Skelestruder Optical Sensor Cartridge with Transparent PFA Protective Lining

Last crawled date: 4 years, 2 months ago

Purpose:
Here's a small upgrade for anyone still using the original optical sensor (not the new IR sensor) with their Skelestruder. The original cartridge has a large open area in the filament path to allow the sensor to see the filament. Unfortunately, this leaves the sensor die exposed to debris and improperly loaded filament*.
As it turns out, PFA (or "transparent PTFE") bowden tubes are also transparent in the region of IR that the optical sensor uses. This remix allows you to line the entire path through the filament sensor cartridge with a short segment of PFA bowden tubing, which completely separates the filament path from the sensor cavity while maintaining full sensor functionality (filament runout and jam detection). This should hopefully require less frequent sensor cleaning and eliminate any risk of mechanical damage to the sensor die.
Required Parts:
This is a drop-in replacement for the original Skelestruder sensor cartridge. The only additional part you'll need is the PFA bowden tube, which is frequently sold under the (technically incorrect) name of "transparent PTFE". Mine was purchased from TriangleLabs on Aliexpress, but it's also available on Amazon.
*The optical sensor that came with my MK3 was killed by my MMU2 during a failed load. Somehow the filament managed to get wedged in the sensor cavity and the MMU2 kept feeding filament until the die shattered. RIP in peace.