garageFab.cc

Over the last couple of weeks I tested the linear motion design where leadscrew is located in the center of the sliding element profile. This allows the room for leadnuts to move and be precisely aligned parallel to the rail, which eliminates entire host of problems like whipping, high friction, uneven torque that I had when the leadnuts were essentially fixed to the corner of the sliding elements once and for all. Because leadscrews moved, I also had to modify the shaft/leadscrew mounts, the motor mount and the belt holder thingy. So far I tested center shaft arrangement with 1/4" all-thread leadscrew and the belt drive. Both appear to work well. I have not yet tested ACME leadscrew with delrin nut, the arrangement with belt-connected dual leadscrews and shaft-connected dual belts.

I also got tired of the coupling problem and used off-the-shelf solution - inexpensive spider hub couplings - I think they're called Lovejoy, $17.50 for 3 motors from McMaster.com. Duh.. They work excellent. I was hoping they would take care of the rattling sound (suspected stepper resonance) appearing at certain feedrates, but they don't and that's another problem to be tackled, probably with some kind of flywheel damper.

These are some pictures of what new components look like:

I'll do few more tests before I update the templates/docs.