The ultrasonic welding process offers many advantages over other welding techniques and is most commonly used in manufacturing wire harnesses, electronic components, and appliances. Ultrasonic welding is used when multiple layers of foil need to be welded onto a terminal or welded together with different combination of metals such as copper, aluminum, lithium, and nickel.
Ultrasonic welding uses a “low power friction” welding process in which little heat is generated and better control can be applied. The basic idea is to scrub work pieces across each other while clamped under pressure to create a bond. Work pieces are placed on an anvil that is knurled with fine ridges that bite into the material, holding it in place during the weld process. The ultrasonic tool is then lowered onto the pieces, clamping them under pressure and creating the needed scrubbing action. This tool vibrates at a frequency of twenty kilohertz for most welding operations and around forty kilohertz for low power applications.
The scrubbing motion helps in dispersing oxide layers and other impurities at the boundary until the base metals are in direct contact. The atoms of the work pieces then diffuse into each other, creating a purely metallurgical bond.
Ultrasonic welding techniques are used in different industrial sectors such as pharmaceutical, medical, food, cosmetic, and household and personal care manufacturing. They have enabled the ironing out of minor flaws in products during the production process, which if left unchecked, can damage the brand value of a product or company.