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February 27, 2003

Mazda Develops World's First Aluminum Joining Technology
Using Friction Heat

- Energy consumption reduced by approximately 99% compared to resistance welding -
Mazda Motor Corporation has developed the world's first aluminum joining technology using friction heat to be applied in the aluminum body assembly process for automobiles. The new technology drastically reduces energy consumption and requires little equipment investment. 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.


Mazda's aluminum joining technology using friction heat


Up until now 'resistance welding' has been the most feasible joining technology available for assembling aluminum body parts of commercially produced vehicles. However, resistance welding requires that a large current be instantaneously passed through the aluminum. This approach not only uses a large amount of electricity, but also requires large, specialized equipment. Through the new spot joining method developed by Mazda, a welding gun holds the parts from both sides with a welding tool. The welding tool is then made to spin while force is applied, which in turn generates frictional heat. This heat is utilized to soften the aluminum and generate plastic flow to join the parts.

Features and Advantages of the New Aluminum Joining Technology:
1) Reduced Energy Consumption
The only energy consumed in this latest joining technology is the electricity needed to rotate and apply force to the welding tool in order to create frictional heat. 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 percent in the case of aluminum, and 80 percent 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 specialized joining equipment. This has achieved a 40 percent reduction in equipment investment compared to that of 'resistance welding' for aluminum, 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.

Use of aluminum for automobiles is one important approach to make vehicles lighter, which leads to enhanced fuel efficiency and improvements in safety and dynamic performance. In the future, it is expected that aluminum will be widely introduced in many areas. Previously, it was difficult to join parts with welding methods such as 'resistance,' 'arc' and 'laser,' due to the fact that aluminum is a much better conductor of electricity and heat than steel. In addition, other methods presented cost issues. For example, 'riveted joints' use expensive rivets, resulting in higher joining costs, while 'mechanical clinching' requires large equipment.

This energy- and cost-saving aluminum welding technology through the utilization of friction heat, developed ahead of other global makers, has widened the future possibilities for the application of aluminum in automobiles. At the same time, it is also beneficial for all manufacturers that use aluminum in their work, and is expected to significantly contribute to environmental conservation in a wide range of fields.

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."
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