RFSSW – Refill Friction Stir Spot Welding

Refill Friction Stir Spot Welding (RFSSW)

Innovative technology with exceptional electric transmission
Refill Friction Stir Spot Welding (RFSSW) is a new solid-state joining process, which produces similar and dissimilar overlap connections in different material combinations.  
RFSSW – Step A


The sleeve of the tool is plunged into the material with a defined rotational speed. Material is generating sufficient frictional heat to plasticize and displace the material to the inside of the tool. 
RFSSW – Step B

Plunge process

The pin is moved in the opposite axial direction, creating a cavity between pin and sleeve for the accommodation of the displaced material. 
RFSSW – Step C

Refill of entering area

When the set plunge and time are reached, the pin pushes the plasticized imprisoned material back into the workpiece, refilling the volume of the sleeve.
RFSSW – Step D


At the end all 3 pieces of the tool are retracted from the workpiece, resulting in a refill friction stir spot weld. 

The advantages of RFSSW

  • High joint strength
    FSW produces welds with excellent mechanical properties, due to no solidification and a forged, fine-grained microstructure.
  • Minimal distortion
    FSW operates at lower temperatures and low heat input compared to fusion welding, welded components have a reduced distortion and residual stress levels, ideal for welded parts with tight tolerances.
  • Excellent fatigue behavior
    FSW generates a fine-grained forged microstructure in the joint line, which lead to excellent fatigue properties.
  • Joining dissimilar materials 
    FSW can join dissimilar materials due to the low heat input high forcing action, including different aluminum alloys, like wrought aluminum to aluminum cast or aluminum to steel or copper, and even advanced composites.
  • Environmentally friendly
    FSW produces no fumes, gases, or radiation; no protective gas, additional material or preparation of the joining edges required.
  • Automatization
    easy to automate and monitor because it´s a mechanic mixing process.

The disadvantage is the remaining exit hole, the high forces during the welding process, require a rigid machine and a tight clamp.

RFSSW – Busbar

Applications for RFSSW

Charging Systems / Busbars

Charging Systems / Busbars

Flat busbar and dissimilar connectors (aluminum-copper)
More about Charging Systems / Busbars
Dominik Kaineder

Your contact person: Dominik Kaineder

Are you interested in determining the feasibility of a new concept using Friction Stir Welding? Or do you require assistance in choosing the most-sufficient system for serial production for your application?
Please contact us directly - we'll gladly provide guidance and support.

+43 676 30 93 922