I have 2 problems that are related, but opposite. I’m periodically underextruding.
I’m noticing periodic slippage and skipping steps in the extruder of my Printrbot Simple.
I’ve marked the bearing with lines (using a marker) and can see that sometimes the bearing isn’t turning (and sure enough, the line thins out) but only for a second or 2 and then it goes again.
I also sometimes (and this is independent of the first symptom) hear and observe the stepper skipping steps.
I have cleaned the teeth on the hobbed wheel, and increased the tension, but there’s still period stalling of the feed.
I have increased the current to the stepper, and it now runs much warmer, and there are still times when it skips steps.
I’m printing black PLA at 195C.