Adjustable IR Sensor Chimney for Prusa i3 MK3s with MMU2s

thingiverse

As of February 14, 2020, I will no longer update this thing on Thingiverse.com. Over the last few years, this website has not developed new features that most users actually care about, and the site has become unusably slow. I will continue to respond to comments on Thingiverse but all future updates will live and grow on PrusaPrinters.org. https://www.prusaprinters.org/prints/21963-adjustable-ir-sensor-chimney-for-prusa-i3-mk3s-with-mm2 This is a remix of ad_lamy's great work, the Pass Through tool head and motor mount. His design has many improvements for the tool head on the original Prusa i3 MK3s with MMU2. I give him kudos. This mod is specific to the IR Sensor mount also known as the Chimney. This mod uses a small metal spring to push against the Motor mount. To adjust, tune or calibrate the IR sensor, you simply tighten or loosen a single M3 screw. UPDATE: February 5, 2020: I made a V2 that uses a 5 mm diameter metal spring instead of the original plastic spring. This has the advantage of not wearing out so quickly. I will continue to test and update later but I firmly believe this will solve most of my previous problems. November 19, 2019: I have used this thing on two printers for a couple months now. I like this design, but I have noticed three problems that are worth sharing. 1. (Solved with V2 metal spring) The plastic spring loses its effectiveness over time due to pressure and heat exposure. This can be easily solved by using a metal spring from the spare parts bag in a future remix. I plan to implement this when I have the time. 2. The tall chimney can flex too much in my opinion. Pressure from the PTFE tube as it moves along the X axis causes the chimney to flex a few microns. The best way to solve this would be with a firmware update, moving the carriage into the middle of the X before loading filament to the nozzle. This would ensure consistent tension from the Bowden tube at all times. Using other materials that don't flex as much as PETG could also help. 3. TPU and flexible filaments are still a problem due to excessive flexing, which prevents the arm from moving far enough. Although this design allows for fine-tuning with these filaments, you would need to re-tune when switching back to other materials.