Fundamental study of ultrasonic polishing of mold steel

Ultrasonic Machining (USM) is conventionally used for machining hard and brittle materials. As polishing of steel mold has been a serious concern in the industry, an innovative cost-effective ultrasonic polishing system is developed for this purpose. The ultrasonic tool moves in a patterned path to cover the entire surface to be polished. Microcutting, plowing and indentation by abrasives are observed on the polished surface. The experiment was conducted on typical mold steel with the emphasis on the effects of the abrasive size and the static load on the surface finish. The optimal abrasive size depending on the surface roughness prior to polishing is identified. Large static loads possess an advantage in that the abrasives are more effectively activated for polishing.