Extruder skipping on new i3 mk2 build
First off, I want to congratulate everyone involved with the design, production, packaging, and documentation of the i3 Mk2 kit. Took a while to build, and the only time I had a problem is when I misread a step (my own fault).
I got everything calibrated, it puts down a decent bead using the calibration print (after some live Z tuning) and I printed a couple of models in the free provided PLA spool (copper).
Last night I started printing the included gear bearing from the SD card, this morning when I checked the printer I noticed the top layer looked a little rough but didn't think anything of it. Later I printed something I sliced myself using the settings provided from Prusa and a .25mm layer height. After about the 20th layer or so I heard a clicking noise and realized the extruder had stopped pulling in filament. I stopped the print, assumed that somehow the nozzle was clogged, cleaned it out and backed out the filament. I noticed a concave section of the filament where it was clear the extruder gear had rubbed into (I wasn't in the room when it first happened). So I cut the filament and reloaded and tried again. It appeared to happen at around the same area though I can't be certain.
I decided to switch up to ABS (since it's what I'm more familiar with) and a known good roll from my old Solidoodle 3 (yuk). Resliced the model for ABS and began printing. I left the room after it looked like everything was sticking down and came back 30 or so minutes to find it clicking again. This time, I did another "load filament" while gently pressing down on the filament to get past the spot where I assumed it had ground away. It pushed out the filament just find with no need to clear the nozzle.
I have both tightened and loosened the idler bearing, everything appears to be lined up properly from what I can tell. It definitely goes several layers before it exhibits a problem.
I'm wondering about the spool holder and if it might be binding or creating too much tension. It didn't feel that way to me but it might just be too much for the extruder motor to pull. It doesn't appear as though the shaft is slipping on the gear, my next step is to pull the extruder apart and check things out.
Searched the forums and the googles and tried a few of the suggestions above but looking for any other thoughts.
Bill Church
Saint Petersburg, Fl USA
Original Prusa i3 Mk3 Kit Stock v3.8.1-2869
Original Prusa i3 Mk2 Kit Stock v3.2.3
Re: Extruder skipping on new i3 mk2 build
I am experiencing the same problem too here. Still trying to figure out whats the issue. Most likely will be the idler and the pulley alignment.
Re: Extruder skipping on new i3 mk2 build
Well, not sure if I've fixed it yet, I need to print a bigger model, but I played around with the filament spool holder a bit and reloaded the filament (back to Prusa provided PLA). So far I've printed 5 of these: http://www.thingiverse.com/thing:1091422 for my daughter and they've come out perfect. I think I'm going to setup some sort of rod arrangement for the filament spool. I've seen a few printed bearing setups out there that look interesting as well.
Currently I don't have the idler pulley tension all that tight, finger tight until about half way, if that makes sense.
My next step was to see if spooling off some loose filament caused the same problem, to eliminate the friction from the reel or any binding that might be happening there. I never had this issue before with the Solidoodle, but I sure as hell couldn't get prints as nice as the ones I'm getting even with a new E3D, so I'm not going to complain. 🙂
I've noticed thought that once it starts slipping, that's it and you have to back out that filament and cut that part off since it's been chewed up.
Oh, one other thing I noticed, when I switched to ABS I saw that I had black transfer on the idler pulley from the black ABS filament... That's odd to me, it ran all the way around the circumference of idler pulley.
Bill Church
Saint Petersburg, Fl USA
Original Prusa i3 Mk3 Kit Stock v3.8.1-2869
Original Prusa i3 Mk2 Kit Stock v3.2.3
Re: Extruder skipping on new i3 mk2 build
Just to follow up, I've printed a new spool holder and I no longer have the issues with skipping.
Printed this one: https://www.thingiverse.com/thing:1688923 in Taulman TECH-G, because why not. 🙂
Bill Church
Saint Petersburg, Fl USA
Original Prusa i3 Mk3 Kit Stock v3.8.1-2869
Original Prusa i3 Mk2 Kit Stock v3.2.3
Re: Extruder skipping on new i3 mk2 build
Just to follow up, I've printed a new spool holder and I no longer have the issues with skipping.
Printed this one: https://www.thingiverse.com/thing:1688923 in Taulman TECH-G, because why not. 🙂
Good to hear. I printed that filament guide/spool holder as well. Seems to work great!
Re: Extruder skipping on new i3 mk2 build
I had similar issues with the gear bearing. That model has alot of retractions and a tendency to cause underextrusion/clogs. It would be better it setup for fewer/shorter retractions.
For me I managed to make it work by increasing the temp from the default 210 up to 225 and did NOT change the file. It would have been better to reslice it with less retractions but this also did the trick.