Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: dakmonf on May 23, 2011, 01:25:14 PM

Title: Motor Tuning Issues
Post by: dakmonf on May 23, 2011, 01:25:14 PM

I am having a difficult time tuning my steps per inch. I am able to cut a square 5 x 5 piece of plywood within 5/1000 ths of an inch but when I use the same settings to measure a distance (sheet of 97" melamine), the DRO reads just over 88 inches.  Very large discrepancy and if I set the steps per inch in relation to the 97" melamine my 5 x 5 inch square is more like a 5 x 4 rectangle.
I have searched but I do not see anyone else that has had such a large diff. in readings.  This only occurs in the x-direction, as the y and z seem fine.

Thank-you for any assistance.

Greg

Title: Re: Motor Tuning Issues
Post by: Overloaded on May 23, 2011, 01:56:02 PM

I'd say you are most likely experiencing either mechanical slippage or missing/skipping steps on the long run.
Set a zero point, then traverse the full length a couple of times and return to the zero point and see if "0" is in exactly the same physical position.
Russ

Title: Re: Motor Tuning Issues
Post by: dakmonf on May 23, 2011, 02:04:17 PM

Russ,  I have tried as you suggested and it does not resume to the original location.  Does this mean I am losing steps?  If so, how do I correct? I do not see any slippage but would it be noticable?

Greg

Title: Re: Motor Tuning Issues
Post by: Overloaded on May 23, 2011, 02:37:22 PM

If its slipping, it could be when at a tight spot on the slides. Binding maybe.
This is also where it would most likely be loosing steps.
Check for freedom of movement.
Mark all couplings / sprockets/ shafts to indicate any slippage.
Reduce rapid and feedrtes/accellerations and try again.
Missed steps can be from a multitude of things.
Lets rule out slippage and excess velocity/accel first.
Russ

Title: Re: Motor Tuning Issues
Post by: dakmonf on May 23, 2011, 04:44:02 PM

Russ;
I will do what you suggest tomorrow.  Will post results when I can.

Thanks

Greg

Title: Re: Motor Tuning Issues
Post by: dakmonf on May 24, 2011, 02:37:45 PM

Russ;

I believe that the grub screws on my motors were slipping. All seems to be fine now. Thanks for the help.

Greg

Title: Re: Motor Tuning Issues
Post by: Overloaded on May 24, 2011, 03:07:21 PM

Great news Greg, glad you found it.
Russ