Optimization of vacuum brazing quality of water cooling plate

With the rapid advancement of electronic technology, the power density of electronic devices continues to increase, and the relationship with temperature has become closer. Traditional air cooling methods can no longer effectively cope with the growing demand for heat dissipation. With its high heat dissipation efficiency, water cooling systems have gradually become the mainstream technology for heat dissipation of modern power devices. As the core component of the water cooling system, the water cooling plate plays an important role in heat dissipation. Once leakage or deformation occurs, it will directly affect the normal operation of electronic components. Therefore, the structural reliability and pressure resistance of the water cooling plate play a key role in ensuring the safe and stable operation of electronic equipment. At present, the commonly used materials for water cooling plates are copper and aluminum alloys, and vacuum brazing is the most common connection process.

Optimization of vacuum brazing process for water-cooled plates

1. Factors affecting the pressure resistance of water-cooled plates

The pressure resistance of water-cooled plates is mainly determined by the following factors:
A. Selection and quality of brazing filler metal: The wettability, fluidity and compatibility of the brazing filler metal with the base material directly affect the sealing and strength of the welded joint. High-quality brazing filler metal can effectively fill the weld, enhance the sealing and strength of the joint, and thus improve the pressure resistance of the water-cooled plate.
B. Control of vacuum brazing process: The control of vacuum brazing temperature and holding time during vacuum brazing is crucial for the flow and solidification of the brazing filler metal. Too high or too low vacuum brazing temperature may cause the brazing filler metal to fail to fully fuse, thereby affecting the structural integrity and pressure resistance of the water-cooled plate.
C. Design of vacuum brazing fixture: The design of vacuum brazing fixture has an important influence on the stability and accuracy of parts during welding. The material, thermal expansion and precision of the fixture are directly related to the position control and temperature uniformity during vacuum brazing.
D. Material matching: The compatibility of the aluminum alloy material used in the water-cooled plate with the brazing filler metal has a great influence on the welding quality. It is necessary to select suitable brazing filler metal according to the characteristics of aluminum alloy to ensure welding quality.

2. Optimization of vacuum brazing process

In order to improve the pressure resistance of water-cooled plates, vacuum brazing welding process is adopted. The vacuum brazing process is mature, the product has high precision and good sealing, and can significantly improve the structural strength and pressure resistance of water-cooled plates without affecting production efficiency.
Vacuum brazing: Mainly used for welding the internal fins and cover plates of water-cooled plates. The vacuum brazing process can effectively avoid oxidation and improve the sealing and strength of welded joints by connecting parts with low-melting-point brazing materials in a vacuum environment, thereby significantly improving the overall pressure resistance of water-cooled plates.

3. Performance improvement of vacuum brazing furnace

The temperature control accuracy of the existing brazing furnace is ±3℃, the temperature uniformity is insufficient, and the qualified rate of high-sealing cold plates is less than 90%. Although the pressure rise rate of the vacuum brazing furnace is <0.3Pa·h⁻¹, it meets the standard, but the gas leakage rate still affects oxidation control.
The heating/cooling rate of vacuum brazing is not flexible enough, which can easily lead to brazing flow or part deformation.
Improvement suggestions: Improve the temperature control accuracy and uniformity of the vacuum brazing furnace. The vacuum brazing furnace produced by SIMUWU is selected. It is a high-performance vacuum brazing furnace with a temperature control accuracy of ±1°C and uniformity of ±2°C. It is combined with multi-point thermocouples and infrared temperature measurement technology to achieve real-time monitoring. The latest furnace model integrates an advanced regional control system to accurately manage the temperature distribution of different parts. It adopts multi-zone heating technology to optimize temperature uniformity and reduce local temperature differences by independently controlling the heating zones (such as upper and lower, front and back zones).