I’m banging my head against the wall trying to figure out why I can’t get the MK8 extruders working. I have set the vref on the DRV8825 anywhere from 0.5V to 0.75V. I am able to have the extruder pull filament through the drive gear and down to the throat. It seems to be hit or miss if the filament actually makes it into the throat, or just gets caught on the lip and the motor clicks and does not push it any further.
On the occasion that the filament makes it into the throat and down towards the nozzle, it seems to jam at this point. No plastic will extrude anymore. I have taken the assembly apart several times and cleaned the nozzle and throat. Is it possible that I do not have enough cooling via the heatsink and fan to prevent heat from creeping and expanding the filament higher up in the throat?
The only other thing I could think of is a higher vref on the DRV8825 but I’m already at 0.75V on a 1.5A rated stepper and I do not want to push it too much higher. The stepper is relatively cool, though.