Computer-Aided ProcessPlanning (CAPP) bridges design and manufacturing, crucial for saving time and reducing work in progress. Important consideration in CAPP is setup planning, particularly when there are multiple processing requirements and alternate processes and resources. This paper presents a heuristic rule-based procedure for process and setup planning as modules within the intelligent planning system IMPlanner. The process selection module generates manufacturing processes for each feature of metal mechanical parts, considering dimensions, and specific geometric and dimensional tolerances, resulting in multiple processing requirements to achieve the tolerances and alternate processes. The setup planning module considers those processes and combines them into setups considering the approach directions, tolerances and available machines. The heuristic procedure based on minimizing the number of setups has been implemented using a rule base approach. Using rules, it defines tool approach directions, forms setups based on GD&T requirements, resolves cyclic setups, and sequences operations. These rules are adaptable for generating valid setups on both 3-axis and 4-axis milling machines. The approach is demonstrated with several examples, highlighting its practicality and effectiveness.