This roller guide is maintaining filament feeding angle. When filament runs low, the feeding angle could be very sharp and that could increase the motor burden. With this roller guide, filament is fed with perfect angle all the time.

Updated 20-04-2025

After tested for some time, in previous design the roller bracket can detached from the main base when filament is pulled with force applied on it. So I have updated the design having the roller bracket inserted all the way from bottom, make sure there is no possibility it can detached. I have also move the roller about 1mm ahead, I think this is a better filament feed angle.