Patent ID: 6234726
Filing Date: 2001-05-22
Classification: B23B,Y10T

Abstract:
An indexable insert comprising:a tip body formed of a polygonal flat plate, an upper surface of said tip body serving as a rake face;edges of said tip body being formed along an outer periphery of said rake face;the rake face having a sector-shaped portion at at least one corner of the rake face, an outer periphery of the sector-shaped portion forming a nose portion edge, the sector-shaped portion and having a rake angle which continuously increases along the outer periphery of the sector-shaped portion toward a center of the outer periphery of the sector-shaped portion;a chip breaker formed on said rake face to protrude upwardly from said rake face and to extend toward the outer periphery of the sector-shaped portion, the chip breaker having a first breaker wall protruding upwardly from said rake face and a second breaker wall protruding upwardly from said first breaker wall at a gentler gradient than that of said first breaker wall,wherein said first breaker wall and said second breaker wall satisfy the following relationships;10.degree..ltoreq..alpha.,.beta..ltoreq.90.degree. and 1.degree..ltoreq.b.ltoreq.30.degree.where a tangential angle of said first breaker wall at an intersection between said rake face and said first breaker wall is .alpha., the tangential angle of said first breaker wall at an intersection between said first breaker wall and said second breaker wall is .beta., and a rising angle of said second breaker wall is b in the section taken along the center of the outer periphery of the sector-shaped portion.