Grblshield Micro stepping Settings

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TheMonkeyStink
Posts: 12
Joined: Mon Jun 02, 2014 3:41 am

Grblshield Micro stepping Settings

Post by TheMonkeyStink » Fri Jun 06, 2014 2:28 pm

Hey All,

What are the proper micro stepping settings for the SO2? Right now I've got this:

X=8
Y=8
Z=2

And given that I'm a complete noob, what is the practical implication of altering these settings?

Thanks!
________________________________________
Shapeoko 2 #5177: DW660 with nema 23. Acme Z axis (I believe these come from the same company that Wile E. Coyote gets his stuff)
# of failed cuts (a.k.a. Shapeoko Ohnos): 7
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cvoinescu
Posts: 4442
Joined: Thu Jul 19, 2012 6:50 pm
Location: Camberley, UK
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Re: Grblshield Micro stepping Settings

Post by cvoinescu » Fri Jun 06, 2014 2:40 pm

Those settings are fine.

Finer microstepping can be smoother, but requires more pulses from the controller; and since the controller is a slow processor, that becomes a limitation and restricts the maximum speed (GRBL can emit at most 30,000 pulses per second -- each pulse is a microstep). Coarser microstepping is jerkier, louder, and may not be able to accelerate as fast. Because it's screw-driven, the Z axis needs many more turns to move the same distance -- so it makes sense to have a lower microstepping setting for it (fewer steps per turn).

There is also a limitation of GRBL 0.8, which doesn't go faster than the maximum step rate for any axis, even when the slowest axis is not being moved. Thus, higher microstepping on Z will slow down X and Y. That's why 2x on the Z is a good choice. Without that limitation, I would use 8x microstepping on the Z too, just because it's smoother.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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