| 摘要 |
PURPOSE:To control a focus of a laser light so that it is always formed onto a work by placing a thermocouple temperature sensor in the vicinity of a laser beam after it transmits through a condensing lens. CONSTITUTION:A laser light 1 which passes through a condensing lens 2 is converged toward one point on a work 3, and a cross section of a converged light is circular. When a lens temperature rises and a focal distance is varied, the diameter of the laser light 1 is varied. Accordingly, a temperature measured by a temperature sensor 8 in the vicinity of its periphery is varied. The variation of this diameter is caused by a variation of a converged state of light, therefore, the variation of the focal distance appears in a temperature rise in a real time. When its measured value is inputted to a computer having a thermal analysis software determined in advance, the variation quantity of the focal distance of the lens 2 can be known. Accordingly, when a laser beam machine provided with an automatic focal distance controller is used, an optimization control of the focal distance of the lens 2 can be executed in a real time by a lens position control by the computer. |
