| 摘要 |
<p>PROBLEM TO BE SOLVED: To execute machining of a fine hole of a nozzle with high precision and accuracy in accordance with design by beforehand imparting a temperature difference between inner and outer peripheral surfaces of a part to be worked so as to cancel each other a temperature difference generated on the part to be worked in the direction from the incident side to the emitting side of laser beam in laser beam machining. SOLUTION: It is preferable to execute piercing through cooling of the outer peripheral surface of an injector nozzle 1 by cooling atmosphere 4 and at the same time through heating the inner peripheral surface. The outer peripheral surface of the injector nozzle 1 is pierced in a state that is protected with an inorganic film, and after the machining, the inorganic film is removed. The outer peripheral surface of the injection nozzle 1 is cooled by cooling atmosphere 4, and at the same time the inner peripheral surface is heated by a heater 5. Laser beam 3 is emitted on the injector nozzle 1 to machine the fine hole 2. The difference in temperatures of the inner and outer surfaces of the injector nozzle 1 is preferably 150-300 deg.C. The cylindricalness of the fine hole 2 becomes <=5/100.</p> |
