AN INTEGRATED FIXTURE PLANNING AND ANALYSIS SYSTEM FOR MACHINING PROCESSES

Fixture planning is an important part of computer-aided process planning (CAPP), which is the link between design and manufacturing in a CIM environment. This paper presents a rational approach to computer-assisted fixture planning (CAFP), emphasizing integration of fixture planning with process planning, an issue that has not been adequately addressed until very recently. A systematic approach to fixture selection is outlined for planning of modular fixtures. A prototype CAPP-CAFP system has been developed at UCLA and linked to a commercial CAD system, namely, CADAM. Part design information can be extracted from the CAD model and multiple-view engineering drawings of a part stored in the CADAM system. Modular fixture elements can be selected automatically by the CAPP-CAFP system and the generated fixture layout can be displayed on the screen. Included also in the system is a fixture analysis module for verification and rationalization of a fixturing scheme. The force analysis module has a built-in local optimization routine that can determine the clamping forces of more reasonable magnitudes. The friction forces between the fixture elements and the workpiece can also be considered for simple cases.