Extruder motor stops mid print.

Such a weird problem.

Specs:

*The printer is in a heated chamber, 50C ambient. All stepper motors gets hot, but not too hot to touch. So should be okay.
*The motor is a pancake motor on a E3D titan extruder, with A4988 driver.
*All other motors on the printer are controlled by DRV8825 drivers.

Problem:

*Extruder motor stops mid print, but can also just stop when testing to extrude some filament, when the stepper motor isnt even a bit hot.
*After a while it usually starts again when letting the print continue, but will stop shortly thereafter.

I have touched the extruder driver(A4988) when this issue occurs, and I must say that the other drivers are hotter, this one I almost can't say if it is above room temperature or not.

What could this be??

Do you have a loose wire on your pancake stepper that could be breaking connection and remaking connection later on in your print? All it would take is a minor wire break in 1 of the 4 stepper wires for the motor to stop turning, and with your comments of the printer resuming later and then stopping again makes it look like there could be an intermittent issue with your wiring as the head travels around pulling on the wire.

That is really a good suggestion! I'll try to check that tonight, although it will be hard to troubleshoot.

What I've done to try and troubleshoot something like this is tell the extruder motor to extrude say 100mm of filament. While its doing that, I try and pull, tug, and twist the motor cables around to see if it stops. If not, I move the head into another location and do it again. Eventually you'll find a spot that has the issue and then can break out a multi-meter and ohm out the motor wiring while in that spot. You could probably ohm out the wiring if you have 2 multi-meters without power on the motor and watch to see if you loose ohms on a motor pair while you move it around also.

Also make sure your cables to the head are secured to the carrier and that there is enough slack in them. When I first set my machine up it would partly pull the plug out of the extruder stepper when in certain positions. This wasn't enough to be obvious, but it was enough to cause intermittent connections. I increased the cable slack and tied the wires, no more problems since.

You guys were correct! The black wire to the extruder motor was loose in the solder joint. Thanks so much!