QIDI iFast reverse boden ptfe tube filament sensor housing

prusaprinters

I wanted to have a reverse boden setup for my iFast yet retain the use of the filament sensor. The benefit of this setup is the filament is kept under tension which reduces the chance of issue when the extruder is making large moves back and forth. It will also help with some filaments which are best kept dry.It reuses all the existing parts plus 2 x M6 couples2 x short length PTFE (4mmOD)You would also need 2 x long PTFE to connect to the extruders if you aren't already using some.Print two of the parts.I printed both parts from PETG but most materials would do. If you run the chamber hot then PLA may not be appropriate. I printed using 0.4 nozzle with 0.2 layers.Once printed I use a drill to ensure the hole clearances are ideal. The only one you will need to do is the rear feed tube which I used a 4mm bit to ensure a nice fit for the short PTFE.3mm for the four fixing holes and 2.5mm for the ones to hold the sensor in the housing.Assembly is simple, screw the coupler in to the front. Place the sensor in the housing and fix with the two existing screws. Push the PTFE in the rear until it is flush with the gap for the sensor lever. The length of this PTFE doesn't really matter, I have a bit sticking out proud at the back which helps guide the filament in from the reel. You can always trip it once in place if it's too long.Attach the sensor to the cables (it only goes one way) then use the 4 screws to hold the sensor back in position. Connect the long PTFE's to the sensor and extruder. Done! I find fastening the two long PTFE tubes together works best, they keep a better path that way.Step included in case you want to remix.