Topsy's Printer! (Some pics NSFW-ish)

So I discovered a neat little trick for PLA, if you have a large part that's warped in printing, or if you have some parts that need to snap together or fit closely but don't -quite- work and you don't want to have to sand.

Boiling water. Put your part in a heat-proof container (pan, mug, whatever - if you're concerned about non-food-safe pigments or additives in PLA, use something you're not going to use for food. I used my dye pot that is only ever used for yarn). Boil some water in a kettle, and then pour it into the side of the container (not right on your part) until the areas that you want to bend are submerged. Let it sit for a few seconds to heat up, then carefully remove it. Of course wear proper hand protection, it's just been in boiling water. Carefully bend the part to shape - don't force it and if you hear crackling sounds, or you can't adjust it as much as you want to before it cools, stop and heat the part again with more boiling water (sometimes the first time doesn't work so well as the water cools quickly in a cool container). Repeat until it's adjusted, and it's cooled back to room temperature.

You have to be a little careful as PLA loves to soak up water and any holes in the part will allow water to the interior. But if you do it quickly, it works great.

Can also do similar just heating with a lighter but it's harder to deform thick pieces this way (as you have to heat both sides) and very easy to scorch the plastic.

Worked beautifully for the two halves of my doll's upper torso that I printed - they're large pieces that warped slightly, pulling away a little bit from the print bed, so there was about a 1mm gap at top and bottom where the two halves come together. I've not gotten them glued yet so no pics but there's now just a hairline between them, perfect for supergluing in a bit when I can get into my workshop.

 

I am so intensely pleased with how good this printer can get with just the stock nozzle, stock... everything, actually.

I've been redesigning some doll parts to add stops/locks, so each joint will have a finite number of positions it can take, but will be far more stable in those. I added some bumps to the bottom of the ball which forms the ankle (just finished printing, still need to glue the halves), and some pits to the cup to match, so it'll click along and won't tend to try to twist.

It's really important that these be placed -exactly- right or they won't work properly and... man, all I'm gonna have to do is just touch each one with a little sanding bit on the Dremel and they'll all be just right. No distortion at all even on the very top, where the layers were small and tend to smush. For reference, the width of that hole you see there is 4mm in diameter and each of the divots is about 1.5mm in diameter.


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By the by, does anyone have any recommendations on dealing with PLA curling on overhangs? Stuff like printing the ball of the heel, those areas tend to sort of ruffle up or curl and really pointy, thin sections of overhangs can even curl over themselves and then the nozzle skips over them every layer after that till it's smoothed out, and that's a real problem for me if it's on a joint surface. Slightly curled areas usually sort themselves out eventually, and there's not -terrible- distortion on the finished part, but the surface ends up very bumpy, like a sandstone texture. I've tried additional cooling (fan is running all the time, layer times are never under 60 seconds) running the temp lower after the first few layers, and that seems to sort of help, but it's still doing it some, and I'm hitting the bottom of the temp range for PLA (I still get good surface quality and layer adhesion down to about 182-ish).

 

I've been reading that where you place the model and which orientation it's in can fix or ruin a print. PLA can be affected by rapid cooling. Try turning off Air conditioning or surround the printer or box it and see if that helps.

Someone also stated that slic3r can be the problem when doing I fills and such. The used kisser and it came out better.

Slic3r also came out with an update that has better fill algorithms. Try upgrading the software.


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Hmm. Well, unfortunately I've got all that pretty well covered, I think...

I orient the models as best as I can to try to minimize the curling, but the pieces I'm doing, surface quality really matters (I really need to minimize the sanding I have to do, and make sure areas that joint together are printed in a good orientation so they won't be rough), so I have to sort of balance that. Sometimes I slice pieces in half and glue them back together after, just to avoid printing issues.

I've tried the room both especially cold, and especially warm (~6C vs. 25C) and it doesn't seem to make a whole lot of difference to the curling specifically (though it does matter for cooling of small parts like pointy tops of things or anything where individual layers are quick). I suppose I can try an enclosure for it, but not sure what that would do that would be different than having a draft-free warm room.

I can try different slicing software, but it happens with both Slic3r and Cura, which slice very differently, and it's an actual physical curling of the pieces after the filament is laid down - I can watch the wall be slightly compressed as the extruder comes by and puts down a layer of fresh plastic, and then it takes a second or two for it to curl up. Been meaning to try some different slicers though, as I switch between Slic3r and Cura depending on what I'm making (small things with fine detail are better in Slic3r, large things that don't need much support are better in Cura) so I guess perhaps I need to add another tool or two to my toolbox.

 

This is not the sort of solution that makes realistic sense, but with your level of detail and my OCD... I have attempted to cure the curl by physically pushing it down after each pass. Using my handy cricut spatuala I smooth the area gently with a circular motion immediately after the nozzle clears. Fortunately for me, when I have run into this problem it only requires a few layers until there is either enough material to hold its shape or a connection is made. I find bed adhesion is good with heating and hairspray. Unfortunately, after a number of layers there is a differential between the warm bottom layers and the cooler upper layers that can result in the ends pulling up slightly. As long as the piece holds through the print it doesn't usually bother me - I'm a function over form sort in these regards - but I doubt you want that in your pieces. A heated enclosure might help you by keeping the entire piece a uniform temp throughout the process. Crank that workshop up to 60C and let her rip! Well, maybe some thing a tad smaller than a whole workshop. Maybe a few flowers to just brighten the outlook...cheer the pieces up, y'know? Good luck.

 

I've actually done that sometimes, and for some areas, that does help. I have some lovely palette knives that I've used for that purpose. It helps a bit on larger pieces that do it (especially, as you say, if I can get it working so I can just stop after a few layers), but for stuff like... um.... toes, for example, they're all ball-shaped and they're all -tiny- and with super fine detail, and if I do anything to them before they all get linked up to the foot around layer 50 or so, they just get knocked off (even with a raft/support, and with good adhesion - they're just delicate). I've had to kill a couple of prints that I screwed up by trying to smooth things down. :\

Maybe I'll give a go to the opposite way - print hotter, turn off cooling, turn on/up the heated bed. If it is the temperature difference between upper and lower layers that should help - it does definitely help with minor warping on large pieces. I'd like to do an enclosure but not sure when I'll be able to devote some time for that, as I've got some masonry/carpentry work to do on my workshop first before I can justify doing anything else. BAH.

 

Printing hotter seems to have helped some with the curling and distortion. At about 195 and the bed heated to 70, it looks more like lightly-dropped loops than ruffling, which results in a lot less distortion and can just be sanded off rather than needing filling.

Also... pics below may be slightly NSFW, if your work frowns on pictures of naked dolls, but... Eee, she's all starting to come together:









The tape on the body is just to hold the halves together as I ran out of superglue last night. And... yes, my bed is covered in tape around the edges, because the printed bed clips it came with suck, and binder clips get in the way. I really want to replace the bed with the newer design but I haven't gotten any reply back from the Robo guys about whether the upgrade is available separately.

 

Baaah. Well I knew my streak of good luck couldn't last too much longer. I clogged the hot end, and tried to remove it and unclog it as per the instructional video. However, this is what my hot end looked like when I took it out:





... No wonder it was so hard to get those screws out... they were screwed into the hot end itself. Buuuut I couldn't get the damn thing unclogged, and broke the PTFE tube trying to pull it out, so I'm ordering an E3D.

Should be interesting learning how to install it...

 

Its not too bad to swap. You need a 12v constant for new fan. Wire new heater leads to old ones...but trace back where the wires are thicker and connect there(easiest way to do it). The rest is easy. You have already done most of the hard part.

 

Topsy, you'll do great swapping in the E3D. look at all you've already accomplished


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E3D achieved and printing! I still need to print a new fan bracket for the part cooling fan (I tried tesseract's but it broke pretty much immediately... :\ ) and maybe replace the printed part for the E3D fan as well as it is quite loose (that's why those zip ties are there - the installation guide says it'll be quite tight and careful not to break it - mine is super loose and wants to come off...).

Not near as tough as I was afraid it'd be, once we realized the wires for both the thermistor and heater are pretty much interchangeable, and you can just reuse the existing heater and thermistor wiring without having to run any new wires. The E3D cooling fan can also be wired in thusly:



Red with red, black with green. Easier than trying to get the power supply out to wire it in there, and seems to work just fine.

ETA: Seriously, fuck kapton tape. Using it to try to stick stuff on is crazy-making. After screwing up my first thermistor trying to stick it on with kapton tape, I just insulated the spare I got (using a single small piece, folded over and then trimmed - done with tweezers because if you even lightly brush the kapton tape with a finger it no longer sticks to anything) and stuck it on using this stuff:


... 7.99 for a tube and I used a dab about the size of an eighth of a pea, applied with a toothpick in a thin layer - the thermistor weighs nothing so it really just has to lightly stick it on and it's fine.

OH YEAH. Make sure you run your wires to the -right- side of the hot end, not the left, or they may be in the way of the X-stop. Temporarily have put a longer little bolt in there so it triggers anyway but it means I lose a few millimeters of X range.

 

Hum. So. Last night, my printer tried to escape again.

This is the second time it's done this. If the filament binds up and doesn't continue feeding, the extruder climbs the filament to the top of the smooth rods and pops off.

This time, I didn't actually catch it - I'd gone to bed. When I woke up, the whole carriage was up at the top of the case, there was filament flung everywhere, and... clearly, things had gone Wrong.

It appears eventually it chewed through the filament so much that the filament just broke, so at least it didn't have anything to struggle against anymore... but both my extruder gears look like they've been through a war now. There was tiny flecks of black plastic all over my failed print... there's a chunk out of the side of the little gear, and the big gear has a lot more wiggle room to it. The linear bearings for the z rods also seem to have been damaged somehow, and have begun shedding a few tiny ball bearings and don't move quite as smoothly as they did. Oh, and the printed part cooling fan bracket for the E3D snapped as well when it hit the top of the case, so the fan was dangling. Fun morning!

It is still printing, and seems to be okay at it, but the wiggle in the gears is not nice, so I'm printing new ones from a different spool of filament, and probably ordering some new linear bearings to replace the slightly wonky ones.

And trying to think of ways that I can detect if this happens and kill the print automatically, cos I would much rather lose a 14 hour print than deal with damaged printer parts. Any ideas? Something that can detect whether the filament is still feeding and power down the printer if it's not above X in Y seconds? This doesn't happen often but it -sucks- when it does.

 

Sorry to hear this, Topsy. Trust me, I feel your pain. I don't have a monitoring solution, but in terms of the filament and in the words of Henri le Chat, "I have learned a few things." Spooling at factory is a continuous process from extruder to spool and, as such, there is no overwrap which is what causes what you have experienced. When it has happened to me it is because the springy filament sprang from the spool in sufficient quantity to deceive me when I wound it back on and fed it into the printer. Foolishly, I thought it would all work out just fine but, no. Nowadays, when the nasty filament tries to put one over on me, I unwrap it until I come to the overwrap and then carefully spool it back on. No problems since my own printer made a break for it. I also found one teeny ball bearing and have successfully ignored it with no repercussions as yet. Good luck!

 

Would it be possible to fit a micro switch to the top of the smooth rod to kill the power / print if the carriage winds itself to the top again

 

The firmware should support a top z-stop. The key is getting it mounted properly.

 

Knowing the gears are the most likely pieces to fail, I took the gears from Robo 3D's thingiverse page and sent them to shapeways and had them print replacement parts for me. They seem to have come out great. Cost a bit, but this way I have emergency replacement parts Just In Case.


All around uberGeek
thingiverse Profile: http://www.thingiverse.com/melodybliss/overview
Robo 3D User's FAQ: http://lele.io/robo3dfaq
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Auggh. I seem to have clogged my E3D. The filament stopped feeding after only 1 or 2 layers of a print, and could not manually be pushed through. And when I took the E3D out, I couldn't even pull the filament out except with a ridiculous amount of force... and there's still a bit left in there, a melted glob at the very top of the cold portion of the E3D. It can't be pushed through, no stub to pull out.

What the hell am I supposed to do now?

 

Hmm... I'm really afraid of breaking it... though I guess worst case, I can just order a new set of metal parts.

I did find a liter of MEK for under 15 euros with shipping, from within the Netherlands, so I'll have it by Tuesday. I have a respirator, gloves, and a well-ventilated area to work with it, so I suppose I can try that, at least to clear out the majority of the goop in it. I don't think I have a drill bit that'll get down in there without damaging it, though I can probably take the nozzle off and at least see if the clog is there or further up. Thanks, tesseract.