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From section 6.5.3 Explanation of Profile Tolerance in ASME Y14.5M-1994 "Dimensioning and Tolerancing":
“The tolerance value represents the distance between two boundaries equally or unequally disposed about the true profile or entirely disposed on one side of the true profile.”
Please also refer to Section 6.5 Profile Control of ASME Y14.5.1M-1994 "Mathematical Definition of Dimensioning and Tolerancing Principles". ASME Y14.5.1M-1994 specifies the profile tolerance value as the sum of t+ (the tolerance disposed in the positive direction) and t- (the tolerance disposed in the negative direction), where t+ and t- are positive values. This is what PC-DMIS normally reports.
For ISO 1101, the tolerance value is the diameter of a sphere centered on the surface, so in this case the tolerance value would be 2 times the maximum deviation. Starting in V40, we added a registry setting to allow users to report the profile result as 2 times the maximum deviation. This registry setting is Option\UseISOCalculations. You can use the settings editor for V40+ to set UseISOCalculations to 1 if you want the profile results reported as 2 times the maximum deviation. This setting is used only for reporting the profile tolerance value.
PC-DMIS does not pass bad parts. The out-of-tol value is calculated based on the max deviation versus the upper tolerance and the min deviation versus the lower tolerance. So parts that violate the users +/-tol value will be flagged as out-of-tol regardless of how the measured value was calculated. |
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