Libro-Struder 2

thingiverse

Libro-Struder 2 is essentially the original Libro-Struder, but with a built-in planetary gearbox. This lets you use a standard Nema 17 motor without having to use a stepping gearmotor. This thing is experimental, but shows promise! Libro-Struder: The Libro-Struder design uses friction between a grooved inner gear and 11 outer gears push filament down an tube toward a hot-end. This type of extruder is unique because it does not require a hobbed wheel, and so can be assembled from mostly hardware store parts. The use of friction distributed over a large gear instead of pinching action between a small set of rollers lets this mechanism grip and push filament with high power and without slipping. Print Settings Printer Brand: MakerBot Printer: MakerBot Replicator Rafts: Yes Supports: Yes Resolution: Low is fine Infill: 50 to 100 % Notes: I recommend printing everything at 50% except for the object "Planetary Gears" which should be printed at 100% (solid plastic). Post-Printing Cleaning up the orbital gearing It is tricky to get it to run smoothly, have broken several sets of the planetary gears. It is important to make sure the pair of revolving planets are exactly opposite each other with respect to the center gear. You may also wish to sand the teeth or to use a jeweler's file to smooth the surfaces slightly. There is some natural taper to the gears that happens during printing. The box provides a nearly 60:1 advantage. Wearing in the Gearbox The planetary gearbox is a bit rough and may be too tight to run smoothly when first assembled. I recommend putting grease into the teeth of the internal gears and then turning the box with a cordless drill at high speed for 4-5 minutes. This will 'wear-in' the teeth of all of the gears involved, and will make everything run much more smoothly. Cleaning up the Filament Groove in the Big Gear Printing will leave some amount of support material in the groove around the big gear. This groove must be cleaned out and preferably sanded with the folded edge of sandpaper. If the groove is not clean or not quite deep enough, it will put too much pressure on the filament and may cause the motor to stall. The small gears that encircle the big gear are held on small spring arms, and the arms are quite a bit shorter & stiffer in the Libro-Struder version 2 than in the version 1. This may or may not be a design problem/limitation. R&D continues!