| 摘要 |
<p>The present invention relates to a cutting tool for a composite material. A drilling tool according to one embodiment includes a drill body and a shank. The drill body includes ribs formed in a spiral shape along the axis direction of the drill body, chip discharging grooves formed between the ribs, and a drill head formed at one end of the drill body where the shank is not formed. The drill head is formed in a multi-stage and first and second cutting edges are formed interposing a step portion therebetween, and the second cutting edge is formed toward the drill head. A point angle of the first cutting edge is 90º to 130º, a dish angle of the second cutting edge is 5º to 15º, and a twist angle between the chip discharging groove and the rotational axis of the drill body is 20º to 40º.</p> |
