# US 11,897,043 B2 · Cutting inserts for use in milling tools > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,897,043 B2 - Document ID: US11897043B2 - Status: Granted - Kind: B2 - Application number: 17/566,916 - Filed: 2021-12-31 - Published: 2023-07-06 - Granted: 2024-02-13 - Earliest claimed: 2021-12-31 - Assignees: Kennametal Inc. - Applicants: Kennametal Inc. - Inventors: Jean Luc D. Dufour; Gilles Festeau - Web page: https://patentgrep.com/patent/US11897043B2 ## CPC - B23C 5/202: {Plate-like cutting inserts with special form (special form related to securing of the insert B23C5/22)} - B23C 5/06: Face-milling cutters, i.e. having only or primarily a substantially flat cutting surface - B23C 2200/0455: Square - B23C 2200/125: discontinuous - B23C 2200/28: Angles - B23C: MILLING (broaching B23D; broach-milling in making gears B23F; arrangement for copying or controlling B23Q) ## Abstract Cutting inserts are disclosed having four cutting edges and milling tools comprising the cutting inserts installed in pockets on a rotatable cutting tool holder. The cutting inserts comprise a front face, a rear face and four side faces extending between the front and rear faces. A cutting edge is provided at the intersection of the front face and each side face. Each cutting edge comprises a plurality of cutting edge segments, including a facet cutting edge that forms the flat surface of a workpiece being milled, and a straight lead cutting edge that extends at an angle away from the facet cutting edge. The lead cutting edge angle is selected to provide effective milling of the workpiece at entry. The cutting inserts have side seating surfaces that allow the inserts to be more stably supported in cutting insert pockets. ## Claims ### Claim 1 A cutting insert comprising: a front face; a rear face; a plurality of side faces, wherein each side face extends between the front face and the rear face; and a cutting edge at an intersection of the front face and each side face, wherein each cutting edge comprises: a facet cutting edge; and a straight angled lead cutting edge extending from the facet cutting edge at a lead cutting edge angle with respect to the facet cutting edge of from 5° to 40°, wherein the straight angled lead cutting edge extends to a cutting nose edge. ### Claim 2 (depends on 1) The cutting insert of claim 1, wherein at least a portion of the facet cutting edge is straight. ### Claim 3 (depends on 1) The cutting insert of claim 1, wherein the straight angles lead cutting edge angle is from 10° to 25°. ### Claim 4 (depends on 1) The cutting insert of claim 1, wherein the straight angled lead cutting edge is from greater than 2.0 mm to 10.0 mm in length, and the facet cutting edge is from 0.1 mm to less than 2.0 mm in length. ### Claim 5 (depends on 1) The cutting insert of claim 1, wherein a ratio of the length of the straight angled lead cutting edge to the length of the facet cutting edge is from 1.5:1 to 20:1. ### Claim 6 (depends on 1) The cutting insert of claim 1, further comprising a clearance edge extending from the facet cutting edge at a clearance edge angle of from 0.2° to 5.0° with respect to the facet cutting edge. ### Claim 7 (depends on 6) The cutting insert of claim 6, wherein a ratio of the length of the facet cutting edge to the length of the clearance edge is from 5:1 to 0.2:1. ### Claim 8 (depends on 1) The cutting insert of claim 1, wherein each side face comprises a side lead surface intersecting the straight angled lead cutting edge at a side lead surface angle measured from the front face of from less than 90° to 60°. ### Claim 9 (depends on 8) The cutting insert of claim 8, wherein each side face comprises: a side seating surface; and a rear corner foot extending from the side lead surface defining a rear corner intersection line with the side lead surface, wherein the side seating surface comprises: a second forward seating surface boundary intersecting the side lead surface; a rear seating surface boundary intersecting the rear face; and a rear corner foot seating surface boundary intersecting the rear corner foot. ### Claim 10 (depends on 9) The cutting insert of claim 9, wherein the side lead surface comprises a planar surface. ### Claim 11 (depends on 1) The cutting insert of claim 1, further comprising a rear corner chamfer between adjacent ones of the side surfaces and intersecting the rear face disposed at an angle of from 10° to 50° measured from the central longitudinal axis. ### Claim 12 A cutting insert for installation on a rotatable cutting tool holder, the cutting insert comprising: a front face; a rear face; a plurality of side faces, wherein each side face extends between the front face and the rear face and comprises a side seating surface; a cutting edge comprising a straight angled lead cutting edge at an intersection of the front face and a side lead surface of each side face; and a rear corner foot extending from the side lead surface defining a rear corner intersection line with the side lead surface, wherein the side seating surface comprises: a second forward seating surface boundary intersecting the side lead surface; a rear seating surface boundary intersecting the rear face; and a rear corner foot seating surface boundary intersecting the rear corner foot. ### Claim 13 (depends on 12) The cutting insert of claim 12, wherein the second forward seating surface boundary comprises a straight line. ### Claim 14 (depends on 13) The cutting insert of claim 13, wherein the rear corner foot seating surface boundary comprises a straight line. ### Claim 15 (depends on 14) The cutting insert of claim 14, wherein the straight line of the second forward seating surface boundary and the straight line of the rear corner foot seating surface boundary are angled with respect to each other and meet at an inflection point. ### Claim 16 (depends on 12) The cutting insert of claim 12, wherein the side lead surface comprises a planar surface, the rear corner foot comprises a planar surface, and the rear corner intersection line is straight. ### Claim 17 (depends on 12) The cutting insert of claim 12, further comprising a rear corner chamfer between adjacent ones of the side surfaces and intersecting the rear face, wherein the side seating surface comprises a first rear corner chamfer seating surface boundary intersecting the rear corner chamfer. ### Claim 18 (depends on 17) The cutting insert of claim 17, wherein the first rear corner chamfer seating surface boundary comprises a straight line. ### Claim 19 (depends on 17) The cutting insert of claim 17, wherein the rear seating surface boundary intersects the first rear corner chamfer seating surface boundary. ### Claim 20 (depends on 17) The cutting insert of claim 17, wherein the rear corner chamfer comprises a second rear corner chamfer seating surface boundary intersecting a side seating surface of an adjacent one of the side surfaces. ### Claim 21 (depends on 12) The cutting insert of claim 12, wherein the cutting edge comprises a facet cutting edge, and the straight angled lead cutting edge extends from the facet cutting edge at a lead cutting edge angle with respect to the facet cutting edge of from 5° to 40°. ### Claim 22 A cutting tool assembly comprising: a rotatable cutting tool holder having a longitudinal rotation axis and comprising a plurality of cutting insert pockets; and a plurality of cutting inserts insertable into the cutting insert pockets, each cutting insert comprising: a front face; a rear face; a plurality of side faces, wherein each side face extends between the front face and the rear face and comprises a side seating surface; a cutting edge at an intersection of the front face and each side face, wherein each cutting edge comprises: a facet cutting edge, and a straight angled lead cutting edge extending from the facet cutting edge at a lead cutting edge angle with respect to the facet cutting edge of from 5° to 40°, and wherein each side face further comprises: a side lead surface intersecting the straight angled lead cutting edge; and a rear corner foot extending from the side lead surface defining a rear corner intersection line with the side lead surface, wherein the side seating surface comprises: a forward seating surface boundary intersecting the side lead surface; a rear seating surface boundary intersecting the rear face; and a rear corner foot seating surface boundary intersecting the rear corner foot. ### Claim 23 (depends on 22) The cutting tool holder and cutting insert assembly of claim 22, wherein the side lead surface comprises a planar surface. ### Claim 24 (depends on 23) The cutting tool holder and cutting insert assembly of claim 23, wherein the side lead surface intersects the straight angled lead cutting edge at a side lead surface angle measured from the front face of from less than 90° to 60°. ### Claim 25 A cutting insert comprising: a front face; a rear face; a plurality of side faces, wherein each side face extends between the front face and the rear face; and a cutting edge at an intersection of the front face and each side face, wherein each cutting edge comprises: a facet cutting edge; and a straight angled lead cutting edge extending from the facet cutting edge at a lead cutting edge angle with respect to the facet cutting edge of from 5° to 40°, wherein the cutting insert further comprises a clearance edge extending from the facet cutting edge at a clearance edge angle of from 0.2° to 5.0° with respect to the facet cutting edge. ### Claim 26 A cutting insert comprising: a front face; a rear face; a plurality of side faces, wherein each side face extends between the front face and the rear face; and a cutting edge at an intersection of the front face and each side face, wherein each cutting edge comprises: a facet cutting edge; and a straight angled lead cutting edge extending from the facet cutting edge at a lead cutting edge angle with respect to the facet cutting edge of from 5° to 40°, wherein each side face comprises a side lead surface intersecting the straight angled lead cutting edge at a side lead surface angle measured from the front face of from less than 90° to 60°.