Extruder issues...

I have all my steppers pretty close to perfect accept my extruder. Whenever it's under any extra load it just start shimmering not turning. I understand that this happens when you have your current too low on your driver, but when I turn mine up it either stops or whines and stops. If dial it back it will sometimes turn the motor but even if starts turning it will quickly stop turning....
it's a Wade's extruder on a prusa mendel v2
1.8 degree 200 step

any idea? turn up the temp? the hot end is running about 195 C with PLA

Are you sure you have the correct thermistor set up in Marlin?

Is your extruder set to run the proper amount of filament (steps calibrated) with no hot end?

Are your extrusion rates rational ?

Is your steps per mm correct for your extruder motor?

If you want to go back to basics:

1) Pull the motor off of the extruder, pull the extruder off the printer.
2) Check the gear on the shaft, make sure the screws holding the gear to the shaft are tight.
3) Power up the motor, try to twist the shaft with your fingers. It should not twist
4) Tell it to extrude, the motor should turn one way at a rational speed
5) Tell it to retract, the motor should go the other way at a rational speed

At this point you are reasonably sure the motor it's self is not broken. It may be incorrectly calibrated, but it's not broke. It's not mounted to the extruder yet, so you don't know anything about the extruder.

6) Check the hobbed bolt, make sure it turns freely
7) Make sure the hobbed bolt is tight enough it does not wiggle.
8) Make sure the second nut on the bobbed bolt shaft is tight.
9) Mount the motor, make sure the gears are tight when you do.
10) Make sure the bolts on the clamp springs are tight, almost tight enough that you can't get filament in the gate.

You should now have the motor on the extruder, check the hinge bolts on the gate, and you are ready to check the extruder.

11) Use your software to tell the extruder to feed 20 mm of filament.
12) Measure what it does feed
13) Correct your steps / mm if needed.

If you still do not extrude properly:

14) Get out the data sheet on your stepper motors
15) Check the rated DC current per winding
16) Use a DVM to set the stepper controller to run 1/2 that amount of current.

Edited 1 time(s). Last edit at 12/27/2013 11:17AM by uncle_bob.