How does ultrasonic metal welding work ?

Ultrasonic welding makes it possible to assemble metal components, particularly copper, aluminium and other non-ferrous metals (nickel, brass, etc.) that are difficult to weld using traditional methods.

It ensures a true connection and mechanical strength combined with excellent electrical and thermal conductivity.

Ultrasonic metal welding is a cold welding process, with very little heat generated outside the joint. This process is also non-destructive and non-invasive as it requires no filler materials or soldering flux.

The parts are welded between the Sonotrode and the anvil. Both of these components are ridged. The anvil holds one workpiece while the Sonotrode sets the other workpiece in motion in order to create friction allowing assembly. (see diagram)

This process, using friction, is also called molecular seizure.

Drawing on our expertise and mastery of ultrasound developed over more than 30 years, SONIMAT has evolved solutions integrating this ultrasonic metal parts welding process.

APPLICATIONS: The ultrasonic welding process is used in the assembly of electric batteries, electronic equipment, automotive components, etc.

But what is the ultrasonic energy ?

Ultrasonic mechanical vibrations have a frequency above the hearing range of the human ear (greater than 16 kHz). This is used in many applications, particularly in industry for cutting and welding processes of various materials (composite, textile, food, metal, plastic). Ultrasound, for cutting or welding a part, works with using an acoustic assembly.

The accoustic assembly

An ultrasonic acoustic assembly is a unit that uses high frequency sound waves. The operation of this acoustic assembly depends on several main components:

1. Ultrasound generator: This is an electrical energy converter that transforms electrical energy into high-frequency acoustic energy.
2. Piezoelectric converter (or transducer): It transforms high-frequency acoustic energy into mechanical vibrations of the same frequency. The energy is then mechanical.
3. Booster or amplitude modifier: This increases or reduces the amplitude produced by the converter.
4. Sonotrode: This is a metal part that transmits ultrasonic energy to the part to be welded.

Diagram of ultrasonic welding (molecular seizing) of metal parts