used both Astroprint and Octoprint, I’ve been using Octoprint for the last few months for the extra features it has. Like telling you how much space is left on the SD card, being able to send directly from Slic3r to the printer and so on.

Astroprint could do the same things since it’s really nothing more than a pull of Octoprint with a beautiful GUI and limited controls. However it’s also targeted at a completely different audience so…who knows.

Until today, one of the things that annoyed me about both of them is their inability to create a WiFi hotspot should their normal WiFi network be absent.

I tend to bring my printer to demo’s and the only way to connect it is via USB. Which works, kinda, but Repetier Host and Pronterface are somewhat dodgy on the Mac so there’s starts and stops in communication. Whereas connections with both Octoprint and Astroprint never miss a beat.

As I said, today that changed…

I found this complete step by step description of how to do it:

Painless Wi-Fi for OctoPrint

In short, you create a list of ALL the known WiFi spots that your printer might encounter in a special file. When Octoprint starts up it tries all of those links and if none of them are found, it then creates it’s own WiFi hotspot.

You do need to download a more recent stable image of Octoprint that is configured to use the special list of Wifi hotspots, but that’s not hard to do.

You connect to the printers hotspot, and talk to the printer with an IP address of 10.0.0.5 in your browser. It works perfect. The best thing is that it’s a password protected WiFi hotspot so just anyone can’t connect to your printer during demo’s and create havoc with it.

Kenneth gave credit to the original creator of method here. This information was available last May, but in all my Google searches I never found it.

I’ve since downloaded both pages and saved them as PDF’s.

Just a little nugget of info…certainly the individuals have my sincerest thanks!

9
Mar

3D Printer Webcam

After doing some testing with webcams I’ve come to the conclusion that you need one wide-angle of a brute to get the job done without having to end up setting the webcam up 30+cm or more away from your print bed.

Awkward to say the least.

What I wanted was to put the camera on one of my delta’s towers and have it catch the whole print bed. Impossible.

I duplicated the setup on my bench so this is what it can see… The webcam, standard el cheapo USB version on the left edge, printed 50mm LED light housing sitting on a 220mm bed.

IMG 0966

Through the web cam, this is what I can see…

Webcam Normal

Ah yeah, that’s useful. More like a macro cam. I had to keep in mind that these are meant to sit on the top of your monitor or laptop and grab your happy smiling face for those online chats. Nothing more.

I couldn’t find a wide angle webcam but I did notice that a lot of eBay sellers had some “wide angle” lens attachments you could use on your cellphone to photograph wide angle scenes. Cheap enough, wasn’t worried about the quality, so I ordered one.

IMG 0969

The description:

fisheye:
Angle: 175°- 180°
Magnification: 0.33X
Lens Construction : 3 Element 3 Group
Max Diameter: 25mm
Length: 15mm
 
Wide Angle :
Angle: 130°
Magnification: 0.67X
Lens Construction : 2 Element 2 Group
Max Diameter: 20mm
Length: 11mm
 
Macro :
Magnification : 10X
Min Object distance : 10-15mm
Lens Construction : 1 Element 1 Group
Max Diameter: 20mm
Length: 15mm

The “wide angle” one is fairly useless but…the fisheye one hits the mark!

I merely held the one marked “Fisheye” in front of the webcam lens and got this:

Webcam Wideangle

Probably some edge distortion, but at least it covers a fair portion of the print bed compared to the standard webcam.

I plan on printing up a simple mount to fix it to the front the webcam.

While I’m at it, I should advise that if you get a web cam, make sure you get one that allows you to adjust the focal ring. I have a couple that are fixed focus and a pain to adjust, whereas most of the budget ones I have allow easy focus adjustment.

10
Feb

Soldering Gear

Soldering

A word that can strike mind numbing fear into first timers. I kind of remember learning how to do it, from a ham radio operator no less. Frustration for me, laughter for him. When I was 10 years old.

Now admittedly most parents wouldn’t dream of letting their 10 year old grab hold of a hot soldering iron because, well, they’re kids. And you never know what could happen.

Fortunately I was born in an era that believed if you grabbed something hot and burned yourself, you instantly gained the experience to never do that again. My parents bought me a wood burning kit for Xmas when I was 10, and with it came the responsibility that I wasn’t going to “burn the house down”. To their delight, I’m sure, it was never an issue.

Soldering came to me because I was a model train nut in my pre-teens. Running wires and switches for tracks, sidings, lights and so on with nothing more than electrical tape was, really, more of a hazard than my wood burning set.

This blog won’t teach you how to solder. Neither will too many of the online videos or “instruction” pages I’ve seen. You want to learn to solder, find someone who can do it well, beg or bribe them to teach you. One on one. Makerspaces are a fabulous resource for this.

The dead giveaway for someone who lacks soldering skills? They use the gun or iron as a “paint brush” to “flow” the solder around the connection. You don’t wipe a solder joint with an iron to flow the solder. Unless you’re sculpting.

Guns, Irons, Stations, Torches

When you’ve got soldering under control, and don’t expect instant miracles, you may want to actually buy some soldering gear of your own.

If you’re under the impression that you can buy a 25W soldering iron and you’re good to go, my best advice would be save your money. Go see a movie. Why? Because the pleasant experience of the movie will last a heck of a lot longer than a 25W soldering iron experience will.

So let’s start with the cheapest thing that will melt solder..and the thing to avoid buying if you can…

Wellar

First, Weller makes some truly great products. A pencil styled soldering iron isn’t one of them. Think of these more as a fabulous wood burning tool and you won’t go wrong. True, they will solder, in some cases, but as you get better with soldering, you’ll toss this thing. Main drawback? No temperature control adjustment.

Next up we have soldering guns. Like this one:

Weller 8200n

Runs 100 to 140 watts, easy tip to replace. You can use it for almost any gauge of wires from 14 to 26. You won’t use it to solder any components on a printed circuit board. The tip is too large. If you’re building a 3D printer, the one place you need this gun?

IMG 1218

That’s right. When you soldering the wires on to the bed heater. The bed heater is a big chunk of aluminum with a copper pattern on it. The metal dissipates the heat so fast from a soldering iron, only a gun will work. Plus the gun has to match the area. That’s a 220mm plate with a 100/140 watt gun. If you have a large metal plate, like 300mm, you need a 220/260 watt gun.

These old Weller guns last, well, at this point…here’s a snap of me at 15 when I was fixing my guitar amp (yeah on the kitchen table)…that is the SAME gun in the heated bed photo above. It is 50 years old and it still works just fine and the only repair was I put a new plug on the end of the power cord.

Mel Soldering

Plus in a pinch when I didn’t have a replacement tip (they do wear out), I’ve grabbed a piece of house wiring, 14/2 (NMD7), stripped the insulation off it, bent it in the shape of the original tip and it works, just fine until I can get a replacement tip. Which they still make…

As to why I am fixing my amp, I couldn’t afford to take it to a tech so I learned enough electronics that I could do my own repairs.

On the list next are soldering stations. To me, even a lousy one of these is better than a pencil iron.

Stations vary in quality. A lot. Typically a Hakko (genuine) is the cream of the crop, everything else is a wannabe. However, if you don’t do a lot of soldering, you don’t need a top of line station either. Again, match what you want to do with the gear to do it.

What you want in a station is first, replacement tips, with a chisel tip of 1.2mm or 1.4mm being the standard tip for component use. There are scads of tips to pick from if you have special requirements. Order a few extra when you buy the station. If they stop making tips for your iron, the iron is a conversation piece.

Second, you want temperature control. And not some analog gauge that looks like the black/green/red one from an old battery tester either. A digital read out one that has a knob to control not push buttons.

Below is an example of a relatively inexpensive station that will do a decent enough job and not put you in the poor house. Notice the place that holds the iron? It has both a sponge and a wire shavings area to keep the tip of the iron nice and clean. Oh, and don’t forget to wet the sponge before you use it. It’ll last a lot longer…:-)

Station

Last on the list is a torch. And again it depends what you’re doing. Like plumbing. Torches are great! Working on a printed circuit? Not so great. Pay attention to what the pros use, get something along that line.

Solder

Of course, having the melting tool isn’t going to do anything unless we have something to melt. In this case, solder.

And all solder is created equally right? Nope. You need to match the solder to what you want to use it for. Unless it’s an emergency or some stop gap measure in which case, yeah, we’ll use whatever we can lay our hands on.

Lets start with the big stuff…as in plumbing…typically 60/40 or 50/50 (lead to tin mix). You’ll need some solder paste, clean joints and a spool of this stuff:

50 50

And a torch. This is big heavy stuff, takes a fair bit of heat to melt it.

Moving on, we get to electronic stuff. Printed circuit boards, wiring, finer detail stuff. And in a pinch, automotive as well.

Solder Type

Here things get a little complicated because there are two very different types of solder in use. One is the age old lead/tin and the other is lead free. There are pros and cons for both so pick a camp on your own choice. One thing to keep in mind is that if you’re repairing something that was made with lead free solder, you need to use the same.

Solder Diameter

Soldering diameter is also important. You want something with a .31 or .32mm diameter if you’re doing PCB work (or general smaller gauge wiring). Buying by the pound, Kester for example, is usually the best way to buy. But it’s not cheap and if you have to mail order it, keep in mind that it is a pound weight…

Quick Review

I recently got a tube of MG Chemicals solder, lead/tin, to try out. My normal brand is Kester 44 sn63/pb37 (tin/lead).

The first thing I asked myself is who in world decided to ship solder in a tube? So I thought about that for a minute and I think that they are saving on packaging. Normally solder comes on a plastic spool, inside a cardboard box. By shipping it in a tube, for a small quantity, they move away from that problem. Cost effective, don’t know about the plastic tube in landfill though…

Course the day I buy a small quantity of solder isn’t going to happen any time soon.. So the first thing I did:

IMG 2360

Yep, pull it out of the tube and coil it up. And I have to say it does make a nice sized coil. But it got me to thinking… MG sells solder wick, and I readily admit I have used wick about 3 times in fifty years), in a “spool”. I’d suggest the plastic tube would be better served with a simple spool like the wick. But I’m not a marketing guy so…just what I’d prefer.

IMG 2361

As I mentioned before, I’ve used Kester solder for a long, long, long, oh heck, since I started.

When using the MG, I found that it doesn’t flow as easily or nicely as the Kester does. And really, 63/37 solder is 63/37 solder. Thus the difference has to be in flux.

MG Chemicals says, “RA-like flux core” and “It generally exceeds J-STD-004 and J-STD-006 specifications

Kester says, “The high mobility and fast-spreading action of this flux results in more reliable production line soldering. 44 is classified as ROM1 per J-STD-004

Whatever all the heck that means. Me? I’m just an end user and I like the flux wetting action of the Kester by far.

While I really like the new MG Chemicals PLA, the solder? True is does do the job, but …meh.

23
Jan

Octoprint Webcam

One of the nice things about Octoprint is that it’s relatively easy to add a webcam so you can easily view your print progress from your local network, or from anywhere on the internet if you so choose.

What’s not so nice is trying to get a camera working sometimes.

I picked up a couple of Logitech C270 webcams when a local store put them on sale. Plugged them into the USB on the Rasp Pi 3 (the other went on a Rasp Pi 2), booted the PI and printer up. Working. No muss, no fuss.

And the first problem. I hadn’t thought about it but when sitting in front of a computer you’re about 30″ away from the monitor in most cases (arms length), so that’s the fixed focus point for the majority of webcams. On Thingiverse there are any number of focus ring hacks for the C270 cameras so you can actually adjust the focus as need be.

Therein exposing the second problem. Depth of field. Ever notice those telephoto shots in National Geographic are sharp on the subject but the background is typically out of focus?. Webcams suffer the same thing. If you focus on the center of your printer bed, when the head moves to the edges of the bed, they can go out of focus.

Once you get the focus adjusted to where you want it, the camera in a nice convenient position, I’ve found that the field of view is very narrow. In other words, you see about a 4″ square in the center of the bed. Outside of that is beyond the cameras view.

For a webcam to work nicely, it should be a wide angle lens, and adjustable focus.

First Webcam Test

I scoured fleaBay for some of the cheapest webcams I could find and ordered some. As in $3 webcam. No doubt the ultimate quality. Or not. For the price, if it didn’t work, who cares.

The first one I tried was described as: 8 Mega Pixels 50M 6 LED USB Webcam Camera. Whatever the heck all those numbers meant. Essentially 640 x 480 with a manual focus ring. USB 2.0.

When I plugged it in, no soap. Where the image should have shown in Octoprint there was a place marker.

8 Mega Pixels 50M 6 LED USB Webcam Camera with Mic for PC Laptop Computer | eBay 2017 01 23 12 44 58

Octoprint really doesn’t do the webcam any way, there is a jpeg Streamer it links to on the Raspberry. Obviously something was off.

A quick Google and I found the Octoprint Webcam Compatibility List.

Reading down through the list I found this reference:

Webcams known to work  foosel OctoPrint Wiki  GitHub 2017 01 23 12 50 07

I didn’t bother checking the USBid of the camera, just looked at the configuration needed to make the camera work and what file to modify. This info is right at the top of the webpage as boot/octopi.txt

Going to have to SSH to make the change. So off to another computer on the network to run a terminal program. Mac guys can use the Terminal app in /Applications/Utilties. Windows users seem to prefer using PuTTY. Since I’m not a Windows user, I can’t help with PuTTY but most term programs work the same any way so my screen shots should look more or less like what you might see.

Raspberry Pi IP

You’ll need to know the IP address of your Octoprint installation. If you can’t figure it out, there’s actually a plug-in for Octoprint that’s quite useful. It’s called “Detailed Progress”.

Oct Detailed

To install it, click on Settings–>Plugin Manager–>Get More and look through the list of plugins you can download.

After the plugin is installed, the Pi will reboot and when it starts back up your LCD display will show the IP it has on your network. That’s the IP you’ll use in the Terminal program to SSH to it.

The plug in will also display, during a print, the elapsed time, the time that the print will finish, the estimated elapsed time of the print, and percentage done.

SSHing We Go

Run your Terminal application and you should get a prompt where you can type in commands…and you type in the following line replacing the IP with the IP of your Rasp Pi and press return:

SSH PI IP

On the Mac, you might see something like this if you have never SSH’d into it before:

SSH PI Authen

What it’s saying is it doesn’t have a ECDSA, encrypted digital signature for the host, so…type in yes, we want to make sure in future the Term program knows who this host is.

Next up you’ll be greeted with the Password prompt. No brainer, if you’ve never changed your Pi’s password, it will be raspberry

If you’ve used a different password, use it. A successful login looks like:

SSH PI LOGIN

When you arrive on the Pi, you’re in your users directory so use this line to give yourself admin status and go into the text editor on the Pi:

sudo nano /boot/octopi.txt

This is a text editor, you don’t use the mouse. You use CTRL keys and your keyboard arrow keys to move around.

SSH Nano 1

Use the arrow keys to move the cursor down to just below where it says, “# for available options”. The # symbol means the line is a comment, not a command.

Press Enter to start a new blank line and type in the configuration for your webcam. In my case the line will read:

camera_usb_options=”-r VGA -y” and end the line with the return key.

Press CTRL O, this will write out the file and yes, you want to overwrite the old file.

Press CTRL X, to exit the Nano text editor

Back in the terminal now, type in:

sudo reboot

You can now quit your Terminal application.

The Rasp Pi will drop the connection to your computer, reboot and you should then be able to pull up Octoprint and have your web cam work.

19
Jan

3D Printing Power Meter

Just wandering through fleaBay sometimes produces a “hey that looks kind of interesting”…which then unlocks the labyrinth of bunny trails.

Since energy seems to be a topic, when I spotted a simplistic energy monitor, well, heck, let’s take it for a spin..

Energy Monitor

This is a 20 AMP AC monitor, a cumulative monitor no less. For the rock bottom cost of $10 CDN. For bucks like that, it’s probably so accurate it’s even used in medical applications. Or Not.

IMG 2295

A whopping four screw terminal is all you need to connect said wee beastie to the AC source. Which in my case (in the event you are not in North America) 120VAC.

IMG 2297

The unit brags that polarity is not an issue, none the less I tried to keep the neutral and hot leads where they might go logically. This is using the broad assumption that the engineer who designed this anticipated such logical thinking. Or Not.

Instead of leaving those uber friendly 120VAC lines laying around, I made a quick box and printed it to house the hazards.

IMG 2301

Next, up, what to measure?

3D Printer

This was solved fairly quickly since I had a 16 minute print job to do. I plugged in the Energy Meter, turned on the printer. Darn thing worked. Am I surprised? Yes, I am. Many is the time I have received things from fleaBay only to have the smoke leak out on the first power up.

From the first power up, with no printer even turned on I got this information:

PM Start

Next I turned on the printer. In my case it’s a Kossel 360W 12Vdc 30A power supply, Raspberry PI Octoprint AC adapter). I initiated the print and the bed starting heating. According to the Energy Meter, it’s using 10.3W of power, 140ma. Not exactly a power sucker.

I examined the 12V power supply to see what the current draw was when connected to the AC line. Yeah, what was I thinking. I dunno. Line voltage is the only spec for AC they give you.

PM Bed Heating

Once the bed was up to temp, the hot end kicked in. Oddly I thought the bed would be the demanding one. Turns out the hot end is actually the energy sponge. At this point the bed is not on. Just the hot end.

PM Printing

And then the bed kicked in, with the hot end. With both heaters on, we have a 2A load. Not exactly a heavy power user. To put it perspective, five of these printers would use less than an electric kettle, although it will run longer…

PM Bed Printing

After the print job was completed, the energy meter displayed the Wh (watt hours) used for the 16 minutes. Of course the printer was still on and drawing power so that is displayed as well.

PM Complete

Summary

So what’s the point of all this? Honestly it was more curiosity than anything else.

I can’t see this saving any money or anything, and considering the energy meter itself is a load, if left on for long enough it would add itself to the energy cost.

Plus it’s not like companies who build/clone 3D printers are going to suddenly get energy responsible any time soon. You can’t compare energy costs of this printer vs that printer, magazines don’t even give out that sort of info in their reviews.

I’ve never a review that stated, “While this printer turns out incredible print jobs, the energy cost is far above/below normal”. Wait. I’ve never seen the latter, I’ve seen the former too many times without any supplied hi-res photos of actual print output.

So there you go, for what it’s worth. Which could be slightly less than some of the reviews you’ve read. Or not.

13
Dec

Octoprint – Webcams – Slic3r

Not a day goes by that I don’t learn something new about 3D printing. Sometimes it’s fairly important, other times it’s more of a “Hey, how’d I miss that one?”

This entry is more of the latter.

For the past several months I have been throughly putting both Astroprint and Octoprint through their paces. Originally Astroprint was winning and that’s kind of odd when you stop and consider that Astropint is really a fork (subset of code) of Octoprint.

Astroprint simplicity for setup and usage, plus it’s fairly limited capabilities were the advantages. However the Octoprint crowd hasn’t been sitting by either and with the last two or three updates, I’ve completely swung over to that side of the platform. So who would want to use Astroprint? Someone who wants the absolutely easiest setup and an interface that actively scales astoundingly well to any device you connect with. Cellphone, tablet, computer, all look and work exactly the same.

What you give up with Astroprint is control during a print job. Therein lies the major difference. Octoprint is like running Repetier Host but remotely.

For the reminder I’ll stick with Octoprint. Note, this isn’t meant to be a guide on getting Octoprint running, there’s plenty of info on the net for that.

Webcams

Octoprint allows you to connect almost any USB webcam to the Raspberry PI it runs on. Webcams vary, in quality, price, mounts, well, just about every aspect you can think of. Octoprint has a web page that shows webcam compatibility so if you’re not sure, check it.

The benefit of having a webcam is not that you can watch your print in progress, it’s that you can CHECK your print in progress. Normally when you log into Octoprint you can see a progress bar. This more or less tells you the printer is still running. Not what it’s actually doing.

Hence if something has went wrong during the print, you’ll be able to see it immediately. A side benefit to this that you can even do a time lapse photo session of the print. Not to watch your print in fast motion but more to say critique the progress and spot any weak areas. Least that’s what I do with it.

As it happens, Staples had a sale on the Logitech C270 web cams so I took advantage of it and picked up a couple. These are HD web cams, 1280 x 720 wide screen support. Small too…

C270 Webcam

To make them work, I plugged them into my Rasp PI’s running Octoprint. Done.

Webcam Gotcha

After plugging in the webcam, a few things become abundantly clear. The first is if you are thinking about mounting the camera to your printer, keep in mind any vibration from the printer is not going to help it.

Second, these are WEB CAMS. Think about how close to you those web cams will be and you’ll get the feel for the minimum focus distance. Some web cams have adjustable focus, the C270 does not. I found anything closer than 30cm was starting to get blurry.

Lastly, once you have found a place for the webcam at a decent focus distance, you still have to mount it. Seriously these things have lousy mount options.

So let’s assume you need the camera close to the build surface. You need to modify the camera for manual focus. Fortunately Thingiverse has some items you can print to assist you with this. Like a complete new camera front with manual focus.

For mounting, a quick search of Thingiverse will reveal all kinds of mounts. I chose this mount and modified it for my own setup.

IMG 2053

Yep, some PLA, 3M screws and nuts, chunk of 2×4. True maker style. Sits nicely between the two printers I have.

IMG 2055

Running my web browser and pulling up Octoprint, this is what I see from the webcam on Bullwinkle:

Bullwinkle WebCam

I did have to remove one bank of LED lights I had on the build platform because they washed out the camera too badly. But I still got to leave one connected. It helps.

One other advantage of keeping the camera further back from the build area is you can see the full height (200mm).

Slic3r Coolness

Slic3r options:

Send Gcode OLD

So normally what I do for slicing is, run Slic3r, open the STL, change any settings I want, slice the STL, save it to my drive, quit Slic3r, run the web browser, connect to the printer, locate the GCODE file, and either drop it on the browser window to upload it, OR use the “upload” button in the browser to send the GCODE file to the printer.

So imagine my surprise when I spotted a couple of screen shots from other Slic3r users…mmmmm and then the Octoprint posting news…

Send GOCDE

What manner of silicon snake oil do we have here…turns out it’s the healthy kind!

First off, get Octoprint running. Then run Slic3r on whatever desktop computer you normally use it with. Click on the “Printer” tab and you’ll see this:

Slic3r Octoprint

See the heading “Octoprint Upload”…click on the BROWSE button and Slic3r will look for your printer, pop up a dialog with what it found to allow you to select that printer (handy if you have more than one on the network).

Slic3r Find

If you click the TEST button, it’s not going to work. Nope. There’s a blank field under the IP address you need to fill in. To do that, point your browser to Octoprint and select “Settings”–>”API”. See that BIG LONG line of hex in the API key? Copy it.

Octoprint API

Switch back to Slic3r and PASTE that API key under the IP address. SAVE the printer configuration and that’s it.

From now on, when you slice, click the SEND to Octoprint button and the GCODE will be stored on the microSD card for you. It won’t clutter up your hard drive any more. If you have more than one printer, as I do, just select that printer profile in Slic3r and that’s where the GCODE will go.

Since I’ve started to slice this way I’ve found it super handy. Oh, if you open multiple STL’s in slicer and you’re wondering what the file will be saved as, it’s almost always the name of the first STL you opened so that’s what you look for on Octoprint.

7
Dec

Printer Vibration Iso – Part 2 et al

Before I get into the meat of the topic, I’ve noticed something rather interesting with the Arduino IDE and the Marlin firmware, at least on a delta printer.

During my tests with the firmware I’ve found the RepRap Smart Controller (an LCD2004) is very unresponsive when I was using the button on the controller. The whole printer “worked” fine, but, it was obvious that something had changed.

I initially thought that one of my “mods” in the firmware had affected it. However after going over my notes I couldn’t find anything that should affect the response of the rotary knob.

Purely by accident I was making yet another change to the firmware, when, much to my surprise, the rotary knob was back to fully responsiveness again. Say what?

I had inadvertently run the 1.6.5 version of the IDE and compiled and uploaded the firmware. Ah ha! I quickly ran the 1.16.13 version, re-flashed the firmware, ah yes, dodgy again.

Couple more tests and I found any Arduino IDE after version 1.6.8 caused the rotary to be flaky. I have no idea why, if it’s something in the IDE that has changed, if one of my libraries isn’t happy, or what, but it warranted a post-it note on the printer to remind me…

Printer Vibration – correction…

After my initial tests with my db meter a few days back, there’s been something gnawing at the back of my brain. Trying disparately to get out. Apparently. See, the 82db just didn’t ruddy sound, skip the pun, right. In my recording studio I’m well versed with sound check levels and something was wrong.

Tonight the penny dropped. I was metering the printer again with some new feet I made and I was sitting at 54db. What? How the? And then, as I said, the penny dropped. So for you audio geeks, here’s the scoop.

When I measured the original sound level previously, I was standing 1 meter in front of the printer. Cause sound measurement levels are supposed to be 1 metre away from the source. Tonight I was standing about 45 degrees off the front, but still one metre away. After scratching my head for a second or two…bingo. It hit me.

Or rather it didn’t “hit” me. What didn’t? The air stream from the fan. On my printers the fan blows directly towards the front of the printer. All db meters have very sensitive microphones and what I was measuring was the air pressure from the fan that blows 8CFM. If I put my hand in front to block the air flow, of course the sound level dropped.

But from the side, yeah, no air stream. Room was 50db without the printer doing any print job, and 54db with printing.

Live and learn. Again.

Feet Version 1

Here’s a recap of the original concept feet. I threaded the center of the vertical 2020 beam with a 5mm tap, screwed the mount to the corners, added the cute dollar store balls.

IMG 1987

Within a couple of days I found a couple reasons why this wasn’t a terribly bright idea. The first is, the damn balls roll. When I whack the stuck off the print bed, the whole printer wants to move because the print is stuck there. I also found the when printing with any speed, there’s a lot of movement going on. No, not so much it’s going to roll off, but enough that I didn’t get any warm fuzzies.

Lastly, there was the quality of the balls themselves. We’re talking dollar store stuff. I had visions of one of the balls splitting in half and the printer looking like the leaning tower of Pisa. Or worse, on my floor. In pieces.

This, of course, lead to a rethink.

Feet Version 2

It sort of started with, gee, I wonder what the balls are made of. Out came the box knife and I halved one. High density foam rubber. And not a lot of air holes in it either.

As I stared at the half, there was a spark of, ingenuity? Okay, so I didn’t want to throw out the pieces..I designed a holder for them.

IMG 2010

I used the same 5mm screw location from the last test set, added some double sided tape in the holder and mounted one on the corner.

Feet Mount

True it does stick out somewhat but the center is directly under the corner and the print is using a 50% infill.

Foot In Action

Now if the ball splits or whatever, the most the printer will lean is about 15 degrees. Plus with the design the printer doesn’t roll around or shift it’s weight on faster print jobs.

Just for the heck of it, I thought I would add three more cups for a total of six.

Iso V2

Safe to say that once you have the corners done, adding more doesn’t do much. Perhaps makes it a touch more stable but not by any margin that I could measure.

The other printer I have, I stayed with the corner design only.

Iso v1

Of course this printer has more weight pressing down on the corners than the one with six support points but really, I don’t see any difference in the amount of noise being transferred into the cabinet below.

All I hear now is stepper motor noise.

Isolation Enclosure

One of the disturbing things I see is 3D printer owners building all manner of cabinet enclosures to assist in printing the tricky ABS, or trying to keep the noise from the steppers at a level where they can get some sleep at night.

Why is this disturbing? Pretty simple. Electronic components are designed to work within a specific temperature range. The majority of commercial components are designed to work from -30 – +70C.

The ATMega2560 CPU is designed to work -55 to +85C. With a heated bed, in an enclosure, warmed up to 80C+, the not so earth shattering news is the component is not going to last as long as if it was in the free air.

On the printers that are designed to be enclosed, there’s no doubt a cooling fan for the electronics and a vent out of the enclosure. However, these are brand name printers, not the knock off junk one finds on fleaBay, BangGone, or AliExpleatedDeleted…

Secondly, the RAMPS board has some MOSFET’s on it and while those handle heat quite well (depending on the MOSFET on the board), adding some 90-110C heat to it, you know, just to keep it warm, isn’t going bode well over time either. Plus if you have under gauge wire for the bed, a bad connection to the terminal block on the RAMPS board, yeah, not going to bode well. At all.

Food for thought any way.

6
Dec

Raspberry PI Monitor Mount

I’ve been using a couple of Raspberry PI’s for Astroprint (Astrobox) and Octoprint (Octopi) for the last few months and both of them have been performing perfectly. Although, what I have noticed is that running two Octoprints on two Rasp Pi’s Wifi connections take a little longer to establish.

Whereas with Astroprint, easier to setup, easier and faster to connect to. Resizes well to fit smaller screens like iPads or mobile phones. The gotcha is you give up a fair bit of control (like speed, flow rate, etc). Thus, pros and cons.

But I digress so…I have a couple of Rasp Pi’s that I use for various purposes and they work well. Except for a few things. Like being small, compact, easy to access and so on. While the Rasp Pi is billed as a true $35 computer, in fact it’s probably closer to a $250 computer. Add a keyboard, mouse and monitor, power adapter (a good one), Wifi dongle if you use a Pi 2 and it doesn’t exactly look like so good of a deal.

If you have spare components laying around, of course it does get more cost effective, but it’s still going to cost as much as a budget laptop in the end. Something to keep in mind.

What I loathe is setting it up, plugging it in to a monitor, keyboard, rat, because I want to do something in the GUI (Pixel) not the command line. Then tear it down and put it away. Ugh,

I have an ancient Samsung monitor, VGA, and that’s not going to plug into any Rasp 2 or 3 easily. So off I go to find an VGA to HDMI adapter…Amazon has them so I order one and it shows up.

Adapter

The adapter works but I do wish there was side nuts on that VGA portion so I could screw in the VGA cable from the monitor. Good thing it holds fairly well…

Unfortunately now I have this unruly 6′ VGA cable, power adapter cable for the PI and so on… It’s still not neat…

The back of the monitor doesn’t have any place to mount a Rasp Pi, there is no room on the swivel base that allows easy access to the microSD slot, HDMI and USB ports…so…

IMG 2023

I found a VESA mount for the Raspberry on Thingiverse…and printed it out. Then I looked at the back of the monitor and thought, what about if I designed a hanger…

IMG 2022

The expression is quick and dirty. I used a protractor to measure the angle off the back of the monitor the PI would need to be mounted at to make it vertical. Designed a simple hanger, screwed in the PI, added some stand off feet…and then zap strapped the VGA cable to the monitor stand.

IMG 2026

No cables running on the desk, all behind at the back of the monitor. When I need access into the PI to remove the flash card or get to the ports, it’s exposed and easy. I can use bluetooth or 2.4Ghz dongles for keyboard/rat and less cables.

Before I had a 3D printer, there would have no doubt been some project box, double sided foam tape, and an appreciable amount of misery involved when it comes to stuff like this. This is one of the aspects that really draws me into 3D printing. Making needed stuff…

27
Nov

Printer Vibration Isolation

Honestly I have no idea how I get started on these projects somedays. I suspect it’s like a an idea or concept that’s been trapped in the dark cobwebbed corners of my mind and suddenly, they burst to the forefront. Or something like that.

As a guy with not just one printer, but two, Kossels, when both of them get going, the radio in the shop, which isn’t exactly top quality in its own realm, loses out to them.

It’s been a sort of quest to find a way to get them to be a little quieter. A few months back I had a Turnigy on loan and it actually made my Kossels sound quiet. But it’s gone now and I hear the drone of my own printers.

Today I’d had enough and it was time to do something.

In the past I’d try any number of things and in the process I’d learn a few things. The first thing is if you put a printer on top of a cabinet or table, whatever is under it will instantly be transposed into a speaker. Depending on the frequency where everything meshes, and trust me there will be some resonant frequency, it’ll be a mid-range drone, or a sub-woofer growl.

My printers sit on top of a 6ft x 30″ by 42″H cabinet as shown. The shelves aren’t empty and this is a good thing.

IMG 1985

I also tested a printer sitting on top of a wooden table, one that is 2″ solid oak top, 2 1/2″ square legs and solidly built. The drone coming from under the table area was wicked and the legs transmitted the vibration downstairs to the main floor through the floor/ceiling. Yep, easy to tell when the printer was finished its print job if you were downstairs.

I picked up some hardwood floor sliders, rubber on one side, fuzzy backing on the floor side.

Floor Things

They work fairly well, certainly better than setting the printer frame directly on top of a cabinet or table top.

Still I wondered if more couldn’t be done. I set about sleuthing and found all manner of things. From a MagLev setup, that apparently would wander on its own if you didn’t have all the legs absolutely level. Which made sense, sort of like mercury finding the lowest point.

To printed spring feet and even springs inside of holders. They were billed as vibration dampers but really, they just cut down the vibration from transmitting to whatever the printer was sitting on. If the printer shook to start with, it shook when all was said and done.

In a lot of ways, it reminded me of my recording studio. Where the monitors tend to reflect down into the shelf or cabinet they perch on top of. If it was concrete, no vibration at all. But that’s kind of heavy and unruly to deal with…

Just for a test, I lifted one of the printers while it was printing to see what isolating it might sound like. Wow. From the usual drone to little stepper motor noises.

I put it back down on my cabinet and grabbed my DB meter.

IMG 1986

The lowest reading I could get was 83db @ 1 metre. Moving the meter around I could get 85+db though.

I was thinking about mounting the printer on rubber pneumatic bladders like we used to have at work when I happened across a Thingiverse item. A very simple design, used dollar store balls about the size of a golf ball. I modified the mounts slightly and built my own.

IMG 1989

Those are somewhat soft squishy balls, worth all of $1.25. And wowzers, do they work.

All I hear now is the steppers. No more drone coming from the printer/cabinet/table. Because the balls are bouncy, I found the whole printer does move a little more, so I don’t know at this point if that’s a good or bad point.

It could be a good thing since it’s absorbing some of the energy of the printer as it tosses the hot end around. Most deltas tend to have vertical energy as opposed to the Cartesian’s X/Y axis energy.

Out with the DB meter again, doesn’t matter where I measured from at 1 metre, the highest I can get it is 81db. As far as sound goes, 2 or more db is a significant change. A 3db change is often perceived by the ear as twice the volume, because the ear is logarithmic not linear.

There is enough weight on the balls that there is no way it’ll “roll” off, perhaps even different kinds of balls would perform differently as well. No idea at this point. If these “high ticket” items start to sag, well, another $1.25 and all would be well again…

I also saw someone use tennis balls in the same concept. I also have those but the little toy balls seem to work just great so that’s what I am going to test with for the meantime.

So there you go. What to know what your printer would sound like if you did the same thing? Lift it up whilst it’s printing. If you like that, print the mounts and isolate it.

Trendy….

17
Nov

Delta 3D Printers – Mirth, Myths and Madness

3D printing is not new, it’s been around in some form or other since 1989 or so. What is new is the introduction of 3D printing for the hobbyist, we poor unsuspecting souls. This has been gaining momentum since 2011.

A quick search of the net will result in the fact that there are over 1,000 different 3D printers available today and a small percentage of those will be delta style printers. That small percentage is the basis for this blog entry. Dated, today. Stardate whatever…to go where no man has gone…oh wait, we have gone there.

Delta’s owe their heritage to Johann the person who provided the jumping off point, not to be taken literally, for the delta’s we have today. His first prototype was the Rostock, followed by the more refined Kossel.

While it seems like age ago now, a mere short 18 months ago what I knew about 3D printing could be written on your fingernail, in large type and the nail would still be plainly visible. I suffered from D.A.A.P at the time. What’s DAAP? Dumb As A Post. To put it into perspective.

When I started I understood there was some hardware and software to make the thing work. Software I assumed would be fairly easy because I’ve been writing software since 1979. That was a bit of a mistake looking back, but at least I had the background to figure things out.

The hardware, that looked amazingly easy, turned out to be not quite as straight forward as I assumed. Thus I decided I’d better have a good backup plan before I “built” any type of printer.

As it happened, David, one of the members of Fraser Valley Makerspace had cobbled together some extrusion, electronic bits and mechanical pieces, and made them available through the Makerspace as a Kossel kit. He had a working one, so…I decided it must work and bought one.

The Madness

There are seemingly two kids of people who want 3D printers.

The first are those who want to use it like a toaster. Take it home, plug it in, briefly read enough of whatever documentation there is to make toast and use it. Of course there’ll be some burnt bread, but there’s a better chance of it working at the on set, the learning curve will be mainly filaments and software.

My first piece of advice, if you’re this first type, buy a Cartesian printer. Brand name. Make friends with other people who have them, even better if they are local to you. Check out any local maker spaces, they make great resources. Something eventually will not make sense and/or break, you need a backup plan to keep the toaster toasting.

If you must build a kit, find someone who has built one that can help you build it. As a friend of mine put it, two heads are better than none.

The second types are the tinkerers. My ilk. Folks who love to build stuff, take it apart, tweak it, make it work better, change it, redesign it, use it and educate themselves to no end on it. Whatever it might be. There is as much joy in building as there is using for me and my ilk.

My logic at the time was that if I got stuck at some point in the build, I needed a parachute to help me over the rough areas and that would be where the Makerspace came in.

I had zero clue at the time I’d be dangling off that rip cord for more than a month with the ground rushing up at Mach 3.

I owe my sanity in my initial build to one of the FVM members, Rob. While he’d hadn’t built one of the kits himself, he did own a Ditto 3D printer and had single handedly got the mini-Kossel working at the space. Thus when I got stuck or didn’t get something, Rob to the rescue. A lot. He become, unbeknownst to him, Rob Rip Cord.

Even with a well equipped workbench, micrometers, scopes, power supplies but I have to say that I found I needed a metric tap and die set, metric drill bits, metric hex wrenches, metric hex screw drivers. I did a lot of shopping on fleaBay.

Plus my kit didn’t include any preformed wiring harness, no Dupont ends already in place, no power supply, or power supply wiring, thus for a fair chunk, I was on my own. However, having built circuits since I was 13, it didn’t really present much of a challenge in many respects.

There was a manual that I downloaded. It was supposed to be a guide on how to build the Kossel. Pretty evident from the start that the downloaded manual was for a different printer. Everything from the nuts and bolts to the extrusions were different. Sort of like building a Chevy with a Honda manual.

While I thought this lack of instructions must be unique, in hind sight I have now found scads of printers in kit form that clearly state, “If you don’t know how to assemble one of these, don’t buy this because we offer no manual or limited technical support”. Of course the price of the kit reflects this but still…not what a first time builder wants to start with. Me? I suffered DAAP, I was undaunted.

I finally reached the frustration point where I was either going to toss it out, or find the humour in it. Fortunately I found the humour.

IMG 0119

And while I’d like to think that I know what I am doing when it comes to building things, yeah, not so much for a 3D printer. Mostly due to the fact I didn’t know how the thing worked in the first place. DAAP.

I did everything backwards, wrong, or just dumbly. Heavy on the dumb. Hey I even lost some of the ball bearings out of the linear rails because I didn’t know they just slid off the rail…oh yeah. A comedy of errors abounded.

Yet, I still remember the first print…and no, it’s not supposed to be a lace doily cube. It’s what you get when you don’t have the foggiest notion of what you’re doing but you do it any way.

At this point, I wasn’t believing in miracles, I was relying on them.

IMG 0188

So I churned out a few of these stringy things, and they might have made good scouring pads for pots and pans, but something was amiss and I didn’t know what it was.

The Myths

And of course like every desperate individual I turned to the internet for help.

I was still suffering from DAAP I should add.

Using the net without knowing much is like using Dr. Google as your personal physician. There are thousands of DAAP sufferers like myself whose opinion and help is about as useful as a milk bucket under a bull.

Thus it was finally through the Makerspace gurus that I learned something new. A thing called “bed levelling”. My prints didn’t adhere to anything because, well, my basic point of reference didn’t exist. At least in this world.

My Kossel kit had an auto level probe, but for the Marlin firmware version I had, it seemed like every time I levelled, just before the print started the firmware tossed all the bed info it just collected and proceeded to print yet another scouring pad. Handy. Not. Auto level working? Not.

After learning many tweaked the firmware to adjust for the bed level I decided against that avenue. My logic was that if anything happened to the firmware I’d be doing it again, i.e. bugs in the levelling routines or whatever, well, yeah.

I decided to do bed level via mechanical style.

When I inquired how anyone levelled their beds manually, I was greeted with tales of woe, daring do, silicon snake oil and just plain dumb luck. I had copious amounts of dumb, just seemed to lack the luck.

The tragedy was that you loosened the top end stops with the micro switches on them and moved them up or down less than a cats whisker and hoped you got it right. For all three towers. With a flat blade screw driver. 1/8″ thick. Like that old saw, “Measure it with a micrometer, mark a line with chalk, cut it with an axe.”

I looked at the problem, pulled out a drill bit and did my first mod, on the 7th day. The ‘x’ marked the spot, put in an M3 x 6 bolt, the head triggered the end stop switch.

IMG 0199

What used to take days of fiddling manually to get right, took all of 30 minutes, 3 minutes to set the scripts in Pronterface. The only firmware tweak required was if the center of the bed was concave or convex. You had to change one of the rod lengths and re-level. Again, do it a couple of times and you can do it in your sleep.

For the X/Y dimension size, print a cube, measure it, calculate how much too big or too small it is, change a number in the firmware, level the bed if needed, reprint, check. Having built a number of Kossels for others, worst case from power on was out .21mm, best case build was out .06mm. You need that kind of accuracy to print a.. ah… Pokemon. Or something.

Eventually the FVM kit would be upgraded to include the screw carriage adjusters and better belt grips. Huge progress.

However the myth still exists today that delta printers are next to impossible to level, or will take days to do. So you must have auto level.

The real truth is, if you understand (or take the time to understand) how to do it, you’ll find you can manually level the bed, exactly, once. And unless you change the hot end, diagonal rods, effector or something that will change a dimension in the build area, you don’t level it again. Period.

I printed over 900 hours on my first Kossel before I changed the nozzle and did a re-level. In 15 minutes. Big whoop.

The fact is all 3D printers come with their own little bag of issues. Be it the slicer, firmware or how you communicate with the printer. Pros and cons. Plan on doing a lot of research and look for actual A/B print examples not opinions in a forum.

Lastly it helps, especially if you build a kit, to be an information sponge. Obtaining little bits of info from others with the SAME kind of printer as you and then TESTING that bit of info to see how it fairs on your printer will enable you to produce better prints.

Even after logging over 2,000 hrs on my first printer, I am still learning and testing what I can do to turn out better quality work.

The Mirth

You’d think that just having a printer that works would be joy enough. Truly it is very satisfying, but I’m going to step back a moment here and think out loud as to WHY my Kossel kit was more than I’d even hoped for.

LongJaw

For the two FVM kits I built for myself, my thanks goes to the FVM’er, David who, either by shear good luck or design managed to cherry pick most of the best parts for a Kossel build.

The one shallow item in the kit was the full graphic display (12864). As a software programmer I know how CPU intensive just updating these displays can be. I think I had mine on the Kossel for about 3 days before I tossed it in the dumpster (along side the auto level probe setup) and replaced it with a Smart LCD 2004 controller.

The rest of the kit, stellar. Just stellar.

The first is the linear rails. These are premium items that will give hundreds if not thousands of printing hours. Nowadays you see what I call the cheapskate bearings like the Rostock used for the carriages. They are big, burly, have mass, and will not wear well over the long term.

Second is the carriage pieces that I had a hand in modifying. The current ones hold the belts so much better and have the adjustment screws.

Third is the massive stepper motors in the kit. These are 1.68A steppers, probably overkill to the nth degree compared to the whimpy ones I see now, but they run great and cool.

The 2020 open beam extrusions do a good job of keeping the frame rigid, even when when printing up to the 210mm height on mine.

Then the stepper drivers. Out went the old A4988’s and in came the DRV8825’s. The 8825’s can deliver more current and/or finer stepping if you need it. Nice to have that additional overhead.

Heat bed. Many printers still don’t offer or come with a heated bed. My Kossels have a 220mm heated bed, large enough to print everything I’ve needed so far.

Top drawer extruder. Three redesigns later, the current one is the best design I’ve seen and I’d select it over any of the metal ones I’ve seen.

So…thanks FVM, David and Rob, from Rocky and Bullwinkle (and me of course)…

Twins Printing

9
Nov

Black is BAACCKKK…MG Chemicals

In my ever expanding quest to try out new filaments, I’ve always found that if you want to see how any filament performs, at the worst, just try out a roll of anything they make. In black. Seriously.

I’ve read that black filament is the toughest to print because of the dyes go into the production. Or magic. Yeah, one of those for sure.

Regardless of which of my delta printers I use, black has always been a bit of a duck shoot when it comes to getting good quality. Any other colour, no issues. Thus, must be magic. Yep.

As I sat staring at the two brand new unopened black spools of filament on my workbench I was undecided which I should try first.

The first was PLA, the new “improved” brand from MG Chemicals.

IMG 1911

The second, PETG. Truthfully PETG is my compromise to avoid printing with ABS (which gives me royal headaches) but it is so darn stringy and unpredictable that I haven’t printed with it much. Some would call that being a smart coward.

IMG 1912

Of course, I used common sense and did one at a time. And pigs can fly. Forget the common sense thing… I loaded up one of my deltas with PLA and the other with PETG. On the PLA I had to print out some tank treads for a robot I’m building so, 15 treads at a time. In black.

The treads are from Thingiverse Caterpillar Tracks. Although labeled as a work in progress, I’m doing it any way. Although I’d really like to build a fairly large Wall-E…maybe in time.

IMG 1903

My settings, 0.3 layer height, 50C bed covered in Elmers glue stick, 208C for the first layer, 200C after that. I’ve made 60 treads so far and they have come out absolutely perfect. No strings, no separation, just way better than I expected.

On the other printer, I decided to make something to hold my SD cards and flash drives. With PETG no less. Again, merely a design I found on Thingiverse called Moby_Stick

IMG 1910

My settings, 0.3 layer height, 50C bed covered in Elmers glue stick, 224C for the first layer, 222C after that. Used Slic3r’s built in support for the whale tail. Not the default supports but “rectilinear grid”, which I have found out is far better than the default support patterns.

On the whale the supports literally fell off when I chipped it off the heated bed. You got that right, I had to use a metal spatula to get it off the bed.

I’ve never had any issues with adhesion with Elmers and a 50C heated bed. I’ve read many a horror story from others about getting PLA or PETG to stick to the bed, heated or otherwise. With every solution from 70-100C heated bed to hair spray on painters tape, to Kapton tape. Me? Borosilicate glass, heated bed, 50C, Elmer’s stick.

Perhaps with a delta because the bed doesn’t move the glue stick approach works fine. But I’ve done the same with the standard Cartesian printer I had here and it stuck just as well. Thus the problem must lie elsewhere.

After the prints, I measured the diameter of the filaments. In hindsight it should have been done first but, well, in my excitement I kind of missed doing it. None the less, both the PLA and PETG measured out 1.75 on my micrometer.

Last year I used a number of different MG Chemical PLA filaments, which I will call “old stock” now. While colours like their gold or white were superb, some of the others, not so much. But this year, things are not the same old.

MG Chemicals has changed their products on Amazon. The new stock has cardboard sides and is labeled “Improved”. They aren’t kidding. I’ve noticed a few complaints about the size of the center hub not fitting some spool holders. Since I use spool rollers, spool center is a non-issue.

No idea what kitchen they are using to create this new improved brand of filaments they are selling, but so far in my tests, I’ve found that I don’t need my go to brands any more. I can grab a roll of MG, thread it up, and I know exactly what it is going to come out like.

When I add in the fact that MG is less expensive than what I usually buy, well, that’s just icing on my cake, sprinkles on my donut, gravy on my fries, well, you get the idea….:-)

21
Oct

Thermochromic PLA – MG Chemicals

Thermochromic filament is filament that changes its colour according to ambient temperature. I’ve mostly seen ABS filaments that change colour with even the slightest heat from your hand.

Thus it was with much anticipation at the outcome when I found myself with a spool of Mg Chemicals latest offering of Thermochromic RED PLA. Yep, PLA.

Staying in line with the rest of MG’s new products offering, it’s delivered in a zip lock bag, cardboard sides, and large spool center hub. All pluses in my book.

IMG 1839

I don’t know about the rest of the printing world, but it seems to me that RED filament must be next to impossible to make. Without fail, every red I have seen looks more orange to me than red. In my case, if it’s not fire engine red, it’s not red. So I of course, immediately looked at what MG ascertained was red.

IMG 1840

If you’re mumbling to yourself, that’s NOT red, well, you’d still be correct. Still, let’s look at the spool without a flash from the camera adding or subtracting anything from the colour. And for giggles, I’ll put a spool of eSun RED beside it.

This is MG Thermochromic on the LEFT and eSUN red on the right. MG’s is more in the purple hue range, and eSun is more to the orange. Still, if I have to pick something that at first glance is going to pass for red, it’s going to be the MG. No contest to my mind.

IMG 1843

Printing with the Thermochromic is no different than printing with any other PLA. I used the same temps, same retraction, same speeds. Wasn’t stringy or blobby in any way. Actually the more I use the new MG products, the more I like them. For the simple reason they are extremely consistent across the colour spectrum. I love not having surprises when I print…

One thing that catches you a little off guard though is when you look at the spool during the print job. It’s redish purple. And then you look at the print under the hot end. There’s a slight pink hue to it and other than that, it looks white.

IMG 1847

The beauty of thermochromic filament is of course that it changes colour. According to ambient temperature around it. One would assume that MG would have indicated the temperature range that will affect the colour. Which of course, at the time of this writing is the wrong assumption. There was nothing on the box, nothing on the filament label, no information that I could find that specified the temperature range. An oversight? Lack of data from the manufacturer? I honestly don’t know but it is something that should be addressed.

According to my own less than scientific tests, there’s about a 20F working range. Below is the finished print (Fossil Fish from Thingiverse) and the temp of the top of the print is 123F (50.5C the temp of my heated bed). You can see the tip of the tail fin has started to cool.

IMG 1849

Get down to 115F (46C) and you start to see more areas, again thinner areas cool faster…

IMG 1851

At 108F, 42C, things are starting to really change. Again, the thicker areas retain the heat better so you have to wait longer for them to cool.

IMG 1853

Finally at our human body temp, it’s completely gone through the colour change. This means that you can’t just pick up the print and have your hand affect the colour. If you’re looking for that temperature, MG’s thermochromic isn’t going to cut it for you.

Further, if you scan around the net looking for thermochromic filament specs to find the temperature range for the colour change, you’ll find what I did. Zip. I couldn’t find one company that actually spouted the specs for a PLA temp range for the colour change. All I could find was recommended melting temp. I found this odd, but seems to be the way it is. For whatever reason (plus I’m thinking the guys who dye the stuff have either never heard of Pantone or are colour blind).

Remember I said that this is more purple red? Heres the print from MG Red on the left, eSun red on the right. Natural lighting.

IMG 1855

If you’re like me you’d say the eSun is more red. But lets take the same fish and put them in front of a red toolbox lid.

IMG 1856

Isn’t perception a pain in the butt…so the key to the red/orange/purple thing is lighting, background, and frame of mind. There’s still no hands down colour winner but at least you know what to expect.

To summarize, I really like the new MG PLA. Thus, yet another winner for myself and MG.

The thermochromic is super useful where the temperature range will be hotter than the human body.

Where would that be? A few seconds to search Thingiverse for water tap nozzle should give you a few hints. Imagine you have kids and a PLA printed nozzle, if the nozzle is white the temperature is 115F to 120F+. Don’t touch it! Or jump in the shower unless you want to perform an equally quick jump back out.

Or make an ornament that hangs on the mirror in your car. When you come back to the car in the summer time, a quick glance will tell you if you want to open the door and jump in, or just take a step back as you open the door. Course if the ornament is on the floor mat, best to have someone else open the door, just to be on the safe side.

Something that sits on the mantle over the fireplace…in short, lots of places to use this higher range PLA. Just keep in mind the glass transition point…(60-65C).

Update: MG Chemicals informed me that the Red colour changes to natural at 43 °C / 109 °F. This is a little different than my somewhat unscientific approach with the IR temp gun readings. They stepped up to the plate with the info. Nice.

25
Sep

Sore Throat…On The E3D HotEnd

How’s that old saying goes, when it rains, it pours. Seems like just yesterday I was replacing a RAMPs board that went south. Oh, wait, it was yesterday…

Today, something else. As if. Like magic. As in print quality…more specifically, extrusion.

Last three days, I’ve been also having some prints that were under extruding. Of course after you crank up the tension on the extruder to the point that if it does burst under pressure the resulting shrapnel is going to be hard to dig out of the walls. And me.. So then you crank the heat to the point that the furnace in the home is no longer required. After which you blow torch out the hot end nozzle to get the printer working in case there was something causing an issue with the filament.

Murphy’s Law has already decided that you’ve missed the problem completely. Mainly because the part that is not working correctly is in the least accessible place. Inside the hot end. Of course.

Two things to keep in mind here, my printer has just under 2,000 hours on it (certain parts of it are original) and these prints I use for quick tests I print at a fairly fast speed. So I’m trading quality for speed.

This is what the prints had been looking like…bad one on the left, after the repair, good one on the right.

IMG 1753

Pretty easy to spot the one on the left that looks like there is an extrusion problem. And it’s true, there is. Just not where I was looking. As usual.

A closer look reveals how bad the ugly one was…now at a fast speed the infill doesn’t always drool up tight to the perimeters. I know that, so I don’t pay much attention to it. But for the large plain infill areas there shouldn’t be all those gaps. Houston, we have a problem.

IMG 1754

For the last year I’ve avoided taking the hot end apart other than to clean out a nozzle. I don’t know why. Probably because I didn’t want to re-level the printer to the bed. Which in reality takes me all of 10 minutes at the outside because I’ve done it so many times (not a fan of auto levelling delta printers).

Any way, when you rip apart the hot end, inside the cooling tower you find one of these:

Tube

The filament enters the metal tube and goes into a PTFE tube so it doesn’t melt in the cooling tower when you’re printing. Consider this a good thing.

I pulled the throat tube out of my E3D head and compared it to a replacement I have. You won’t have much trouble guessing which is the 2,000 hour tube (it’s the one on the left if you’re stuck)…

IMG 1757

Using a 1.5mm rod, I tried to push it through the tube and well lookie that, it was binding like crazy. Apparently the tubes do wear out but out of sight, out of mind.

On my replacement tube, the PTFE tube is a lot longer. Not sure if that’s a good or bad or indifferent thing.

Installed the new tube, adjusted the firmware for the new Z height, re-levelled the bed (10 minutes)… and printed the same Jack.

IMG 1755

The outline is closer, but not perfect cause the head is just flying around this small design (it’s a book marker), but the large infill is huge improvement.

Delta printers, because of their simple openness design, are at least easy to fix once you figure where the problem is. So add this little throat thing to your list of parts you’re going to need in the future.

24
Sep

Smokin’ RAMPS

My main Kossel printer has slightly less than 2,000 hours on it but the RAMPS 1.4 board on it gave off a very familiar odor the other day so I shut it down until I could get to it.

Later, I fired it up and it seemed okay. For about eight minutes. Then the room got sort of filled with smoke, accompanied by that familiar burnt electronics smell. No fire, but it did jam home a point that if I was 3D printing, I don’t want to leave the thing unattended.

Ripping the printer apart revealed the culprit. The heated bed MOSFET.

IMG 1748

Apparently it overheated, was laying against the terminal block and started to melt its way through, which then shorted out the terminals and…as they say, the smoke leaked out. End of life for short.

According to the specs for this particular MOSFET, it’s “supposed” to dissipate 110 watts at 25C. There is a heated bed about 2″ above it that is heated to 50C, which, probably isn’t helping it any either.

I thought I had a spare around here someplace, because, the simple fact is if you’re going to own a 3D printer, your best bet is to build one so you can also fix the thing when it will inevitably break. It’s not a question of will it break, but when will it break.

No way I could find a RAMPS board but David (FVMaker designer for this Kossel kit) had some spare boards. Life saver!

I replaced the RAMPS board and presto, up and flying. And of course, that’s more or less the same time I found the replacement RAMP board I’d ordered who knows when off eBay.

IMG 1751

This eBay special I found came with all the jumpers on and I thought I might as well set it up properly and once I’d done that I thought I’d also test it to make sure it was going to work.

Surprise. Surprise. It kind of worked but when I told the head to move, it only went half way. Ah ha. Stepper jumpers were not right. After rechecking about eleven_leventy times, they were set right. But I was still only getting half movements.

I started searching the net for schematics for RAMPS 1.1, 1.2, 1.3, 1.4 hoping to find what the heck was going on. No soap. I had a 1.4 board, no two ways about it.

Next step was pulling all the jumpers and testing with a digital multimeter. Imagine my surprise when I found it didn’t matter if the jumpers were on or off, there was continuity between the jumper pins regardless. Which, is, of course, wrong.

Pulled the plastic off the jumpers so I could see the circuit traces and wow. There is definitely some village that’s missing their idiot. See all the arrows? You can see the foil traces on the PCB.

RAMPS 14

Every set of jumpers for the steppers was done the same way. But why?

What I think was, no, not that it was a design error, but, for the A4988 stepper drivers, all jumpers had to be shorted to get to 1/16 steps. The PCB was designed with all shorted jumpers to save on the cost of adding those little jumpers, actually they didn’t even need to add in the pins.

However when the DRV8825’s came along, the jumper positions changed. But these boards were probably so plentiful they were sold as “proper” RAMPS 1.4 boards with all the jumpers.

Quick work with prying off the plastic holding the pins and a couple of minutes with an sharp blade and the board worked just like the other.

While I was comparing the two boards I had a look at the MOSFETs. The main original board used P55NF06 and the “repaired” board used IRF3205. According to the data sheets, the IRF3205 is the more capable MOSFET.

Under closer look at the data sheets you walk away with the idea that neither one of these is exactly what you’d call a performer. When the Vgs is less than 5V, there are better choices. Personally I’d suggest the IRLB3034pbf which would work well within the limits the 12V main supply to the RAMPs and voltages less than 5V for control.

To keep the MOSFET slightly cooler I added a small heatsink to my RAMPS. It’s not pretty by any stretch but it does help.

IMG 1752

Yes I know it’s mounted incorrectly (it’s not touching any other MOSFET even if it looks like it is in the photo), they didn’t design the PCB to have a heatsink so this worked out to be the best way. Unless you want to remove the heatsink and mount it somewhere off the board. Another option if you want to go that far.

The more closely I look at the RAMPS board I can see too many cost cutting short cuts on it. Thus, a good idea to have a spare….or two

10
Sep

Put a sock on it!

E3D would like you to put a sock on your hot end: E3D Sock No, really. I’m not kidding.

Silicone Sock Fillets

Seems there was this REDDIT thread where someone did this a while back and it’s been the single most requested item since that point. People have be clamouring for it. Not sure exactly what people but by reading the rest of the announcement you’d have a better understanding.

The socks come in bundles of three. Silicone, even high temp, custom poured, massaged by virgin ants, will eventually succumb to the high temp of the hot end (call it the Priestess end) and be sacrificed. Poof. Yep, you need more than one.

E3D is even including these socks with every new hot end they sell. You know, so you can keep your filament in your…I mean in check…safe PLA’ing and all that.

And really what 3D printer enthusiast doesn’t want a clean nozzle? Take a look at the photo of what your hot end looks like before and after being protected with a sock on it:

V6 with and without silicone

That’s right kids, if your hot end looks like the one on the left, you might want to have it checked. By a professional.

And SHARPER prints! The laws of heat transfer tell us that if your hot end is moving so slow above the printed object that it’s melting and distorting the layers as it goes, you’ve got more than a hot end problem. You got a SPEED problem. Big time and this little blue bandaid isn’t going to lower much of anything. Except your bank balance.

E3D even clearly shows how you install your sock to prevent dribble and just the tip of your hot end is visible.

Sock placement

Now perhaps Cartesian printers suffer from this hot end malady, but on my delta, with 1887 hrs on it, I barely have the beginnings of the disease… Whew, lucky huh?

IMG 1713

I do use tweezers when my hot end is getting up to temp and if there is any filament drool I whisk it away. Possibly that’s the reason mine doesn’t look like the one at E3D. Or maybe E3D was just going overboard for the shock factor.

Fascinating to see a market sort of created where there never was a market before. You know, because. Of. REDDIT. Where all the “experts” hang out (“ex” – the unknown quantity, “pert” – a drip under pressure). Like going to “Dr. Google” for medical advice.

Maybe I’m just old fashioned or not in the know, but apart from my tongue planted firmly in my cheek as I was penning this, I have no idea why a silicone sock for a hot end even exists. Maybe it’s the solution for those without some common sense. Like E3D. Who. Thinks. This. Has. A. Market.

[Addendum] It was pointed out that if you have fans blowing around the hot end, the sock can act as an insulator to maintain better control over the temperature of your nozzle. As opposed to wrapping your nozzle in insulation and Kapton tape (which is not nearly as inviting to lusty filaments). So perhaps in this case, a sock does make some modicum of sense. And I’ll leave it at that.

9
Sep

A PLA-sible day

3D printing tends to attempt to shorten the supply of printer filament on any given day. The keyword there is “attempts” for the simple reason there is so much filament available I seriously doubt we’re going to even make a dent in the current supply.

Having said that, it’s also worth noting that more and more manufacturers are appearing with offerings and promises of filaments that will take your prints to the next level. Having worked in the manufacturing industry for a long time, I have no doubt that a lot of the filament is simply a slight rebrand or remix of some existing filament.

So eSun, Hatchbox, AMZ3D, MG Chemicals, to name but a few, kind of boggles the mind as to which one to use. One would even think that PLA filaments are all basically the same. This would be incorrect, but a common assumption.

When I started with PLA, the two brands available were eSun and MG Chemicals PLA 1.75mm. Although both were PLA, they printed quite different in every aspect from flow to temperature. Depending on what I was printing more or less determined what PLA I used.

PLA Overview

While eSun hasn’t changed, MG Chemicals PLA certainly has. I’ve tested almost 3Kg of MG’s PLA thus far and it’s a marked improvement.

What used to come in a nondescript brown box, looking like something you buy in a back alley (hey, kid, over here, wanna buy some filament)…now comes in a colourful box that at least lets you know what it is.

IMG 1705

When you open up the box you’re greeted with a bunch of things I’ve never seen before…

First, the PLA is packed in a zip lock bag. You read that right. A zipped locked bag. You cut it open above the zip lock and you can pop the filament back inside and reseal it.

The second is the HUGE center spool hub.

The third is the sides of the spool are NOT plastic, it’s heavy cardboard.

IMG 1707

So let’s examine those items one at a time. First, the zip lock bag. The bag is vacuum sealed when you get it with the usual desiccate inside. What is not clear, nor could I find any mention on the box or a loose page inside the box, is, if you put the PLA back into the bag with the desiccate and zip lock it, does it remove any moisture or not?

Depending on that answer, if no, why the zip lock bag? If yes, MG should mention that because it’s a good thing!

So on to the hub. And my main gripe for a lot of PLA. PLA that is wound on a small hub is a pain when you got down to the last 1/3rd of the spool if you were using a bearing straddle spool roller. There is so much tension in the windings that the extruder would drag the filament off the roller. And on the floor, or wrap around the USB cable, or flopping about like a fish out of water.

Therefore the new larger hub is a WONDERFUL upgrade!

Last up we have the cardboard sides. Below on the right is a typical 1Kg spool of PLA (AMZ3D) and on the left is MG’s cardboard sided version, again a 1Kg spool. MG’s is obviously wider by a significant amount, but it is also significantly smaller in diameter. So it kind of depends if your spool has to fit in a specific area.

IMG 1710

Where I use my filament is in a spool roller off to the side of my delta printer. It’s obvious from the vacuum sealing process that the cardboard sides tend to suck in somewhat so I wondered what that might affect.

IMG 1721

As it turned out, it affects nothing. There is a slight tic you do hear once in a while where the cardboard is really pressed into the filament on the edges, but it’s not enough tension to drag the spool off the roller. So, 3Kg later, nothing to be concerned about.

Size wise, I used a micrometer and measured the filament diameter through out the prints, I found the filament was slightly oval, so a cross section would be 1.76 x 1.74 at worse case. I suffered no under extruding so it evens itself out.

First Print

The first roll of MG PLA I printed was green Glow In The Dark. When I opened the box I was shocked because it was already green. Wow, already glowing in the … ah…daylight? What? Apparently unlike any other glow stuff I’ve printed, MG decided to tint their PLA green to start with.

IMG 1708

Initially I though this was kind of dumb…and then, maybe not so dumb after all.

Most GITD (glow in the dark) filaments print some dismal shade of white/gray so in normal lighting they look about as exciting as a gravel pit. It’s only when the light dies that they start to glow.

MG’s on the other hand looks green to start with and in the absence of light, glows in the same green hue. Which means they look the same in light, or not. I’ve come to the conclusion this is a good thing.

That’s not the only difference either. The majority of GITD filaments I have used have a VERY textured surface on the RAW PLA. MG’s GITD RAW PLA is smooth as silk.

When both print, then the prints will exhibit the texture. Which I suspect is the globs of luminous stuff that makes it glow.

Of course, the big question, is, always, how long does it glow? Yeah, well, I found that MG’s glow permanence was no different than any of the others (eSun for example; but the eSun green not the blue). Matter of fact unless the room was pitch black, it was kind of hard to tell that MG’s had tapered off because of the green tint. The eye’s do funny things like that…

Two Pounds Later

Using a new filament is always a bit of a duck shoot when it comes to finding what temperature it likes to run at. Notice I said what it likes, not what we want. Big difference there.

MG’s old PLA liked heat. Although rated for 190 to 220C, I always got better results when I shoved that up to the mid-220’s. With the new filament, they changed the range from 190 to 230C. And really, about low 220’s is where the stuff really worked well for me (in a delta).

Raise the temp up high enough, you get “strings” as the print head moves around the job. Drop the temp by a few degrees and presto, strings disappear almost completely. I found the first layer was about 3 degrees hotter than the rest of the print.

The only drawback to heat, is that when you’re doing small areas and laying hot filament on top of hot filament and you don’t have any cooling on your printer, you’re like a piece of installed sheetrock/drywall. Screwed.

Keep in mind that this isn’t unique to MG, regardless of what filament you use, at whatever temp it wants, the saggy results will be exactly the same. In short, you need cooling if you’re going small and fast. Some try to go really really slow but at best it’s a loose bandaid to the problem.

MG PLA Summary

How many times have you read the “newer”, “better”, “faster” ads and walked away wondering what drug that ad agency was using?

With MG’s new offering, I have seen an upgrade that is a better all round product. One of the best is that if you used any of the old MG product the change to the new product is almost seamless. I’ve enjoyed how the first of the spool prints, to the last of the spool prints, it’s easily controllable, extremely predictable and overall I give it two nozzles up.

I’m looking forward to trying more of MG’s new PLA in different colours in the coming months. As I see it, a win for MG and a big win for me.

30
Jul

The Cycle of 3D Life – Thermistors

3D printing, undeniably, has to be one of the most fascinating, frustrating, researched, and misunderstood hobbies of all time. Not that I’ve actually had every hobby known to man to compare this to, but in the ones I have had, 3D printing runs at the top for the aforementioned.

Inevitably it starts with either a 3D printer kit, or a plug and pray…er I mean play printer. At some point, something breaks. Somehow. Quite mysterious in some respects. I’d blame the cat. Except we don’t own a cat.

Generally if you built the printer, fixing it is slightly more straight forward because you usually have a good source for parts and you know, more or less, how it goes together. On the other hand, if you have a ready to go printer, it can be somewhat tasking to find a shop that can or will fix it. Makerspaces are usually good sources for help or information in either event.

The two delta printers at the Wanch here, Rocky & Bullwinkle, have seen their fair share of repairs, mods, tweaks, adjustments and some mayhem that I throw in for good measure. Bullwinkle is the original printer, now 14 months old with 1800+ hours of printing time on it. Rocky is only 5 months and 170 hours.

Within the last couple of months, both printers have broken in the same way. Specifically the hot end thermistor. I suspect some collusion between the two of them for this to have happened but I can’t prove it. I’ll stick with, darn cat. You know, the one I don’t have.

You can find these little thermistors littered all over eBay and are very inexpensive. These are glass bead 100K styled and used to be stuffed inside a piece of brass tubing. There is a set screw on the hot end that tightened on the brass tubing to hold it in place. If you over tightened it, which took a fair bit of force, the glass bead shattered. Bad mojo.

A bigger issue was that companies would crimp the tubing on the end to stop the thermistor from sliding out. They got a little too carried away sometimes and the crimp would cut into the extremely fragile wires from the thermistor and cause a wire to break at that point. That’s what happened to both of mine.

Hot End Type1

At any rate, I suppose a lot of thermistors were getting broken because most of the replacements now are merely the glass bead and you reuse the tubing the thermistor came mounted in. I uncrimped the tubes so there’s some wiggle room.

None the less, now you’ll find a lot of thermistors that look like this:

Hot End Type 2

Or this:

Hot End Type 3

Much more friendly to mount and replace.

Ultimately on a delta because of the motion of the head, there is always some flex in the wiring and, yep, at some point, breakage.

Once I’d replaced the two thermistors, the first thing I noticed was that the heat cycles are different. Both printers seemed to struggle to maintain a nice even temperature. As in hoping all other the place, like +- 9c. That’s a big swing for the printers.

I have a window in the shop as well and if it was open, well, yeah, made things a lot worse.

Just for the heck of it I started looking for solutions and what do you know. Turns out all these thermistors that might look the same are hardly the same. Thus if you replace one, you’re supposed to tune for it. Who knew? I didn’t.

Low and behold, there is already a tuning routine built in the Marlin firmware (I’m using 1.02). Start with a COLD hot end, connect to your printer and send the following GCODE:

M303 E0 S200 C8

Your printer will start a self test cycle to determine the thermistor settings, S200 is the temperature it will use for the cycle. If you normally run your printer hotter or colder, use that for the temp setting.

Here’s a transcript of what the firmware does. Takes about 3 or 4 minutes to complete.

PID Rocky

At the end you get Kp, Ki, and Kd (not to be confused with Kraft Dinner) and you put those values into your Marlin firmware:

PID Configuration

After doing this with both printers, the temp control is FAR superior to what it was.

As an aside, I do notice that one one printer, the hot end temp will always overshoot by 5 or 6c during the initial heating but it settles back down to the correct temp nicely and stays there. Doing a little testing I find out that the heater itself is the culprit. Yeah, they aren’t all made the same either. Who would have guessed…:-)