What is Resistance Brazing?

With the development of the new energy vehicle industry, which primarily relies on electric power, there’s an increasing use of copper busbar soft connections. Consequently, the welding of copper busbars is becoming more frequent. To ensure reliable and strong welds, resistance brazing is an excellent method!

The Principle of Resistance Brazing

Resistance brazing involves placing a filler material between two copper busbars. Using a medium-frequency welding machine, electric current heats the copper busbars until the filler material melts and flows. Once the current is cut off, the filler solidifies, forming a strong joint. This method is known as resistance brazing.

How to Choose a Resistance Brazing Machine

When selecting a resistance brazing machine, the power of the machine should be chosen based on the area of the workpieces to be welded. It’s important to consider the machine’s duty cycle. During brazing, to ensure the filler material has adequate fluidity, prolonged electric heating is often necessary to melt and flow the filler. This aspect must be taken into account. Additionally, the welding pressure must be appropriately matched; excessive pressure can deform the workpieces when they are heated.

How to Choose Resistance Brazing Electrodes

Electrodes for resistance brazing are typically made from materials like tungsten, molybdenum, or graphite. Tungsten and molybdenum are often used in forms like copper-tungsten or copper-molybdenum composites. These materials have high resistance, generate significant heat, and dissipate heat slowly, making them suitable for welding large copper busbars. External cooling is usually required to cool the electrodes during the process.

Quality Inspection of Resistance Brazing

For resistance brazing of copper busbars, quality is typically assessed through three methods: tensile strength, resistance, and appearance.

1. Tensile Strength:

The welded workpiece is subjected to a tensile test using a universal tensile testing machine to determine if the tensile strength meets the product’s target values and usage requirements.

2. Resistance:

A precision resistance tester is used to measure the resistance at the welded joint to ensure it meets the specifications required by the design.

3. Appearance:

During the resistance brazing process, the melting filler material often overflows at the weld. The flow and overflow of the filler can provide a preliminary assessment of the weld’s quality, although final judgment should be based on tensile strength and resistance measurements.

As modern industry evolves, resistance brazing continues to upgrade and has become an indispensable technique in metal processing. If you want to learn more about resistance welding machines, feel free to contact us.