Micromachining process with ductile tooling

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The proposed research is about the development of a novel automated manufacturing process designed to replace tedious hand-polishing operations involved in the fabrication procedures of mass production injection molds. Injection molds are expensive pieces of equipment required to produce at reasonable price, any kind of polymer parts contained in a large variety of consumer products such as cars, computers, cell phones, electric tools, toys and others. The main cavity of an injection mold is carved out of a block of tool steel material with a powerful CNC milling machine, followed by secondary manual processes to obtain the desired surface finish. Up to 30% of the mold production cost is related to the latter secondary finishing processes because most of these operations involve handwork. In the proposed research our intention is to design a automated manufacturing process, based on the EDµM electric discharge µmachining and UAµM ultrasonic abrasive µmachining principles. In EDµM, electric discharges are produced between a tool and the workpiece to be polished. Each discharge attacks the surface peeks and vaporise tiny amount of the material. For UAµM, an ultrasonic activated tool generates powerful yet small displacement to propel abrasive particles over the surface of the workpiece which removes or displaces tiny amount of material. The novelty of this approach resides in the possibility to combine the advantages of both processes within the same numerically controlled machine tool. Such characteristic is made possible by the development of a ductile, electrically conductive and wear resistant polymer tool which, once compression molded can be used as a tool to perform either material removal techniques in the hardest metals. The entire process is environmentally friendly since it is conducted in air or with abrasive particles (like sand) and does not generate toxic by-products. Mold manufacturing represents a 3 to 4 billion dollars business in Canada, and competition from emerging countries is fierce because of lower wages. Thus, the proposed research endeavours giving back a worldwide competitive edge to our mold manufacturing industry.