Profile Tolerances

Abstract

A geometrical tolerance on a profile is one of the most versatile and powerful instruments that can be used for functional dimensioning, and is the tolerance most frequently used by designers. A profile may in fact be used to control the size, form, orientation and location of a feature. Because of the flexibility in the level of control that can be achieved with the profile tolerance, this control may be used to substitute the classical coordinate dimensioning method. The present chapter covers the ISO rules on profile tolerances in order to appropriately specify the control of a profile with a combination of the SZ, CZ, UF symbols and the bidirectional and unidirectional zones that are specified with profile tolerances. A composite profile tolerance is used in the ASME standards when the design applications require stricter tolerances on the form than is needed for the orientation or location of the same feature. The new ASME symbols, that is, From-To and dynamic profile, are presented.