| 摘要 |
PURPOSE:To aim at improvements in drilling quality and positional accuracy, by performing a following operations that a drill is moved from a work starting position to the initial intermediate position at infeed rate, then up to the drawing position at rapid traverse rate further up to the next intermediate position at cutting feed rate, respectively. CONSTITUTION:A drill 4 is fed op to an intermediate position M from a work starting position A at infeed rate, piercing through an upper plate 2, and such a hole that is bitten into a printed board 1 formed therein. Afterward, it is put back up to a drawing position C at rapid traverse rate, chips sticking to the drill 4 are dropped down, and the heated drill 4 is colled. In succession, it si fed up to the next intermediate position M2 at cutting feed rate, and the printed board is drilled. Again it is put back up to the drawing position C, and discharge of chip and cooling of the drill 4 are carried out. Furthermore, it is fed up to a work end position B at cutting feed rate, forming such a hole as reached to a lower plate 3, and it is put back to the work starting position A at the rapid traverse rate. With this constitution, drilling quantity becomes improved. |
