| 摘要 |
PURPOSE: To increase strength and life by constituting a chip breaker groove by a plurality of recess groups disposed along inner end edges of land areas, making two recesses nearest to cutting corners longer than other recess groups and forming cutting edges into straight shapes at recesses near to the cutting corners and other cutting edges into corrugated shapes. CONSTITUTION: An insert 10 is constituted of side walls 11 with round corners, triangle tops joined with these side walls 11 and a bottom chip breaker surface. Land areas 12 are extended around surroundings of each top and bottom surface. Cutting edges 13 are regulated by the intersection of the side walls 11 and the land areas 12. A chip breaker groove along each cutting edge is constituted of recess surface parts 14a extended from an inner end of each land area 12 of the corners and many second recess surface parts 14b are disposed between the recess surface parts 14a. The length of the recess 14a which is measured along the cutting edge is made about twice as long as the length of the second recess 14b, and the cutting edges are formed into straight shapes along the recesses 14a nearest to the corners and are formed into corrugated shapes in short size recesses 14b. |
