What is ultrasonic copper tube sealing?

Ultrasonic copper tube sealing, as the name suggests, is a process that utilises the energy of high-frequency ultrasonic vibrations to seal and cut copper or aluminium tubes in a single step, without the need for solder or an open flame.

The core principle is as follows: the equipment converts electrical energy into high-frequency mechanical vibrations, which are transmitted via the welding head to the contact surface of the copper tube. This causes the metal molecules to rub vigorously against one another, generating heat and instantly fusing to form a molecular-level solid bond. The entire process does not melt the metal, produces no scale, and the strength of the seal is close to that of the base material.

Why is the refrigeration industry phasing out flame brazing across the board?

Traditional copper tube sealing relies on flame brazing, which involves heating the copper tube with a mixture of oxygen and fuel gas to melt the solder and complete the seal. This process is being rapidly phased out in the R600a/R290 era for three reasons:

Policy restrictions: R600a and R290 are classified as Class A3 flammable refrigerants; national standards explicitly prohibit the use of open-flame processes on production lines charging flammable refrigerants.

Cost inefficiencies: Flame brazing requires certified welders and the continuous consumption of oxygen and fuel gas. According to industry data, ultrasonic welding can reduce labour costs by over 60% compared to flame brazing.

Quality Variability: The quality of flame welding depends on the welder’s skill, whereas ultrasonic sealing is performed automatically by the equipment, ensuring high consistency and traceability.

What problems can an ultrasonic copper tube sealer solve?

Safety and Compliance: The flame-free process fundamentally eliminates the risk of R600a/R290 combustion and explosion, complying with the production line safety requirements of the Kigali Amendment.

1-second sealing: With a welding cycle of just 0.5–1 second, production line efficiency is significantly improved.

Zero consumables: No oxygen, fuel gas, welding rods or flux are required; the savings on gas costs in the first year alone are sufficient to cover the equipment investment.

Operable by general staff: No certified welders are required; new staff can be operational after a simple training session.

Controllable quality: The smart version of the equipment monitors sealing thickness, energy and time in real time, with automatic alerts for out-of-tolerance conditions, ensuring defective products do not pass through.