Conversions of Feature-Based Design Representations Using Graph Grammar Parsing

Abstract

In order to trade off required functionality with manufacturing, cost, and other life-cycle considerations, it is necessary to evaluate designs in these secondary view-points. Representations of mechanical components designed with design features must be converted into representations containing relevant secondary viewpoint features. When describing a design verbally, designers often use languages of design features. In other viewpoints, different languages of viewpoint-specific features are used. Thus, translation capability between viewpoint languages is needed to convert from one representation to another. The approach taken here is to use formal graph grammars to define the feature-based design of thin-walled components and the secondary feature languages. Features are defined by graphs that explicitly represent the feature, its geometric entities, and their connectivity. Components are built up by combining feature graphs based on designer specified feature connectivity. To convert from the design to a secondary viewpoint, a three-step process is used where the last step is parsing by a grammar from the secondary viewpoint. To illustrate the conversion process, a converter for tool cost evaluation in injection molding and die casting is developed and applied to an example component.