Neotko FatIRobertI Bondtech Feeder for UM2+ / UM3

youmagine

You'll need to download the LATCH from the IRobertI original design: https://www.youmagine.com/designs/alternative-um2-feeder-version-two. Primarily, I wanted a dual Bondtech drivetrain on my UM3. However, buying two complete kits is approximately 300€, by creating this design I could utilize the 40€ drive gears Bondtech sells and modify my 2 feeders reusing the Geared Extruder system from the UM3. To avoid feeder spool contact, you must reverse motor direction. The easiest approach is to switch the first two color cables from 1234 to 2134. If you're unfamiliar with this process, this feeder isn't for you. If you don't want to reverse the motor, you might need to use an alternative spool system and print all parts in mirror image. Use supports for anything over 50 degrees or more. Also, utilize 50% or so support density; otherwise, the nut holes will print poorly. Same goes for the feeder arm and areas requiring support. I didn't design my supports because it wasn't necessary. Default S3D support settings with 50% support density worked perfectly and were easy to remove. The inside area between parts a-b should hold a small piece of bowden tube. If you can't accomplish this, feeding the filament might be problematic since it's designed this way for several reasons. The Printable-Shaft-Adapter MUST be printed at 80-90% infill with 2-3 perimeters and I used -0.03 horizontal expansion to print this part (not the feeder). This adapter holds the bondtech drivetrain and uses a m3 30mm inside; you'll notice that the screw passes smoothly until the end, which needs to be screwed in without force – it's designed to fit perfectly. If anything fails, your filament size might not be accurate, so check it with a caliper. To print the Feeder use 0.18 or less resolution, but more isn't necessary; 0.2 is possible, though I dislike how the part where the filament passes looks. 0.18 worked perfectly on all test prints while creating this design. To print the second Core extruder, mirror all parts. There are three Versions: 1.75mm using 6mm-4mm bowden 1.75mm using 4mm-2mm bowden 2.85mm using 6-3mm classic UM bowden Using this feeder requires a Bondtech Drive gears and a 4mm Shaft 22mm long (bondtech sells them too). This Feeder could be quickly adapted to use MK8, but would need changes on the IRobertI Arm to fit the UM2+/UM3 feeder bearing. I utilized a spring that bondtech used to sell before it's no longer included; if they don't offer it to you (asking never hurts), you can reuse the UM2+/um3 spring, but be aware that you'll need an M3 35-40mm. Also, note that the force of this spring is quite too much for bondtech gears, so mind the force.