All thermoplastic materials are made from polymers. Various polymers are not necessarily compatible with one another, however, meaning they cannot be welded together. The main difference between ultrasonic welding and ultrasonic riveting is that a melt deformation occurs during riveting and only one of the two joining elements is plasticized. This allows any thermoplastic materials to be connected with one another without polymer compatibility or also with non-plastics. The result is rivet connections with almost no gaps or play, as the cold rivet tool cools the melted rivet head under pressure.
As in ultrasonic welding, in ultrasonic riveting the sonotrode serves to transmit the mechanical vibratory energy to the stud. It is the riveting tool and is manufactured in accordance with the desired stud design and the number of pins which are to be riveted at one stroke. It is possible to carry out several rivetings with a sonotrode. Multiple-head installations are used in the riveting of large parts (e.g. dashboards in the car industry).