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Author Topic: "softer" filament seems to squish up at the gear and stop up  (Read 318 times)

jonyo3d

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"softer" filament seems to squish up at the gear and stop up
« on: April 04, 2014, 07:32:51 PM »
I've been trying to print with t-glase.  It's much more flexible than ABS / PLA and feels softer when I'm cutting it..  Have been going back and forth with Tom at Taulman 3d, he's been a great help dialing in the settings to get it to print.  But I think he's on vacation or something lol... Normally he responds within hour or so but hasn't replied back now in a few days.  So while I'm waiting to hear back from him, I'm impatient and wanted to see if anyone else might have experienced this with t-glase or another "softer plastic" and what the solution might be...

problem:  part way into a print, it will stop spitting out plastic.  Well there were other problems but Tom helped me fix those, this is the latest problem.  They actually sent out a replacement spool as the one I had the normal thickness varied, and sometimes went above 3mm, which was definitely the cause of the problem "before".

But now, with new spool that I've verified has max width around 2.90 or 2.95 or so (average around 2.85), it still stops extruding plastic.

I put digital calipers to the filament at the actual "fail point".  At the part that has the "teeth marks", it's actually slightly squished up, measured one way it is 2.95-3.00 the other 2.75 or so.  And here is the part that is the "reason" for not spitting plastic out: at the point it goes into the hole for the hot end, it's really squished, about 3.10 one way and 2.6 ish the other!  And there is the part that it has the plastic carved out from trying to shove something in a hole that is smaller than it is...  Which is weird, in past it just "skips", this seems to "quietly carve" up the plastic as I never hear any loud ticking noises like I do when it skips normally...

So question is, what is the best way to fix this on the buko (bukobot 8 v2 duo)?  I was thinking there may be some "bukobot specific" tips here that the Taulman folks may not be aware of.  My theory is that even with the fan it's getting hot enough to deform more than normal and get all squished up, that's why it doesn't just fail right away, it doesn't fail until things have heated up a bit.  Perhaps the gear itself is heating up or something?

Any ideas?

midoco

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Re: "softer" filament seems to squish up at the gear and stop up
« Reply #1 on: April 05, 2014, 10:21:00 PM »
We have been having similiar problems with some PLA's.  Take a look here http://forum.bukobot.com/index.php?topic=3067.msg4802#msg4802

whosawhatsis

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Re: "softer" filament seems to squish up at the gear and stop up
« Reply #2 on: April 06, 2014, 06:57:13 PM »
I've been getting good results with T-glase printing at 250C at 50% of the normal speeds. I'm also using the firmware retraction feature available in the latest firmware (https://github.com/whosawhatsis/Marlin) to run retraction recovery much slower (closer to printing extrusion speed) than the retraction to get rid of the force that is most likely to cause the filament to buckle. The same settings have been working well with Ninjaflex, though it requires an extrusion multiplier of about 1.1 due to the soft filament being pressed deeply into the drive gear, reducing its effective diameter.

 

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