V/T-slot bowden extruder by austingeorge

Last crawled date: 3 years ago

This extruder was designed by myself specifically for my C-Bot clone build.
It uses some commonly available components, and tools that i happened to have lying around.
I've managed to get 8mm3/S volumetric extrusion through my e3Dv6 hotend with this extruder; so it is capable of some grunt
The extruder is intended to be mounted directly to T-Slot or V-slot 20mm extrusion with 2x M5 bolts and washers. I've put a recommended size for the M5 bolt in the required list, incase you are mounting this to aluminium extrusion like i have.
The extruder at the moment, only fits 1.75mm filament. I don't currently intend to expand this to any other sizes.
I recommend not to use filament with a bad diameter tolerance. I typically use good quality filament with stated +-0.03mm tolerance and haven't had a jam or slip.
There is no need for a print or suspension mechanism for the idler arm in this design. The springiness is exerted on the idler arm itself. Another good reason to print in PETG or similar strong filament.
Parts
Required:
5x M3x16mm bolts (preferentially hex head)
5x M3 washers
1x M3 brass heat-set insert
2x M5x12mm or M5x10mm bolts and washers (M5x10mm might be a bit short) (to attach mount to extrusion)
1x skateboard bearing (608 - no flange!)
1x MK8 9mm external diameter, 7mm drive diameter gear
1x NEMA17 motor with rotor length of minimum
1x BPT bowden connector (drill out the hex hole to >=4mm if you would like the bowden tube to extend up to the drive gear - This isn't essential though)
Optional:
1x BPT bowden connector for reel-side bowden tube if you're intending to print air-sensitive filaments
Assembly tools:
Soldering iron with temp control
M3 bolt fastening tool (allen key, screwdriver)
9mm spanner or adjustable wrench
Print settings:
I printed at 0.3mm layer height in PETG. I have not tried this design in PLA, or ABS.
Care should be taken pirnting and using this in PLA as it's possible that PLA is too brittle and weak. I have no experience of ABS strength, so can't comment.
Instructions:
Print all 3 parts. ensuring that relevant supports are included wherever required.
Remove supports
Clean up any bolt holes, and bowden connector holes
Test fit the three parts together with bolts. The idler arm should swing on the top left M3 bolt and the extrusion mount should slot nicely into the motor mount and allow the two M3 bolt holes to be fitted to hold them together.
(optional) Drill out bowden tube hole in outlet of extruder. Minimum 4mm drill bit
Carefully, thread the bowden connectors onto the outlet (and inlet if required, using optional bowden connector) motor mount plate. Make sure they thread in straight. They do correct thmselves slightly as they thread in, but be weary that threads are hard to remove once created.
Test fit one of the M3 bolts through the idler arm to the motor mount plate. The hole in the motor mount plate can be threaded with a tap instead of a heat set insert, but i can't imagine it'll hold very well under tension.
Using your soldering iron set to [hotend extrusion temp - 30degC], push the heat-set insert into the hole in the motor mount plate.
Check the heat set insert is lined up with the idler arm bolt by repeating step.608
Push the idler bearing onto the bearing arm
Attach the motor to the back-side of the motor mount.
Mate the extrusion mount and motor mount and bolt together using the motor as the fastening nut. The bolt holes are snug. This is intentional, just keep threading the bolts in
Bolt the final lower right bolt of the motor mount to the motor.
Thread in some filament, insert bowden tube, attach to your printer, and tension the idler arm to suit.