Having trouble getting filament started through the Bowden extruder? This should help.

It's a small funnel thing that helps guide the filament into the exit hole of the Bowden extruder.

The dimensions are critical. Too loose, and it will flop around and possibly jam the passageway. Too tight and it will not install. Too high and it will interfere with the mechanism.

Because of this, and because not all printers are well calibrated, I have provided the SCAD file. The variables are self-explanatory, and easily changed to allow you to get the best fit after a few test prints.

To install, remove the extruder. Remove the fan. Remove the bottom filament guide. Insert the funnel with the wide end up (toward the drive mechanism). Best is a press fit, with the height just right to not quite interfere with the drive idler. Press it in far enough to allow the bottom extruder threads to bite, and tighten it. Double check the dimensions.