Toyota Jidosha Kabushiki Kaisha

Sumitomo Electric Industries, Limited

Kanto Jidosha Kogyo Kabushiki Kaisha

Hideki Kamogawa

Akio Asai

Toshikatsu Hirose

Masao Kishi

Kazuhiro Totsuka

It is profitable to oscillate a beam on objects when a high power CO.sub.2 laser beam or a high power YAG laser beam welds or anneals the objects. In order to let a laser beam scan, a device for reciprocating a lens or a device for rotating two mirrors synchronously has been proposed. These devices suffer from the difficulty of cooling. Prior devices are not applicable to a high power laser. A parallel laser beam is first reflected by a parabolic mirror. Then a mirror which is reciprocally swaying by a galvanometer reflects the beam toward the objects. A water inlet and an outlet are mounted on a rear surface of the swaying mirror. Cooling water is carried out through coiled tubes. Excellent heat diffusion prevents the galvanometer from malfunction.

Laser beam scanner

Metal sheets having different thicknesses are abutted and laser-welded. During laser welding, the laser beam weaves from side to side with respect to a weld line. As a result, the width of the weld bead is increased and the gradient of the weld bead surface is decreased whereby no sharp edge remains at the weld line. The resulting one-piece sheet can be used as a press material without any pre-pressing processing, such as grinding.

Method of laser-welding metal sheets having different thicknesses

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Toyota, Japan

Hideki Kamogawa