Manufacturing involves the conversion of raw materials, usually supplied in simple or shapeless forms, into finished products with specific shape, structure, and properties that fulfill given requirements. This conversion into finished products is accomplished using a great variety of processes that apply energy to produce controlled changes in the configuration properties of materials. The energy applied during processing may be mechanical, thermal, electrical, or chemical in nature. The results are meant to satisfy functional requirements that were defined during the product design stage.

In the past, design, materials engineering, and manufacturing were often treated as independent engineering specialties. However, modem manufacturing must be cost-effective and timely. This requires that everyone involved in the entire product life cycle work together concurrently to provide a functional product that can be produced efficiently, can be operated reliably, and is easy to maintain and recycle (Taguchi, 1993). This report identifies a large number of opportunities for improving unit processes. These can be considered as future options for the concurrent engineering teams.

Manufacturing a product or component usually requires the integration of a number of processes. For example, the initial process may involve casting a metal into a mold to produce a desired shape. Next, the casting may be machined with cutting tools to generate surfaces of specified form. Finally, a surface treatment may be employed to improve the durability of the part. Each of these three individual operations—casting, machining, and surface treatment—is a unit manufacturing process. For brevity, in this report they will be referred to as ”unit processes.” They are the individual steps required to produce finished goods by transforming raw material and adding value to the workpiece as it becomes a finished product.

Mass-Change Processes

Mass-change processes are characterized by the removal of material through the use of mechanical, thermal, chemical, or electrical energy.¹ In most instances, the workpiece density is not altered; however, the material microstructure may be modified, particularly at the work surface. Workpiece chemical composition is, in some cases, affected in a small surface region. Mass-change processes are employed in most manufacturing enterprises in intermediate and final processing operations. Workpiece materials span the spectrum of metals, ceramics, polymers, and their composites. High-performance workpiece materials generally are processed by tooling made from higher-strength materials. For example, diamond is used as a tooling coating to process ceramics and ceramic matrix composites.²

Processing costs associated with mass-change processes are directly related to the material properties of the workpiece and to the tolerance and surface finish requirements of the final part. Considerations of operation setup time and cost of fixtures and tooling must be included in the evaluation of the process economics.

Mass-change processes can be grouped into traditional (chip-making) and nontraditional processes. Chip-making processes remove unwanted workpiece material by exploiting shear deformation and fracture mechanisms. The basic