Ultrasonic welding is a technique that generates vibration through high frequency sound waves. The vibrations are transferred to the subject that is to be joined under pressure, thus welding the subject together. This technique is primarily used in the welding of plastic. One of the advantages of ultrasonic welding is that no bolts, solder or glue is needed to assemble the item.
Ultrasonic welding is a great alternative to other assembly methods such as screws, click assemblies and glue, and it helps achieve a very consistent quality in the assembly.
How does it work?
The joining of injection molded thermoplastic subjects is done by means of a welding horn, which is adapted to the geometry of the subject. The welding horn is then connected to a transducer which transforms electrical energy into physical vibration.
The subject is placed on a fixture which supports the subject on the areas to be welded, after which the welding horn is pressed down over the subject and the welding itself is carried out.
When using ultrasonic welding to weld plastic, the interfaces of the two subjects are typically designed to help concentrate the melting process. One part will typically have a shape with a tip that acts as an energy conductor to start the melting process.
The energy from the ultrasound melts the plastic into the contact surfaces between the two subjects and creates a perfect weld.