| 摘要 |
PURPOSE:To automatically and precisely operate to focus by obtaining, a beginning and finishing time of generating a blue frame based on a plasma generating state and a positional data of a machining lens and calculating a suitable focus position from the position of the machining lens. CONSTITUTION:A machining table 14 and a work W are kept in a definite distance and relatively moved with a called focus deciding program. Then, a laser beam L irradiate the work W and together a machining lens 9 is driven upward and downward with a machining lens driving mechanisms 4, and a sensor information and a positional information of the machining lens are observed. While executing this motion, the generation of a blue flame is observed, if the blue flame is generated, a sensor output and the positional information of the machining lens are memorized in an information storing part 5a, 5b together with the time. If the blue flame is not generated, the machining lens is again moved upward and downward, and whether the blue flame is generated or not is observed. An NC controlling part 15 controls a lens driving controlling part 6 by using the data of the information storing part 5a, 5b. |
