Indexable drill insert
AssigneeKennametal India Limited
InventorMahesh Todkar
Life of this patent
Estimating the term…
Abstract
An indexable drill insert (10) includes a top surface (12), a bottom surface (14), and a plurality of side surfaces (16) adjoining the top surface (12) and the bottom surface (14). A plurality of cutting edges (20) is formed by an intersection of a respective side surface (16) with the top surface (12). One aspect of the invention is that the top surface (12) includes a protruding portion (50) having a backwall (50a) and a segmented portion (52) extending radially outwardly with respect to the protruding portion (50) for effective chip breaking. Another aspect of the invention is that a rake surface (48) has a positive rake angle (RA) that varies along a first cutting edge section (22) of the cutting edge (20) to lower cutting force.
Claims19
An indexable drill insert, comprising:
- a top surface, a bottom surface, and a plurality of side surfaces adjoining the top surface and the bottom surface;
- a plurality of cutting edges formed by an intersection of a respective side surface with the top surface;
- a protruding portion formed on the top surface and disposed about a mounting through hole of the drill insert;
- and
- a segmented portion formed on the top surface and extending radially outwardly from the protruding portion,
- wherein each cutting edge comprises:
- a first cutting edge section extending away from a first corner edge portion, wherein the first cutting edge section is formed with a first cutting edge angle with respect to a horizontal reference plane of the drill insert such that the first cutting edge section extends radially outward from the first corner edge portion;
- a second cutting edge section connected to and extending radially outward from the first cutting edge section by a transitional cutting edge section, wherein the second cutting edge section is formed at a second cutting edge angle with respect to the horizontal reference plane of the drill insert, and wherein the second cutting edge section is tangential to an imaginary inscribed circle (IC) of the drill insert;
- and
- a third cutting edge section connected to the second cutting edge section by a convex curve and extending toward a second corner edge portion, wherein the third cutting edge section is formed at a third cutting edge angle with respect to the horizontal reference plane of the drill insert.
An indexable drill insert, comprising:
- a top surface, a bottom surface, and a plurality of side surfaces adjoining the top surface and the bottom surface;
- a plurality of cutting edges formed by an intersection of a respective side surface with the top surface,
- wherein each cutting edge comprises:
- a first cutting edge section extending away from a first corner edge portion, wherein the first cutting edge section is formed at an angle with respect to a horizontal reference plane of the drill insert such that the first cutting edge section extends radially outward from the first corner edge portion;
- a second cutting edge section connected to and extending radially outward from the first cutting edge section by a transitional cutting edge section, wherein the second cutting edge section is formed at an angle with respect to the horizontal reference plane, wherein the second cutting edge section is tangential to an imaginary inscribed circle (IC) of the drill insert;
- and
- a third cutting edge section connected to the second cutting edge section by a convex curve and extending toward a second corner edge portion, wherein the third cutting edge section is formed at an angle such that the third cutting edge section extends radially inward with respect to the horizontal reference plane of the drill insert,
- wherein the top surface of the drill insert includes a land surface adjacent to and extending radially inwardly from the first cutting edge section and a rake surface adjacent to and extending radially inwardly from the land surface, and
- wherein the rake surface has a positive rake angle (RA) that varies along the first cutting edge section.
Dependencies are inferred from the claim text.