Milling cutter and cutting insert therefor

A milling cutter comprising a tool body having the general form of a circular disk and a plurality of identical cutting inserts releasably mounted in insert pockets;

• the tool body having two oppositely facing generally circular side faces connected by a peripheral mounting face, an axis of rotation (A) passing through the side faces, the axis of rotation (A) defining a direction of rotation (R) of the milling cutter;
• the insert pockets being spaced angularly around the peripheral mounting face;
• the cutting inserts comprising:
• generally square shaped top and bottom surfaces;
• four substantially identical side surfaces extending between the top surface and the bottom surface;
• two diametrically opposite protuberances extending away from each other in a top or bottom view of the cutting insert, each protuberance having a peripheral side surface comprising and intermediate side surface and two minor side surfaces, the intermediate side surface being located between and merging with the two minor side surfaces, each side surface comprising a major side surface connected to an adjacent minor side surface, adjacent major side surfaces merging at two diametrically opposite corner edges of the cutting insert;
• eight identical major cutting edges, formed at the intersection of the major side surfaces with the top and bottom surfaces;
• and
• eight identical minor cutting edges, formed at the intersection of the minor side surfaces with the top and bottom surfaces, each minor cutting edge being connected to an adjacent major cutting edge;
• wherein each minor cutting edge forms an external obtuse angle (α) with its adjacent major cutting edge, in a top or bottom view of the cutting insert;
• the cutting inserts being arranged in a staggered formation in pairs with one of the top or bottom abutment surfaces of each cutting insert facing in the direction of rotation (R),
• a first cutting insert of a given pair of cutting inserts having a radially and axially outermost first protuberance protruding axially at least partially from a first side face of the tool body, a second cutting insert of the given pair of cutting inserts having a radially and axially outermost second protuberance protruding axially at least partially from a second side face of the tool body.

An indexable cutting insert for use in a milling cutter comprising:

• generally square shaped top and bottom surfaces;
• four substantially identical side, surfaces extending between the top surface and the bottom surface;
• two diametrically opposite protuberances extending away from each other in a top or bottom view of the cutting insert, each protuberance having a peripheral side surface comprising an intermediate side surface and two minor side surfaces, the intermediate side surface being located between and merging with the two minor side surfaces, each side surface comprising a major side surface connected to an adjacent minor side surface, adjacent major side surfaces merging at two diametrically opposite corner edges of the cutting insert;
• eight identical major cutting edges, comprising four major cutting edges formed at the intersection of the major side surfaces with the top surface and four major cutting edges formed at the intersection of the major side surfaces with the bottom surface;
• and
• eight identical minor cutting edges, comprising four minor cutting edges formed at the intersection of the minor side surfaces with the top surface and four minor cutting edges formed at the intersection of the minor side surfaces with the bottom surface, each minor cutting edge being connected to an adjacent major cutting edge;
• wherein, in a top or bottom view of the cutting insert, each minor cutting edge and its adjacent major cutting edge are connected at a concave portion of a periphery of the cutting insert.

An indexable cutting insert for use in a milling cutter comprising:

• generally square shaped top and bottom surfaces;
• four substantially identical side surfaces extending between the top surface and the bottom surface;
• two diametrically opposite protuberances extending away from each other in a top or bottom view of the cutting insert, each protuberance having a peripheral side surface comprising an intermediate side surface and two minor side surfaces, the intermediate side surface being located between and merging with the two minor side surfaces, each side surface comprising a major side surface connected to an adjacent minor side surface, adjacent major side surfaces merging at two diametrically opposite corner edges of the cutting insert;
• eight identical major cutting edges, comprising four major cutting edges formed at the intersection of the major side surfaces with the top surface and four major cutting edges formed at the intersection of the major side surfaces with the bottom surface;
• and
• eight identical minor cutting edges, comprising four minor cutting edges formed at the intersection of the minor side surfaces with the top surface and four minor cutting edges formed at the intersection of the minor side surfaces with the bottom surface, each minor cutting edge being connected to an adjacent major cutting edge,
• wherein, in a top or bottom view of the cutting insert, said two diametrically opposite protuberances extend farther outward from a center of the cutting insert than said two diametrically opposite corner edges at which said adjacent major side surfaces merge.