Process planning for aluminum tubes: An engineering-operations perspective

Metal-forming operations such as extrusion, drawing, and rolling offer many opportunities for operations improvement through better process understanding and improved planning practices. This paper addresses medium-term planning issues in aluminum tube manufacturing operations. First, we identify certain distinctive characteristics-the inherent process flexibility, close interdependence between successive stages, and economies of scale-of metal-forming operations, and identify performance tradeoffs across stages. To exploit the strategic potential of process planning, it 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 and with less emphasis on 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 effective process plans that exploit process capability, and adopt proactive process improvement strategies that focus on critical constraints. We describe a medium-term planning model to select standard extrusion sizes, illustrate the close linkages between planning and engineering activities, and identify research opportunities spanning management science, materials science, and mechanical engineering.