DAU - A Miba Group Company

Friction Stir Welding FSW

As a manufacturer of High Power Heat Sinks, DAU offers common welding techniques as well as advanced joining techniques such as Friction Stir Welding (FSW) for economic and robust production of large heat sink units.

FSW involves the use of special shaped rotating tools to join two pieces of plate material together.

As the tool travels along the joint seam, intense frictional heat is generated due to the wear resistance between the welding tool and the working materials.

This heat causes the materials to soften (plasticize) without reaching their melting point.

In this manner, the plasticized materials of the two joining parts are stirred together and form a solid robust bond after cooling, eliminating the need for any type of additional bonding agent or material.


  • Welding of same or different aluminum alloys without using filler materials (as typically necessary for MIG welding), and also no gas shielding necessary
  • No structural change in the materials
  • Less weld distortion and shrinkage due to the lower welding temperatures
  • Non-porous joint/bond-line
  • Reliable and repeatable process due to controlled machine parameters
  • Homogenous and leak free weld joints – therefore FSW is ideal joining method for use in production of liquid cooled units 
  • Economic method for producing very large width heat sinks - by welding smaller low cost heat sink pieces together
  • Superior weld joint strength in comparison to MIG welded joints
  • No thermal performance penalty across the welded joint


FSW was invented and patented by The Welding Institute (TWI) in Cambridge UK.

DAU Austria is a registered Industrial Member company of the TWI.

DAU is able to weld aluminum materials up to 30mm in thickness.

The advantages of FSW include the ability to produce long lengths without any melting of the base material.

This eliminates the possibility of solidification cracking which is often a problem when arc welding some aluminum alloys.

The Friction Stir Welding process is used in industries such as aerospace, aircraft, automotive, railway, shipbuilding and others.

The design of the tool is very important as it influences the quality and speed of the FSW process.

Due to DAU’s extensive experience with FSW, DAU has the ability to make its own tools for any application.

Please do not hesitate to contact our FSW specialists if you have any further questions about this process.