Vacuum Brazing Aluminum: A Comprehensive Guide
Vacuum Brazing Aluminum (VAB) is a cutting-edge technology that has revolutionized the manufacturing industry. This process, which involves joining aluminum components in a vacuum furnace, is considered fluxless brazing. The absence of flux means that oxides are not used to remove oxides. Instead, vacuum pumps evacuate the furnace, reducing the PPM oxygen level in the brazing chamber and inhibiting oxide formation.Get more news about Vacuum Brazing Aluminum,you can vist our website!
Magnesium plays a crucial role in vacuum aluminum brazing as a getter. It enhances the purity of the braze environment and facilitates oxide removal. One of the significant advantages of brazing over other metal-joining technologies is that it does not melt the parent metal of the joint. This allows for more precise control of tolerances.
The utilization of aluminum brazing spans various industries, from semiconductor to aerospace. It is particularly well-suited for parts with thin and thick cross sections, components with joints located below the surface or with restricted access, and assemblies with a large number of joints.
Vacuum Aluminum Brazing offers several advantages over other processes. It provides a clean joint without the need for additional finishing and cleaning. It minimizes part distortion because the complete assembly is uniformly heated and cooled compared to localized joining processes. Assemblies with large surface areas and numerous joints can be successfully brazed in vacuum. The process offers highly repeatable results because critical furnace parameters are controlled with every load.
Commonly, VAB furnaces are single-chamber batch type and are usually loaded horizontally but can be vertical loading type. Horizontal furnaces tend to be simpler in design, less expensive, and easier to maintain. The VAB cycle is typically relatively short due to the pumping and heating characteristics of the furnace, excellent temperature uniformity, and high thermal conductivity of the aluminum assemblies being brazed.
Low pressure (high vacuum) is an important process parameter because it ensures a relatively pure environment (less PPM of oxygen) for brazing. The pumping capacity required for an aluminum brazing furnace depends on the load surface area being brazed. Larger load surface area requires larger pumping capacity. Pumping systems must have adequate capability to minimize pump-down time to a low pressure.
In conclusion, Vacuum Aluminum Brazing is a reliable means of manufacturing devices such as critical microchannel devices, cold plates, cold walls, radiators, microwave antennas, and waveguides. It is a fluxless process resulting in cleaner assemblies. The process is relatively nonpolluting and no post-braze cleaning is necessary. Therefore, it is the go-to process for joining aluminum components that cannot tolerate the risk of flux or salt bath corrosion inherent to other brazing methods4.
