FSW Welding or Vacuum Brazing: Which joining technology is right for your cooling application?

When designing a heat sink, there is rarely a single joining technology that is best for every application. The requirements of the specific application are the deciding factor.

FSW welding (Friction Stir Welding) and vacuum brazing offer different options for manufacturing high-performance heat sinks. Which technology is used depends, among other things, on the desired cooling capacity and the specific requirements of the application.

Miba Cooling uses both processes. Our starting point is not a specific manufacturing technology, but rather your thermal challenge.

In this article, we’ll show you:

• how FSW and vacuum brazing work,
• what possibilities these two processes offer for heat sinks,
• and why the technical requirements determine which solution is suitable for a given application.

Our comparison of heat sink manufacturing processes provides an overview of the various joining methods.

What is FSW welding and what advantages does it offer for heat sinks?

FSW welding (Friction Stir Welding) is a joining process in which metallic materials are joined together without melting the base material. A rotating tool generates the necessary heat through friction and mechanical deformation, joining the materials along the joint.

Miba Cooling uses this manufacturing process for various water-cooled heat sinks designed to cool power electronics, among other applications.

What possibilities does FSW offer for heat sinks

Friction Stir Welding enables

• the creation of strong and durable joints,
• relatively low heat input compared to conventional welding methods,
• joints with minimal distortion and high strength,
• as well as the processing of suitable aluminum alloys and other materials that are difficult to weld.

The joint is formed specifically along the FSW weld seam. Whether this design principle is suitable for a heat sink depends on the specific technical requirements.

FSW can therefore be a technically sound solution for many cooling applications.
 

What is vacuum brazing and what advantages does it offer for heat sinks?

In vacuum brazing, components are joined together in a vacuum chamber through a controlled thermal process. This process makes it possible to manufacture even complex heat sink structures with large-area joints.

Vacuum brazing opens up additional design possibilities, especially when very high cooling capacities are required.

What possibilities does vacuum brazing offer?

Among other things, the process enables:

• large-area joints between components,
• more complex internal cooling structures, such as honeycombs, diamond shapes, or others,
• various heat sink geometries,
• as well as highly efficient heat transfer.

This makes vacuum brazing an attractive solution, particularly when very high thermal requirements are involved.

FSW or Vacuum Brazing: which is the better solution?

The short answer is: It depends on the requirements and the application.

• FSW and vacuum brazing are not technologies where one is fundamentally better than the other. They offer different technical possibilities.
• FSW can be a technically and economically viable solution for many cooling applications. However, when highly complex internal cooling structures, high power densities, or large-area joints are required, vacuum brazing can offer additional design possibilities.

If thermal or design limitations arise with an existing FSW concept, vacuum brazing is a viable alternative. Read more about this in our article “When vacuum brazing can be an alternative to FSW”

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