Chapter 5 - Ultrasonic Welding

Abstract

This chapter describes the procedure pertaining to the ultrasonic welding, which is the most widely used welding method. Ultrasonic welding uses ultrasonic energy at high frequencies (20 - 40 kHz) that are beyond the range of human hearing, to produce low amplitude mechanical vibrations. The vibrations generate heat at the joint interface of the parts being welded, resulting in melting of the thermoplastic materials and weld formation after cooling. Ultrasonic welding is the fastest known welding technique, with weld times of less than one second. Ultrasonic waves were first used after World War II for flaw detection equipment and for cleaning and degreasing; ultrasonic welding of rigid thermoplastics was developed in 1963. Ultrasonic welding is used for both soft and rigid thermoplastics and for thermoplastic composites. In addition to welding, ultrasonic energy is commonly used for processes such as inserting metal into plastic parts or reforming thermoplastic parts to mechanically fasten dissimilar components.