Traditional flame brazing has been the industry standard for decades. However, it requires gas, flux, and filler materials; depends heavily on operator skill; and exposes workers to open flames and harmful fumes. For AC manufacturers working with flammable refrigerants, these risks are particularly concerning.

Ultrasonic metal welding offers a fundamentally different approach. The technology uses high-frequency mechanical vibrations (typically at 20 kHz) to fuse copper molecules at the joint interface. No current passes through the tube, and no welding arc is generated-5. The process requires no gas, flux, or filler materials, and involves no open flames – making it inherently safer for use with flammable refrigerants-10.

A study published at the 2024 International Conference on Electrical, Computer, Communications and Mechatronics Engineering (ICECCME) confirmed the effectiveness of this technology. Researchers demonstrated that ultrasonic welding of copper can achieve both robust mechanical strength and reliable hermetic sealing. Experimental results showed that for tube sealing applications, the optimal conditions were a welding time of 3 seconds at a pressure of 4 bar, achieving effective gas- and liquid-tight seals-7.

The outdoor unit of a typical heat pump or air conditioning system consists of approximately twenty main components, one of which is a complex network of copper pipes and sheets welded to valves, connectors, and other fittings – involving over thirty welded joints per unit. This highlights a significant opportunity for process optimization through ultrasonic welding technology-7-6.