Square-shaped cutting insert having curved secondary and corner cutting edges, and rotary cutting tool

Patent metadata

Field	Value
Publication number	US-10384278-B2
Application number	US-201715727770-A
Country	US
Kind code	B2
Filing date	Oct 9, 2017
Priority date	Oct 9, 2017
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

An indexable cutting insert has upper and lower surfaces with a peripheral surface extending therebetween and having four side surfaces alternating with four corner surfaces. The side and corner surfaces intersect the upper surface to form side and corner cutting edges, respectively. Each side cutting edge includes a primary cutting edge adjoining one of the corner cutting edges at a first endpoint and a secondary cutting edge adjoining another one of the corner cutting edges at a second endpoint. In a top view, the four primary cutting edges define an imaginary first square, each primary cutting edge is tangential to its adjoining corner cutting edge, and each secondary cutting edge is curved and entirely located in one of four imaginary quadrants. The insert is removably secured in a rotary cutting tool such that one of the secondary cutting edges contains the axially forwardmost point of the insert's upper peripheral edge.

First claim

What is claimed is:

1. An indexable cutting insert ( 20 , 120 , 220 ), comprising:
opposing upper and lower surfaces ( 22 , 24 ) with a peripheral surface ( 26 ) and an insert axis (A 1 ) extending therebetween,
the peripheral surface ( 26 ) intersecting the upper surface ( 22 ) to form a continuous upper peripheral edge ( 28 ), and including four insert side surfaces ( 30 ) alternating with four insert corner surfaces ( 32 ),
each insert side surface ( 30 ) intersecting the upper surface ( 22 ) to form a side cutting edge ( 40 ), and each insert corner surface ( 32 ) intersecting the upper surface ( 22 ) to form a curved corner cutting edge ( 42 ),

wherein each side cutting edge ( 40 ) includes a primary cutting edge ( 46 ) adjoining one of the corner cutting edges ( 42 ) at a first endpoint (N 1 ) and a secondary cutting edge ( 48 ) adjoining another one of the corner cutting edges ( 42 ) at a second endpoint (N 2 ),
wherein in a top view of the cutting insert ( 20 , 120 , 220 ) along the insert axis (A 1 ):
the upper surface ( 22 ) is square-shaped with each of the four primary cutting edges ( 46 ) being straight, and the four primary cutting edges defining four sides of an imaginary first square (S 1 ),
each primary cutting edge ( 46 ) is tangential to its adjoining corner cutting edge ( 42 ), and
each secondary cutting edge ( 48 ) is continuously curved and entirely located in a corresponding one of four imaginary quadrants (Q 1 , Q 2 , Q 3 , Q 4 ) defined by two mutually perpendicular imaginary lines bisecting the imaginary first square's four sides, and
wherein:
each insert side surface ( 30 ) includes an insert side relief surface ( 50 ) intersecting the upper surface ( 22 ), and an insert side abutment surface ( 52 ) between the insert side relief surface ( 50 ) and the lower surface ( 24 ), and
in a cross-section taken in a second plane (P 2 ) perpendicular to the insert axis (A 1 ) and intersecting the four insert side abutment surfaces ( 52 ), the four insert side abutment surfaces ( 52 ) define four sides of an imaginary third square (S 3 ).

2. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein:
each corner cutting edge ( 42 ) is continuously curved and has a constant first radius of curvature (R 1 ) and a first radial center point (C 1 ),
each continuously curved secondary cutting edge ( 48 ) has a constant second radius of curvature (R 2 ), and
the second radius of curvature (R 2 ) is greater than the first radius of curvature (R 1 ).

3. The cutting insert ( 20 , 120 , 220 ) according to claim 2 , wherein the second radius of curvature (R 2 ) is at least three times greater, and at most ten times greater, than the first radius of curvature (R 1 ).

4. The cutting insert ( 20 , 120 , 220 ) according to claim 2 , wherein in the top view:
the four first radial center points (C 1 ) define four corners of an imaginary second square (S 2 ), and
the imaginary first square (S 1 ) is rotationally offset from the imaginary second square (S 2 ) by a first offset angle (θ 1 ).

5. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein the imaginary first square (S 1 ) is rotationally offset from the imaginary third square (S 3 ) by a second offset angle (θ 2 ).

6. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein:
each insert side relief surface ( 50 ) includes a primary relief surface ( 54 ) adjacent its associated primary cutting edge ( 46 ), and a secondary relief surface ( 56 ) adjacent its associated secondary cutting edge ( 48 ), and
each primary relief surface ( 54 ) is planar, and each secondary relief surface ( 56 ) is convex.

7. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein in the top view:
a first imaginary straight line (L 1 ) contains one of the second endpoints (N 2 ) and is tangential to both its associated secondary cutting edge ( 48 ) and also to the adjoining corner cutting edge ( 42 ), and
the first imaginary line (L 1 ) forms an acute primary cutting angle (α 1 ) with the primary cutting edge ( 46 ) contained in the same side cutting edge ( 40 ) as its associated secondary cutting edge ( 48 ).

8. The cutting insert ( 20 , 120 , 220 ) according to claim 7 , wherein the primary cutting angle (α 1 ) is at least 5 degrees and at most 15 degrees.

9. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein the entire upper peripheral edge ( 28 ) is contained in a first plane (P 1 ).

10. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein in the top view:
each primary cutting edge ( 46 ) tangentially adjoins the secondary cutting edge ( 48 ) contained in the same side cutting edge ( 40 ) at a transition point (N T ).

11. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein:
each primary cutting edge ( 46 ) has a primary cutting length (L P ),
each side of the imaginary first square (S 1 ) has a first side length (Ls 1 ), and
the primary cutting length (L P ) is greater than half the first side length (Ls 1 ).

12. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein in the top view:
no portion of the upper peripheral edge ( 28 ) extends outside the imaginary first square (S 1 ).

13. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein the entire peripheral surface ( 26 ) is devoid of ground surface portions.

14. The cutting insert ( 20 , 120 , 220 ) according to claim 1 , wherein in a side view of a given insert side surface ( 30 ):
at least a portion of the primary cutting edge ( 46 ) associated with a circumferentially adjacent first insert side surface ( 30 ) is visible, and
at least a portion of the secondary cutting edge ( 48 ) associated with a circumferentially adjacent second insert side surface ( 30 ) is visible, the first and second insert side surfaces ( 30 ) being opposite one another.

15. The cutting insert ( 120 , 220 ) according to claim 1 , wherein:
the upper surface ( 22 ) includes a continuous land surface ( 34 ) intersecting the upper peripheral edge ( 28 ), the land surface ( 34 ) having a first land width (W 1 ) and a zero or negative acute first land angle (β 1 ) at each first endpoint (N 1 ), and further having a second land width (W 2 ) and a zero or negative acute second land angle (β 2 ) at each second endpoint (N 2 ), and
either the second land width (W 2 ) is greater than the first land width (W 1 ), or the second land angle (β 2 ) is greater than the first land angle (β 1 ), or both.

16. A rotary cutting tool ( 58 ) rotatable about a tool axis (A T ) defining a forward-rearward rotation direction (D F , D R ), and comprising:
a cutting body ( 60 ) having at least one insert receiving pocket ( 62 ); and
at least one cutting insert ( 20 , 120 , 220 ) in accordance with claim 1 removably secured in the insert receiving pocket ( 62 ).

17. A rotary cutting tool ( 58 ) rotatable about a tool axis (A T ) defining a forward-rearward rotation direction (D F , D R ), and comprising:
a cutting body ( 60 ) having at least one insert receiving pocket ( 62 ), each insert receiving pocket ( 62 ) opening out at a forward end surface ( 64 ) of the cutting body ( 60 ), and
at least one cutting insert ( 20 , 120 , 220 ) removably secured in the insert receiving pocket ( 62 ), the cutting insert comprising:
opposing upper and lower surfaces ( 22 , 24 ) with a peripheral surface ( 26 ) and an insert axis (A 1 ) extending therebetween,
the peripheral surface ( 26 ) intersecting the upper surface ( 22 ) to form a continuo

Assignees

• Iscar Ltd

Inventors

• Shapir Adi

Classifications

• B23C2200/366

  Variable · CPC title

• B23C2200/243

  bevelled or chamfered · CPC title

• B23C2200/125

  discontinuous · CPC title

• B23C2210/168

  Seats for cutting inserts, supports for replacable cutting bits · CPC title

• B23C2200/0455

  Square · CPC title