Toleranced feature modeling by constraint of degree of freedom for assignment of tolerance

The purpose of this study is the faithful expression of toleranced feature in machines or drawings following the current tolerancing, and the proposition of the feature model that is able to evaluate the effect of tolerances against the designer’s demand such as performance, costs and so on. We examined the tolerance zone ISO recommend and classified the relationship between tolerance and feature. The tolerance zone is the set of allowable feature and the behavior of feature is represented by using matrices and constraint equations that limit the degree of freedom (DOF) of feature. And the relationship of features and tolerances were classified by the feature, datum, size and tolerance information as unit. Every behavior of toleranced feature is expressed by the combination of them. Furthermore, in addition to these DOF constraint model, we proposed the functional expression of each manufacturing lot for the current geometrical feature model. The manufacturing group of it consists of the material, manufacturing and functional shape to connect the manufacturing information. We also considered the assignment of tolerances that satisfies the target cost or performance using the manufacturing cost.