Cutting tool and cutting insert having a mounting cut-out therefor
A cutting tool has a cutting insert removably secured to a holding portion of an insert holder. The cutting insert has opposing first and second end surfaces with an insert peripheral surface and a central axis extending therebetween, at least one cutting portion, and at least one mounting cut-out. Each cutting portion has a cutting edge and an adjacent relief surface facing in a first rotary direction about the central axis. Each mounting cut-out extends between the first and second end surfaces and has a first flank surface and an adjacent first upper slope surface. The first flank surface faces in a second rotary direction about the central axis and the first upper slope surface faces away from a median plane located midway between the first and second end surfaces. The first upper slope surface extends away from the median plane with increasing distance from the first flank surface.
1 . A cutting insert ( 20 ) comprising opposing first and second end surfaces ( 22 a , 22 b ) with an insert peripheral surface ( 24 ) and a central axis (AC) extending therebetween,
the cutting insert ( 20 ) having at least one cutting portion ( 26 ), at least one mounting cut-out ( 28 ), and a central through bore ( 30 ) extending between and intersecting the first and second end surfaces ( 22 a , 22 b ),
a median plane (M) perpendicular to the central axis (AC) is located midway between the first and second end surfaces ( 22 a , 22 b ), and
the first and second end surfaces ( 22 a , 22 b ) are located on first and second sides (S 1 , S 2 ) of the median plane (M), respectively,
each of the at least one cutting portion ( 26 ) having a cutting edge ( 34 ) formed at the intersection of a rake surface ( 36 ) and a relief surface ( 38 ),
the at least one rake surface ( 36 ) and the at least one relief surface ( 38 ) formed on the insert peripheral surface ( 24 ), at least one of the at least one rake surface ( 36 ) facing in a first rotary direction (DR 1 ) about the central axis (AC),
each of the at least one mounting cut-out ( 28 ) extending between and intersecting the first and second end surfaces ( 22 a , 22 b ) and having a cut-out peripheral surface ( 40 ), the cut-out peripheral surface ( 40 ) including a first flank surface ( 42 ) and at least one adjacent first slope surface ( 44 a , 44 b ),
the at least one first flank surface ( 42 ) facing in a second rotary direction (DR 2 ) about the central axis (AC) opposite to the first rotary direction (DR 1 ), and
one of the at least one first slope surface ( 44 a , 44 b ) being a first upper slope surface ( 44 a ) located on the first side (S 1 ) of the median plane (M), facing away from the median plane (M),
wherein, in a cross-section taken in a first plane (P 1 ) parallel to the central axis (AC) and transversely intersecting one of the at least one first flank surface ( 42 ) and the adjacent first upper slope surface ( 44 a ):
the first upper slope surface ( 44 a ) extends away from the median plane (M) with increasing distance from the first flank surface ( 42 );
a first imaginary straight line (L 1 ) tangential to the first upper slope surface ( 44 a ) forms an acute first slope angle (α 1 ) with the median plane (M); and
the first slope angle (α 1 ) is greater than five degrees and less than twenty-five degrees.
2 . The cutting insert ( 20 ) according to claim 1 , wherein:
the cutting insert ( 20 ) is indexable and has at least two cutting portions ( 26 ), and
each of the at least one mounting cut-out ( 28 ) has a second flank surface ( 52 ) and at least one adjacent second slope surface ( 58 a , 58 b ) disposed on its cut-out peripheral surface ( 40 ),
and wherein:
at least one of the at least two rake surfaces ( 36 ) faces in the second rotary direction (DR 2 ) about the central axis (AC), and
the at least one second flank surface ( 52 ) faces in the first rotary direction (DR 1 ) about the central axis (AC).
3 . The indexable cutting insert ( 20 ) according to claim 2 , wherein:
the first and second flank surfaces ( 42 , 52 ) of each of the at least one mounting cut-out ( 28 ) diverge away from each other with increased distance from the central axis (AC).
4 . The indexable cutting insert ( 20 ) according to claim 2 , wherein:
the median plane (M) intersects each of the at least two cutting edges ( 34 ), and
the median plane (M) intersects the first and second flank surfaces ( 42 , 52 ) of each of the at least one mounting cut-out ( 28 ).
5 . The cutting insert ( 20 ) according to claim 2 , wherein:
the at least one second slope surface ( 58 a , 58 b ) faces away from the median plane (M),
and wherein, in a cross-section taken in a third plane (P 3 ) parallel to the central axis (AC) and transversely intersecting one of the at least one second flank surface ( 52 ) and the adjacent second slope surface ( 58 a , 58 b ):
the second slope surface ( 58 a , 58 b ) extends away from the median plane (M) with increasing distance from the second flank surface ( 52 );
a second imaginary straight line (L 2 ) tangential to the second slope surface ( 58 a , 58 b ) forms an acute second slope angle (α 2 ) with the median plane (M); and
the second slope angle (α 2 ) is equal to the first slope angle (α 1 ).
6 . The indexable cutting insert ( 20 ) according to claim 2 , wherein:
the central through bore ( 30 ) extends through a central body portion ( 60 ) of the cutting insert ( 20 ) and intersects first and second central sub-surfaces ( 62 a , 62 b ) of the first and second end surfaces ( 22 a , 22 b ), respectively.
7 . The indexable cutting insert ( 20 ) according to claim 6 , wherein in a direction parallel to the central axis (AC):
each cutting portion ( 26 ) has a cutting width (WC) defined by its cutting edge ( 34 ),
the central body portion ( 60 ) has a body width (WB) defined by the first and second central sub-surfaces ( 62 a , 62 b ), and
the body width (WB) is less than the cutting width (WC) of each cutting portion ( 26 ).
8 . The indexable cutting insert ( 20 ) according to claim 6 , wherein:
the first and second central sub-surfaces ( 62 a , 62 b ) define fourth and fifth planes (P 4 , P 5 ) perpendicular to the central axis (AC), and
the first upper slope surface ( 44 a ) and the second slope surface ( 58 a , 58 b ) of each of the at least one mounting cut-out ( 28 ) are entirely located between the fourth and fifth planes (P 4 , P 5 ).
9 . The cutting insert ( 20 ) according to claim 2 , wherein:
the at least one second slope surface ( 58 a , 58 b ) is a second lower slope surface ( 58 b ) located on the second side (S 2 ) of the median plane (M).
10 . The indexable cutting insert ( 20 ) according to claim 2 , wherein:
each cutting edge ( 34 ) has a radially outermost cutting point (NC), and in an end view of the cutting insert ( 20 ), the at least two radially outermost cutting points (NC) define a first imaginary circle (C 1 ) having a first diameter (D 1 ) and a center coincident with the central axis (AC),
the central through bore ( 30 ) has a cylindrical inner bore surface ( 32 ),
in an end view of the cutting insert ( 20 ), the cylindrical inner bore surface ( 32 ) defines a second imaginary circle (C 2 ) having a second diameter (D 2 ), and
the second diameter (D 2 ) is less than twenty percent of the first diameter (D 1 ).
11 . The indexable cutting insert ( 20 ) according to claim 10 , wherein:
a sixth plane (P 6 ) perpendicular to the central axis (AC) intersects the cylindrical inner bore surface ( 32 ), and
the sixth plane (P 6 ) is located further from the median plane (M) than at least a portion of the first upper slope surface ( 44 a ) and at least a portion of the second slope surface ( 58 a , 58 b ).
12 . The indexable cutting insert ( 20 ) according to claim 10 , wherein:
the central through bore ( 30 ) has a first axial extent (EA 1 ) along the central axis (AC),
the cylindrical inner bore surface ( 32 ) has a second axial extent (EA 2 ) along the central axis (AC), and
the second axial extent (EA 2 ) is greater than sixty percent of the first axial extent (EA 1 ).
13 . The indexable cutting insert ( 20 ) according to claim 2 , wherein:
the cutting insert ( 20 ) has exactly two mounting cut-outs ( 28 ) and exactly four cutting portions ( 26 ).
14 . The indexable cutting insert ( 20 ) according to claim 13 , wherein:
the cutting insert ( 20 ) exhibits 2-fold rotational symmetry about the central axis AC.
15 . A cutting tool comprising an insert holder and the cutting insert in accordance with claim 1 retained therein,
the insert holder ( 76 ) having a holding portion ( 78 ) extending along a longitudinal tool axis (AL),
the longitudinal tool axis (AL) defining a forward-to-rearward direction (FW, RW), and
the holding portion ( 78 ) having a front end surface ( 80 ) transverse to the longitudinal tool axis (AL) facing in the forward direction (FW) and a seating surface ( 82 ) disposed on the front end surface ( 80 ),
the seating surface ( 82 ) having spaced apart first and second mounting protuberances ( 86 , 88 ) protruding therefrom,
the cutting insert ( 20 ) is removably securable to the holding portion ( 78 ),
wherein, in an assembled position of the cutting tool ( 74 ):
one of the first and second end surfaces ( 22 a , 22 b ) is in abutting contact with the seating surface ( 82 ),
the first mounting protuberance ( 86 ) occupies the central through bore ( 30 ),
the second mounting protuberance ( 88 ) occupies one of the at least one mounting cut-out ( 28 ),
exactly one of the at least one cutting portion ( 26 ) is operative, and
in an end view of the cutting tool ( 74 ), the rake surface ( 36 ) of the operative cutting portion ( 26 ′) faces in an operative rake direction (DRO) about the central axis (AC).
16 . The cutting tool ( 74 ) according to claim 15 , wherein:
the second mounting protuberance ( 88 ) has a first reaction surface ( 102 ) transverse to the seating surface ( 82 ),
the first reaction surface ( 102 ) faces in the operative rake direction (DRO) about the central axis (AC), and
the cut-out peripheral surface ( 40 ) of the mounting cut-out ( 28 ) occupied by the second mounting protuberance ( 88 ) is in abutting contact with the first reaction surface ( 102 ).
17 . The cutting tool ( 74 ) according to claim 15 , wherein:
the second mounting protuberance ( 88 ) has a first mounting undercut ( 92 ) with respect to the forward direction (FW), and
the cut-out peripheral surface ( 40 ) of the mounting cut-out ( 28 ) occupied by the second mounting protuberance ( 88 ) engages the first mounting undercut ( 92 ).
18 . The cutting tool ( 74 ) according to claim 17 , wherein:
the first mounting undercut ( 92 ) has a first undercut first sub-surface ( 94 ) facing in the rearward direction (RW) and an adjacent first undercut second sub-surface ( 96 ) facing in the operative rake direction (DRO) about the central axis (AC).
19 . The cutting tool ( 74 ) according to claim 18 , wherein:
the cut-out peripheral surface ( 40 ) of the mounting cut-out ( 28 ) occupied by the second mounting protuberance ( 88 ) is in clamping contact with the first undercut first sub-surface ( 94 ).
20 . The cutting tool ( 74 ) according to claim 18 , wherein:
the cutting insert ( 20 ) is indexable and has at least two cutting portions ( 26 ),
at least one of the at least two rake surfaces ( 36 ) faces in the second rotary direction (DR 2 ) about the central axis (AC),
each of the at least one mounting cut-out ( 28 ) has a second flank surface ( 52 disposed on its cut-out peripheral surface ( 40 ), and
the at least one second flank surface ( 52 ) faces in the first rotary direction (DR 1 ) about the central axis (AC),
and wherein, in each index position of the cutting insert ( 20 ):
one of the first and second flank surfaces ( 42 , 52 ) of one of the at least one mounting cut-out ( 28 ) occupies the first mounting undercut ( 92 ) and is located between the first undercut first sub-surface ( 94 ) and the seating surface ( 82 ).
21 . The cutting tool ( 74 ) according to claim 20 , wherein:
each of the at least one mounting cut-out ( 28 ) has a second slope surface ( 58 a , 58 b ) disposed on its cut-out peripheral surface ( 40 ) adjacent the second flank surface ( 52 ), and
the at least one second slope surface ( 58 a , 58 b ) is a second lower slop surface ( 58 b ) located on the second side (S 2 ) of the median plane (M).
22 . The cutting tool ( 74 ) according to claim 21 , wherein:
the cutting insert ( 20 ) has exactly four cutting portions ( 26 ) and exactly two mounting cut-outs ( 28 ),
the two mounting cut-outs ( 28 ) are identical to each other,
and wherein, in each index position of the cutting insert ( 20 ):
one of the first upper slope surface ( 44 a ) or second lower slope surface ( 58 b ) of the mounting cut-out ( 28 ) occupied by the second mounting protuberance ( 88 ) is in clamping contact with the first undercut first subsurface ( 94 ).
23 . The cutting tool ( 74 ) according to claim 22 , wherein:
the holding portion's seating surface ( 82 ) has a third mounting protuberance ( 104 ) protruding therefrom, and
the third mounting protuberance ( 104 ) occupies one of the two mounting cut-outs ( 28 ).
24 . The cutting tool ( 74 ) according to claim 23 , wherein:
the third mounting protuberance ( 104 ) has a second mounting undercut ( 106 ) with respect to the forward direction (FW), and
the second mounting undercut ( 106 ) has a second undercut first sub-surface ( 108 ) facing in the rearward direction (RW) and an adjacent second undercut second sub-surface ( 112 ) facing in the operative rake direction (DRO) about the central axis (AC),
and wherein, in each index position of the cutting insert ( 20 ):
one of the first upper slope surfaces ( 44 a ) or second lower slope surface ( 58 b ) of the mounting cut-out ( 28 ) occupied by the third mounting protuberance ( 104 ) is in clamping contact with the second undercut first sub-surface ( 108 ).