Printing in red, green, yellow, and blue ABS? Hells yeah.
Now, I haven’t even made a dent in my black ABS supply, so I can’t really justify dropping $320 + shipping on more plastic. However, I’m certainly hoping someone asks me to print something up in color so I have an excuse to buy some…
Kinda rhymes, no?
Given Rick Pollack’s PLA printing success and temperatures at barrel entry rather than nozzle, I should probably start delineating between temperatures at the barrel and nozzle. If barrel entry temperature is truly a critical factor, then he’s totally right about how going by nozzle temperature is like driving a bus with just the rear view mirrors.
However, this gives me pause. Everything I’ve read about ABS suggests it may be best to melt it right at the nozzle as quickly as possible. I’ve found that ABS cools very rapidly too. PLA on the other hand takes a while to cool (but, then again, I was running my extruder too hot) – with the parts being quite flexible for some time after printing. If barrel entry temperature is that important, then it seems that PLA must need a longer time to melt. If this is the case, should the nichrome be wrapped higher on the barrel? If so, then Rick’s heater cores (which already seem very convenient) are downright brilliant – since you can probably easily adjust where the heat is being applied.
From Nophead’s comment I gather that I was, indeed, running my extruder too hot. I found that at my ABS temperatures (220+) made the PLA just drip right out of the heater – and once that had basically stop it would then intermittently release little amber droplets of plastic. I must have been really cooking it.
With the limited printing I managed with PLA I found that it printed well with my non-temperature ABS Skeinforge settings. So, before I go back to PLA I think I’ll finish tuning my ‘bot using Nick Ames’ Skeinforge tutorial.
Don’t leave your extruder on and not running too long. It will drip, then the PLA will turn amber, and then it will clog.
That’s all I’ve learned about PLA first hand.
Oh, well, that and it’s a royal pain in the ass.
Over the weekend I rebuilt my extruder after some adventures with a blowtorch.
I used Rick’s single nichrome wrap method, which served me well on my last re-build. The documentation of his method is absolutely fantastic and a must-read if you’re rebuilding your heater. (That page is about PLA, but the nichrome wrapping is pretty universal).
I’m not sure if I wrapped my thermistor better or what, but I seem to be getting more consistent readings from it. Perhaps this is due to RepG v12? I would tend to think not since I’m using RepG v12 with the Zach 1 temperature table – the same table I was using before RepG v12.
I’d like to print in PLA, I really would. No warping? No rafts? Smells like syrup? Makes kittens and rainbows? Sign me up!
Rick from MakerGear has the following suggestions for printing in PLA:
Nick McCoy offered several pieces of wisdom:
Nick’s results suggesting a nozzle temperature of 180-210 seem to match up with Rick’s findings of 190 or so. I think I’ll give Polly another shot and see if I can extrude at those temperatures.
Long story short – it’s possible.
I was concerned that after having PLA ooze through the threads that I would be forced to use my backup PTFE barrier. However, I’ve been pleasantly surprised to discover that I can print just fine with my reassembled unclogged extruder. I’ve been able to print several things without so much as a hiccup.
So be delicate with your PTFE even after plastic has oozed into the threads – you may just be able to use it if you can clear out the plastic from the threads.
Jrombousky designed his Leonardo Robot based upon the ratios in Leonardo DaVinci’s Vitruvian Man. He mentioned that it was based on these very cool papercraft Paper Robot. I just used his gcodes and they turned out just fine. This just supports my belief that a good set of Skeinforge settings may be nearly universal. In any case, here it is!
Ddomo arigato, Mr. Roboto
I designed this in Sketchup, exported to STL, Skienforged to gcode, RepG’d to an S3G file, and printed. The feature I’m the most proud of is the pendulum inside his chest.
Digital Cogsworth
Physical Cogsworth
The design needs to be tweaked a little since parts of him have too much plastic and a few parts have too little. But, overall I’m quite happy with the result.
Nozzle and barrel apart
Here’s the process I used to unclog my extruder barrel and nozzle without a lot of extra equipment. Obviously you should take all reasonable safety precautions with goggles, gloves, tongs, with a fire extinguisher, etc. Plan ahead and be safe.
Cleaning the inside of the nozzle - kinda gross
Extruder barrel and thick yarn
Flossing the nozzle with copper wire
Well, not really playing. But, I suppose not really “working” either. Here’s how my experiments in unclogging a clogged extruder barrel went:
You can see where there is some minor plastic residue left over from the PLA in PTFE insulator which oozed into the threads. I had used a precision screw driver to follow along the threads and chip out plastic.
PTFE insulator, mostly clean
Here’s the clogged barrel. I had chipped out plastic from the threads using the same precision screwdriver. You can see some of the scar marks from my brilliant idea to use a wrench on the smooth part of the barrel at one point. (FYI, that was sarcasm – don’t use a wrench on the barrel. It was, in fact, a bad idea). I was totally unable to remove the nozzle from the barrel.
Extruder barrel, clogged
This was my idea for the setup so that the flame/heat would not discolor everything. You can see where the nozzle has gotten a thin layer of black ABS fused to it. Again, you can also see the marks on the nozzle where I tried to use a wrench. And, again, not a good idea. All I managed to do was just scar it up.
Extruder barrel with nut partway on
This is similar to the setup I settled on for trying to unclog the barrel. I’m going to cut the suspense and let you know – this doesn’t work and you shouldn’t try it. This setup did not work for two very important reasons you can learn from. First, it was too low to the ground and the blow torch kept going out when I tilted it to get to the heater barrel. Second, it relied on kitchen tiles – which is a terrible terrible idea.
Kitchen tiles - good intentions, bad idea
Here’s the next part of the setup: blow torch, flint, wrench for picking up hot things, and fire extinguisher. Off camera right is a garden hose. Again, this setup relies on kitchen tiles – which will actually shatter when this kind of heat is applied. So don’t do it. Oh, and it turned out I did have a blow torch – but it was empty. :)
Setup - empty propane tank, bad kitchen tiles
This is a better setup – with a brand new propane tank – but still a terrible idea with kitchen tiles.
Setup - FULL propane tank, bad kitchen tiles
This was a good setup. Friend nearby with a garden hose and fire extinguisher, no nut on the barrel so it sits in the washer and is easier for me to heat the entire barrel, suspended in air by a metal hook, held down by a big rock, high enough that I didn’t have to tilt the blow torch. Here you can see the scorched and shattered kitchen tile in the pile on the right.
GOOD setup with extruder barrel suspended in air by metal
Since I was in charge of the blow torch and my friend had the fire safety equipment I really only pictures of stuff as it was in a relatively cool state. This means I did not get a picture of the barrel as I was heating it – I had gotten it glowing red hot which was pretty nifty. I also missed out on getting a picture of flame spewing from the nozzle as the ABS inside ignited. It was like a mini flame thrower tossing out a thick black smoke.
I was expecting some of the ABS to leak out of the bottom – but the barrel was essentially clean. I could see all the way through the nozzle with no problem.