A Feature-Based Classification Scheme for Fixtures

Abstract

Summary: This paper presents a feature-based classification scheme for futures using a 3D solid modeller, a feature extractor and an object-oriented expert system shell. Its intended use lies in variant fixture designs as well as its association with machining operations, machining environment, cutting tools and workpiece features. The operations begin with a solid model where machining features are extracted and grouped into setups based on machining directions and tolerance factors. A knowledge base is used to infer the operations involved and the cutting tools required for a given machining environment. Different classes and sub-classes of fixtures are identified based on setups, operations, and fixturing rules. Instead of using numerical taxonomy, the fixture is coded in feature-based symbolic representations which can be compared easily for its similarity with existing fixtures. © 1992 CIRP.