I'm checking a plate with some holes in it and attempting to check the holes back to an origin. I can measure all the holes with the Romer without any sort of rotation and they are the size they should be (0.406± 0.020) However, if I create a line created using two of the circles (they are both on the Y origin) and then rotate to that line, the holes measure 0.179. I'm using a 3mm ball on an Infinite Romer arm.
So, in summary...
Level to plane.
Measure all 12 holes.
Create a line using 2 holes on the Y origin.
Rotate to line.
Create Origin
Holes are 0.406 (accurate). True positions are good.
Level to plane
Measure two holes on Y origin.
Create a line using those two holes.
Rotate to line.
Measure remaining 10 holes.
Create Origin
Holes are 0.179 (not accurate). True positions are good.
Why the difference? Perhaps this will help me in the future. Thanks.
Thanks for your help guys. I changed "IN" to "OUT" on the circle on a different part and I got the right measurement, but this kind of thing has not happened before. What would start to suddenly cause this on parts?
A seemingly related issue is happening when I check ANY OTHER PART in the X-axis. The measurement is off by .116 or suspiciously close to 3mm which is the size of the ruby I'm using. I don't know all the ins and outs of PC-Dmis, so if you could point me in the right direction, it would certainly be appreciated.
I thought of something while reading your replies. I had recently updated PC-Dmis 2016 to their service pack 1. I used 2015 which is still on my laptop and when doing the same checks, I got the correct measurements. Would it be a bug or simply a setting change?
Yes, there are bug reports on probe compensation in 2016 SP1 for arms (PCD-102333 for example) - it looks like the probe compensation can go wrong when machine axes and physical part axes don't coincide.
I've had the same problem with SP2 recently and had to revert back to 2015 SP6 for it to work properly. I'm told by tech support that a fix is "in the works".