The ultrasonic machining process uses a nonabrasive tool, called a sonotrode, attached to a transducer/booster combination which vibrates at a frequency of approximately 20,000 cycles per second. A machining action occurs as sonotrode vibrates fine abrasive particles flowing throughout the machining gap and propels themagainst the workpiece material. The form tool itself does not abrade the workpiece; the vibrating tool excites the abrasive grains in the flushing fluid,causing them to gently and uniformly wear away the material, leaving a precise reverse form of the sonotrode shape.