Optimization for process plans in sheet metal forming

Determining a process plan in the early phase of the sheet metal forming process is a mandatory task for a process planner. The objective of a process planner is to find a feasible and cost optimal process plan which, in particular, optimizes the assignment of processing elements to processing steps of the production process. We propose to find such an assignment in an automatic way for all the hole features by splitting the entire task into three subsequent steps. At each step, the combinatorial optimization problem is modeled as a bin packing problem with conflicts, and heuristically solved by a specifically designed ant colony optimizer. It is ensured that, at each step, the process plan is feasible while minimizing the tooling costs. In our computational results, we compare our approach to the existing greedy heuristic when computing a process plan for five different practice-relevant sheet metal parts, and show that we can save up to 50 % of the entire tooling costs.