I’ve recently had to disassemble my machine because of a couple cracked pieces, and when I reassembled it, I noticed that the two bearing on the “internal” side of each carriage (the ones facing the cutting area) are not engaging the tube correctly and do not rotate.
The bearing and the tube have marks on them which confirm that they were indeed working before, and I didn’t touch the carriages themselves.
What could cause this? I haven’t checked if under strain they issue straigthen itself out, because I’d rather not break an endmill or ruin some stock just to check.
Tough to say. Maybe swap the two parts. I t could just be tensioned differently now. It is best to test them individually for a tight fit before making a full assembly when having issues.
The bearings on all 4 carriages don’t engage, not just one, they rotate without an issue if I rotate them by hand. I’m thinking that maybe when tightening the tubes I angled them a bit and now they don’t touch the EMT anymore, and I’m going to try and rotate the tube in case it developed a flat spot. If I placed them manually on a tube they work, so I’m thinking it’s just bad positioning on my part.
We just had an issue a few days ago, his printer was improperly calibrated. Could that be the case? I highly suggest you take it apart and try the pieces individually. This lets us track the issue down to what is wrong. If you keep using the entire assembly it could be any number of issues.
Individually they work correctly, and before the last reassembly they used to work also when assembled.
Edit: I’ve did a bit more testing, and they actually work, sometime.
As far as I could see, for small movements, they worked, on larger ones one bearing wouldn’t touch the tube after a while. Also, I’ve got no repeatibility in my movements: if I move 300mm in a direction and go back, I’ve got around a cm left at the end.
I’m probably losing steps along the way, and if it happens on different motors it obviously desincs and twist the carriages out of the way.
I’m going to try and use another board with other drivers, and see if it still happens after all.
Something isn’t right. Your Z assembly could be twisted forcing the XY parts to do odd things Loosen the tool mount and check the rails are parallel. Before you start worrying about movements, the bearings should all be touching at all times.
The bearing are touching when I manually align the carriages. After a bit they are not. At least, that what I noticed before while I was trying to figure out what was going on.
I’ll check the Z assembly when I can, anything to look out for?
Still, it used to work without an issue (at least on that front) before, and when I changed the pieces I didn’t touch the Z assembly at all.
I have no idea why it would be different now. Without seeing it in person it is difficult. The only advice I can ever give is start fresh, check every piece individually, make sure every tension bolt is as loose as possible. they are all interference fit. If any are loose individually then you found the problem.
I will try and see what I can do. But first I’m going to change the board, because I’ve had it with driver problems (since it clearly skips at different points, I’m not chalking it up to unexpected resistance in the tube).
It was a salvaged board with a blown MOSFET and it probably had more damage than I thought.
I initially used cheap (100 pack) bearings from Amazon and have since swapped them out to Ceramic (hybrid) and love them, wish I did that from the start. I also asked about 8mm bolts vs imperial and went the imperial route and regretted it also and switched out to 8mm. I found there was just too much room for play, even after adjusting them after awhile they would become loose again.
James, I’m using cheap bearings, so that may be it. However, individually they spin fine, even with some force applied to it, so I’m not sure if it’s really that (and don’t have any ideas on how to test, I’d rather not buy more expensive ones blindly because, well, money).
I’m using all metric hardware though, being in Europe, so it surely isn’t caused by the bolts.