| 摘要 |
<p>A cutting tool is provided with a tool body which rotates about an axis thereof, and a cutting insert mounted removably on the outer periphery at the tip of the tool body, wherein: the cutting insert has a front/back-reversal symmetric substantially regular heptagonal plane shape having two heptagonal faces parallel with each other, a side face continuous with each of the heptagonal faces at right angles, and a cutting edge provided on each ridge line between the heptagonal face and the side face; the cutting edge includes a main cutting edge projected onto the side of the regular heptagon, and sub-cutting edges that extend from opposite ends of the main cutting edge so as to incline toward the center of the heptagonal face and connect the adjacent main cutting edges, and the tool body is equipped with a mounting seat that retains the cutting insert such that one of the main cutting edge is directed toward the tip side of the tool body and in a radial-outer direction in order to make it to work in cutting, and a corner angle ± between one of the main cutting edges and the axis satisfy a relation 40°‰¤±‰¤44°.</p> |
