Cost of Photochemical Machining

Photochemical machining (PCM), also known as photoetching, photofabrication or photochemical milling, is a non-traditional manufacturing method based on the combination of photoresist imaging and chemical etching. PCM uses techniques similar to those employed for the production of printed circuit boards and silicon integrated circuits. The PCM industry plays a valuable worldwide role in the production of metal precision parts and decorative items. Parts produced by PCM are typically thin, flat, and complex. These parts have applications in electronics, mechanical engineering, and the aerospace industry. The increasing popularity of industrial applications, together with greater competition, means that there is a need to understand the costs involved in PCM so that the right technology can be selected for manufacturing. The paper identifies the costs involved in Photochemical Machining and presents a cost model for PCM using a bottom-up approach. The research used IDEF3 representation (work breakdown structure, WBS) to identify the process used in PCM. Expert interview, literature survey, and participant observation were used to identify cost drivers at each stage of the manufacturing process. The WBS and the cost drivers were used to develop the cost model, which is focused on stainless steel machining. Spreadsheets were used to implement the model, while the workbook is divided according to the main process steps and general costs. The worksheets contained in this workbook are: General Costs, Produce Drawing, Process Phototool, Select Metal, Prepare Metal, Coat the Metal, Process Photoresist, Etch Metal, Strip Photoresist, and Check & Package. Each of these sections is divided into the following types of costs: Materials, Direct Labour, Environmental and Indirect Costs. The workbook contains relevant data acquired from the PCM laboratory at Cranfield, PCM industry, and literature. The model is validated through expert judgement obtained on case study results. The model presented in this paper can be extended to include other PCM techniques to machine other materials.