CAD-CAM integration using machining features

Abstract

Commercial mechanical CAD/CAM packages provide a rather low level of automation of process planning tasks and a weak connection between their CAD and CAM/NC part programming modules. Features have primarily been used as geometry construction 'macros' without fully realizing their potential in supporting downstream applications, such as process planning. This paper demonstrates the use of features in automating certain process planning tasks and integrating CAD and CAM modules in commercial CAD/CAM software. Automated process planning involves two important tasks; machining feature extraction and feature-based process planning. The CAD model of the part and the stock is exported via STEP from the commercial CAD system to an external machining feature recognition system. The recognized features are used in conjunction with knowledge-based methods to prepare a process plan for the part. Set-up Planning, Operation Sequencing and Tool Selection are performed automatically based on criteria such as feature shapes, feature locations, tool access directions and feasibility of workpiece locating and clamping. Features and manufacturing attributes are exported to a commercial CAM system for toolpath generation and verification. A prototype system was implemented in conjunction with a commercial CAD/CAM package, SDRC/I-DEAS.