Alternative process sequences - products
Even when the type of process flow has been established, there remains the task of determining the particular sequence of processes to be used. Just as in the conceptual phase of product design, there are, typically, many different ways of producing a product. To illustrate this issue we will consider two ways of manufacturing the gas-turbine component shown here. The working part of the component, the aerofoil, is positioned in the gas stream by the fixing, which is retained by a slot in the engine casing. Although, in both cases, the complete transformation process will actually begin with extraction of metallic ores from the ground, for simplicity we will consider only the processes following bar and strip production.
Again, for convenience, the alternative ways of producing the component are presented as flow process charts. Consider the implications for the operations manager of these alternatives. For process sequence A the input material supplies to be purchased would be cylindrical steel bars; for sequence B the materials required would be rectangular bars, precision-rolled aerofoil strip, and brazing paste. The equipment used by sequence A would be forging and clipping presses, milling machines, polishers, and a transfer machining line. Sequence B would require a quite different set of processes: milling machines, cropping and piercing machines, and a vacuum-brazing plant. There would also be consequent differences in the types of process operators to be hired, and tooling to be designed and purchased.