A simple and robust setup planning scheme for prismatic workpieces

Abstract

Computer Aided Process Planning (CAPP) is a link between Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM). Setup planning is the main function to integrate the designing and manufacturing processes. Despite significant progresses in the modern manufacturing, setup planning is still being considered an experience based activity. Its reason can be fixturing constraints, tolerance requirements (specially stack-up in tolerancing), geometric relationships among machining features, and Tool Approach Direction (TAD). All aforementioned limitations introduce setup planning as a complicated nonlinear task. Setup planning not only determines features must be machined in each setup but also defines locating datum for each setup. This study focuses on the development of a simple and easy-understanding series of steps to generate feasible setups. Tolerance stack-up has been eliminated using datum face as a reference plane in the fixture design. Three concepts namely “control face”, “control factor”, and “machining priority” have been employed for this aim. The capability of proposed scheme has been proved by applying it on two practical case studies. The suggested algorithm has successfully reduced the number of setups from 7 to 6, which is the least number of achievable setups and shows its sufficiency.