In the process of Ultrasonic Machining, material is removed by microchipping
or erosion with abrasive particles. The tip of the tool vibrates at low
amplitude (2-5 mils) and high frequency (20 kHz) which transmits a high velocity to
the fine abrasive grains between the tool and the workpiece surface. The grains
are usually boron carbide, aluminum oxide, or silicon carbide ranging in grain
size from 100 for roughing to 1000 for finishing, and are used in a 20-60%
slurry that also carries debris away from the cutting area.
Ultrasonic machining is best suited for hard, brittle materials such as ceramics, carbides, glass, precious stones, and hardened steels. With fine abrasives, tolerances of 0.5 mil or better can be held with this process.
