This is a direct drive extruder for the E3D v6 and MK8 drive gear, fitting directly on the x carriage. Read below what other goals have been considered in the design.
Along with the switch to an e3d hotend i also wanted to upgrade to a direct drive extruder. Unfortunately none of the designs i could find on thingiverse suited all of my needs completely, so i decided to make my own.
I am coming from a JHead paired with Gregs extruder. So this is my version of a direct drive extruder meeting the following goals:
- no bowden design
- extruder should not narrow the build volume (with my old extruder the motor hit a bracket, limiting the z height)
- weight balanced design (should not "fall forward", of course the success is limited by the clearance the motor has to the frame)
- symmetrical design to ease fan mouting
- cable management (optional)
- flag for optical endstop (optional, this one here)
- mk8 drive gear
- suitable for E3D v6 1.75mm, therefore the extruder should have a 4mm bore so that the PTFE tubing of the E3D can be extended into the extruder, just below the drive gear
- attachable to a x carriage with 30mm hole distance
- a little bit more rigid than other designs ;-)
An optional fan duct fitting this design is available here.
The extruder design was vaguely inspired by the Hackerbot direct drive extruder.
mandatory printed parts:
nuts & bolts required:
- 1x MK8 drive gear for 1.75mm filament
- 1x MR105ZZ bearing (5x10x4)
- 1x M4x50 screws
- 4x M4x30 screws
- 5x M4 nuts
- a spring for the idler
- a few M4 washers (optional, use to increase tension on the idler if your spring is to weak, or try to use a shorter screw)
- 1x M3x16 screw
- 1x M3x20 screw
- 1x M3 nut
- 2x M3 washers
- 3x M3x10 screws
and of course an E3D v6 and some PTFE tubing
replace 2x M3x10 by 2x M3x20 screws
1x MR105ZZ bearing
- print everything with 0.2mm layer height (or 0.1mm, but thats overkill) to not mess up the item heights. You should not need additional support as all needed support is included (you need to rotate some things prior to printing)
- remove support material
- MountPlate: break the 4 pillars free from the M4 nut shafts. Remove the support at the flag for the optical endstop (about 2mm) or break the whole flag off if you do not want it.
- DDIdler: remove the support so that you can clip the idler later into the extruder
- DDExtruder: the support is a little bit hard to see. You must remove support on the top right corner, there where the idler is supposed to go later.
- put everything together
- DDIdler: Put the bearing on the the shaft, then put two M3 washers onto the M3x16 screw and screw it into the shaft. Secure the bearing on the other side with a M3 nut. This gives the shaft extra rigidity. The two washers are required to get the clearance to the DDExtruder right.
- DDExtruder: Put the DDIdler into the extruder. Move it a few times to make sure it can move freely. Use the M3x20 screw for attaching the extruder to your motor while also holding the idler in place. Use 3 M3x10 screws for the remaining screwholes. Insert the Mk8 drive gear and line it up with the filament bores. Do not assemble the M4x50 screw and the spring until you really want to put filament into the extruder.
- MountingPlate: Put the M4 nuts into the 4 holes. Attach the DDExtruder with 2 M4 screws to the mountplate. Take your E3D hotend, put the PTFE liner into it and hold it into its place on the moutning plate, so that you can measure the required length of the PTFE liner. The liner is supposed to be extended into the extruder and reach right below the MK8 drive gear. If you have cut your liner to the right length, insert the liner into the extruder, press the hotend into place and secure it with HotEndBracket and 2 M4 screws.
- attach the extruder to your x carriage.
optional parts assembly:
- If you want to use the cable management bracket simply print 2 of them and scew them into place using 2 M3x20 screws instead of 2 M3x10 screws. Use the zipties to tie the cables to the brackets.
- If you do not trust the little shaft (of rather the bearing of the stepper) to withstand the load applied from the idler, print the BearingExtender, put an additional MR105ZZ bearing into it, push the whole thing onto the motor shaft and clip it into the corresponding place in the extruder.