Hi,
Last year when I was testing Fisher, I found it would be impossible to do continuous printing when filament is running out.
When the tension is weak, extruder fails to push the filament, it produces filament starvation. I had spend many hours to troubleshoot weird retraction problem in my Kossel Mini for months without knowing the design flaw of the extruder.
Pushing requires more force than pulling filament in retraction. If the biting force between idler bearing and hobbed gear is weaker than the pushing force, any object that demands a lot of retraction would produce many hairs or filament starvation.
I had to adjust the tension of extruder so that retraction would work properly in Fisher to get decent retraction quality. But the problem was that pressing the tension lever wouldn't be able to take filament. Due to the location of tension adjuster which is upper side and inside panel, if Fisher is running, continuous printing is extremely hard or impossible.
I just replaced all the acrylic plastic parts with steel and aluminum. First thing I had in mind was the problem of continuous printing.
