Ball and socket feed tube anchor

thingiverse

I designed this part because I was experiencing erratic print failures, which led me to suspect that the filament feed was the culprit. It turned out that my initial conclusion was only partially correct - I had a severely damaged idler shaft in the extruder. This component reduces friction on the filament as it enters the feed tube. The rigid end of the extruder tube contrasts with the rotating and tumbling ball end, which is designed to handle the stresses of printing. With an extended Teflon or PTFE tube, the exposed end can also function like a fishing line spring, helping to balance average filament tension from spool rotation friction. The angle of the PTFE tube is carefully constrained at approximately 40 degrees in one direction and 90 degrees in the other. The thread on this part is a 4-40 with a countersink head. Unfortunately, I didn't have the correct length, so I had to grind it down to size - but I forgot to measure the final length, which is crucial for determining the length of countersink bolts (measured from top to tip, not thread length). I lightly sanded the ball end but now think that was unnecessary. The tube hole is 4 mm in diameter, and I had to drill through it to clean up the hole and achieve a snug fit for the PTFE tube. This design was created using Fusion 360 software and printed on a Cetus MK2 printer. Have fun! - Peter