Occasional alignment error ?!?

[[Da...]]

Anybody else get an occasional ( really not very often ) alignment error. We run lots of different parts all day long , and every now and then the cmm goes to a different location and attempts to touch off on the part. Problem is it's off by 1/4 to 1/2 of an inch !!! 😮

It rarely happens but when it does, it gets us all scratching our heads. It's not a leftover position from a previous alignment.

Al we do is run a man alignment , and everything's fine from there on out.

[[No...]]

We had a few measurement plans that did this when we ran a manual alignment at CNC start. We stopped doing that and now always do the manual alignment prior to CNC start from the base alignment dialog. Problem gone.
Another cause may be when points of directional features are probed in the wrong order, causing a flipped feature axis and thus a flipped alignment.