Friction Stir Welding: From TWI to ABB Robot Cells

Friction stir welding joins metal without melting it. A spinning tool with a short pin plunges into the joint, heats the metal by friction until it softens, and stirs the two sides together as it travels along the seam. The process came out of a British research lab in 1991 and went into ship decks, trains and rockets before carmakers took it up for battery trays and cast parts. This post follows that path, shows where robots and ABB's large arms fit into friction stir welding today, and looks at what still limits it.

A friction stir welding tool on a NASA welding machine, 2009. Photo: NASA via Wikimedia Commons (public domain)

How a stirred weld left the lab

The idea is older than the process. Yu. Klimenko patented the concept in the Soviet Union in 1967, but it was not developed into a commercial technology at the time. The Welding Institute (TWI) in the UK proved it experimentally and commercialized it in 1991, and TWI held the patents. Since the metal never melts, the weld avoids porosity and solidification cracking, the usual troubles when arc welding aluminium. That made the process a good match for wrought and extruded aluminium parts that need strong, long seams.

A friction stir welding head joining aluminium parts at the German Aerospace Center DLR, 2004. Photo: DLR / Wikimedia Commons (CC BY 3.0)

Scandinavian aluminium extruders were the first commercial users. In 1996 Sapa used the process to make fish freezer panels, and Marine Aluminium Aanensen used it for ship deck panels and helicopter landing platforms. Rail came next. Hitachi friction stir welds its Japanese A-train commuter cars and the British Class 395 trains, and Sumitomo Light Metal makes Shinkansen floor panels with it. Most of these jobs are long, straight joints between extrusions, welded on large dedicated machines.

A Class 395 Javelin train at Ashford International; Hitachi friction stir welds these trains. Photo: TheFrog001 / Wikimedia Commons (CC0)

Aerospace took the machines to a much bigger scale. NASA contractors used friction stir welding on the Space Shuttle external tank, and later on the Space Launch System core stage and the Orion spacecraft. For SLS, NASA built the Vertical Assembly Center at Michoud, a welding tower more than 50 meters tall that joins barrel sections and domes into whole tanks. SpaceX used the process on Falcon 1 and still uses it on Falcon 9. Eclipse Aviation made FAA-approved wings and fuselage panels this way and delivered 259 Eclipse 500 jets.

NASA's Vertical Assembly Center at Michoud, the friction stir welding tower for Space Launch System tanks. Photo: Chad Davis / Wikimedia Commons (CC BY 2.0)

Robots take friction stir welding into car and battery plants

Cars brought shorter, curved seams. Tower Automotive made the first friction stir welded car parts, suspension parts for stretched Lincoln Town Cars, and later used the process on the engine tunnel of the Ford GT. On the 2013 Honda Accord it joined aluminium to steel in the front subframe. Batteries are the newest job. Honda has said that its Ohio plant casts each battery case in two halves on 6,000 tonne machines and joins the halves with friction stir welding, and Kuka has reported a follow-up order for welding cells that join battery cases and cooling jackets.

A friction stir weld seam sealing the case of a helium filled hard drive. Photo: Phiarc / Wikimedia Commons (CC BY-SA 4.0)

Cooling hardware is another growing use. On 28 September 2026 Data Center Frontier published a tour of CoolIT Systems' plant in Calgary, which makes liquid cooling for AI data centres. The article credits skiving and friction stir welding with making its cold plates perform better and more reliably, and it describes a 6 megawatt thermal test rig used to check systems before they ship. A cold plate is a sealed part with channels inside, and leak-tight joints of that kind are what friction stir welding does well.

An ABB IRB 7710 or IRB 7720 robot set up for friction stir welding. Photo: ABB

Robots have a harder time here than in arc welding, because the tool presses down with large forces that can push the arm off its path. TWI says it runs robotic friction stir welding on two ABB robots, one with a 500 kg payload and one with 800 kg. Both carry servo spindles and measure force and torque, so the controller can hold contact force and heat input steady. ABB launched its IRB 7710 and IRB 7720 robots in 2024 and listed friction stir welding among their high accuracy contact applications, with path accuracy down to 0.6 mm at speeds up to 1,600 mm per second.

A 9,000 tonne IDRA Giga Press at the maker's open house in Italy, the size of machine that casts large car parts. Photo: Paul Sladen / Wikimedia Commons (CC0)

Where friction stir welding goes next

In factories, most of the growth will likely come from electric cars. Battery trays, cooling plates and large cast parts are mostly aluminium, and casting a car section in fewer pieces leaves a few long seams that still need joining. A robot can follow a three-dimensional seam that a gantry machine cannot reach, so more robot cells next to casting lines seem likely. At home the effect is indirect: the welds end up inside the car in the driveway and in the data centres behind the apps on your phone. Our post on EV battery assembly covers the rest of the pack.

The open battery pack of a 2011 Nissan Leaf, with its modules and wiring inside the tray. Photo: Mariordo Mario Roberto Duran Ortiz / Wikimedia Commons (CC BY-SA 3.0)

Programming these cells is mostly a planning job. Tool angle, plunge depth and travel speed have to stay inside a narrow window along the whole seam, and the robot has to brace against the load at every point. Engineers usually build and test the path in RobotStudio first, checking reach and joint loads before a real part is clamped. When the part has to turn during the weld, it can sit on a positioner set up as one of the robot's external axes, which keeps the tool at the right angle.

Engineers plan a cell on screen next to an ABB IRB 7710 or IRB 7720 robot. Photo: ABB

Several problems are still open. Robot arms are less stiff than dedicated machines, so force control and path correction have to make up the difference. A weld that runs too cold can leave a "kissing bond", a defect that X-ray and ultrasonic testing have trouble finding, which means process data has to be logged and reviewed. Tools wear out, fixtures cost money, and welders need to learn force control and data review. I found no current ABB source naming an IRB 7600 friction stir package, so for large ABB arms the documented route today is the IRB 7710 and IRB 7720.

An ABB IRB 7600 holds a wax tree in a falling sand curtain at TPC Components, Sweden, the kind of heavy arm used in contact work. Photo: ABB

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