Process Planning for Metal Forming Operations: An Integrated Engineering-Operations Perspective

Metal forming operations such as rolling, extrusion, and drawing offer many opportunities for operations improvement through better process understanding and improved planning practices. This paper addresses short and medium term planning issues in sheet, plate, and tube manufacturing operations. First, v^e identify certain distinctive characteristics-the inherent process flexibility, close interdependence between successive stages, and economies of scale-of metal forming operations, and identify the planning and performance tradeoffs. We argue that, just as product design plays a critical role in manufacturing of discrete parts, process planning has strategic importance in the metal forming context. To be successful, process planning must be closely coupled with process engineering efforts, and must simultaneously consider the facility's entire product mix. In contrast, current process engineering efforts are mainly reactive, focusing on fixing problems at individual operations, ignoring the interactions between successive stages. Similarly, planning activities are incremental, considering only individual products or orders one at a time rather than the entire range of product sizes to be manufactured. By working together, planners and engineers can develop principled practices and process plans, analyze the sensitivity of production p)erformance to current process constraints, and adopt a proactive process improvement strategy that focuses on critical constraints. We illustrate these concepts using examples from aluminum tube arid sheet manufacturing. We present an integrative process engineering-planning framework, and identify several interdisciplinary research opportunities spanning management science, materials science, and mechanical engineering.