集光点におけるビームプロファイルが溶接変形に与える影響

－レーザ溶接による自動車部品のミクロン・サブミクロンレベルにおける変形挙動に関する研究（第2報）－

抄録

Laser welding is generally considered as a method to join parts with small distortion. However, demands for earth-friendly and high-precision processing automotive components such as fuel injectors with low volume of residual hydrocarbons in exhaust emissions become stronger than ever. For example, the circularity of cylindrical parts is designed to be less than one micrometer, and welding distortion become most critical. Not only a welding system but also a beam itself such as peak power, pulse width, beam profile and so on are dealt with in order to solve such a severe specification.
In this paper, we treat an effect of a beam profile at a focal point on welding deformation so as to have understanding which profile is efficient to reduce welding deformation generating a deviation of the circularity. The beam with flattop profile has a high potential of distortion the deviation because of a high-efficiency melting. Furthermore, with the flattop profiled beam, process speed can be accelerated compared with the currently used gaussian-like profiled beam.