I built a friction drive for my bike with a load-bearing PLA motor mount (cheap crappy PLA, too), since I don’t have the equipment or ventilation for much else. With a bit of overengineering, it’s been doing great for almost a year now, despite all the heat and force thrown at it.
Comment on DIY eBike Mid-Drive
andrewrgross@slrpnk.net 1 day ago
This is pretty impressive. It looks like they’re using PLA, though? That seems wild to me. I skipped around, so if he described using something else someone let me know.
I don’t know if other people have some kind of magic print settings that make PLA a durable, high-strength material that I’m not aware of, but tbh this looks like building a bike out of hot glue and cardboard. I think it can be done with high-end filaments, though, and the work overall looks solid, so I’m looking forward to seeing more of this project.
mlfh@lm.mlfh.org 1 day ago
andrewrgross@slrpnk.net 19 hours ago
That’s awesome to hear. Do you have any special techniques, like annealing? Maybe it’s just the consequence of my always buying bargain filament.
mlfh@lm.mlfh.org 1 hour ago
Nothing too fancy! Mostly just designing a lot of thickness and buttressing into the part, and then slicing with thick walls, dense triangle infill, and an orientation that puts the layer lines perpendicular to the highest stresses.
It seems like he is rapid prototyping with that material, not expecting it to hold very long. He also admits later in the video to having underestimated the forces and doing the calculation showing that it is way worse than he thought.
Mac@mander.xyz 18 hours ago
Yeah it’s geared way, way too long. That motor wants to turn thousands of RPM.
Using a motor from an angle grinder clearly seems to be a bad choice. But I have heared of other similar projects using cordless screwdrivers more or less unmodified and those worked quite ok.