Profile Tolerances

There are several calculation methods available to evaluate profile tolerances:

These methods lets you evaluate profile tolerances in different ways. The Min and Max calculation methods (min/max calculation methods) operate differently than the CONT# calculation methods (contour calculation methods).

Min/Max Calculation Methods

The min/max calculation methods operate as a pair. These methods support profile tolerances that reference the ASME Y14.5M – 1994 standard. Specifically, ASME Y14.5.1M – 1994 §6.5 indicates that profile tolerances have two actual values. One corresponds to the maximum deviation and the other corresponds to the minimum deviation. The *MAX and *MIN calculations support these two actual values, respectively. In the .TOL file, you want to make sure the limits of these calculations correspond to the maximum and minimum limits for the profile deviations.

For these calculations, the negative tolerance is usually -0.5 of your drawing callout value and the positive tolerance is usually +0.5 of your drawing callout value.

For example, suppose the profile callout is 0.008, the negative tolerance is -0.004 and the positive tolerance is +0.004.

You can use the min/max calculation methods to support profile tolerances that references the ASME Y14.5 – 2009, ASME Y14.5 – 2018, and ISO 1101 standards. The two measured values are not the same as the single actual values defined in those families of standards. With the limits set correctly in the .TOL file, the conformance decision can be made correctly for both equal bilateral and unequally disposed profile tolerances.

These calculations support non-bilateral drawing callouts.

For example, suppose the profile callout is 0.008, the negative tolerance is -0.003 and the positive tolerance is +0.005.

Contour Calculation Methods

The contour calculation methods operate alone. They support many types of profile tolerances:

For Blade 5.0 and earlier versions, the contour calculations have no options to control the result's calculation. There are Form Only profile tolerances that means the maximum deviation minus the minimum deviation. This is same as dynamic profile defined in ASME Y14.5 – 2018, and same as OZ profile tolerances defined in ISO 1101.

For these calculations, the negative tolerance is always 0.0000 and the positive tolerance is your drawing callout value.