Free Pc Grinding Games

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Ellyn Krucke

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Aug 5, 2024, 9:02:03 AM8/5/24

to lyagranamlo

Helloall, was looking for guidance in my issue of filament grinding. While I've been 3d printing for well over a year, this is my first Prusa printer (self assembled). I'm having an issue of filament grinding when printing benchy's. The quality of the prints is amazing, if the machine would keep printing. I've attached photo's of the printed parts, as well as the filament grinding and will describe what I've tried to fix it.

1. Loosened the idler door screw (the one with the spring on it, my mk3s only comes with 1 screw as opposed to what used to be 2 screws). I played with how screwed in it is from being only attached by 2-3 threads (to the point where on one attempt the idler door actually popped open because it was barely screwed), all the way up to being "over screwed" where the end of the screw protrudes past the nut. Nothing has worked, print goes 10-20 layers and stops.

2. Re-aligned the filament guiding gears. While I initially made sure when assembling the printer that the gears were perfect, it seems at some point after the first few prints, the gear attached to the extruder shifted a mm or two (probably didn't tighten the screw holding it to the rod enough). I thought this to be the problem for sure, so I realigned, this time making sure it wouldn't move. While this gave me a good 30 layers, it did not solve the problem.

4. After each time filament was grinded, I would remove the filament, airdust the gears and filament shaft, and clean the nozzle with a nylon cleaning filament. There seemed to be no clogs as the filament always extrudes perfectly in a straight line and dimensionally looks and feels perfect.

**My theory is that the bondtech gear attached to the extruder may be pushing on its side of the filament too hard (so hard that it doesn't matter what tension I use for the idler door). In the last image of the actual grinded filament you will notice that the grinding is happening more on one side, this side (as far as I can tell) is coming from the extruder gear, NOT the idler door gear.

It's worth noting that I have gotten successful prints out of this, so it may only be happening when there is too much retraction in a print, causing it to constantly squeeze the same part of the filament over and over (I've noticed benchy's get a lot of retraction/z-hop).

The interior temp of the enclosure is probably a few degrees above room temp but with the benefit of not getting air drafts from the AC. There's a gap which air can freely come in and out on all walls of the enclosure. Basically it's definitely not too hot in the enclosure if that's what you were alluding to.

My problem comes from the extruder gears or extruder assembly of the printer being too tight/wrong? Either that or it's the retraction settings but I haven't messed with retraction at all from the defaults provided in slic3r.

I re-read my response and it was pretty condescending and rude. My apologies, I've just been frustrated with this problem and shouldn't have taken it out on you. I've edited my response, even though it doesn't matter. I appreciate you trying to help anyway and understand that you don't want to try anymore. Thanks anyways.

Also - I assume you were hinting at the fact that if the enclosure got too warm, the PLA would be malleable enough to have the gear's grind it? I just never ran into anything like that so excuse my assumptions. I would be more concerned about heat creep but I messed around with temp's enough to semi rule that out, unless somethings wrong with the hot end.

If it helps I have had a bad day and am lacking patience so I will apologise also to you for being a bit sensitive. It is funny because your apology has restored a little faith. Yes my day has been that bad.

OK I was thinking of heat creap up into the cool zone of the hot end so during retraction molten filament gets where it shouldn't and then solidifies causing a jam. If my memory serves me correctly some versions of the Mk3 were affected by this because the fan wasn't up to the job and with it being in an enclosure It can magnify the problem. After a bit of thought If this was happening I would expect you to get a clog in the cool zone.

So that does make sense that the retracted filament would go up the cool zone enough to end up getting grinded. To answer your question though, it doesn't seem that there's a clog. I've been able to "unload filament" after it stops printing using the feature on the printer, and reload filament without a hitch. I've only ran the nylon filament cleaner as a just-in-case method to try to rule out clogging, but not because it was actually clogged.

Wondering if there's a definitive way to test for heat creep. Although I've never seen heat creeping before (never had that problem), I would assume the filament I unload would be kind of melted and deformed looking, which it's not. (Refer to image of the filament I pulled out of the printer above).

Coincidentally found this fresh posting while troubleshooting an issue with several prints stopping at about 90% complete. Interesting to hear about heat in the enclosure possibly playing a role. I've been printing about a dozen identical prints, about 11 hrs per print. The first 8 went perfect with no issues. I've had my printer in an enclosure the whole time but I had to special order the glass on the front door and installed it... you guessed it, right after the 8th print. The enclosure is almost airtight and the temp in the print chamber climbs up to about 37c when printing. I had thought I was cooking my Pi running octoprint but will try printing with the door open as well. I wish I would have know this before I designed the enclosure : (

Love my enclosure. Makes ABS easy to print(almost). I found my PETG prints to be stronger also. I have done a little printing worth Nylon but not in the enclosure. That will be next. I've printed with PC but not on the prusa yet. They are both a pain not because of printing difficulties but the way they absorb moisture.

So these pics were super hard to take but there's a photo through the door, and I tried my best to show the hole where filament goes into on top of the extruder. Nothing looks out of the ordinary with the side photo of the gears. HOWEVER, if you look closely in the top picture (again I know its hard to see), you'll notice that about half the hole seems to be covered by the extruder gear. So my suspicion is beginning to get stronger that the gear is slightly off from where it needs to be, explaining why the filament is more grinded on one side (the extruder side).

Before I print with the enclosure door open, I'm going to see what I can do about shifting the extruder gear over slightly. I'm fairly sure this is the issue now. Check out my latest reply with images!

Lightburn up to date 1.3.01 and now the laser when framing is going ballistic grinding and not framing right. I have projects to do on a time line and if Lightburn will not run when I need it maybe I need to find another software.

If you did not update Lightburn, it sounds like you may have some mechanical problems related to you laser. Make sure all the grub screws are tight, the belts are not lose or worn and mechanical limit switches (if so equiped) are working properly.

Can you please describe the framing error? Is the laser traveling to the wrong spot? Are you comfortable sharing the Lightburn file that demonstrates these issues? If so, post it here and other people will certainly take a look at it to see if the problem exists with the file.

It is not a mechanical issue I have an image when framing will grind when it gets to the third side of project and then it will go off project and stop. I then took the same image made it smaller and still grinding when framing. I then shut down computer and laser restarted and framed smaller image and it frames just fine until I make the image larger again then it will do the same until I shut down and make smaller. I need this to work today.