| 摘要 |
The present disclosure provides a quadrangular indexable drill insert comprising a substantially flat top surface and bottom surface, a side surface adjoining the top and bottom surfaces; four identical cutting edges formed at intersection of side surface and top surface, each cutting edge comprising, a concave curved part edge of predetermined radius at corner of the insert; a first part edge oriented towards axis of drill body and is having negative slope, said first part edge is connected to the concave curved part edge through a nose portion; a second part edge connected to first part edge through a transitional edge, said second part edge is tangentially oriented to an imaginary inscribed circle; a third part edge connected to the second part edge through a transitional edge, and a nose portion of adjoining the third part edge with concave curved part edge of succeeding cutting edge. |
