Patent ID: 6979154

Claim:
A combination of a milling cutter with a four-sided insert for milling cutters, said insert comprising: cutting edges and a negative radial angle of the cutting edges for three-dimensional milling from a solid, having a lower face and an upper face, or rake face, that is delimited by four sides that constitute the cutting edges of the insert, said four sides being opposite in pairs and being connected to corresponding sides of the lower face by lateral faces, two opposite sides of said four sides constituting main cutting edges of the insert, the other two sides constituting secondary cutting edges, wherein the lateral faces that connect said main cutting edges to the lower face of the insert have, proximate to one end or tip of the cutting edge, a positive lower relief angle that is greater than the lower relief angle proximate to the other end or tip of said main cutting edge, further wherein the lower relief angle proximate to said one end of the inner tip or main cutting edge is greater than, or equal to, a negative inner radial angle formed by an imaginary plane that passes through the axis of the milling cutter onto which the insert is to be mounted and through the inner tip of the insert that faces the workpiece and by an imaginary plane that passes through the axis of the cutter and is parallel to the upper plane of the insert.