Automated setup selection in feature-based process planning

Setup planning is a critical part of automated process planning. Setup is determined by several factors, tool approach direction and tolerance specification are two major ones. Most of the current process planning systems consider only the tool approach direction. This results sometimes in incorrect parts. To convert the tolerance requirements from design into a process plan, tolerance analysis must be applied. Correct datums must be selected for an optimum setup plan that will assure the required tolerances. This paper describes an approach that uses the tolerance specification in a feature based design system to generate setup plans with explicit datum elements. These setup plans are ranked by the number of setups required and the estimated accuracy of the resultant dimensions. The ranked setup plans are then reported to the fixture planner for fixture selection. The focus on this research is an automated tolerance analysis approach for selecting setups and datums for prismatic workpieces in the design system.