Using STEP to integrate design features with manufacturing features

摘要

There are several parametric or variational feature-based solid modeling design tools that aid the user in productively creating a product design. However, most of these systems do not address mapping from the design feature to the manufacturing feature. We present a representation for manufacturing features that integrate with design features using the ISO 10303 STEP product definition standard. We extend the STEP AP203 entities with feature definitions in a way similar to AP224, the working draft of STEP Features. The manufacturing features presented here provide a means to link design changes to manufacturing feature and/or process changes. Currently, most systems depend on humans to detect and propagate design and process changes to manufacturing features and plans. Toward solving this problem, we are working on a manufacturing feature representation that can detect a design or process change and correct some, or at a minimum, flag the manufacturing engineer where the change affects manufacturing operations. We define manufacturing features as a collection of faces and edges. It is important that these faces and edges can be uniquely identified in the design feature representation. The STEP entity Shape-Aspect is used to permanently name the face or edge. Our features are built from expressions that reference the design feature's faces and edges that can be reevaluated to propagate a design change. In this paper we present this new approach for representing manufacturing features and discuss its current and planned implementation.