COMPOSITE FEATURES

COMPOSITE FEATURES & COMPOSITE TOLERANCE REPORTS

CAPPS now has a new tolerance and reporting option for handling Composite Tolerances and Composite features. Before we review how Capps works with them, we need to clarify what Composite tolerance is.

Composite Tolerance:

Composite tolerance is actually a very complex concept which is used for many different purposes. The main idea is to generate a single report item which includes multiple tolerance call outs. The following are examples of this composite tolerance reports:

• Creating a group of features in a Pattern and reporting its centroid as a position callout and reporting its members using a different tolerance (usually tighter) at the same time.

• Reporting the true position of a feature such as a cylinder while reporting its perpendicularity at the same time.

• Reporting a surface for its profile while controlling each point on the surface with a different tolerance.

In this first attempt of reporting composite tolerances, we implemented the first method, which is creating a composite pattern by using several features, then treating this as a single feature and report its position as well as position of each element. Other methods will be incorporated in future releases of Capps.

Pattern Feature:

Pattern feature is a feature representing a group of features in order to treat and generate reports representing the whole group.

Creating a Pattern Feature:

Pattern features can only be created by constructing with previously measured features.

On the top menu, Measure/Feature now has a PATTERN option.

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Since Pattern can only be created in construct mode, as soon as this option is selected, Capps will open the construct dialog with a similar method as the Bestfit along with the feature list brought up.

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Once the features are selected to create this Pattern and Computed, a new feature will be generated. Note that, the nominal pattern feature may not be visible on the screen at this time. However a DMIS code and a report if output option was enabled will be generated as follows:

Different Pattern features can be created in for different groups. These names will be listed in the feature list and can be used like any other feature as they will also have an location (X Y Z) coordinates

COMPOSITE TOLERANCE:

A Pattern feature can be used to generate a composite tolerance. A new Composite option can be found in the GDT menu as below. When selected and after the feature is selected, it will bring the Composite dialog window. Notice that there are 2 tolerance fields in this window. As we are using this only for true position reports, both will be a true position tolerance, the top for the composite Pattern feature, and the second will be for the individual elements used to create that feature.

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Once the tolerances are entered, the following report will be generated.

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The DMIS code that generated is as below:

T(ComPos)=TOL/COMPOS,PATERN,0.1000,RFS,DAT(A),DAT(B),DAT(C),FEATUR,0.0500,RFS,DAT(A),DAT(B)

OUTPUT/FA(PTRN14),TA(ComPos)

The report at this time is calculated as RFS in the current alignment. We have the tolerance statement generated as shown to comply with the DMIS standard. Next versions of this report will also incorporate these datums in the calculations.