TABLE OF CONTENTS It is crucial that management consider total cost per finished workpiece, when comparing various processes for possible use. Many elements enter into any cost comparison, including capital equipment, depreciation, maintenance, labor, and power costs. The cost of perishable items, such as media, compound, and water, must be analyzed. Overhead costs include management, supervision, insurance, heat and light, floor space, and waste disposal. The possible need for subsequent cleaning or other processing can also affect costs. Additional expenses include scrap, rework, and inspection. This chapter presents charts and equations for calculating and comparing approximate cost. More complex equations may be developed readily for including factors such as waste removal, scrap, etc. Descriptions of several examples of costs for mass finishing processes are described elsewhere (Kittredge 1985a; Balz 1983; Johannsen 1977; Ostwald 1983, 1985/1986; Rhoades 1981; Ioi et al. 1985). At least two basic computer programs make evaluation of alternatives much easier than it would be if manual calculations were used (Kittredge 1985a; Balz 1983). Computer-aided selection of processes and, in at least one plant, total computer-control of finishing, are the standard (Ioi et al. 1985). Additional cost considerations for these processes can be found elsewhere (Johannsen 1977).
There is a four-step process for evaluating costs: Step 1: Understand current finishing costs. Step 2: Understand potential costs of other approaches. Step 3: Understand detailed costs per part and operation in the using facility. Step 4: Reduce costs and optimize the process.
Step 1 involves evaluating real...
