Extruder Motor Overheating
Hello,
I've been posting in the MMU2 forum a bunch about this, but I figured it doesn't actually fall under the initial thread that I was in, so I'm going to move to this thread as an ask for help.
During printing of a few pieces using Single Mode of MMU2, I have been getting filament breakage inside of my extruder bowden. I suspect that this is due to my extruder motor overheating, but I do not have an IR thermometer or a thin temperature probe to double check actual temperatures. I do know that as the extruder prints, it ends up getting so hot that I am unable to touch the motor for more than half a second.
Peter had thought that the problem is due to the current changes that they made in 3.5 firmware, so I downgraded back to 3.4.1 and still see the same issues now. I also included a bit of different start g-code to try to set currents, but that also was unsuccessful. I've posted my last reply in the previous thread below, and I have some photos after that.
For the sake of it, I've also included my Slic3r g-code in case there may be something hidden in there from my presets.
Printer: MK3 MMU2 (Single Mode)
Filament: 3dSolutech PLA
Mods: Rebuilt printed parts in PETG. Removed filament sensor and using pass-through adapter for festo.
I am able to print small prints successfully. I last successfully printed parametric rewind spool holders using 3.5.0, and I also printed the new extruder body (to remove the sensor), but it required about 10 tries to get it to finish.
Can you describe "broken filament" in more detail? Hot extruder motor is usually only leads to jams during slow prints.
So at the idler/extruder bowden section of the extruder, the filament appears to soften enough from the heat to not grip anymore on the bowden, which leads to failed extrusion. When I use the LCD panel to Stop Print, the filament comes out from the bowden connection and then I have a portion of filament stuck from the bowden to the nozzle that I have to pull out.
I'll take a picture the next time that it happens. I'm re-printing my filament cover using a lower layer height to make better M10 screws. Then I'll start trying to print my longer-print again and see how it looks. (I'm using Peter's gcode in the start just to see how it works).
Print did end up failing last night. I was feeling the e motor and it was warming up still as I was going through the print (using Peter's start gcode and 3.4.1 firmware). I had reset the idler completely and kept it a bit loose to make sure that I wasn't causing a jam to occur.
First is the inside of the extruder/bowden:
Next is the ejected filament after the print was "completed":
Last is the "tip" of the filament after I pulled it out of the hotend. Since the print "went" for another 4-6 hours after the print failed, I suspect that melted plastic just "pooled" at the nozzle. The plastic is also pretty brittle to the touch.
Any help that could be provided will be welcomed! I was considering a heatsink, but since I haven't had this issue happen before, I don't think it's right. I'd like to fix the problem before adding parts.
Re: Extruder Motor Overheating
Here are my couple cents:
-> Looks like the filament you're using is too brittle (manufacturer error?). Fresh and good PLA/PETG/ABS can be bend by 90 degrees without breaking apart. Make sure it's still elastic and don't break easily.
-> Release the pressure on the extruder gears. They biting too hard. Even in case of nozzle jam you should see 1/3 of the filament bone between the gears.
-> The filament tip looks like you've printed too cold. Increase the nozzle temperature by 10-20C and compare the results. (after you verified your filament is still good (1))
Don't change too much in the hardware/firmware/software. Stock hardware/firmware/software is doing already a good job. Because there are more people running original hardware, it's much harder to investigate the root cause of the issue.
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Re: Extruder Motor Overheating
Here are my couple cents:
-> Looks like the filament you're using is too brittle (manufacturer error?). Fresh and good PLA/PETG/ABS can be bend by 90 degrees without breaking apart. Make sure it's still elastic and don't break easily.
A piece of filament I cut off actually folded 180 degrees without breaking, but that doesn't mean that the whole roll is like that (obviously)
-> Release the pressure on the extruder gears. They biting too hard. Even in case of nozzle jam you should see 1/3 of the filament bone between the gears.
Definitely will be trying this out.
-> The filament tip looks like you've printed too cold. Increase the nozzle temperature by 10-20C and compare the results. (after you verified your filament is still good (1))
Trying this too. I was using the "Pretty PLA" profile, but that may not be sufficient anymore.
Don't change too much in the hardware/firmware/software. Stock hardware/firmware/software is doing already a good job. Because there are more people running original hardware, it's much harder to investigate the root cause of the issue.
My original intention was to make the "printer mine"... Sadly, with the MMU2 upgrade, that is more difficult than it has been in the past.. I'll report back on the above changes and see how things look tomorrow.
Re: Extruder Motor Overheating
-> Release the pressure on the extruder gears. They biting too hard. Even in case of nozzle jam you should see 1/3 of the filament bone between the gears.
Definitely will be trying this out.
-> The filament tip looks like you've printed too cold. Increase the nozzle temperature by 10-20C and compare the results. (after you verified your filament is still good (1))
Trying this too. I was using the "Pretty PLA" profile, but that may not be sufficient anymore.
As an update. I failed my first print because I had the idler too loose. I tightened it up slightly and increased the nozzle temp by 10C and it printed wonderfully. Using a different filament.
I'm going to try it again with my original filament and see if it was the idler and/or temperature. If it works with the original filament, will check 3.5 firmware again.
Re: Extruder Motor Overheating
So I was able to fix the overheating issue but now I have a new issue that appeared.. I'm getting the Bowden to skip, causing under extrusion.
I tried tightening and loosening of the idler and it doesn't seem to affect three print quality. I'm unsure if maybe I stripped the gears of the Bowden, causing the skipping even with a good idler tightening?
I've pushed filament with no issue through the extruder, but it seems like something is causing a clog... My only thoughts are either replace the extruder, or maybe try running super slow, which would minimize the amount of resistance the Bowden would see.
Any other thoughts? Thanks
Re: Extruder Motor Overheating
That big blob on the filament tip shows that the teflon tube in hotend is not properly positioned.
For some reason, the tube has slid up and a cavity has formed below the teflon tube.
The blob should not be longer than the diameter of the filament.
You should disassemble hotend and push down the teflon tube so that it bottoms in hotend. Press down the Teflon tube while pulling up the black locking ring on the top of the hotend.
Bear MK3 with Bondtech extruder
RE: Extruder Motor Overheating
So I was able to fix the overheating issue but now I have a new issue that appeared..
What did your issue end up being? I'm using the MMU2S / MK3S with stock parts and firmware, and my extruder motor is getting way too hot to touch. Looking for any solutions.
RE: Extruder Motor Overheating
So I was able to fix the overheating issue but now I have a new issue that appeared..
What did your issue end up being? I'm using the MMU2S / MK3S with stock parts and firmware, and my extruder motor is getting way too hot to touch. Looking for any solutions.
Same issue on my end. The extruder stepper motor gets really hot, so that the filament at the bowden drivegears is melting, so that the filament will not be moved anymore.
When the printer is cold, it prints a few layer. However when the stepper motor of the extruder gets too hot, it stops to move the filament.
See attached image.
The printer is a Prusa i3 MK3 (one of the first models). All parts are fromk stock. Printed with normal PLA and 215°C/60°C.
Any idea?
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RE: Extruder Motor Overheating
Same. Just posted up in the general discussion. May be more people will check there.
The extruder is really hot such that the heat transmit to the bondtech gears.
Therefore my machine is able to print material with higher melting temperature e.g ABS/PETG but not with PLA for a longer period of time.
RE: Extruder Motor Overheating
This helps very good, i installed this and let it blow to the top.
I adjusted the stl to clamp without glue.
https://www.thingiverse.com/thing:2975582
Prusa i3 MK3 Extruder Stepper cooler
Also wen printing pla use a extra fan to blow air in the enclosure if you use a enclosure, blow low in the enclosure so the hot air can go to the top, and leave door open.
If someone makes a new enclosure, make more doors to open.
Ofcourse check if your heatbrake and nozzle and tube is build 100%, check manuals and youtube movie for instructions, no gab allowed.
RE: Extruder Motor Overheating
This helps very good, i installed this and let it blow to the top.
I adjusted the stl to clamp without glue.
https://www.thingiverse.com/thing:2975582
Prusa i3 MK3 Extruder Stepper cooler
Also wen printing pla use a extra fan to blow air in the enclosure if you use a enclosure, blow low in the enclosure so the hot air can go to the top, and leave door open.
If someone makes a new enclosure, make more doors to open.
Ofcourse check if your heatbrake and nozzle and tube is build 100%, check manuals and youtube movie for instructions, no gab allowed.
Looks great! Unfortunately, that design doesn't work with the new chimney (that comes with the MMU2S upgrade).
RE: Extruder Motor Overheating
Hi again,
I made some tests with my i3 Mk3 again. I placed a temp. sensor on the extruder (backside, where the label is printed on). I measured about 54°C after a few minutes of print (15-20 min). Then the extruder (drivegears) started to make "clicking" noises and no filament was coming out of the nozzle at that state.
I paused the print and pressed "unload filament" and then load it again. This was working, so it's not a jam at all. After that, a few lines later, the same starts again with the clicking nois of the drive gears.
I now replaced the complete hotend. Time will see if this helps.
Best,
Andy
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