| 摘要 |
PURPOSE:To prevent the infiltration of boring slug into a metallic cylindrical body by holding a prescribed pressure in this cylindrical body and subjecting the body to laser boring. CONSTITUTION:Both ends of a hollow extrudate 1 are sealed by plug bodies 10, 10 and a gas introducing pipe 2 is connected to the one plug body 10. Air or inert gas is encapsulated at about 1 to 6kgf/cm<2> into the hollow part of the extrudate 1 and holes 6 are bored in the position to be bored of the peripheral wall by a laser torch 7. The air flow to the outside is generated by the atm. pressure difference between the inside and outside of the hollow part of the extrudate the instant the holes are bored in this boring stage and, therefore, the infiltration of the boring slug into the hollow part is suppressed or prohibited and the cylindrical material having a high quality is produced. |
