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Archive for September, 2016

28
Sep

Wi Fi Fo FM

I’ve had a cheesy FM radio over the work bench in the shop for a considerable time now. A simple FM radio that can play a memory stick, runs off 5V, maybe 3 watts of audio power. Big maybe actually…

To use it you can smack a bunch of tactile buttons or an IR remote. When I can find it.

Wandering through eBay a while back I came across an FM radio, that looked a little better than my previous “cheese special” but what caught my eye was the “serial control” option for the radio. There is no card reader or USB port so it can’t play from a memory stick. But I rarely did that any way.

The radio itself isn’t much bigger than a standard sized business card. The usual jacks give you power in, speaker outs, a serial connection port and something labeled GRSV which I have no idea as to its purpose.

IMG 1759

There’s a blue LED backlight in the LCD display and the display is quite difficult to read at any angle other than straight on.

The eBay listing gave the basic serial port config (9600, 8, N, 1) and you send commands like AT+FREQ=1035 with no line endings to direct select a frequency. Which to my shock and surprise works quickly and seamlessly. There’s even a squelch setting in the radio so you can “omit” weak stations if you’re doing a seek up or down.

In reference to “seek”, the radio does not scan through the band and store the stations for you. That wasn’t why I wanted it any way. I normally just flip around between a few stations until I find something tolerable to listen to.

The FM radio works best when you power it from 3.3V, but it will take up to 5V. I found at 5V it got a little noisy at times, whereas at 3.3 it was better behaved.

I’ve found no way to have the backlight on all the time, in spite of others who outline a procedure to make it do so. But I don’t look at it much any way.

I had an old set of Apple speakers from an aged iMac. Put some Dupont connectors on the cables, shoved them into the FM board and they work really well.

IMG 1763

There’s no fancy EQ, if you can call what passes for EQ in these budget things an EQ any way. Sounds nice, that’s all I care.

The MOST annoying thing about the radio is fact that the knobs work backwards. Turning them clockwise decreases the volume or the frequency. I think who ever drew the PCB was either mounting the rotary decoders from the rear or with a jumper cable. So I modified mine to work like it is supposed to.

IMG 1760

Took all of 5 minutes. Works perfectly this way too.

For serial control, you can test things out with a USB to Serial adapter (keep the voltage at 3.3V) but I wanted Wifi control so I don’t have to go looking for a silly remote, I can turn off the radio from the network.

The simplest WiFi control I’ve used, over and over, is the ESP8266’s. Either as stations or access points. Great little work horses. And cheap as borscht… I used a Lolin version 3, with the cruddy CH340G on it for usb to serial and programmed it with the Arduino IDE.

IMG 1762

I didn’t use the RX/TX since that’s the USB serial connection. To keep the separate i used the Serial.swap() command. This moves the 8266 TX/RX to pins D8/D7 respectively. Ran those to the FM radio’s serial TX/RX and it works like a charm for control. In the sketch for the 8266, I hard coded in the FM stations I wanted.

Type in “radio.local” in any browser on the network and the radio shows up (it has MDNS or Zeroconfig as some call it). Pick what you want, away you go.

Radio FM Web UI

The buttons labeled Radio ON/OFF are not actually power ones. They are the MUTE controls for the radio.

The volume goes from 0 to a maximum of 15, and with a 3D printer running in the room, about 7 is good enough. With the printer off, 2 or 3 is ample for background music. According to what I read if you run the volume fairly loud, the two IC’s on the back for the amp tend to run hot so a heat sink for them is advised. At a setting of 7, they don’t even get warm.

Last, there is a place to solder in a wire for an antenna, and true for some stations just adding a few cm’s of wire helps reception. However for the most part the radio is quite sensitive any way.

One of the things I would have liked would be for the radio to have RDS (that’s where they broadcast the station name, and the song title; buried in the music broadcast itself). The radio IC in use has it, but the PIC chip that is controlling it obviously doesn’t support RDS. Which may not be a bad thing anyway since I’d have to put a full display on the radio so I could read it. Once in a great while…

A cool little one afternoon project that I’ll have to print a box for after I’ve tested it out for a while…

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.