Closed Loop Filament Sensor

thingiverse

This is my version of a filament sensor for 1.75mm filament. If it is supported by the printers software, it can be used for building a closed loop monitoring system. This means, the printer calculates the amount of filament which should be used and it gets feedback how much has been really used. This way, the sensor can not only detect a simple out of filament condition, but also most kinds of filament jams or clogged nozzles. Be aware, that this is still a work in progress! So far I've tested it only on my desk, not in the printer. Next, I have to find out how to modify Marlin for doing the job... I will update this description as soon as it has been tested in the printer. If you like to give it a try you need these parts: - 1x optical endstop: https://www.aliexpress.com/item/Free-Shipping-Optical-Endstop-Light-Control-Limit-Optical-Switch-for-3D-Printers-RAMPS-1-4/32246136817.html - 3x 686ZZ ball bearings. - 1x small Lego Tire 14 x 6 mm, Part Color Code: 4246901, Item No: 50945. You can get it from Lego, ebay or Bricklink: https://www.bricklink.com/v2/catalog/catalogitem.page?P=50945 - 2x E3D Embedded Bowden Couplings: https://e3d-online.com/embedded-bowden-couplings-for-metal-1-75mm-filament - 2x screw M3x10, DIN912, with nuts - 4x screw M3x30, DIN912, with nuts - one drop of cyanoacrylate glue (CA) Some hints for printing the parts: It is crucial that you print the encoder wheel from solid black material, otherwise you don't get a clean optical and electrical signal! Also you have to make sure, that there are no visible gaps in it. You may control this with printing speed or parameters like 'Outline Overlap' (S3D) in your slicer. I had to set 'Outline Overlap' to 25% in order to get best results. Further I recommend you to print the housing from clear or transparent material so the lighting of the endstops LED is visible. I've printed everything with PETG, the small parts with 100% infill, the housing parts with 35% infill (Honeycomb). If you don't intend to use the sensor within a closed chamber 3D printer, PLA should work as well. Every part should be printable without any support. Both pieces of the encoder wheel are designed to be glued together with some CA and a short piece (max. 10mm) of 1.75mm filament for aligning them. The Bowden Couplings can be inserted by carefully using a solder iron, prefered a temperature controlled one with temperature set not too high (200°C works for me).