Ultrasonic welder utilizes high ultrasonic frequency, vertical motion to produce heat and the flow of thermoplastic material at the interface of mated parts. Pressure is maintained after the delivery of energy is stopped to allow re-solidification of interwoven plastic at the joint, securing the parts with a homogeneous or mechanical bond. This process offers an environmentally friendly means of assembly as opposed to conventional adhesives or mechanical fasteners.

The ultrasonic welding technique that is normally used in plastic welding solution by inducing ultrasonic frequencies in plastic components that is converted into heat between the welded plastic laminates. Frictional heat is produced so that thermoplastic parts melt and an insoluble connection between parts is forged in a very short period of time. The melting point of both working pieces is nearly equivalent which helps to form a uniform weld area. The welded area is usually as strong as the matrix material.