Smaller way of welding aluminium

Researchers at TWI have developed a way of joining thin aluminium alloy sheet, by modifying the friction stir welding process

Researchers have developed a way of joining thin aluminium alloy sheet by modifying an existing process. TWI claims that the technique, micro-friction stir welding (µFSW), has produced perfect and permanent lap-welded and spot-welded joints in less than 0.3mm material thickness and butt welds in around 0.5mm thickness. Welding speeds are 100 -500mm/min. Nee Joo Teh, the project leader, said: “The process uses no glues, chemicals or welding fillers, fluxes or wires and a minimum amount of energy.” Pressure is applied to the joint through a rotating tool. Friction causes the temperature to rise, so that the metal sheets become soft enough to be stirred together. The technique could be used to seal packages within the electronics and photonics industry, or for welding aluminium foil in the aerospace industry. Other potential beneficiaries include medical devices, consumer goods and food packaging. The equipment to make the welds was designed by TWI. “We are finding the limits for the process and seeing how small our welds can be,” said Dr Teh.