| 摘要 |
PURPOSE:To form a highly accurate groove free from undercut by forming a film made of material liable to absorb a laser beam onto the outside periphery of a shaft made of material unliable to absorb the laser beam and by removing the above film by the laser beam in manufacturing a fluid bearing shaft. CONSTITUTION:In manufacturing the fluid bearing shaft, a shaft body 2 is made of tempered glass etc. unliable to absorb the laser beam, on which periphery the film 1 is formed by use of a material liable to absorb the laser beam by electroless Ni plating or another method. Subsequently, the laser beam 4 is concentrated with a lens 5, with which the film 1 is irradiated so as to be removed, so that the groove 3 of accurate shape free from undercut and sag at the edges which occur at etching, etc., can be formed resultingly, the stability as well as accuracy in rotation of the fluid bearing shaft 6 can be improved. |
