Made some minor changes to the awesome upgrade designed by rmcniff: https://www.thingiverse.com/thing:222667
Original remix by rmcniff improved printing with NinjaFlex and other flexible filaments, but I often would still have to continually clean the nozzle after every print and it would often jam during the print, forcing me to restart.
Fixed a few crucial dimensions to provide better extrusion and have had great results so far.
- Added an additional upper filament guide tube above the gear. Although the lower guide hole helped, I still had problems with the filament bunching up above the gear. This provides an even more directed path for the filament.
- Increased height of the base below the spring to increase the compression of the spring. I had an issue with the recommended McMaster spring not providing enough tension to pull the flexible filament through the extruder. This could also be solved with purchasing a more rigid spring, but was easily solved modifying the design.
- Decreased the depth of the channel to allow for the screw to fully tighten. For some reason the recessed channel in the lever arm for the shoulder bolt was too deep, which meant I couldn't fully tighten the screw down.
- Decreased the thickness of the extruder block. The lever arm was too thick and came into contact with the heat sink resulting in added friction, making it difficult for the spring to push the arm up.
The combination of the drive gear providing more force and an almost fully enclosed filament guide allows the printer to successfully extrude flexible material. These modifications have greatly improved both my print quality and success rate using flexible filament with the MakerBot Replicator 2X.
I have attached STL files, but can provide STEP files if someone wants.
Refer to the instructions from rmcniff for post processing and installation if needed. However, I did not have to do any post processing and was able to use my parts as is. https://www.thingiverse.com/thing:222667
Note: This is for the right extruder, you can simply mirror the STL files if needing an upgrade for the left extruder.