"The Orbiter" 140g direct dual drive Extruder with up to 10 kg pushing force

thingiverse

Hi everyone! This is my latest design, a high-precision direct extruder using a planetary gearbox plus the big (12mm diameter) dual-drive bondtech style gear-set. Short spec: - Gear ratio - 7.5 (new option 7.2) - Filament pushing force for LDO-36STH17-1004AHG 17mm stepper ~7.7Kg (7.5 gearing ratio, based on measured motor torque characteristics. The actual motor torque is less at lower operating current and RPM than the nominal max torque rating of the stepper). - Filament acceleration up to 660mm/s^2 - Retraction speed: 60mm/s - Overall weight is about 140g **Please do not run the LDO stepper above 500mA without proper cooling, it can heat up too much and melt the SLS printed plastic gears** The orbiter printing @ 200mm/s on my MachCube 2.1: https://youtu.be/aZolOWtBbME In the last months I have experimented with worm gear based extruders with very good results, however not perfect so I decided to go for a different approach. What I have learned is that the worm gears are not the best choice for extruders. Although high gear ratio gives a good theoretical filament pushing force in reality this is not always true, mainly because the worm gear efficiency is pretty low. The plastic printed gears are even worse, at high torque their efficiency is well below 50%. The plastic worm gears tooth's are bending a little causing pressure variation in the nozzle which leads to some tiny wavy artifacts on the printed surface. 20-30:1 gear ratio reduces a lot this effect but the stepper will not be able to provide decent filament acceleration slowing your printed drastically down because it has to wait for the extrusion (this is the case for the Zesty Nimble, the flex3drive drive with Nema8 and my previous worm gear based extruders as well, acceleration of 300mm/s^2). The agreement with them is in such a way that they support me and the development of future Orbiter versions. By buying from them will support our efforts, Thank You!. I've uploaded an option with 62:26:10 gearing ratio which is a perfectly meshing gear combination. However due to the 0 clearance before using a pre-run cycle is needed to wear down the printed gears so they will run smooth. The gear ratio of this is 7.2:1. Be aware this variant requires very precise gears dimension, printing with 0.2mm nozzle or SLA, MJF is recommended.