| 摘要 |
PURPOSE:To reduce the piercing time for a work made of thick plate. CONSTITUTION:The melting light L2 generated at a piercing part 5a is received by a detecting means 15 during the piercing operation to a work 5, and inputted into a control device 4. The control device 4 is provided with a focal point correcting part 4A, and this focal point correcting part 4A lowers the position of the focus F of a converging lens 2 to the height matching with the piercing part 5a by driving a motor 8 every time the quantity of light of the melting light L2 to be inputted from the detecting means 15 becomes smaller than the prescribed reference value. This constitution realizes the efficient piercing even with the work 5 of thick plate and reduces the time required for the piercing. |
