Tolerance analysis in setup and fixture planning for precision machining

Tolerance analysis is an important issue for automated computer-aided process planning (CAPP). Most of the existing CAPP systems are limited in tolerance check and allocation. This study presents a new approach for comprehensive tolerance analysis in CAPP. It focuses on the error analysis and control strategies in setup and fixture planning for precision machining. Error sources are investigated and corresponding calculation methods are proposed. Transformation matrices between the machine, fixture and workpiece coordinate systems are derived for tolerance calculations. Datum selection and error stack-up are also discussed. An example is provided for detailed illustration