Microswitch filament runout sensor

thingiverse

Here's a simple filament runout sensor that I designed using an optical sensor, but due to my use of clear filament sometimes, I decided to opt for microswitches instead. These particular switches have a flag but no roller (https://www.amazon.com/gp/product/B00UBWSMKC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1), so I slightly bent down the end of the flag to ensure that the filament would slide either way, with the primary direction being the same as the flag. To identify which way the filament goes, I marked the outside of the assembly accordingly. Three M2x12mm bolts and nuts are required to secure the two halves together. I created versions for both 3mm and 1.75mm filament, allowing it to clamp onto entry or exit tubing. For the 3mm filament, I assumed a 6mm tubing size, while for the 1.75mm filament, I used a 4mm tubing size. Print Settings: Printer Brand: LulzBot Printer: Mini Rafts: No Supports: No Resolution: .2 Infill: 20% Notes: The design is straightforward and doesn't require any special settings. However, it's worth noting that the channel where the filament passes through could eventually grind down with prolonged use, so using a tougher material like HIPS might be beneficial.