| 摘要 |
PURPOSE:To increase the speed of feed to aim at enhancing the finished surface roughness and the efficiency of cutting by a metal cutting throw-away chip, by forming each cutting edge in the vicinity of the apex of an imaginary polygon to have a radius of curvature which is larger than the radius of a circle inscribed in the imaginary polygon. CONSTITUTION:The radius R of curvature of each curved cutting edge 5 of a triangular chip 3a is set larger than the radius (r) of a circle 2 which is inscribed in an imarginary triangle 1a that indicated the contour of the triangular chip 3a, and as well the mid-point of the cutting edge 6 is contacted to the inscribed circle 2 while ends of each curved cutting edge 5 are joined with the ends of the adjacent curved cutting edges 5 within the imaginary triangle 1a. Since the finished surface roughness is proportional to the square of feed and as well inversely proportional to eight times as large as the radius R of curvature of the curved cutting edge, the larger the radiaus R of curvature the less the finished surface roughness may be made without the feed speed being decreased. With this arrangement, the efficiency of cutting may be enhanced by increasing the radius R. |
