PTFE tubes detaching from side filament sensor
Do other people have a problem with Prusa collet design not grabbing enough on the PTFE tube, which causes the tube to detach while pushing the filament through tube and past the extruder filament sensor? Seems that the #1 sensor has the best grip, but #2 and #3 sensors can't hold the PTFE tube in place.
I've tried pulling the collet out after inserting the tube and pulling the collet out while pushing the tube in. Also tried swapping the collets to other holes, didn't help either. Any other suggestions?
RE: PTFE tubes detaching from side filament sensor
I had this issue earlier, I eventually discovered that a shaving of ptfe had wedged inside the filament sensor, plus early versions of the sensor's printed parts had issues with the ball bearing inside getting stuck.
I would take it apart for cleaning, Prusa has a step-by-step here: https://help.prusa3d.com/guide/how-to-clean-the-side-filament-sensor-xl_547477
RE: PTFE tubes detaching from side filament sensor
Took the sensor apart, no shaving etc. in there. I'm guessing the part print has tolerances and the holes for retaining collets are just slightly too big on #2 and #3, so the collet doesn't grip properly on the PTFE tube...
RE: PTFE tubes detaching from side filament sensor
I got this thing sorted by trial and error with trying all the collets from the input and output sides of the sensor housing to find which one had the best grip in which hole. I inserted the PTFE tube while the sensor was detached from the printer, probably this caused the tubes to be at slightly different orientation when inserted and that also helped the collets to grip better.