M3 T1 Extruder Motor pausing/skipping/retracting

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zahn
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Joined: Thu Dec 21, 2017 10:54 am

M3 T1 Extruder Motor pausing/skipping/retracting

Post by zahn » Sun Mar 04, 2018 3:06 am

Hi Everyone,

Basically when I feed filament through the motor, it comes through the nozzle but you here a skipping noise ever so often, when you look at the gear/motor on the extruder you can see that it slows down, stops, and retracts all in a matter of seconds before it continues going forward. I thought it was a clogged nozzel/barrel but I have checked both and they are clear. Does anyone have any suggestions as to what could cause this? It was working fine yesterday and suddenly today it is skipping.

Thanks in advanced!
Zahn

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ednisley
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Re: M3 T1 Extruder Motor pausing/skipping/retracting

Post by ednisley » Sun Mar 04, 2018 2:46 pm

zahn wrote:It was working fine yesterday and suddenly today it is skipping
The single best debugging advice ever: "What's new and different?"

Whatever you changed, un-change it and try again. If you're absolutely certain nothing changed, think again:
  • Different solid model?
  • Different STL file?
  • Different slicer settings?
  • Different filament material?
  • Different filament spool?
The symptom suggests the extruder motor is overloaded and skipping steps, which (in the absence of different slicer settings) is usually a mechanical problem:
  • Filament snagged on the spool
  • Filament too large for holes in filament drive
  • Worn filament drive
  • Misalignment between filament drive and hot end
Basically, whatever you're doing differently, no matter how small the difference, will point you toward the problem.

For me, the hardest part is not insisting "Nothing changed!" [sigh]

zahn
Posts: 13
Joined: Thu Dec 21, 2017 10:54 am

Re: M3 T1 Extruder Motor pausing/skipping/retracting

Post by zahn » Sun Mar 04, 2018 11:02 pm

Thanks ednisley, that was very helpful.
After taking of the fan and look at the extruding mechanism, the gear with teeth appeared fine and was rotating normally, however the smooth wheel was slowing down and stopping occasionally, thus not pushing filament through consistently. I took of the ABS piece attached to the motor and saw that the screw holding the smooth wheel in place had gotten loose! Fixing this and adjusting the tension screw solved my problem!

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ednisley
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Re: M3 T1 Extruder Motor pausing/skipping/retracting

Post by ednisley » Mon Mar 05, 2018 1:16 pm

zahn wrote:the screw holding the smooth wheel in place
That's a new one!

The screw is a shoulder bolt through the middle of the bearing and, obviously, it should always be snug in its nut. If it works loose again, a dot of threadlocker will be in order.

Now we all have one more thing to check ... [grin]

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