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MOST RepRap extruder
|By Michigan Tech's Open Sustainability Technology Lab.
Wanted: Students to make a distributed future with solar-powered open-source 3-D printing.
Extruder and X-carriage
|MOST Prusa RepRap Navigation|
|Dual Build overview|
|Extruder & x carriage|
|Z-axis & alignment|
Gather all of the red printed part and the black x-carriage (Batmobile).
|Hot end retainer||1||Black|
|Large helical gear||1||Red|
|Small helical gear||1||Red|
|M4 x 50mm hex head cap screws||4|
|M4 x 16mm cap screws||2|
|M3 x 10mm cap screw||4|
|M3 x 8mm set screw||1|
|M8 nylon lock nut||1|
|3/8" x 9/32" spring||4|
|8mm x 25mm drill rod||1|
|Hot end retainer||1|
|1/8" ID x 1/4" OD x 630mm PTFE tubing||1|
|J-head hotend, assembled||1|
Assembly - Summary
- Prepare printed parts
- Assemble extruder drive
- Assemble x-carriage
Assembly - Step-by-Step
- With a 3mm drill but, ream out the filament path through the extruder drive body and clean up the slots for the motor mounts. Use the 3mm drill bit like a file to ream out the 4mm openings for the idler mounts. Open the hobbed bolt hole with a sharp knife and ream with an 8mm drill bit. Clean any flashing from around the bearing recesses.
- With a 5mm drill bit, ream the mount holes in the idler holder.
- Clean up gears with a sharp knife, removing any protrusions from teeth, flashing from the print-surface-side of the gears and open up the set screw nut trap on the small gear. With a 5mm drill bit, ream the small gear shaft opening. Use a 3mm drill bit to ream the set screw opening in the small gear.
- Ream the filament path in the extruder drive spacer and mount with a 3mm drill bit.
- Push the hot end retainer into its slot in the x-carriage and use a 3mm drill bit to ream the retainer screw holes. Use a sharp knife to open the retainer nut traps being careful to not remove too much material; remove any obstructions in the Bowden sheath opening.
- Clean the tube really well, by removing any (almost) loose shards from the ends, and pushing a length of filament through the tube. If any of the PTFE makes its way into the nozzle, it will block the path and the printer will not work. Therefore it is really important to make sure that does not happen!
- Use a wire tie to clamp the power and thermistor wires to the bowden tube. Put it on loosely; don't compress the tube.
- With the set screw aligned with the flat on the motor shaft, push the small gear onto the motor. The gear should be tight but still able to be moved on the shaft.
- Loosely attach the motor to the extruder drive body with M3 x 10mm screws with washers. The motor should be free to slide in the slots.
- Remove the hobbed bolt and large gear to expose the remaining motor mounting screws and tighten them. Replace the large gear and hobbed bolt insuring that all the spacer washers are in place. Recheck hob position relative to filament path.