Modified MMU2 Spring Selector Plate for Prusa MMU2

thingiverse

The Prusa MMU2 device jams too much filament into its extruder body, causing a mess and grinding away at the side of the filament with its pulley motor during filament changes. This results in future load/unload jams when trying to switch filaments. To prevent this problem, I modified the "selector front plate" from the original one provided by Prusa. Here's what I changed: * The screw holes were replaced with larger holes that fit 4.7 mm (3/16") brass tubing snugly. * A concentric channel was added to hold a spring in place around the enlarged hole. Here are the parts you'll need to make this fix: * 1x Brass Tube: https://www.mcmaster.com/8950K522 * 2x Spring: https://www.mcmaster.com/9657K412 * 2x 50 mm M3 screws * 2x 8 mm washers * 1x M6 threaded insert (the brass one that came with the selector plate on the MMU2) To assemble this fix, follow these steps: 1. Print the modified selector front plate in your favorite material - I recommend PETG. 2. Add the M6 threaded insert to the biggest hole in the middle of the modified selector plate. Use a small vice to force the brass insert into the printed part. 3. Cut the brass tube to around 16 mm in length and deburr both ends. 4. Gently force the brass tubes into the remaining holes, making sure they'll point away from the MMU2 assembly once installed. 5. Add 50 mm M3 screws, washers, and springs to fit the modified selector plate to the MMU2 front selector assembly. This mechanical buffer should prevent filament grinding when the MMU2 misbehaves. Check out the attached pictures and video for reference.