Fig Specifying Combined Profile And Parallelism Tolerances

6.5.4 Application of Datums. In most cases, profile of a surface tolerance requires reference to datums in order to provide proper orientation, location, or both, of the profile. With profile of a line tolerance, datums may be used under some circumstances but would not be used when the only requirement is the profile shape taken cross section by cross seclion. An example is the shape of a continuous extrusion.

6.5.5 Combined Controls. Profile tolerancing may be combined with other types of geometric tolerancing. Figure 6-16 illustrates a surface that has a profile tolerance refined by a parallelism tolerance. The surface must not only be within the profile tolerance, but each straight line element of the surface must also be parallel to the datum within the tolerance specified. Figure 6-17 illustrates a surface that has a profile tolerance refined by a runout tolerance. The entire surface must be within the profile toler ance and the circular elements must be within the specified runout tolerance. Figure 6-18 illustrates a part with a profile of a line tolerance where size is controlled by a separate tolerance. Line elements of the surface along the profile must lie within the profile tolerance zone and within a size limiting zone. In certain instances, a portion of the profile tolerance zone may fall beyond the boundary of the size limiting zone. However, this portion of the profile tolerance zone is not usable because the line elements of the surface must not violate the size limiting zone.

6.5.5.1 Boundary Control for a Noncylin-drical Feature. Profile tolerancing may be combined with positional tolerancing where it is necessary to control the boundary of a noncylindrical feature. See Fig 6-19. In this example, the basic dimensions and the profile tolerance establish a tolerance zone to control the shape and size of the feature. Additionally, the positional tolerance establishes a

Was this article helpful?

0 0

Post a comment