| 摘要 |
PURPOSE:To obtain a weld zone of good airtightness, high strength and free from cracks by scanning laser more than twice when a gap and stress exist between welded materials. CONSTITUTION:A laser beam 9 oscillated from a laser source is separated into laser beams 10, 11 by a half mirror 6, and the laser beam 10 is focussed and stopped down on the surface of butted part 2 of welded materials 1a, (b). On the other hand, the laser beam 11 is totally reflected by a total reflection mirror 5 in the direction of optical axis, and irradiated on the surface of the butted part 2 as under at a position a little off from the direction of advance of the laser beam 10. Here, the laser beam 10 is used to melt and join the base metals 1a, (b) and the laser beam 11 regulates the speed of melting and solidification and prevents cracking of small part due to thermal stress and generation of blowholes inside due to rapid melting and solidification. |
