Motor tuning

Discussion of Mach3 CNC control software
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etxbkst
Posts: 216
Joined: Mon Sep 02, 2013 7:54 am

Motor tuning

Post by etxbkst » Thu Sep 05, 2013 11:39 pm

Hi! I am using Mach3 with the TB6560 3 Axis board. I can't seem to get my Z motor tuned properly. The X and Y tune ok at 43.5 steps per (1/16 micro stepping), but when I do axis calibration on my Z, it moves, I measure and input the value, then Z barely wants to move. The Z value is always in the thousands.

cvoinescu
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Re: Motor tuning

Post by cvoinescu » Fri Sep 06, 2013 12:03 am

The 43.5 steps per mm is a bit odd for the X and Y axes, unless you have 36-tooth pulleys, or your drivers are actually doing 8x microstepping, not 16x. The correct theoretical value for MXL belts, 18-tooth pulleys, 1.8 degree per step and 16x microstepping is 87.4891 microsteps per mm, which is extremely close to double your number.

With M8 x 1.25 thread, 1.8 degree per step motors, and 16x microstepping, you get 2560 steps per mm (which is "in the thousands", so don't worry about that part). Maybe your Z axis fails to move once calibrated because the speed is set too high for it and the motor stalls.
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etxbkst
Posts: 216
Joined: Mon Sep 02, 2013 7:54 am

Re: Motor tuning

Post by etxbkst » Fri Sep 06, 2013 12:28 am

I had the microstepping on 1/8 and Mach3 calculated the steps as 87 per. After my Z axis issues, I decided to try 1/16, which gave me exactly half of the 87. I see now what you mean though, 1/16 should be more steps per than 1/8, so I'm not sure what happened. I guess I'm going to power everything down, reboot and see what happens.

etxbkst
Posts: 216
Joined: Mon Sep 02, 2013 7:54 am

Re: Motor tuning

Post by etxbkst » Fri Sep 06, 2013 12:35 am

I just ordered a bunch of stuff to expand my machine, including gt2 belts and pulleys, so I guess worrying about tuning my existing setup is kind of moot.

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