Runout
Circular Runout*
Circular runout is a cross-section check that is used to evaluate features relative to a datum axis. With surfaces constructed around a da- tum axis it establishes a width variation normal to that surface evaluating both circularity and coaxiality around the datum axis.
Evaluation Process within SA:
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The actual feature type is first established (circle or cylinder) based on the nominal type (feature to which the annotation is attached), and this feature type is fit to the entire data set to establish the direction vector
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Cross sections are established along this direction vector and the data is divided into groups based upon their position along this vector.
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Measurements are allowed to rotate based on the datum constraints to minimize the point deviations for all cross sections.
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The extent of the max point deviation relative to the surface normal is doubled to describe the fit deviation zone for each cross-section.
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The check returns the worst of the cross section results.
Total Runout
Total runout is used to evaluate surfaces constructed around a datum axis it establishes a width variation normal to that surface. The evaluation zone is continuous providing a cumulative evaluation of deviations in circularity, straightness, coaxiality, taper, and profile relative to this axis.
Evaluation Process within SA:
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Measurements of the datum are fit to the datum feature to establish a nominal axis.
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These features are translated along the nominal axis as al- lowed by any additional datum constraints to minimize the maximum and minimum point deviations.
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The extent of the maximum point deviation relative to the surface normal is then doubled to define the diametric measured deviation and compared to the tolerance zone to report the result.