Mendel Extruder Single 608 & No Epoxy

thingiverse

The design resembles an old direct drive pinch extruder, aiming to reduce bulk and complexity. With two such extruders fitting on a single X carriage like http://www.thingiverse.com/thing:8822 , the stepper motor doesn't require machining. A 608 "skate" bearing serves as one side of the pinch, while when two extruders face each other, the stepper shaft is coated with rough material and epoxy (the "No Epoxy" refers to no PTFE being epoxied in place). The design can be rebuilt under OpenSCAD using thingiverse.com/thing:2192 . The stepper shaft temporarily uses silicon carbide paper for surfacing, followed by a layer of coarse SiC paper embedded in epoxy. Heat shrink tubing ensures an even coating. The bearing has an M8 washer between it and the extruder block, while a larger washer and nut fit on the outside. An M4 x 20mm screw with a nut pushes the motor into filament, with a perpendicular bolt offering structural support. Four M3 x 25mm screws with washers hold the motor to the extruder block. A hole near the filament is for screwing connectors down. Two woodscrews secure the PTFE Hot End barrier in place after drilling through lower holes, warming up the cavity if necessary.