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Calculating Travel Per Revolution

Posted: Wed Nov 20, 2024 6:00 am
by Lance22
When I first set up my CNC with a Buildbotics controller, I tried to convert the values ​​I was using for Mach3 to values ​​for stepper motors (https://www.oyostepper.com/) but ended up with the wrong settings. My old setup used 320 steps per unit for X and Y (my system was set to MM) and for the Z axis it used 400 steps per unit. All my steppers are 1.8 degrees per step. When using Buildbotics, it looks for the travel per revolution but I don't know how to convert.
Through trial and error I came up with 5 for X and Y and 4 for Z, but I would feel better if I knew the math to make sure I was using the right values.

Re: Calculating Travel Per Revolution

Posted: Thu Nov 21, 2024 8:49 am
by MicroController
I don't now anything about the CNC controllers you use, but from what you say I'd guess:

Old setup:
x/y: 320 steps/mm * 1.8°/step = 576°/mm, i.e. 360°/576° = 0.625 mm/revolution (= 5/8 mm/rev)
z: 400 steps/mm * 1.8°/step = 720°/mm, i.e. 360°/720° = 0.5 mm/revolution (=4/8 mm/rev)

Now we need to know the unit for the travel distance the new controller assumes.
The numbers above would fit your experimental data exactly if the new controller used 1/8th mm units. And they would be 'close' if the controller uses 1/10th mm.