Indexable lay-down cutting insert having a central body portion and three circumferentially spaced cutting portions, and cutting tool

Patent metadata

Field	Value
Publication number	US-11534838-B1
Application number	US-202117341991-A
Country	US
Kind code	B1
Filing date	Jun 8, 2021
Priority date	Jun 8, 2021
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

In a cutting tool having an indexable lay-down cutting insert with a central body portion and three circumferentially spaced apart cutting portions, the cutting insert is removably secured to an elongated holding portion of an insert holder. Each cutting portion has a cutting edge with first and second cutting end points, the cutting edge formed at the intersection of an upward facing rake surface and a radially outward facing relief surface. In a top view of the cutting insert, parallel imaginary first and second vertical planes containing the first and second cutting end points, intersect the central body portion at first and second body side points, which are located first and second cutting distances from the first and second cutting end points, respectively. Each of the first and second cutting distances is greater than twenty-five percent of the first radius of an imaginary first circle circumscribing the cutting insert.

First claim

What is claimed is:

1. An indexable lay-down cutting insert ( 20 ) comprising:
opposing upper and lower surfaces ( 22 , 24 ) with a continuous peripheral side surface ( 26 ) extending therebetween, and a central axis (A 1 ) extending therethrough, the central axis (A 1 ) defining an upward-to-downward direction (DU, DD), and a central body portion ( 30 ) and three circumferentially spaced apart cutting portions ( 32 ) radially protruding therefrom,
the central body portion ( 30 ) having lower body surface ( 34 ) facing in the downward direction (DD), and three circumferentially spaced apart radially outward facing central side surfaces ( 36 ),
each cutting portion ( 32 ) having a support surface ( 38 ) facing in the downward direction (DD), a rake surface ( 40 ) facing in the upward direction (DU), a radially outward facing relief surface ( 42 ) extending between the rake surface ( 40 ) and the support surface ( 38 ), and a cutting edge ( 44 ) formed at the intersection of the rake surface ( 40 ) and the relief surface ( 42 ), each cutting edge ( 44 ) having first and second cutting end points (NE 1 , NE 2 ), and
each cutting portion ( 32 ) further including:
an imaginary bisector plane (PB) containing the central axis (A 1 ) and bisecting its cutting edge ( 44 ) at a bisector cutting point (NBC); and
imaginary first and second vertical planes (PV 1 , PV 2 ) parallel to the imaginary bisector plane (PB) and containing the first and second cutting end points (NE 1 , NE 2 ) of said each cutting portion ( 32 ), respectively,

wherein apart from containing the first and second cutting end points (NE 1 , NE 2 ), the imaginary first and second vertical planes (PV 1 , PV 2 ) do not intersect their respective cutting portion ( 32 ),
wherein, in a top view of the cutting insert ( 20 ):
the imaginary first and second vertical planes (PV 1 , PV 2 ) intersect two different central side surfaces ( 36 ) of the central body portion ( 30 ) adjacent their respective cutting portion ( 32 ) at first and second body side points (NB 1 , NB 2 ), respectively;
the first and second body side points (NB 1 , NB 2 ) are located first and second cutting distances (DC 1 , DC 2 ) from the first and second cutting end points (NE 1 , NE 2 ), respectively; and
an imaginary first circle (CC 1 ) defined by the three cutting edges ( 44 ) circumscribes the cutting insert ( 20 ), and has a first radius (R 1 )
and wherein: the three bisector cutting points (NBC) are located inside the imaginary first circle (CC 1 ); and
each of the first and second cutting distances (DC 1 , DC 2 ) is greater than twenty-five percent of the first radius (R 1 ).

2. The cutting insert ( 20 ) according to claim 1 , wherein in the top view of the cutting insert ( 20 ):
each imaginary bisector plane (PB) intersects one of the central side surfaces ( 36 ) at a third body side point (NB 3 ) on the opposite side of the central axis (A 1 ) from its associated cutting portion ( 32 ).

3. The cutting insert ( 20 ) according to claim 2 , wherein:
the three bisector cutting points (NBC) define three corner points of an imaginary equilateral triangle (T 1 ); and
in the top view of the cutting insert ( 20 ), the three third body side points (NB 3 ) are located outside the imaginary equilateral triangle (T 1 ).

4. The cutting insert ( 20 ) according to claim 1 , wherein each support surface ( 38 ) includes a male or female type support element ( 50 ).

5. The cutting insert ( 20 ) according to claim 4 , wherein each support element ( 50 ) is in the form of a radially extending elongated ridge ( 52 ), with respect to the insert axis (A 1 ).

6. The cutting insert ( 20 ) according to claim 1 , wherein:
each cutting portion ( 32 ) has a cutting width (WCT) defined by the distance between its imaginary first and second vertical planes (PV 1 , PV 2 ), and
the cutting width (WCT) is greater than forty percent of the first radius (R 1 ).

7. The cutting insert ( 20 ) according to claim 1 , wherein each cutting portion ( 32 ) exhibits mirror symmetry about its imaginary bisector plane (PB).

8. The cutting insert ( 20 ) according to claim 1 , wherein:
the upper surface ( 22 ) includes three linearly extending coolant grooves ( 62 ), and
each coolant groove ( 62 ) traverses the other two coolant grooves ( 62 ).

9. The cutting insert ( 20 ) according to claim 8 , wherein:
each coolant groove ( 62 ) extends along a groove axis (A 2 ) transverse to the central axis (A 1 ), and
each coolant groove ( 62 ) intersects one of the three cutting portions ( 32 ) at a first groove end region (NG 1 ).

10. The cutting insert ( 20 ) according to claim 8 , wherein:
a through bore ( 28 ) coaxial to the central axis (A 1 ) intersects the upper and lower surfaces ( 22 , 24 ), and
each coolant groove ( 62 ) is interrupted by the through bore ( 28 ).

11. The cutting insert ( 20 ) according to claim 10 , wherein:
the three cutting edges ( 44 ) defines an imaginary first horizontal plane (PH 1 ) perpendicular to the central axis (A 1 );
the lower surface ( 24 ) defines an imaginary second horizontal plane (PH 2 ) perpendicular to the central axis (A 1 );
the through bore ( 28 ) includes first and second bore portions ( 28 a , 28 b ) having different first and second bore diameters (DB 1 , DB 2 ) at cross-sections taken in imaginary third and fourth horizontal planes (PH 3 , PH 4 ) perpendicular to the central axis (A 1 ), respectively;
the imaginary third horizontal plane (PH 3 ) is located axially upward of the imaginary fourth horizontal plane (PH 4 );
the first bore diameter (DB 1 ) is at least twenty-five percent greater than the second bore diameter (DB 2 ); and
the imaginary third and fourth horizontal planes (PH 3 , PH 4 ) are both located closer to the imaginary second horizontal plane (PH 2 ) than the imaginary first horizontal plane (PH 1 ).

12. The cutting insert ( 20 ) according to claim 1 , wherein the imaginary bisector plane (PB) is perpendicular to the cutting edge ( 44 ) at the bisector cutting point (NBC).

13. A cutting tool ( 64 ) comprising an insert holder ( 66 ) and the cutting insert ( 20 ) in accordance with claim 1 retained therein.

14. The cutting tool ( 64 ) according to claim 13 , wherein:
the insert holder ( 66 ) has an elongated holding portion ( 68 ) extending away from a shank portion ( 70 ) in a forward direction (DF) along a tool axis (AT), the holding portion ( 68 ) having a seating surface ( 72 ) transverse to the tool axis (AT) at a front end ( 74 ) thereof,
the holding portion ( 68 ) having longitudinally extending major and minor holding sub-portions ( 68 a , 68 b ), and the seating surface ( 72 ) having major and minor seating sub-surfaces ( 72 a , 72 b ) associated with the major and minor holding sub-portions ( 68 a , 68 b ), respectively,

the cutting insert ( 20 ) is removably secured to the holding portion ( 68 ) in one of three index positions by a fastening member ( 76 ),
in each index position, exactly one cutting portion ( 32 ) is operative and two cutting portions ( 32 ) are non-operative, the operative cutting portion having an operative cutting edge ( 44 ),
the support surfaces ( 38 ) of the two non-operative cutting portions ( 32 ) are in clamping contact with the major seating sub-surface ( 72 a ); and
the support surface ( 38 ) of the operative cutting portion ( 32 ) is in clamping contact with the minor seating sub-surface ( 70 b ).

15. The cutting tool ( 64 ) according to claim 14 , wherein:
each support surface ( 38 ) includes a male or female type support element ( 50 ), and
a correspond

Assignees

• Iscar Ltd

Inventors

• Hecht Gil

Classifications

• B23B27/10

  Cutting tools with special provision for cooling {(drills with lubricating or cooling equipment B23B51/06; features relating to lubricating or cooling of milling cutters B23C5/28; arrangements or devices for cooling or lubricating tools or work B23Q11/10)} · CPC title

• B23C2200/20

  Top or side views of the cutting edge · CPC title

• B23B2205/12

  Seats for cutting inserts · CPC title

• B23C2200/0477

  Triangular · CPC title

• B23B2200/128

  with one or more grooves · CPC title