Belt driven and feeding extruder

thingiverse

A drive belt fed extruder for the RepRap Ormerod. The grip of the belt is more than enough to compensate for the low torque provided by the stepper motor. I use it with 1200mAh and the original NEMA 17 stepper. UPDATE: Added a longer frame (Frame_Long.stl) for use with longer belts. It should work with belts up to about ~245mm. Note that a longer bolt may be needed. 7 printed parts 4 M3 35mm bolts with washers and nuts 1 M3 40mm partially threaded with washers and nut 3 M3 12mm for mounting stepper motor 4 ball bearings (salvaged from PC cooling fans) Outer diam 8mm, inner 3mm, 4mm wide. 1 224mm GT2 belt, 6mm wide 1 16 teeth GT2 pulley Print Settings: Printer Brand: RepRap Printer: Ormerod 2 Rafts: No Supports: No Resolution: .3 and .15 Infill: 20% Notes: The frame was printed with 3 perimeters and 20% infill to make it sturdy. 0.3mm layer height. The rollers were printed at 0.15mm layer height. They have an inner diameter of 8.3mm which produces a snug fit for a 8mm bearing on my printer. Scale + trial and error for the rollers to get a snug fit on your printer. I advise testing with the small roller since the big roller takes some time to print. All rollers need slow print speed and efficient cooling to print well. The parts probably need to be rotated in your slicer software. The Bowden holder should be printed with the side facing towards the camera in the photo/video on the table. The tensioner should be printed standing up with the nut pocket upwards. Assembly: Drill out all 3mm holes, drill the holes for the rollers carefully or backwards to keep them as tight as possible. Preferably use a partly threaded bolt for the big roller to keep the play at a minimum. Press bearings into all rollers, on the big roller one bearing from each side. Note that the small rollers should be mounted with the print bed side towards the main frame. Otherwise they may roll off the bearings when the belt is under tension. Mount stepper motor. Align and mount the rollers and pulley with the holes in the tensioner and Bowden tube clamp using washers towards the frame. Mount the belt and add some tension. Insert the Bowden tube holder from the roller side, put the Bowen tube in place and clamp it in place. Tension the belt until the tensioner piece aligns with the frame. Feed some filament! (If the end of the filament has a sharp edge, it may catch on the Bowden holder. Round the edges a little with heat/file/knife.)