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Author Topic: How to get the lead of the ballscrews on the mill configurated in Mach 3??  (Read 6054 times)

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Offline kayakman

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Hi
Me and a friend managed to get one of the mills started today. We couldn´t get the right configuration in the Mach 3 software though.

Is it under copnfiguratio --> motortuning that it should be done. "Steps per" Is it per revolution or per what? Couldn´t find anything about this in the Mach 3 helpfile.

The mill has steppers with 1,8 degrees steps which gives 100 steps per revolution and the lead on the ballscrews is 4 mm.

Are having the same problem for a servodriven router that I´m building. How should I do it?

Best regards / Anders Molin
You were in the right place for setting up, the motor tuning dialog.  The steps per box is really steps per unit, either inch or mm.  You enter the number of steps Mach has to output to that axis drive to move the table, or whatever you are moving, 1 inch or mm depending on what you want to run in.  It is okay to use metric pitch screws in an inch system too (that question gets asked allot  ;) ).  You just need to remember to convert from metric to standard, 2.54cm per inch.  So if you have 1.8 degree steppers I believe you have 200 steps per rev of the motor, not 100 (360 / 1.8) = 200.  Now this assumes you have no gearing, pulleys, or any other step up/down between the motor and the screw.  So, assuming direct drive of the screw at a 4mm pitch, the nut will travel 4mm per rotation of the screw.  So 200 steps to the motor = 1 rev of the screw = 4mm of travel.  Now we divide by 4 to get the number of steps per 1mm if working in metric.  (200/40) = 50 steps per unit or 50 steps per mm.  If going for inch you need to use the 2.54cm per 1in, or 25.4mm per 1in conversion factor.  We would need to multiply the 1mm travel by 25.4mm per 1 inch to get an inch and thus multiply the 50 step by 25.4 to get the number of steps per 1in.  (50 * 25.4) = 1270 steps per unit or 1270 steps per inch.  How is that?  Clear as mud?   8)

All of this also assumes you are not using microstepping drives, or if you are, you do not have them set up to microstep.  If you are microstepping, you need to multiply the steps per unit number we just found by the microstepping factor.  For example if you are are using 1/10th microstepping, we need 10 microsteps per full step, so we would multiply our above found step number (either 50 steps/mm or 1270 steps/in) by 10.  That result would then be what you entered into the Steps Per Unit box in motor tuning.

Hope that helped a little.  If I messed it up someone else please jump in.  I have only used servos, with inch ballscrews, and inch native units.  If you have any more question, don't hesitate to ask, there is a phenomonal group of people here with a deep, deep, deep well of knowledge, and they always seem ready and willing to help.  I would suggest though that you go to the Mach Support site (www.machsupport.com) and click on the support button.  There you can download and read the Mach 3 manual (click on the PDF Tutorial link) as well as look through the various Wiki's that have been set up.  Good luck and let us know when you get that router going.
« Last Edit: April 06, 2006, 04:35:44 PM by rbleth51 »
Thanks,
Rob

Offline kayakman

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Many thanks for the fast reply. If I look at the servo driven machine degrees per revolution gets replaced by the resolution for the used encoder. Right?

/ ANders Molin
Yes, that is correct.  But are you talking about a quadrature signal encoder?
Thanks,
Rob

Offline kayakman

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I don´t know but can check.

I just tested to put in 50 steps/ 1mm movement of the X-axis but it did not work   :-[

Could there be anything else wrong. Maybe I should test to turn the screw one revolution to see that it moves 4 mm. The markings could be wrong.

Is there anyone who knows if there is a short setup tutorial for mach 3 with xylotex steppercards? What should I ignore in Mach 3 and what is esential that I configur. There are so many things to configure. Easy to get lost.

Best regards / Anders Molin
Are the motors directly coupled to the ball screws?  Is the Xylotex card set to be microstepping?  What kind of mill is it?  Is Mach set to use milimeters for Native Units?  And also what release of Mach 3 are you using?  We can get this figured out for you.   ;D
« Last Edit: April 07, 2006, 07:55:29 AM by rbleth51 »
Thanks,
Rob