I'm running a program that I am reporting out true position for three holes. If you look at the report, it is showing them out of tolerance, but it doesn't look like it is using the bonus tolerance. I calling out the true position to three datums. Primary datum (A) is a plane, secondary datum (B) is a diameter, tertiary datum (C) is another diameter perpendicular to the secondary datum (I constructed a line between the two and rotated to that in my alignment). The print calls out MMC on the feature itself, as well as MMC on B and C. I looked online to see if I could find a math formula to double check PC-DMIS's report output, but I couldn't find any that used three datums. Does anyone know it? Does the report look like it calculated correctly?
For simple situations, this software will calculate true position with MMC on feature correctly.
You do, however, need to group features with datum shift bonuses as "simultaneous evaluation".
Caveat 1: when PC-DMIS calculates datum shift correctly (it doesn't in most versions) it will simply pretend that the datums have moved, which gives the reader a lot of "0.0000" results which is misleading.
Caveat 2: depending on part, PC-DMIS can grossly miscalculate ocking while using simultaneous evaluation and datum shifts.
I have found that it's best to export results and simply use Excell to do the datum shift calculations.
For simple situations, this software will calculate true position with MMC on feature correctly.
You do, however, need to group features with datum shift bonuses as "simultaneous evaluation".
Caveat 1: when PC-DMIS calculates datum shift correctly (it doesn't in most versions) it will simply pretend that the datums have moved, which gives the reader a lot of "0.0000" results which is misleading.
Caveat 2: depending on part, PC-DMIS can grossly miscalculate ocking while using simultaneous evaluation and datum shifts.
I have found that it's best to export results and simply use Excell to do the datum shift calculations.
