Generation of Alternative Feature Representations and Feature Precedence Relations for Feature-Based Process Planning

Abstract

This work deals with the analysis and transfer of design information, expressed in terms of features, from feature-based CAD models to CAPP systems in order to perform process planning. In this paper, we present an integrated system that retrieves design information from a feature-based CAD model, performs feature mapping, identifies interactions between features, generates alternative feature representations and feature precedence relations. The alternative feature representations provides the process planner with more flexibility in terms of process selection and are shown in the form of an AND-OR graph. The feature precedence relations, represented as a directed feature precedence network, assist the process planner in its process sequencing tasks. Feature mapping involves the mapping of design features into equivalent valid machining features. Feature interactions are identified by analyzing part geometry for face adjacency and hence feature adjacency. The interacting features are then analyzed to identify possible alternative feature representations and feature precedence relationships. Procedures for the identification of feature interactions and determination of alternative feature representations and feature precedence relationships are provided. The generated AND-OR graph and the feature precedence network seeks to aid CAPP systems in process sequence generation and serve as a vital step for the integration of design and planning systems.