Motors:
Speed got me back to looking at the steppers that came in a while back. What came in isn't quite what the listing said it would be (welcome to auction sites ...). The motors in the listing did not have any torque vs speed curves on them. The motors I got (3A motors) *do* have torque vs speed curves. Sounds like good news....
The motors pretty much die (torque wise) at 300 rpm. Judging from the bumps and lumps in the curve, I'd guess they get into resonance issues just above that point. I also looked at another motor in the Wanti line that's very close to the 4.2 A motor I ordered. It has pretty much the same issue.
The stepper drivers seem to be good to > 100K steps/ second. That's faster than a Marlin / Ramps / Mega will do. 32 micro steps at 600 rpm is roughly 60K steps / second.
Off to look at other motors ... this time only ones with published curves ....
Why not try it and see on the assembled printer? None of these motors have the same shaft diameter or the same height. You are off to "make some adapters" land when you swap them out. If you go tall, it may be pipe cutting time.
If you look at the example printers in A2's post - they all have significantly over constrained the print area and in some cases gone with very long arms to speed things up. If the arms are all < 45 degrees from vertical, speed is much less of an issue. One printer looks like it's never < 30 degrees from vertical.
Speed got me back to looking at the steppers that came in a while back. What came in isn't quite what the listing said it would be (welcome to auction sites ...). The motors in the listing did not have any torque vs speed curves on them. The motors I got (3A motors) *do* have torque vs speed curves. Sounds like good news....
The motors pretty much die (torque wise) at 300 rpm. Judging from the bumps and lumps in the curve, I'd guess they get into resonance issues just above that point. I also looked at another motor in the Wanti line that's very close to the 4.2 A motor I ordered. It has pretty much the same issue.
The stepper drivers seem to be good to > 100K steps/ second. That's faster than a Marlin / Ramps / Mega will do. 32 micro steps at 600 rpm is roughly 60K steps / second.
Off to look at other motors ... this time only ones with published curves ....
Why not try it and see on the assembled printer? None of these motors have the same shaft diameter or the same height. You are off to "make some adapters" land when you swap them out. If you go tall, it may be pipe cutting time.
If you look at the example printers in A2's post - they all have significantly over constrained the print area and in some cases gone with very long arms to speed things up. If the arms are all < 45 degrees from vertical, speed is much less of an issue. One printer looks like it's never < 30 degrees from vertical.