Rotary cutting tool with hybrid cutting insert design

A rotary cutting tool, comprising:

• a cutting head having a plurality of insert-receiving pockets in a first cutting region proximate an end face of the rotary cutting tool and a second cutting region proximate a shank of the rotary cutting tool;
• a plurality of a first type of cutting inserts mounted in the insert-receiving pockets of the first cutting region of the cutting head;
• and
• a plurality of a second type of cutting inserts mounted in the insert-receiving pockets of the second cutting region of the cutting head,
• wherein the plurality of the first type of cutting inserts provide an increased chip gash volume for effective chip evacuation, and
• wherein the plurality of the second type of cutting inserts provide an increased core diameter to minimize deflection of the rotary cutting tool,
• wherein the second type of cutting insert comprises:
• two opposing end surfaces, two opposing minor side surfaces extending between the two opposing end surfaces, two opposing major side surfaces extending between the end surfaces and the minor side surfaces, each end surface having four corners comprising two lowered corners and two raised corners, the two lowered corners being diagonally opposite each other, the two raised corners being diagonally opposite each other;
• two opposing major edges formed at an intersection of each end surface and the major side surfaces, two opposing minor edges formed at an intersection of each end surface and the minor side surfaces, and two opposing corner edges formed at an intersection of each the corner side surfaces and the major side surfaces;
• and
• a major cutting edge formed at an intersection of each major edge and the end surface, and a minor cutting edge formed at an intersection of each minor edge and the end surface, and a corner cutting edge formed at an intersection of the major and minor cutting edges,
• wherein each end surface includes a seating surface that extends from one lowered corner to the diagonally opposite lowered corner,
• wherein the seating surface is in the form of a U-shaped groove having a first side support wall, a second side support wall and a bottom wall therebetween, and
• wherein the bottom wall is formed with a radius, R2, such that the bottom wall has a concave topography.

A rotary cutting tool, comprising:

• a cutting head having a plurality of insert-receiving pockets in a first cutting region proximate an end face of the rotary cutting tool and a second cutting region proximate a shank of the rotary cutting tool, the first cutting region having a first length, L1, and the second cutting region having a second length, L2;
• a plurality of a first type of cutting inserts radially mounted in the insert-receiving pockets of the first cutting region of the cutting head;
• and
• a plurality of a second type of cutting inserts tangentially mounted in the insert-receiving pockets of the second cutting region of the cutting head,
• wherein the first length, L1 of the first cutting region is greater than 50% of a total length (L1+L2) of the first cutting region and the second cutting region.