Automotive world first

Mazda Motor Corporation has developed the world's first aluminium joining technology using friction heat to be applied in the aluminium body assembly process for automobiles. The new technology reduces energy consumption by approximately 99% compared to resistance welding and requires little equipment investment. Mark Fletcher reports Up until now resistance welding has been the most feasible joining technology available for assembling aluminium body parts of commercially produced vehicles. However, resistance welding requires that a large current be instantaneously passed through the aluminium. This approach not only uses a large amount of electricity, but also requires large, specialised equipment. Through the new spot joining method developed by Mazda, a welding gun holds the parts from both sides with a welding tool, which is then made to spin while force is applied, generating frictional heat. This heat is used to soften the aluminium and generate plastic flow – joining the parts. Mazda will introduce this technology for the rear doors and bonnet of the Mazda RX-8, an all-new four-door, four-seater sports car scheduled for launch this April. Features and advantages of the new joining technology include: 1) Reduced Energy Consumption - The only energy consumed is the electricity needed to rotate and apply force to the welding tool. As the process eliminates the need for the large current and coolant/compressed air required for conventional resistance welding, energy consumption has successfully been reduced by about 99% in the case of aluminium, and 80% for steel. This significantly reduces impact on the environment while having the same or greater level of joint strength. 2) Reduced equipment investment - The new technology has simplified the overall joining system, as unlike resistance welding, a large current is unnecessary, which, in turn, eliminates the need for large-scale electricity supply facilities and specialised joining equipment. This has achieved a 40% reduction in equipment investment compared to that of resistance welding for aluminium, and around the same level for standard steel. 3) Improved work environment - Unlike traditional resistance welding, no weld spatter occurs during the process, resulting in a significantly improved work environment. Mazda Executive Vice President, Hisakazu Imaki, said: "We are making continuous efforts towards achieving plant production that conserves energy and reduces environmental impact. To date, Mazda has developed many original technologies, including the 'Three Layer Wet Paint System' and 'Semi-dry Machining Process'. I am extremely proud that we can clearly demonstrate our determination to the world with the development of this latest technology." MF Images Courtesy Mazda