Process plan validation including process deviations and machine-tool errors

摘要

This paper proposes a tri-dimensional kinematics method for process plan validation confronting a design tree and a manufacturing tree. The main process deviations and machine-tool errors are taken into account. Starting from the CAD/CAM model, the elements involved in a process plan validation are emphasised considering a specific process plan and manufacturing process. A kinematical analogy is used, where the machined features are the elements of a mechanism. We propose an original enrichment process plan graph as an essential tool for the process plan validation, including the process deviations and the functional tolerances. A three stages model is built: Matrix computations, manufacturing simulations and virtual metrology. Different tolerance specifications are verified by simulation using virtual gauges. A further development in symbolical computation allowed performing a sensitivity analysis. This usefully isolates the influences of the dominant process deviations on different tolerances. The computational method is exemplified on an industrial part, and a process plan is validated considering some critical tolerances.