Extruder motor "stuttering"
In the last couple of weeks, I've had some trouble with my extruder motor "stuttering". By that I mean it will print smoothly for 5-10 seconds and then skip a bit (see #2 in picture). It skips because the motor shudders and there is a rapid clicking noise for 1 second or so. The filament rattles during this time.
I don't think it's stuck filament since I ran through a Prusa trouble shooting guide that had me stick an acupuncture needle up the nozzle which worked fine. Also, as you can see in #1 in the picture, filament is extruding.
Other observations:
The PFTE tube is slightly distorted but still fits in the intended fitting.
The gears that feed the filament are shredding the filament because the filament won't go in. (This is also part of the motor clicking)
In the actual printed square, you'll notice I changed the Z height about half way through. The bottom right is -600 and the top left is -900. Even in the top left, the filament is thinner than it should be.
I appreciate your 3D printing wisdom!
Re: Extruder motor "stuttering"
wow. the way the left side outline is not straight might be the clue. the belts tight? or do the shafts have groves in them?
I have a Prusa,therefore I research.
Re: Extruder motor "stuttering"
I am going through something similar.
I've been running non-stop 0.05mm prints for a month now and in the last week I've been catching the "grinding" you mention occasionally. I figured it was loose drive gears, but I was ignoring it as I wasn't seeing any issues with the prints and I was hoping I could delay maintenance until I was done (should have been finished tomorrow).
Thursday, however, a print failed over night (acted like my filament sensor was on the fritz), but when I restarted it had clearly missed multiple layers as the new layer wasn't sticking to anything.
I ran it again and about 6 hours in the grinding became much more frequent than I've heard before. After another few hours when I was certain it wasn't laying down filament, I killed that print too.
I tried manually extruding and it just ground away so I ejected the filament and tried reinserting it. It got passed the gears and then stopped. I pulled the nozzle out (which was clearly gunked up), but I still could not feed the filament through.
I used my heat gun to heat up the nozzle so I could clean it up some and use the needle to reopen it. I also cranked the extruder up to 270 (just been printing with PLA at 215) and this time when I fed the new filament through a plug of the old filament popped out.
I cooled it back to 215, reinstalled the nozzle, and it's been printing fine (0.2mm mostly) for some utility prints since. It is printing a 0.05mm print right now.
I'm not sure what my root cause was (maybe just backing up too much with the 0.05mm layers?), but you might try pulling your nozzle, running the heat well above the normal for your material, and push some scrap filament through to see if it cleans anything out for you.
You could also start with cold pulls, but every time I've tried the filament comes out clean and perfectly shaped.
Re: Extruder motor "stuttering"
Your first layer cal is way too high, even at 900. A stopped up nozzle may be part of the issue.
As for cleaning the nozzle, a needle doesn't replace a cold pull. A partial plug can keep coming back since all the needle does is push the "ball bearing" out of the way; next surge of plastic and the offending chunk moves right back to where it was and starts plugging again.
Re: Extruder motor "stuttering"
wow. the way the left side outline is not straight might be the clue. the belts tight? or do the shafts have groves in them?
Hi Chris,
The belts are tight. I didn't understand what you meant by "do the shafts have grooves in them" but I did get the motor to stop stuttering.
Re: Extruder motor "stuttering"
Thanks for your replies everyone. I did get the motor to stop stuttering by doing the following. I don't know which specific one did the trick.
1. Did two cold pulls (video: )
2. Tightened the screws holding the extruder gears that pull the filament down
3. Switched filaments
4. Tightened the pinda probe.
This has stopped the stuttering though there are still waves in the print. I'm going to ask another question about that because I don't think it's related to the motor stuttering.