What does ultrasound welding process look like?

Ultrasound joining of thermoplastic materials is a technology of welding by using mechanical vibrations to generate heat because of molecular friction. Irreplaceable part is a sonotrode being a welding tool , carrying vibrations onto the components.

Those vibrations cause the movement of molecules in plastics which become soft and start melting . Thanks to that the components are joined or adjusted to the joint shape. After a short period of time under pressure the materials are permanently molecularly joint.