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Problems and severe underextrusion on new M2 Rev E

Posted: Thu Dec 21, 2017 2:03 am
by okayjustin
I got a new M2 Rev E a few weeks ago and I've had a bizarre underextrusion problem that I haven't seen anyone else document (I've pretty sure I've read every extrusion related thread in this forum and other printer forums). When printing a thin 20mm wall cube (Slic3r Prusa Edition, 0.2mm layers, 30mm/s print speed, 210C, MakerGear Black PLA, 1 perimeter, no top/bottom/infill), I expect a wall thickness of about 0.39mm. However, when I measure with a caliper, I get 0.24mm consistently. The layers don't adhere very well either.

Things I've already done:
- Leveled the bed using the M2 Quick Start
- Unclogged the nozzle
- Used a new 0.35mm MakerGear nozzle
- Adjusted the extruder tension so that the bite is ~15% depth and the filament is still round
- Calibrated the extruder (more below)

I noticed some odd behavior while calibrating the extruder. I measured out 100mm and printed 100mm, but each time I did this, it would print a different length (sometimes differing by up to 20mm). The weird thing is that I don't hear any clicking from the extruder motor to indicate skipping. I've also taken off the extruder fan to watch the if the shaft is slipping inside the filament gear but it isn't. I really don't know what else to try at this point. I'm really just disappointed with the M2 because I assumed it would mostly just work out of the box, but I've already spent 30+ hours troubleshooting an expensive, new machine.

Re: Problems and severe underextrusion on new M2 Rev E

Posted: Thu Dec 21, 2017 4:01 pm
by sthone
What is your extrusion multiplier set at?

Just to be sure you are running a brass nozzle and not a stainless steel one correct?

I've never done a length check like that but a 20mm difference sounds like a lot.

Checking if the gear moving is a good first step... in the future it helps to draw a line with a marker on the gear face and across the shaft too so it's real easy to see if it moves.

To determine if the problem is with the hotend or the extruder (and or the gear) you could remove the hot end from the mount and repeat the length test and set if you get 100mm feed that way. (you will have to use the M302 command to allow cold extrusions.)

If you do get 100mm feed now try removing the nozzle and then remount the hotend then just running a bunch of filament through the barrel of the hotend... I've had a clog in the barrel before and I had to push it out with the little Allen wrench. I then did some cold pulls with cleaning filament to make sure I got it all.

Re: Problems and severe underextrusion on new M2 Rev E

Posted: Thu Dec 21, 2017 9:08 pm
by jk42
Great suggestions from "sthone". I am also interested in what your layer height is. Especially, since you are having layer adhesion issues.
I would encourage you to open a ticket with us at support@makergear.com so we can help you get the results you are looking for.

Re: Problems and severe underextrusion on new M2 Rev E

Posted: Thu Dec 21, 2017 11:14 pm
by okayjustin
I'm using a brass nozzle with extrusion multiplier set to 0.9. Added a sharpie line across the gear/shaft.

Just ran a test per your advice. Removed the fan and hotend so it's just the extruder gear. Used OctoPi to extrude 100mm of filament and only 79.2mm came out. No gear slippage. How is this possible!?

Re: Problems and severe underextrusion on new M2 Rev E

Posted: Fri Dec 22, 2017 5:13 am
by sthone
Remove the filament drive and hand feed the filament through it to see if it feeds smoothly. Sometimes there can be a burr in the hole either from wear or maybe even when the drive was printed. Sometimes you even have to hog out the hole with a drill bit.