Prusa i3 "Tweety" Parametric (dual) Compact Extruder

thingiverse

I am obsessed with thinkyhead's ingenious design for a simple geared extruder on my Prusa i3. I took the liberty of customizing it to fit two extruders, one mirrored, and I opted for an mk8 drive gear instead of the mk7. To get this working flawlessly, I implemented several notable tweaks: I moved the motor 2mm forward so that the hobbed gear perfectly aligns with the filament. I spaced the mount holes at a distance of 30mm apart to seamlessly integrate it with a standard dual carriage featuring 30-20-30 spacing. I designed the mount holes to be movable up and down, making it easy to fine-tune the height of the extruder heads and level them perfectly. I eliminated the extra mounting bolt hole so that you don't have to print a custom carriage – just zip tie it into place instead. I removed the cone transition from the hobbed gear to reduce the risk of filament buckling with softer materials. Lastly, I lowered the bore for the J-head mount as mine fit too snugly. To top it off, I also modified the fan mount since I'm using a smaller fan. I've included the one I use and appreciate the designer's innovative # – unfortunately, I've misplaced the reference link. You'll find the original Tweety Openscad file within this bundle for reference purposes. If you're using 50:1 geared stepper motors from 2engineers.com, make sure to employ a heatsink; I discovered one designed for the PG35L at ultibots.com. Considering their motor options, it might be worth modifying this design to accommodate them. Print all components in ABS, as the motor generates significant heat – I've learned that the hard way after my idler deformed when printed without a heatsink in place. Additionally, modify your firmware according to 2engineers.com instructions to prevent acceleration-related damage, while also enabling dual extrusion. Enjoy!