Minimalistic Mk8 Replacements

thingiverse

This design spins around two versions of a replicator extrusion part, MK7 and MK8, which are both top sections of replicator extrusion equipment. The stock makerbot replicator has a stepper motor that controls the feed rate of filament into the heater element below it. A plastic delrin plunger pushes the filament against this stepper motor; however, due to friction and changes in filament diameter, it can wear out. To ensure constant pressure on the filament, a spring-loaded lever was invented. This part was later modified using bulldog clip handles. The design has been tweaked to remove support elements, fix mesh errors, modify bearing dimensions, and simplify the pin design. Dual extruders require smaller outer diameter bearings. Disassembly of the extruder involves removing fans and plastic frames, cleaning the stepper motor's drive wheel, and replacing parts with the new assembly. Bulldog clips provide spring pressure to maintain filament feed, and the reassembled equipment is tested.