M2 stops extruding after an hour or two

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prosumer
Posts: 8
Joined: Tue Jul 27, 2021 6:51 pm

M2 stops extruding after an hour or two

Post by prosumer » Mon Oct 24, 2022 4:08 pm

As the title says, I can print a Benchy, but any long print will eventually fail. I hear occasional clicks from the extruder motor. I've ensured there are no blockages, the filament path is clear. This is a new extruder case, but my M2 is about a year old. Everything is working otherwise. I've adjusted the temp higher and that may have improved things, but I'm looking for other ideas. Can I log the gcode in octoprint and find out if the extruder motor is reporting overheating?

airscapes
Posts: 570
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 stops extruding after an hour or two

Post by airscapes » Mon Oct 24, 2022 7:30 pm

Assuming you filament tension is set correctly the following have happened to me over the years

Bad Thermistor in the hot end or intermittent wire (they break at the hot end)
Bad heater or wire in hot end
Bad wiring harness

Filament Drive gear loose on the shaft.
Filament Stepper motor Pinions Gear spinning on the shaft (have to remove extruder housing and the gear housing off the front of the drive.
(A way to know if this is the cause is once your filament stops extruding, if temperature is still reading correctly, use a flash light and look a the filament dive gear and shaft it is on. If neither is moving, look at the back of the stepper motor. You will see the saft in the center of the motor, if it is moving then your pinion gear is spinning on the shaft

If when you view the filament drive it is moving, the software says the hot end is hot, the hot end is physically hot, but nothing is extruding, you could have filament that is very over sized or undersized in places causing slipping or jamming. Or an intermittent heater that goes cold, causes the drive to strip out the filament. What does the filament look like when your extract it, is there a chunk out of it?

I have had all of the above happen.. Thermistor, heater, gear and really messed up roll of filament.

prosumer
Posts: 8
Joined: Tue Jul 27, 2021 6:51 pm

Re: M2 stops extruding after an hour or two

Post by prosumer » Mon Oct 24, 2022 11:56 pm

thanks airscapes.

Filament tension was my first thought. Before I get into what I've done with that, let me tell you about my printer. It's an E.1 that has had the F/G cooling kit added to it. It's mostly an F/G, I would think, apart from the stepper motor for Z. The nozzle and hot end are brand new. I am doubtful that it is the wiring, and if not the tension, I would look at the filament gear or motor as the problem.

I've played with filament tension. Loosening it fails to pull filament, and tightening it seems to jam. Unfortunately, it can take several hours before I know if things have improved. A Benchy is almost certain to print perfectly, so I need to find prints that are multi-hour. I can confirm that there is no play on the screw and it does not move during printing. I can confirm that filament will immediately start flowing again, if the print is stopped and restarted, or filament is extruded. This leads me to believe it's something in the filament drive/gear.

I don't think I mentioned that prior to the failure, I am hearing some clicks from the extruder. It's similar to the sound it makes when a piece of filament is stuck, but it is temporary and does not stop the printing. I think this is the same issue, and that every time it happens there is a chance the print will fail, and eventually it does.

Things I'll do now:
First, run a multi-hour print with a slight tightening of the filament tension screw.
If that doesn't fix it, I'll disassemble the filament drive and check out the gear, and then reassemble and watch the gear rotation during a print.

I'll let you know what happens. Thanks again for the advice, airscapes.

prosumer
Posts: 8
Joined: Tue Jul 27, 2021 6:51 pm

Re: M2 stops extruding after an hour or two

Post by prosumer » Tue Oct 25, 2022 12:51 am

After 35m, the extruder began to make a noise. Not the clicking it makes when it is stuck, but a thwacking sound, every second or so. I think this was possibly during retraction, while printing infill.

I immediately stopped and retracted the filament which came out cleanly and showed good bite, but I could see where the extruder skipped on a couple of spots. I now suspect it's partially the profile I'm using, which is the one from github for Prusa Slicer. I may need to tweak things. I'll post again after printing.

edit:
After reducing retraction distance and raising minimum retraction distance, the print failed again around the same point.
This time when it failed it was repeatedly clicking.

airscapes
Posts: 570
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 stops extruding after an hour or two

Post by airscapes » Tue Oct 25, 2022 12:52 pm

Sounds like an internal gear issue. If you are not familiar that extrude has a center pinion gear, the one that comes loose, and a set of planetary gears. If the gear is loose, you have 2 options, clean it really good, and apply lock tight or Crazy glue. The glue worked for me until my new extruder arrived. I had bought a new gear but it was looser than the original. Best to just buy a complete unit. That is once you have varified this is the issue.

While it was clicking at the end, were you able to look at the filament drive gear to see if it was moving with the clicking?? There is a 1 mm alen screw that holds that gear to the shaft that can come loose. When checking to see if the shaft in the motor is moving, it can help to use a felt tip pen and put a dot on the saft out at he edge.

I have never found the need to have retraction set more than 1.3mm and that is with a .75 mm nozzle nor the need for any lift..

prosumer
Posts: 8
Joined: Tue Jul 27, 2021 6:51 pm

Re: M2 stops extruding after an hour or two

Post by prosumer » Wed Oct 26, 2022 12:34 am

If the tension was too low, could the filament slip after lots of retraction? I've tightened the tension considerably, and I'm going to try again. If it continues to happen, I'll replace the filament drive motor and gear, although I'd rather not! I will also check for movement, and report back. I can say that, although I didn't see it, I expect it is moving.

prosumer
Posts: 8
Joined: Tue Jul 27, 2021 6:51 pm

Re: M2 stops extruding after an hour or two

Post by prosumer » Wed Oct 26, 2022 2:47 pm

The problem persists, and I can see when it skips that the gear stops turning, so I imagine it is a problem with the extruder motor.

airscapes
Posts: 570
Joined: Wed Jan 31, 2018 11:36 pm

Re: M2 stops extruding after an hour or two

Post by airscapes » Wed Oct 26, 2022 3:22 pm

look at the back end of the stepper motor. You will see hole with a silver shaft in that hole. Put a dot on it near the edge of the shaft with the felt tip pen so it is easy to see it turning as it turns slow. When you see the the shaft at the filament end stop, see if the motor end is also stopping.
If the motor end is not stopping then remove the extruder housing and make sure the filament gear is not loose on the shaft. If it is not, then probably the internal gear slipping and a complete replacement would be simplest ..
https://makergear.com/collections/parts ... 1668418500

prosumer
Posts: 8
Joined: Tue Jul 27, 2021 6:51 pm

Re: M2 stops extruding after an hour or two

Post by prosumer » Wed Oct 26, 2022 4:09 pm

I will do it tonight. I did read that suggestion earlier, but at least last night, it printed for hours before failing, so I didn't see it.

prosumer
Posts: 8
Joined: Tue Jul 27, 2021 6:51 pm

Re: M2 stops extruding after an hour or two

Post by prosumer » Fri Oct 28, 2022 5:43 am

The motor is moving. It seems the problem is actually a clogging nozzle. It's almost brand new, and I hadn't suspected it. I have no idea why it's clogging mid-print, but I suppose since things were fine at the start of this roll that it may be the filament has absorbed too much moisture. It's never been a problem for me before, but I will try some other filament, and then move on to a cleaning filament and perhaps a new nozzle, as I don't have any good ones at the moment.

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