Ultrasonic cutting

Imagine a knife which moves itself backwards and forwards in a sawing action, thirty thousand times a second. True the distance moved is very small but the acceleration is so high that nothing can move with the blade or stick to it. Ultrasonic scalpels are used by surgeons where they want to cut without exerting any pressure. In industry ultrasonic cutting tools are used for products that are difficult to cut by other means.

The heat generated by the ultrasonic vibrations can also be useful. Some man-made fabrics are cut and simultaneously sealed using ultrasonic knives to prevent fraying.