Vibration Welding

Vibration Welding is a very efficient welding method. Vibration Welding requires no additional materials beyond the two pieces of material to be bonded and uses relatively low energy. Vibration Welding has the advantage of being able to handle relatively large parts. It is also a highly cost effective process and has short cycle times. However, because it relies on movement or rotation of the pieces of material to be welded, it is only possible to apply Vibration Welding to 2-dimensional joint contours.

Vibration Welding works through friction and pressure. The two pieces of plastic to be welded are rubbed against each other at a relatively low frequency, usually between 80-300hz. The friction between these pieces of material causes heat, and eventually melting. However, an important distinction to note between Vibration Welding and Ultrasonic Welding is that though like in Ultrasonic welding vibration is used, the pieces are physically moved, and not vibrated through sound. Typically, only one part of the two plastics is moved or rotated, while the other is held stationary. A constant pressure is also applied to the two parts of plastic. As the surfaces of the plastics melt, the pressure forces them to bond. Once the two parts are sufficiently bonded, the vibration stops, and the parts are allowed to cool while smaller "holding pressures" hold the pieces together. The result is one very securely welded piece of plastic. The relatively low pressures involved ensure low rates of pressure-related distortion.

There are three main motions involved in vibration welding. Only one is typically used in any one welding job. Lateral vibration welding involves moving one piece against another in a line- it is also known as "linear" vibration welding. Angular vibration welding rotates a piece on a specific axis. Orbital vibration welding involves rotating one of the parts along a central axis.