The LunchBox Printer

thingiverse

The text appears to be an update from the creator of an open-source 3D printer design, specifically for a small hotend and drive system. Here are the main points: **Hotend:** * The current setup has a max safe temperature of about 220°C. * At 210°C, the top of the heatsink was around 60°C (still hot but passable). * Heat creep is a slight issue, but it's not a major concern unless printing above 220°C. **Drive System:** * Use a more flexible belt (glass fiber, not steel core) due to small belt travel and tight bends. * The creator uses Gates-LL-2GT belts. * Printed belt tensioners may add backlash and weight; zip-ties or spring-type tensioners work fine. * Pulleys should be 16-tooth (~10mm) with bearings on both sides (5mm internal diameter). * Leadscrews are standard 8mm p2 (100mm long); a smaller diameter/pitch could also work, but would require resizing the nut flange holes. **Frame and Components:** * X smooth rods: 6x200mm * Y smooth rods: 6x100mm * Z smooth rods: 6x150mm * Bushings on smooth rods are 6x20mm polymer bushings, press-fit with about 8% shrinkage compensation. **Bed:** * Use old picture frame glass (2mm thick) and cut it to size using a glass cutter. * Drilling holes requires a 3mm glass drill bit. * Holes on the bed plate mount are spaced apart 92.8mm horizontally and 32.8mm vertically (edges of each hole are 2mm from the edge of the glass). **Updates:** * March 2019 Update: The design is safe to start building, with minimal changes expected for upcoming updates. * April 10, 2019 Update: A version of the frame with a top-mounted lid has been added, reducing the frame height by 8mm.