Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: ppollioni on April 21, 2012, 10:56:37 AM
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Hi All
Recently I have built a cnc router and am having an issue with 'drifting' + in the X axis and - in the Y axis. If I calibrate and set the steps per inch with a dial indicator and tell it to move 1" it moves .990 and I enter that number and click OK. Mach3 tells me how may steps per unit it is using and I accept the value. When I then ask it to move +X 20" it moves +20.010". When it goes back to home the X DRO is 0.000 but the location is +X 0.010 if i repeat this the next move goes to +X 20.030" and so on. At the end of the test the DRO's are correct but the location of home is +X0.040. This same thing happens in the Y axis.
Long program run, bigger drift. Any ideas?
PC running windows XP
The computer is dedicated to Mach software only.
All axis use stepper motors.
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I presume its steppers so what is the microstepping of the drives?
What if any gearing do you have between motors and screws?
What is the pitch of the screws?
Hood
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Thanks for the help
All are 1200 oz/in cables with shielded 16AWG
No gearing and all couplings tight
I think the screws are 8 turns per-inch (I can check Monday and let you know with the micro stepping)
Parnell
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Still need to know what microstepping the drives are but say it was set to 10 then your steps per unit would be
200 steps per motor rev x 10 microsteps x 8 turns for 1 unit (inch) 16,000 steps per inch.
Hood