| 摘要 |
PURPOSE:To lengthen the life of a drill by forming a coating layer of hard boron nitride on the drill surface in the surface-coated sintered hard alloy drill to be used such as for drilling a laminated printed-wiring board. CONSTITUTION:A sintered hard alloy drill is held in vacuum vessel, diborane and ammonia are decomposed in the hydrogen plasma excited through microwave or RF, and a layer of cubic crystal boron nitride (CBN) is formed on the drill surface, that is, the drill is coated with CBN. With this constitution, the life of the drill is lengthened and drilling efficiency is improved. |
