Machining mechanism in tilt electrical discharge milling for lens mold

A new machining method for lens molds using tilt electrical discharge milling (ED milling) has been experimentally investigated. Compared with the conventional ED milling, the tilt ED milling enables efficient enlargement of discharge gap by adjusting the tilt angles of the workpiece which results in efficient chip removal and burnish surface quality. On account of this method, micro lens craters were fabricated on the tungsten carbide (WC) and silicon carbide particulate reinforced aluminum metal matrix composite (SiCp/Al) at the optimized machining parameters under various tilt angles of the workpiece. The surface morphology and material removal rate were determined with a laser scanning microscope VK-X100 (KEYENCE, Japan). Experimental results present a 60% rise in surface quality at 25° in tilt ED milling. On the basis of electromagnetic effect, the machining mechanism is analyzed in detail in tilt ED milling for lens molds.