A while back I had my ball screws and nut overhauled. I tried to rescale but it seems what ever I put in doesn’t stay. It reverts back to the factory settings. Is there an unlock function in there that will allow me to adjust it?
Also, any techniques for adjusting backlash in the controler? I can get the jog increments close but I really seem to be chasing that one. It seems that the stepper motors aren’t incrementing evenly through steps.
I basically take a cut, measure, set X offset, then use MDI to drive to a smaller diam and take another cut.
Measure and reset offset. This with the new overhauled screws gives great repeatability.
But I would really like to dial in the scaling.
Are you adjusting step count with the software or at the driver?
On my Mach3 mill I did not want to mess with the software stepper profile because it worked very well. I purchase 3 of these closed loop motor and driver combos. With the digital driver you can change the way the driver reacts to step and direction commands in a range from 0 to 99999. I adjusted the step count at the driver until the axis moved in perfect repeatable .001 increments. or in the case of your X axis .0005 increments to remove ,001 material from the part.
The scaling is in Admin Scale Axis I believe. It is basically a ratio of commanded to measured movement. Or visa versa. So yes in the software. I’m not sure how the backlash setting affects it either. And that is all dependent on how tight the jib is. Kind of a pain.
Actually any CNC is a pain to setup correctly. With axis mapping. Really need good equipment to do it right.
Bruce,
Where are you attempting to enter scale info? There is nothing to change on drivers for scale, except microstep dip switches which will be nowhere near the amount you want to adjust by, they’re far too coarse. Pathpilot has ADMIN commands for scale, ADMIN SET_AXIS_SCALE_FACTOR “n” “m” and ADMIN GET_AXIS_SCALE_FACTOR. The “n” you would replace with the letter of the axis to adjust and “m” with the factor amount, limited to between .995 and 1.005. Backlash setting is done with a similar command, just replace “SCALE_FACTOR” with “BACKLASH”.
Scale factor commands aren’t commonly used, it was a feature mostly developed for internal use with ballbar testing.
Yes, I was using the admin scale axis.
I would assign an axis put in a value hit enter.
Looked like it took it, no error message.
Then I would go back and admin get scaling and the valule would revert back to the original value.
And with get scaling, Z would give a not available or something similar, forget exactly.
So the company that overhauled the nuts and screws put a light grind on the screws and put oversized balls in. Like 0.0012 bigger or something.
So it all came back pretty close, but I wanted to dial it in best I could.
Backlash is pretty tricky and effects scaling I’ve been told.
Seems I’m always out a thou or so on Z.
If I do a MDI to a value in X, cut, measure, set X offset, it’s spot on.
Ideas?
Thanks