Friction Stir Welding (FSW) Technology

Friction Stir Welding (FSW) is a technology that uses frictional heat generated by a rotating tool to join two metal plates together. Productivity can be greatly improved by applying FSW technology to the manufacture of EV-related components such as inverter cases, battery cases and motor cases, as well as the joining of cooling parts for semiconductor equipment.

FSW benefits

Joints with less deformation and distortion

Since materials other than the material are not used and no material is melted, the joint can be strong with little deformation or distortion.


Capable of joining different materials

It is possible to join not only the same materials, but also different materials such as aluminum and steel.


Safe and comfortable working environment

The FSW technology allows for use in a safe environment with no emissions of gases, smoke, sputter, plasma or X-rays.

FSW process

Unlike conventional welding, which melts the materials and joins them together, FSW stirs and joins materials softened by frictional heat at a temperature below the melting point. There are two methods of material joining: butt joining and lap joining.

  • 1: Joint temperature below melting point
  • 2: Junction direction
  • 3: Tool thrust force
  • 4: Direction of tool rotation
  • 5: Shoulder
  • 6: Probe
  • 7: Axis direction plastic flow
  • 8: Rotation direction plastic flow
Butt joining
Lap joining

Examples of proposals for the automotive industry

Mazak FSW benefits

Mazak’s unique FSW technology ensures stable joint quality.

Joint depth 3 mm

Materialspindle speed
A60632500 mm/min
A50522000 mm/min
ADC121500 mm/min
C1020300 mm/min

Improvement of joint strength

Unlike electron beam welds, which have coarse grains, FSW joints have finer grains than the base material, improving joint strength. Joining strength is improved not only when joining the same materials, but also when joining different materials.

Benefits of using FSW for electronic module components

This technology can be used to manufacture electric vehicle (EV) related parts such as inverter cases, battery cases, and motor cases.

  • Compact and lightweight with no need for bolted connections
  • Improved durability due to all-assembly bonding with no need for sealing materials
1: Inverter case 2: Motor Case

Examples of proposals for the semiconductor industry

Use in semiconductor equipment components

Applied to the joining of backing plates and cooling plates used in semiconductor equipment, the process from joining parts to cutting can be completed in a single machine. As a result, lead time can be shortened and work-in-process inventory can be reduced.

Process integration for cooling panel manufacturing

Cooling panel machining video

Videos Aluminum joint of A6061 and A6061

Application Examples

Backing plate (Case: C1020, Lid: C1020)
Cooling plate (Case: A6061, Lid: A6061)

Compatible models

Combined FSW technology with double column and vertical machining centers

Shorten lead time and reduce work-in-process inventory by using a single machine to complete all processes from joining to cutting of medium to large parts

VTC-530/20 FSW

  • Thanks to fixed table, hydraulic fixtures, wiring and piping can be conveniently mounted
  • 2300 mm x 530 mm long table can load long workpieces or multiple workpieces
  • Convenient installation of powered fixtures and robots thanks to stationary table

FJV-60/80 FSW

  • FSW integrated with No.50 taper spindle double column vertical machining center for high accuracy
  • Thanks to the large 2240 mm x 1250 mm table, wide range of applications from large workpieces, thin worksheets and multi-surface machining can be performed

High speed and high quality FSW processing machine

Supports high-speed, high-quality joining and long-time continuous joining, contributing to mass production and improved production efficiency


  • High-speed, high-rigidity FSW spindle for high-speed joining
  • Stable joining accuracy is maintained by a control function that keeps the tool thrust force constant. Automatic tool holder replacement function is also equipped.
  • High-quality corner joints with 0 degree tool tilt
  • Capable of continuous bonding for long periods of time