Fig Specifying Profile Of A Surface For Coplanar Surfaces

for the features being controlled. The tolerance zone thus established applies to all coplanar surfaces including datum surfaces. See Fig. 6-21.

6.5.7 Profile Tolerance for Plane Surfaces.

Profile tolerancing may be used to control form and orientation of plane surfaces. In Fig. 6-22, profile of a surface is used to control a plane surface inclined to a datum feature.

6.5.8 Profile Tolerance for a Conical Feature.

A profile tolerance may be specified to control the conicity of a surface in either of two ways: as an independent control of form, or as a combined control of form and orientation. Figure 6-23 depicts a conical feature controlled by a profile of a surface tolerance where conicity of the surface is a refinement of size. In Fig. 6-24. the same control is applied but is oriented to a datum axis. In each case, the feature must be within size limits.

6.5.9 Composite Profile. Where design requirements permit a feature locating tolerance zone to be larger than the tolerance zone that controls the feature size, a composite profile tolerance may be used.

6.5.9.1 Composite Profile Tolerancing. This provides a composite application of profile tolerancing for location of a profiled feature as well as the requirement of form, orientation, and in some instances, the size of the feature, within the larger profile locating tolerance zone. Requirements are annotated by the use of a composite profile feature control frame similar to that shown in Fig. 3-22(a). Each complete horizontal segment of a composite profile feature control frame constitutes a separately verifiable component of a pair of interrelated requirements. The profile symbol is entered once and is applicable to both horizontal segments. The upper segment is referred to as the profile locating control. It specifies the larger profile tolerance for the location of the profiled feature. Applicable datums are specified in a desired order of precedence. The lower segment is referred to as a profile size/form/orientation refinement control. It specifies the smaller profile tolerance for the feature within the profile locating zone (form and orientation refinement).

6.5.9.1.1 Explanation of Composite Profile Tolerance. Each feature is located from specified datums by basic dimensions. Datum referencing in the upper segment of a composite profile feature control frame serves to locate the feature profile locating tolerance zone relative to specified datums. See Figs. 6-25 and 6-26. Datum referencing in the lower segment serves to establish the limits of size, form, and orientation of the profile form/orientation tolerance zone, relative to the profile locating tolerance zone. See Figs. 6-25 and 6-26. The tolerance values represent the distance between two boundaries disposed about the true profile as defined by the basic dimensions and respective applicable datums. The actual surface of the controlled feature musl lie within both the profile locating tolerance zone and the profile form/orientation tolerance zone.

6.5.9.1.2 Control of Orientation. Other applications for composite profile tolerancing o:cur when the upper segment of the feature control frame contains only an orientation datum(s). It specifies the larger profile tolerance for the orientation of the profiled feature. Applicable datums are specified in a desired order of precedence. The lower segment is a form refinement control and does not specify a datum. It specifies the smaller profile tolerance for the feature within the profile orientation zone (form refinement).

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