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« on: February 14, 2008, 02:46:52 PM »
Here is how you do the math. I will give you mine as an example. What we need to know is, How many pulses from Mach will it take to move the machine 1 of your units? (inch,mm) Mine is in inches. 1 inch = 10,000 pulses on mine. This is how I came up with the number.
My steppers have 200 pulses per revolution. ( 360 degrees divided by 1.8 degrees = 200 )
Micro stepping = 10. So 200 X 10=2,000
Motor to screw gearing is 1-1. So 2,000 X 1=2,000
Screw lead is .200 of an inch. My screw will have to turn 5 rounds to move the nut 1". 1.0 divided by 0.200=5. So 2,000 X 5=10,000.
Once you check to make sure your steps per are correct, check your backlash. Checking your backlash should be no problem if you have an indicator. Put the indicator on something solid. Jog your axis until you move the indicator to a reading of about half of its travel. Write down the reading on the indicator. Jog the axis in the opposite direction by a set amount, say .010" and see how much difference the indicator shows. If the indicator says you moved .005 and Mach says it has moved .010 then you have .005" backlash. You can check your steps per with your indicator also. Set up as before., only this time run the axis in until it just starts to move the needle on the indicator. Write down your reading. Going in the same direction give the axis a move with Mach. If Mach thinks it moved it .010" and your indicator says it moved .010", your steps per are right.
Brett
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