Closed Loop Control of Milling Tool Deflection

BACKGROUND Injection molding is an important manufacturing process for optical and mechanical components. The hard steel dies used in injection molding play a direct role in the quality of molded parts. Traditionally, fabricating the dies involved rough milling followed by heat treatment, grinding and polishing. Recently, high-speed machining of heattreated steel (hardness > 55 Rc) has become a viable approach for reducing fabrication times while retaining the necessary shape control. However, as feature sizes drop below 1 mm with dimensional tolerances on the order of 10 μm, tool deflection can create significant errors in the shape of mold surfaces.