Near net shape manufacturing of metal: A review of approaches and their evolutions

Abstract

In the last 30 years, the concept of manufacturability has been applied to many different processes in numerous industries. This has resulted in the emergence of several different “Design for Manufacturing” methodologies which have in common the aim of reducing productions costs through the application of general manufacturing rules. Near net shape technologies have expanded these concepts, targeting mainly primary shaping process, such as casting and forging. The desired outcomes of manufacturability analysis for near net shape processes are cost and lead/time reduction through minimization of process steps (in particular cutting and finishing operations) and raw material saving. Product quality improvement, variability reduction and component design functionality enhancement are also achievable through near net shape optimization. Process parameters, product design and material selection are the changing variables in a manufacturing chain that interact in complex, non-linear ways. Consequently, modeling and simulation play important roles in the investigation of alternative approaches. However, defining the manufacturing capability of different processes is also a “moving target” because the various near net shape technologies are constantly improving and evolving so there is challenge in accurately reflecting their requirements and capabilities. In the last decade, for example, computer-aided design, computer numerical control technologies and innovation in materials have impacted enormously on the development of near net shape technologies. This article reviews the different methods reported for near net shape manufacturability assessment and examines how they can make an impact on cost, quality and process variability in the context of a specific production volume. The discussion identifies a lack of structured approaches, poor connection with process optimization methodologies and a lack of empirical models as gaps in the reported approaches.