Filament stops feeding consistently during printing
I've had my Mini for a while and never had too many issues with it. Recently, though, the filament wouldn't come out, it seemed jammed. I cleaned the nozzle and that still didn't fix it.
I opened it up and found a bunch of filament dust and bits in the gears. So I cleaned it out and it worked again, for a few prints. Then, during a print, the upper layers became inconsistent and had gaps in the middle. I cleaned it off and tried another test run, this time it ended with spaghetti everywhere.
Here's what I mean about inconsistent layers:
You can see the bottom is fine, but it starts getting inconsistent on the upper layers.
I opened the extruder flap after the spaghetti print and found some more filament dust, which I cleaned out, but it's not permanently jammed or anything. But it kind of looks like the gear teeth are slightly worn out? Do I need to replace this?
Is this damage, and how can I prevent this in the future? Anything else I should check out that could be causing the issue instead? I tried tightening the idle screw one or two turns, and it didn't seem to help at all.
Thanks!!
RE: Filament stops feeding consistently during printing
I haven't looked at those gear teeth in forever but I'm pretty sure yours don't look normal... Don't know how that's even possible.
In any case, do yourself a favor and get the Bondtech dual drive extruder or the Trianglelab clone. The only upgrade to Minis I consider essential. I haven't had a single clog or had to adjust the idlers on my two Minis in a year of printing a lot, with all sorts of filament.
RE: Filament stops feeding consistently during printing
Thanks for the advice - I'll definitely look into that part. This was the first difficulty I've had with this printer but always good to improve.
For now, I actually was able to fix it. What I thought was damage to the teeth was actually impacted filament. I took a nail and dug out each groove. My next print turned out fine - hopefully this fixes the issue.
RE: Filament stops feeding consistently during printing
From your description I would have guessed a partial blockage in the hot end. Wouldn't do any harm to do a cold pull or two and/or flush with cleaning filament.
RE: Filament stops feeding consistently during printing
Well, I let it run overnight, and the gunk is back. Print stopped halfway through (well, it was still trying to print, but it stopped extruding)
Could this be from a partially blocked nozzle, or poor heating? Cold pull could fix it maybe? I'm wondering if the ground up filament is a symptom, not a cause.
RE: Filament stops feeding consistently during printing
When I got a partial blockage, I saw that in the extruder. It was a symptom, but not the problem. I also got clicking from the extruder as it tried to overcome the increased back pressure. A cold pull resolved it and it's been running flawlessly since.
Mini+ (kit) - Revo Micro | Antler Cooling | WiFi (4.4.0RC1)
RE: Filament stops feeding consistently during printing
This kind of problem on a Prusa Mini usually indicates a loose or deformed PTFE tube in the hot end or even heat creep. You can't solve it by replacing the extruder.
You can try a cold pull. You can try to replace the PTFE tube. I've given up on all that and am going to install an e3D Revo Micro hot end.
RE: Filament stops feeding consistently during printing
It is possible this is a symptom of a problem in the hot end. I've had my share of those. However, it could also be an indication that you're applying too much pressure with the idler wheel. According to Prusa too much pressure can lead to grinding. Prusa had a guide here:
https://www.help.prusa3d.com/en/article/idler-screw-tension_177367/
Regards
-Bob
Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit
RE: Filament stops feeding consistently during printing
Thank you all for your input. When I get some time, I will attempt a few cold pulls and see if that fixes the issue. Then I can move on to checking out the tube. As for the idler screw, I ran it with the screw flush with the plastic while unloaded, as well as running it with the screw flush when loaded as well (which should make it looser), so I think it might be less likely the problem is there.
Thanks again everyone. I will try to remember to update with the fix for future forum searches 😛
RE: Filament stops feeding consistently during printing
Ok, I tried a few cold pulls, went fine. Cleaned out the gears again, reassembled, made sure the tension screw was flush with the housing when unloaded. I went to load the filament, and it loaded it in just fine, but when it attempts to purge, the gear just goes back and forth and the filament doesn't move (I have the cover open on the top). It's weird because it LOADS perfectly fine, but when it tries to purge or during first layer calibration test, the gear just stutters back and forth.
RE: Filament stops feeding consistently during printing
Have you tried removing the bowden tube on the hot end and feeding the filament by hand? It's kinda sounding like you have a clog in the nozzle.
Cheers
-Bob
Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit
RE: Filament stops feeding consistently during printing
I did do a few cold pulls, which involves feeding the filament by hand. If I look down the nozzle from the top of the print head, I can see straight through to the print bed, so I think the nozzle is clear.
RE: Filament stops feeding consistently during printing
https://www.bondtech.se/product/ifs-extruder-for-prusa-mini/
Fuchsr, Is this the kind of thing you're talking about?
I'm not sure why the gear is stuttering during purging but not loading/unloading; I'm wondering if a new extruder could fix it.
RE: Filament stops feeding consistently during printing
Yes, that's the one. I actually have the Trianglelab clone of the original Bondtech extruder (without the integrated filament sensor) on my Minis as I ordered them with the Prusa filament sensor.
RE: Filament stops feeding consistently during printing
Ok excellent, thank you. I'll try this out. Hopefully it fixes the issue!
It's possible I just reassembled the stock extruder wrong, or there's something wrong with what I'm doing, but if this thing is an improvement, I might as well upgrade anyway especially at that price.
RE: Filament stops feeding consistently during printing
I've been very very happy with those dual drive extruders. Haven't had any filament feeding issues.
RE: Filament stops feeding consistently during printing
It looks like Amazon has them too, I might get them here to avoid waiting for a month for shipping from AliExpress haha
RE:
I'd be careful. This listing doesn't state it's for the Mini. Trianglelab makes extruders for Enders etc. This one may or may not fit. It certainly doesn't look like mine. BTW, IIRC it took 2 weeks when I ordered on Aliexpress. They usually ship faster than stated in the listings.
RE: Filament stops feeding consistently during printing
Oh good call. Ok, I'll just go with the one you linked 🙂
RE: Filament stops feeding consistently during printing
One more quick note. As I said, the Trianglelab extruder doesn't have the integrated filament sensor of the Bondtech IFS. It's a clone of the original Bondtech Mini extruder. Bondtech sells an upgrade kit from original to IFS. This kit is NOT compatible with the Trianglelab extruder, due to the way the internal gears are attached. I know from experience; I bought a kit out of interest.