| 摘要 |
PURPOSE:To perform drilling and at the same time avoid burrs to eliminate the necessity of deburring by making a brilled hole in a base material using the edge of a drill, which is further pushed therein for the top to perform taper cutting or for the grinding portion to remove burrs. CONSTITUTION:A drill 6 can be horizontally moved with NC control in such a state that it is positioned at an uppest point of keeping the edge 7 at a preset space from the surface of a base material 10, and after positioned at a desired point it penetrates the base material 10 on the top layer of which a fiber paper 15 is placed while keeping a preset lowering and rotating speed to form drilled hole 50 with a preset diameter. Then, the drill 6 is further lowered up to the lowest point, when a tapered portion 2 cuts a surface copper layer 5 around the drilled hole 50 together with the fiber paper 15 into a tapered shape so as to remove burrs which are formed in this area. When the drill 6 is at the lowest point it cuts only a part of a cushion material 20 to establish the elevation stroke length (s) from the uppest point to the lowest point not to put the edge 7 in contact with a pallet 13. |
