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Archive for February, 2016

24
Feb

Wood Filament – Houston We Have A Winner!

I acquired a reel of 1.75mm filament a little while back. Not just any filament, MG Chemicals WOOD filament (Cat No WOOD17W5). It sounded like it might be a cool thing to try out.

After doing some research on printing with wood filament I was more than just a little leery of even threading it up in the Kossel. According to what I could find on the net, you wanted to use a larger than normal nozzle (bigger than .5) and nozzle plug ups were pretty rampant with wood.

Of course no one mentioned what “brand” of wood filament caused them all the grief and exactly why it plugged up the nozzle. That’s the part of the internet where information you really need just isn’t available. I chatted with a couple of guys on the net and got the horror stories. I also talked to some who managed to use it successfully, you know, once or twice before all the wheels fell off the bus.

One of the advantages of building your own 3D printer is you tend to learn the thing inside and out. Whether you want to or not. If you then factor in that your printer is a delta style, a Kossel in my case, you’ll either learn it, or you’ll end up using it as an end table next to the couch.

Thus, as is my usual course of action, it was damn the torpedoes, full speed ahead. I loaded the wood filament into the hot end, used the same .4 nozzle I use for everything else.

Didn’t bother with a test print, picked a print from Thingiverse that I’d be giving to my son as a birthday present (Clash of Clans shield keyring holder). The idea of printing it from wood was that I would be able to paint it.

Clash of Clans Key Ring Shield

For temps or speed, I didn’t change a darn thing from the settings I use for printing PLA. Using 216C for the first layer, 212C for the rest and the same speed I always use, away I went.

There’s a heated bed on the Kossel, I run it up to 50C, use some Elmer’s glue stick. Works fine. Never had a print lift.

IMG 1006

So at 212C the wood filament flows extremely nicely. Almost looks a little fuzzy when the nozzle is laying it down. But man, does it go on smooth. I’ve never seen a honeycomb fill look so pretty.

A side effect of printing with wood is that it smells exactly like you’re using one of those old wood burning irons from 4o years ago. I have no idea what kind of wood it is, so it could be recycled IKEA furniture for all I know (IKEA – Swedish for compressed sawdust)…

Finally we get to the part of the shield where the arrows start. Two things got obvious in a big hurry. First, I was printing too fast, with too much heat. Using the “Tune” menu on the Kossel I slowed it down to 56% of it’s normal speed and I dropped the heat down to 206. It helped a lot but I could have gone further I think.

IMG 1007

When the print was done, I could see where the filament had oozed out as the head jumped from arrow shaft to arrow shaft. When it got to the shaft the little tail of filament would sort of get peeled off.

IMG 1009

I was pleasantly surprised though because a lot of the tails just rubbed off. The picture above is the ones that didn’t just rub off. I used some 220 grit sand paper and took off the rest of it in a matter of minutes. The wood filament sands LOVELY! Sure beats trying to sand PLA and having it go to goo in the process…

Apparently if you want to finish the wood, you can just apply stain when it comes off the printer. And the temp you print at gives you a lighter or darker finish. Probably because it “burns” the wood. According to the box the temperature range is from 185 to 230C. I ran it from 200C to 224C. Looked the same colour when it came out to me.

The packaging also advised a .5 nozzle or larger. I used a .4 as I stated and experienced no problems what so ever. Wish I could say that about all the filaments I’ve tested.

My goal was to finish the shield with paint and I went off to RONA to find a spray can of “primer filler”. It’s made by Rust-oleum and allows you to paint on PLA so I thought it would work just as well for wood. Turns out Primer Filler is an auto primer product and RONA doesn’t carry it. I grabbed a spray can of Tremclad Primer to use instead.

The Tremclad primer works fine on both the wood and normal PLA.

I used some Testers Acrylic Model paints and started in on the shield.

IMG 1020

Testers goes on really nicely, decent coverage and with two days it was all painted and dried.

IMG 1021

Having done a few more prints with the MG Chemicals wood filament, here’s what I found that you may, or may not, find useful.

If you’re doing a small sized print and you have no filament cooling fan, keep the heat down, slow down your printer (20 – 30mms top speed) and if you can, mount a fan off to the side of the print bed. Laying layer after layer of ANY filament will go much smoother if you do. Failing to do this will give you a print warp, sag or something equally annoying. Thus, don’t get in a hurry.

For layer height, I’ve used .1, .2 and .3. Depending on what you’re printing, there’s not a lot of difference in the print. Take a look at the pig at the end of this post, that was .3 and I’m using a macro lens to get the picture. Sand him up, apply a stain or paint and he’s pretty darn smooth any way.

Tonight, the pig. Small, 25mm x 25mm x 30mm. With wood. Slow. Fan off to the side. Nozzle temp 206C. Porky turned out pretty darn good but with better print cooling, I could have gone a lot faster. Then again, like those old highway commercials, “Speed Kills”…

Wooden Pig

I doubt that you’d want to print “everything” with wood. However for those special designs where you want to apply a finish or paint, MG Chemicals Wood has proved itself to me that it’s more than worthy to be in my stock of filament supplies.

15
Feb

Fan Noise

One of the benefits of owning a 3D printer is that they encourage endless amounts of tinkering if you’re so inclined.

One of drawbacks to owning a 3D printing is the same reason.

Truthfully, I have spent a magnitude of time doing everything from software hacks in the firmware to compensate for the inaccuracy of the printed parts, adding bling to it like power supply hangers; job timers; wireless control, to sitting in front of it just watching it print. Which, in some cases has more value to me than whatever might be on the TV at the time.

When I get too focused on some aspect of 3D’ism, David, one of the local FVMakers tends to be my voice of reason and sanity. I think he missed his calling as a Kossel Owner Therapist.

However, there has been something that has annoyed me from day two. Keywords there, DAY TWO.

Day one it didn’t, I was just happy that it barfed some PLA out of the nozzle at that point.

Therefore as the topic of this blog post points out, noise. Specifically fan. As in power supply cooling fan. BOEING wind tunnel. Shuttle launch.

I have a couple of 12V 30A supplies so I took the one apart that wasn’t in the Kossel. Found it’s a 6015 fan. The 60 is the size of the fan, 15 is the depth, 60mm x 15mm. What floored me was the working voltage 14VDC. Now what engineering resume polisher would use a non-standard voltage fan like that? Try to find a source for them. Right. Good luck with that.

That shelved the idea for a while and then, well, noise is noise. It started to bug me again. You know the old saw, “The squeaky wheel gets the grease.”, I just changed that to, “The squeaky wheel gets replaced”.

This time I took the power supply off the Kossel and opened it up. Incorrectly I’d assumed that 360W supplies would all be relatively the same. Nope. The one I took off has a [insert drum roll here]…12V .11A fan. Standard. I suspect this engineer still has his job.

Power Supply Fan Replacement

Now, if I’d have found a 14V supply for the fan in the power supply, I’d have wired two silicon diodes in series with the positive side. At .7V drop per diode that would have dropped it within the 12vdc fan working range.

The replacement fan I got is a GELID Silent 6 fan. These have hydro dynamic bearings instead of the usual sleeve bearings. So longer life, lower noise. The GELID is rated at 3400 RPM, 16CFM, 24dBA. 12V .22A. So the amperage is higher than the original fan, but when I measured it, it certainly wasn’t .22A. Closer to .16A.

Fan RPM is a good indication of just how noisy the fan is going to be. A 5400 RPM fan is going to be a lot noisier than a 3400 RPM fan. But of course the trade off is CFM. Then again, noise doesn’t always correlate with CFM either.

Inside the fan is a standard 2.54 spaced connector, which I just happen to have a lot of. No problem there. You can see it in the photo at the bottom center of the pic, CON2.

Power Supply 360

The GELID fan is actually a 3 wire fan. It reports how fast it’s going on one of the wires. Since my power doesn’t give a fig about how fast it’s turning, I never used that wire. Leaving it disconnected means the fan will run full speed if you connect it directly to 12V. However the supply in these power supplies is temp controlled so they vary in speed any way hence feedback from the fan is not required. Ignored in fact.

One of the sources of noise is the path of the air. Most of these supplies have fan “cut outs” that are supposed to do. Something. Maybe keep you from dropping screw drivers or bowling balls into the fan. Or. Something.

41gXr 7NPFL SY355

My power supply is mounted on the top of the Kossel frame and it sits atop a fairly high work bench. I almost need a step stool to get to the top…I could never lift a bowling ball that high… The cut outs induce noise.

I measured the amount of noise with the fan and cutouts in/out. First in, original fan @84dB. With GELID fan, cut outs in, 77dB.

Armed with a nibbler, there was no going back.

Power Supply Fan Hole

Put the GELID fan back in, remeasured the noise, 71dBA. Yep. The little holes make noise. If I wanted to protect the fan, I’d put one of those foam grill covers on it. I’ll wager that would lower it slightly more.

Power Supply New Fan

So that’s how it sits now. When the Kossel isn’t heating something the fan noise is less than 70dBA. When it’s printing, the steppers are now noisier than the fan is. Used to be that the two would be in competition for who could be the loudest.

My last test was with an IR temp probe and even at the low CFM of the GELID fan, the difference is 2 degrees C warmer. Big deal. There’s more than enough air flowing through the power supply to keep it cool. Maybe in the summer heat that might go higher but not enough to be a concern.

6
Feb

Memory Lane & Bunny Trails

It’s the darnedest thing sometimes. You’re working with some “new’ technology and all of a sudden, bingo, you’re transported back who knows how many years to something from your past.

Happened just yesterday. I was looking for emulators that ran on the Raspberry PI and next thing, I’m at Adafruit’s web site looking at a Mac OS 7 emulator.

Mini Mac Pi

Running on a 320 x 240 TFT display inside a PLA 3D printed case. Talk about RETRO…

Now I remember getting the Mac in 1985. I was actively programming the TRS-80 Model 4 at the time and the company who was selling my software was doing the documentation on a Mac. When I sat down at the Mac in their office to do some documentation changes, I could see that the Mac was a great system for doing the docs so I went out and bought one. I had zero interest in programming a Mac at that time.

Then I wondered what other emulators did the Rasp PI have. Naturally I looked up to see if a TRS-80 emulator was around for it. Which of course turned up this post.

Ah yes the TRS-80. I started with a Model I in 1978, writing in Basic. Ugh. Needed a printer. My first printer was a behemoth Model 15 teletype (from WWII to give an indication of age) with a machine language driver you had to load every time you booted the computer.

M15 KSR 3a

Course this was a Baudot printer which means you didn’t send it ASCII, you sent it five level code, that tickled a relay at a whooping 300 baud. And it printed. Solid steel, heavy as heck. Noisy. Mine didn’t have the keyboard.

Which is how I got started programming in machine language. Someone wrote a driver for the TRS-80, non-relocateable, and if you wanted to change it, you needed to learn how to PEEK and POKE commands. Not to mention learning how to read machine code.

For whatever reason Z80 machine code was fairly easy to learn for me. I never wrote another line of Basic code after 1980. I wrote Z80 assembler until 1992.

In the mid-1980’s I decided to write a program for profit. I had done all the market research, I saw the need, I wrote the code, marketed it. I sold three copies. Wow. LOL. The problem was twofold, first I went for profit, second I had no intention of ever using the program myself. Since then I have never written a program that I did’t intend on using myself. I.e. money has never been a motivator behind writing software. Granted I’ve sold a lot of software since then too, but I needed it and therefore use it myself, apparently others needed it too and have bought it from me.

One of the most successful programs I ever wrote at the time was my BBS (bulletin board software; a precursor to the internet that wasn’t around at the time) and a terminal program called FastTerm. As of 2011, some were still using my FastTerm program in emulators to connect to DEC systems. Or whatever. I dunno. Last FastTerm I did was 1991 if I remember right.

Someone even wrote blogs about how to use my YMODEM protocol in FastTerm. And the screen shots, yep, that’s me. Notice the play on the Mac menu/desktop system.

Fastterm4

But I had the Mac and in 1988 I started programming for it. At the time that started because there wasn’t exactly a lot of terminal programs for the Mac, let alone ones with X and Y modem protocols so as a bit of a challenge I wrote one. It wasn’t like I didn’t know how it worked.

Course this started me programming the Mac and I’ve been programming it ever since.

I did write 3 or 4 programs for Windows over the years, but the programming environment wasn’t exactly friendly, API’s were limiting and it got in my way more than it helped me get the task done. Thus I never pursued it, just stayed with the Mac.

Of course when you start programming so long ago, you get a work flow and it tends to stay with you. Versioning Control was something I never did because I was programming before it came in vogue. Heck I was programming before ethernet got to be a mainstay. When I write software now, I can create umpteen versions of a piece of code in a day or hour for that matter. When I did investigate VCS, I spent more time making notes about what version did what than writing code.

So for me, I start the day with a “Save As” new version number on the filename. If that version works like it should, I do another Save As, increment the version number, carry on. In my mind I can rewind or reopen any version prior, but the way I debug as I write, I’ve rarely ever had to do that. Maybe that comes from writing machine code in the early days…

Now I write piles of code for the Arduino because it’s the part I love best about the whole thing. Code controlling something in the real world. A visual example of working code if you like. This is no doubt why I have absolutely been enthralled with my 3D printer. I can design something and then turn it into a real world whatever with my 3D printer.

For as much as technology has “evolved”, coding hasn’t changed much and frankly neither have some of the protocols. Serial for example. I was programming modems via that in 1980. Shows how robust it is. Actually electronics hasn’t gone off the deep end either. True you have micro controllers in places where discrete components used to live but Mr. Coffee has been around a long time too, so in many cases, same old, same old but with new skin on it. Lift the hood, same old.

So that’s how memory lane can descend into bunny trails in a matter of minutes. Smile worthy though.

3
Feb

Kossel Neatness

When I first built the Kossel the number of wires running to the tops of the towers, to the hot end, over to the power supply, and under the bed were, to say the least, plentiful. Certainly not neat.

One of the FVMakers gave me some plastic inserts that fit in the gap of the 2020 open beam and holds the wires in. These work great for the end stops but leave a little to be desired when it comes to the hot end.

IMG 0396

So you use a lot of zap straps, flexible cable tray, or whatever can be found to neaten it up. I took the easy way out and used zap straps.

Problem is because I tend to “bling” the Kossel more than the average bear, I’m in and out of it any number of times a week. And those dangling wires get caught on stuff and I know at some point, bad things will happen.

I was helping my kid brother wire his truck and he had some plastic loom. Extremely flexible, available in different diameters and looked neat when we were finished. I considered using some to hide the wiring in the hot end and then I realized that the hot end moves around. A lot. That plastic loom tends to have sharp edges so you end up with tape around the entry and exit points to prevent chaffing.

Then someone mentioned “braided” loom… Expandable, soft, flexible and dirt cheap. Off to eBay and then next thing I know, I had 26 feet of the stuff. Did I need 26 feet? No. Did that stop me? No….

IMG 0979

Kind of neat looking stuff, bit a knack to getting the wires through it though. I inched a typical computer power cable through (no ends on the cable) and you work it on like a snake. When the cable popped out the other end, I taped the hot end cables to the heavy power cable and worked it back through. Once you get the hang of it you can do in a minute or two.

IMG 0978

And yep, I still got to use 2 zap straps to hold on the cable package. None the less it works very well, extremely flexible and very neat.

1
Feb

Slic3r Not Always Nicer

Today I needed a part printed (making a new effector mount), so I sliced one up, sent it to my Astrobox (wireless Kossel controller) and started the job.

Second layer and the extruder went bananas. Retracting and injecting at warp speeds, filament grinds going all over the place. Which didn’t do much for the print. Ruined it in a heartbeat.

I thought, bad upload. I resent the sliced file, started the print again, same thing happened in exactly the same place.

Ah ha! A damaged slice. I resliced the object, sent it, same problem.

Time to sit back, sip some coffee, ponder all things…

I loaded the STL into Slic3r, then clicked on the LAYER view. Nope, nothing there was wrong. Changed the density of the infill to 50%. Checked the layers, nothing wrong again. Last step was to change my layer height to .2 (mine normally defaults to .3). I saved the Gcode and sent it to the printer.

Same problem. Oh wait, I didn’t check the layers after the .3 to .2 adjustment. So back to Slic3r and do all the steps and then finally change the layer height and checked the second layer.

This is what showed up.

Slic3r Error

Now where in the float did that come from? Changed it back to .3 height, perfect. Back to .2, all messed up. The GCode was completely screwed up too so no wonder the extruder went on medical leave.

All the layers above or below the second one were correct.

Thus let this be a heads up. I can’t always blame the printer, server, or STL file for a screw up. Sometimes it’s the Slic3r that’s not nicer. Use the Layer View, might just save you a bit of a head scratcher.