Photochemical Machining: from ‘manufacturingʹs best kept secret’ to a $6 billion per annum, rapid manufacturing process

Photochemical machining (PCM) is one of the least well-known non-conventional machining processes. It employs chemical etching through a photoresist stencil as the method of material removal over selected areas. The technique is relatively modern and became established as a manufacturing process about fifty years ago. The processing technology has been kept a closely-guarded secret within a small number of industrial companies but despite this, the sales of parts made by PCM at the end of the twentieth century was approximately US$ 6 billion. This paper examines the state of the art of PCM, the PCM Roadmap and the newly-developed products made by PCM especially relevant to Microengineering, Microfluidics and Microsystems Technology, economic aspects and current challenges requiring research within the PCM industry.