1.1.10 Thermal Joint: Ultrasonic welding
Ultrasonic welding melts the contact surfaces of two substrates by ultrasonic vibration causing friction and, in turn, producing heat. The thermal energy comes from the reciprocating movement of a substrate on another surface. When heated this way under pressure, substrates form a close bond once cooled.
Ultrasonic welding of plastics is popular for its speed, safety and small environmental footprint in industries such as medical, power, automotive and toy manufacture.
The technical requirements of ultrasonic welding of metals are higher than those of plastic. Large metal parts create complex problems for ultrasonic welding, so the most common applications are for small parts such as wire harnesses, terminal connections, and batteries.
Ultrasonically welded metals have the advantages of lower resistivity, electrical conductivity, and high joint strength. The welding process does not require or produce weld spatter, bright light, flux or protective gas, resulting in improved safety and environmental protection.