Base Alignment loop tolerance.

[[Cl...]]

By way of this forum, I have learned that the optimal tolerance to use in the
looped alignment formula is .0005. We had a Zeiss apps engineer in here a
while back, and I noticed that he was using the Base alignment loop with a
.005 tolerance. In addition, he told me that this value is no really a tolerance,
but a sigma value. Any thoughts on this?

[[SH...]]

viewtopic.php?f=13&t=3316&hilit=Delta+value#p21696

Yes it is not a tolerance.

[[Mi...]]

Isn't the sigma value just a standard deviation between the previous alignment and the present alignment? Basically, you are making an alignment and then taking another alignment and as long as it is within .0005 of the first alignment, it passes and the program can continue. Am I wrong in this?

[[Th...]]

The number in the break condition is certainly a tolerance. As in, I'll tolerate a deviation from the previous base system if the calculated value is smaller than the number I provide. As for the discrepancy between your use of 0.0005 and the app engineer's use of 0.005, that looks like the difference between a metric and inch environment.

[[Cl...]]

Nope, he was in inches. Also, the part being measured is a .097 Ø shaft (with runout) chucked in a horizontal rotary rotating 180 degrees on an O-inspect, being measured with CFS, tactile, and camera. Some position tolerances of .001, profiles of .002.

[[Th...]]

Could be that the engineer thinks the values returned by that formula don't respect the environment choice? I recall there was a thread here a year or two ago that mentioned older Calypso versions returned valueA in metric no matter what, but that it got fixed at some point.

[[Mi...]]

sounds to me like he didn't want the program looping over and over unless there was something actually wrong. With 0.0005 the program might have looped the alignment again and he would have had to stand there with his hands in his pockets waiting, with 0.0050 it most likely wouldn't have.