Re: MaxNC modifications

Jon Anderson wrote:

> From: Jon Anderson <janders@...>
>
> Some parts do not lose steps.
> Each part will show a different pattern of lost steps. The pallet base
> has a .500 dia hole that we indicate from to establish datum, all
> pallets and all programming is referenced from this hole. It's real easy
> to drop an indicator in and check for lost steps.
> For example, one particular part run in multiples of 8 parts per pallet
> might show .0013 lost in X and .0003 lost in Y every for every pallet
> load. With the tolerances on this job, Dad can let this accumulate over
> two pallets before having to rezero. This is so consistent that he
> stopped checking after every two pallets and simply would jog X.0026
> Y.0006 and rezero. After running several hundred parts, he'd check with
> the indicator after the last two pallet loads and be off exactly
> .0026/.0006.

Wow! this really DOES sound like a software problem. I really don't
believe this is the motor losing steps due to drag, electrical noise, etc.
It may be due to some characteristic of the control software, under just
the right sequence of G-code comands, produces step pulses too fast
for the motor to follow. But, that bit about fixing the axis offsets blind,
and being dead on after repeating the sequence 50 times, is just to
consistant to be anything other than software (one way or another).

Jon (increasingly happier that I went with servos)