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Wrong sizes
« on: December 05, 2019, 12:33:44 PM »
I just completed setting up a new cnc machine it uses a tp8x8 p2 leadscrews. I configured Mach3 and ran a sample. Everything functioned except sample was a 1x1" block .625 deep. It measures 1.25 x 1.25 . Where did I go wrong?
Re: Wrong sizes
« Reply #1 on: December 05, 2019, 12:39:04 PM »
Hi,
you have calculated the <steps per unit> value incorrectly.

You say you have 8TPI leadscrews, are they two start?
Are your steppers direct coupled to the lead screw or do you have a gear or belt reduction?
What microstepping regime are you using?

With these numbers it possiblt to calculate the required <steps per unit>.

Craig
My wife left with my best friend...
     and I miss him!
Re: Wrong sizes
« Reply #2 on: December 05, 2019, 12:45:28 PM »
Thanks for the quick response. The leadscrews are coupled to nema 23 motors and they are 2 start. I have no idea what microstep regime is?
Re: Wrong sizes
« Reply #3 on: December 05, 2019, 12:55:33 PM »
Hi,

Quote
I have no idea what microstep regime is?

If you don't know you need to find out. How did you set the <steps per unit> value in Mach motor tuning pages WITHOUT
knowing?

The microstepping regime is the number of pulses required to cause the stepper to rotate 1 turn. Most normal two phase steppers
require 200 pulses, this is called fullstep. If the drive is set to half step it would require 400 pulses. 1/4 step 800 pluses and so on.
A good middle of the road setting is 8 microsteps per fullstep or 1600 pulses per rev. You need to set the microswitches on your drive
to do that.

Craig
My wife left with my best friend...
     and I miss him!

Offline Graham Waterworth

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Re: Wrong sizes
« Reply #4 on: December 09, 2019, 07:33:56 AM »
Multiply your current steps per by 0.8 and try that.
 
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