Double-ended cutting insert having diagonally opposed raised corners and diagonally opposed lowered corners and a rotary cutting tool

Abstract

A cutting insert (20) has two opposite end surfaces (22a, 22b) interconnected by a peripheral side surface (24), the peripheral side surface having two main side surfaces (26a, 26b) and two secondary side surfaces (28a, 28b). A main edge (30) is formed at the intersection of the main side surface and the end surface. Each end surface has two diagonally opposite raised corners (RC) and two diagonally opposite lowered corners (LC) relative to a midplane, each raised corner adjoining a main edge at a first main point (NJ1) and each lowered corner adjoining a main edge at a third main point (NJ3). In a main side view, each main edge has a first imaginary straight line (LM1) including the association of its first main point and third main point and an raised edge portion (62) located on one side of the first imaginary straight line. The cutting insert is removably fixed in a rotating cutting tool (82).

Description

Technical Field

[0001] The present invention relates to a rotary cutting tool and a double-ended cutting insert having diagonally opposed raised corners and diagonally opposed lowered corners. The cutting tool and the cutting insert are generally used for milling operations, and in particular for ramping operations. Background Art

[0002] In the field of cutting tools for milling operations, there are some examples of double ended cutting inserts having diagonally opposed rising corners and diagonally opposed lowering corners for performing ramping operations.

[0003] US8,449,230 discloses a tangential cutting blade comprising two opposite end surfaces and a peripheral side surface extending between the two opposite end surfaces. The peripheral side surface comprises two opposite main side surfaces connected to two opposite secondary side surfaces via a corner side surface. A peripheral edge is formed at the intersection of each end surface and the peripheral side surface. Each end surface has two raised corners including associated raised corner cutting edges and two lowered corners including associated lowered corner cutting edges. Each corner side surface comprises a concave clearance recess, which serves as a flank surface of the associated lowered corner cutting edge. The concave clearance recess extends from its associated lowered corner cutting edge in the direction of the raised corner associated with the opposite end surface, but does not intersect with the raised corner.

[0004] US9,649,701 discloses a cutting insert and an indexable insert cutting tool, which includes a cutting edge formed on each of a pair of side ridges of at least one side surface, wherein the insert body is formed into a shape having front-to-rear inverted symmetry, which is 180 degrees rotationally symmetrical relative to a symmetry line passing through the center of the side surface; a back cutting surface adjacent to the cutting edge is formed on the side surface near each of a pair of polygonal surfaces; each back cutting surface is formed in the shape of a twisted face; a pair of side ridges formed with cutting edges intersect with each other so that the second corner portion of one side ridge protrudes outside the other side ridge.

[0005] US10,112,242 discloses a double-ended, indexable, non-positive rake angle ramping blade, which has 180 degrees of rotational symmetry relative to each of the first axis, the second axis and the third axis of the three-dimensional Euclidean space. The ramping blade includes two first surfaces and a blade peripheral surface extending between them. The ramping blade includes four cutting parts, each of which includes a main cutting edge, a scraping edge laterally connected to the main cutting edge by a corner cutting edge, and a ramping edge extending laterally from the scraping edge in a perspective parallel to the first axis. Each peripheral surface includes four non-positive ramping back surfaces, each of which extends from the corresponding ramping edge toward a first midplane defined by the second axis and the third axis and does not exceed the first midplane.

[0006] It is an object of the present invention to provide an improved double ended cutting insert suitable for performing ramping operations.

[0007] Another object of the present invention is to provide an improved double ended cutting insert suitable for performing shoulder milling operations as well as ramping operations.

[0008] Another object of the present invention is to provide an improved double ended cutting insert having a compact and effective mechanism for removing chips during ramping operations. Summary of the invention

[0009] According to the present invention, there is provided a cutting insert comprising:

[0010] two opposite end surfaces interconnected by the peripheral side surfaces and a blade axis passing through the opposite end surfaces,

[0011] Each end surface has a concave central surface,

[0012] The outer peripheral side surface has two opposite main side surfaces and two secondary side surfaces,

[0013] A main edge is formed at the intersection of each main side surface and each end surface, and a main cutting edge is formed along at least a portion of each main edge.

[0014] A secondary edge is formed at the intersection of each secondary side surface and each end surface, and a secondary cutting edge is formed along at least a portion of each secondary edge.

[0015] The middle plane is perpendicular to the first blade axis and intersects with the peripheral side surface to form a blade boundary line, and

[0016] Each end surface has two raised corners and two lowered corners diagonally opposite to each other relative to the midplane,

[0017] each raised corner having a convexly curved raised corner edge formed at the intersection of the peripheral side surface and its associated end surface, each raised corner edge adjoining a main edge at a first main point, and a raised corner cutting edge formed along at least a portion of each raised corner edge,

[0018] each lowering corner having a convexly curved lowering corner edge formed at the intersection of the peripheral side surface and its associated end surface, each lowering corner edge adjoining a main edge at a third main point, and a lowering corner cutting edge formed along at least a portion of each lowering corner edge,

[0019] In the main side view of the cutting insert:

[0020] The first main point and the third main point of each main edge define a main side length measured parallel to the mid-plane, the main side length being divided into equal first, second and third length portions, wherein the first length portion is bounded by the first main point and the third length portion is bounded by the third main point,

[0021] Each main edge has a first imaginary straight line containing the association of its first and third main points and a raised edge portion, the raised edge portion being located on one side of the first imaginary straight line, and a blade boundary line being located on the other side of the first imaginary straight line, and

[0022] Each raised edge has a second major point located: (i) farthest from its associated first imaginary straight line and (ii) within a third length portion of its associated major side length.

[0023] Furthermore, according to the present invention, there is provided a rotary cutting tool rotatable in a rotational direction about a tool axis, comprising a cutting body having at least one insert receiving slot, and at least one cutting insert of the above type removably fixed in the insert receiving slot. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] For a better understanding, the invention will now be described by way of example only with reference to the accompanying drawings in which dot-dash lines represent cut-off boundaries of partial views of components, and in which:

[0025] Figure 1 is a perspective view of a cutting insert according to some embodiments of the present invention;

[0026] Figure 2 yes Figure 1 An end view of the cutting insert is shown;

[0027] Figure 3 yes Figure 1 A main side view of the cutting insert is shown;

[0028] Figure 4 yes Figure 1 A secondary side view of the cutting insert is shown;

[0029] Figure 5 yes Figure 3 A cross-sectional view of the cutting insert shown taken along line VV;

[0030] Figure 6 yes Figure 3 A cross-sectional view of the cutting insert shown taken along line VI-VI;

[0031] Figure 7 yes Figure 4 A cross-sectional view of the cutting insert shown taken along line VII-VII;

[0032] Figure 8 yes Figure 2 A cross-sectional view of the cutting insert shown taken along line VIII-VIII;

[0033] Fig. 9 yes Figure 2 A cross-sectional view of the cutting insert shown taken along line IX-IX;

[0034] Fig.10 yes Figure 4 A cross-sectional view of the cutting insert shown taken along line XX;

[0035] Fig.11 is a perspective view of a cutting tool according to some embodiments of the present invention;

[0036] Fig.12 yes Fig.11 An exploded perspective view of the cutting tool shown;

[0037] Fig.13 yes Fig.11 a side view of the cutting tool shown; and

[0038] Fig.14 yes Fig.11 An end view of the cutting tool is shown. DETAILED DESCRIPTION

[0039] like Figures 1 to 4 As shown, one aspect of the present invention is directed to a cutting insert 20 having two opposing end surfaces 22a, 22b interconnected by a peripheral side surface 24 and a first insert axis A1 passing through the opposing end surfaces 22a, 22b.

[0040] In some embodiments of the present invention, the cutting insert 20 may be indexed about the first insert axis A1 .

[0041] Furthermore, in some embodiments of the present invention, the cutting insert 20 may exhibit rotational symmetry about the first insert axis A1 .

[0042] Further, in some embodiments of the present invention, the cutting insert 20 may preferably be manufactured by forming, pressing and sintering a cemented carbide such as tungsten carbide, and may or may not be coated.

[0043] like Figure 1 and Figure 2As shown, the peripheral side surface 24 has two opposite main side surfaces 26a, 26b and two secondary side surfaces 28a, 28b, a main edge 30 is formed at the intersection of each of the main side surfaces 26a, 26b and each of the end surfaces 22a, 22b, and a secondary edge 32 is formed at the intersection of each of the secondary side surfaces 28a, 28b and each of the end surfaces 22a, 22b.

[0044] It should be appreciated that the primary cutting edge 34 is formed along at least a portion of each primary edge 30 , and the secondary cutting edge 36 is formed along at least a portion of each secondary edge 32 .

[0045] It should be appreciated that the cutting insert 20 may be described as "double ended" or "double ended" due to having cutting edges associated with the two end surfaces 22a, 22b.

[0046] In some embodiments of the present invention, the end surfaces 22a, 22b may each include a major land surface 38 proximate each of its associated major cutting edges 34.

[0047] Furthermore, in some embodiments of the present invention, the end surfaces 22a, 22b may each include a secondary land surface 40 proximate each of its associated secondary cutting edges 36.

[0048] Further, in some embodiments of the present invention, the outer peripheral side surface 24 may include four corner surfaces 42 that are convexly curved alternating with the two main side surfaces 26a, 26b and the two minor side surfaces 28a, 28b.

[0049] like Figure 1 and Figure 2 As shown, the second blade axis A2 passes through the two major side surfaces 26a, 26b (or more precisely, through the plane defined by the major side surfaces).

[0050] In some embodiments of the present invention, the blade through hole 44 may extend along the second blade axis A2 and intersect the two major side surfaces 26a, 26b.

[0051] The second blade axis A2 may be perpendicular to and intersect the first blade axis A1 .

[0052] It will be appreciated that by having the insert through hole 44 intersecting both major side surfaces 26a, 26b, the cutting insert 20 can be retained in a rotating cutting tool in a "tangential" manner as is known in the art, and is therefore described as a "tangential" cutting insert.

[0053] like Figures 1 to 4As shown, a middle plane M perpendicular to the first blade axis A1 intersects the peripheral side surface 24 to form a blade boundary line BL, and the end surfaces 22a, 22b each have two diagonally opposite rising corners RC and two diagonally opposite lowering corners LC relative to the middle plane M.

[0054] In some embodiments of the invention, the second blade axis A2 may be contained in the median plane M.

[0055] Furthermore, in some embodiments of the invention, two diagonally opposite raised corners RC associated with each of the end surfaces 22a, 22b may be positioned at equal distances from the midplane M.

[0056] Further, in some embodiments of the present invention, the cutting insert 20 may be indexable about the second insert axis A2.

[0057] Still further, in some embodiments of the present invention, the cutting insert 20 may exhibit rotational symmetry about the second insert axis A2.

[0058] like Figure 1 and Figure 2 As shown, each raised corner RC has a convexly curved raised corner edge 46 formed at the intersection of the outer peripheral side surface 24 and its associated end surfaces 22a, 22b, and each lowered corner LC has a convexly curved lowered corner edge 48 formed at the intersection of the outer peripheral side surface 24 and its associated end surfaces 22a, 22b.

[0059] In some embodiments of the present invention, each raised corner edge 46 can be formed at the intersection of one of the four corner surfaces 42 and its associated end surface 22a, 22b, and each lowered corner edge 48 can be formed at the intersection of one of the four corner surfaces 42 and its associated end surface 22a, 22b.

[0060] It should be appreciated that a raised corner cutting edge 50 is formed along at least a portion of each raised corner edge 46 , and a lowered corner cutting edge 52 is formed along at least a portion of each lowered corner edge 48 .

[0061] In some embodiments of the present invention, each raised corner cutting edge 50 may extend along the entire length of its associated raised corner edge 46 .

[0062] Furthermore, in some embodiments of the present invention, the end surfaces 22a, 22b may each include a raised corner land surface 56 proximate each of its associated raised corner cutting edges 50.

[0063] Further, in some embodiments of the present invention, the end surfaces 22a, 22b may each include a reduced corner land surface 54 proximate each of its associated reduced corner cutting edges 52.

[0064] like Figure 2 and Figure 4 As shown, each lowered corner edge 48 may adjoin a secondary edge 32 at a first secondary point NN1 , and each raised corner edge 46 may adjoin a secondary edge 32 at a second secondary point NN2 .

[0065] In some embodiments of the present invention, each secondary cutting edge 36 may extend along the entire length of its associated secondary edge 32 .

[0066] In addition, in some embodiments of the present invention, Figure 4 As shown, each secondary edge 32 may be continuously inclined toward the median plane M from its associated raised corner edge 46 to its associated lowered corner edge 48 .

[0067] like Figure 2 As shown, in an end view of the cutting insert 20, each secondary edge 32 may be tangent to its adjacent raised corner edge 46 and tangent to its adjacent lowered corner edge 48.

[0068] like Figure 1 and Figure 2 As shown, the end surfaces 22a, 22b each have a concave central surface 58.

[0069] In some embodiments of the present invention, each concave central surface 58 can be planar and parallel to the median plane M.

[0070] Furthermore, in some embodiments of the present invention, each corner reduction edge 48 may be positioned overall closer to the median plane M than its associated recessed center surface 58 .

[0071] Further, in some embodiments of the present invention, each raised corner edge 46 may be positioned overall farther from the median plane M than its associated recessed center surface 58 .

[0072] like Figure 3 As shown, each raised corner edge 46 adjoins a main edge 30 at a first main point NJ1 , and each lowered corner edge 48 adjoins a main edge 30 at a third main point NJ3 .

[0073] In addition, if Figure 3As shown, in the main side view of the cutting blade 20, the first main point NJ1 and the third main point NJ3 of each main edge 30 define a main side length SL measured parallel to the middle plane M, and the main side length SL is divided into equal first length portion L1, second length portion L2 and third length portion L3, wherein the boundary of the first length portion L1 is defined by the first main point NJ1 and the boundary of the third length portion L3 is defined by the third main point NJ3.

[0074] In some embodiments of the present invention, each main cutting edge 34 may extend at least along the entire extent of its associated first length portion L1 and second length portion L2.

[0075] Furthermore, in some embodiments of the present invention, the end surfaces 22a, 22b may each include a major rake surface 60 adjacent each of its associated major cutting edges 34.

[0076] It should be appreciated that in some embodiments of the present invention, each major rake face 60 may be spaced apart from its associated major cutting edge 34 by its associated major land surface 38 .

[0077] like Figure 3 As shown, in the main side view of the cutting insert 20, each main edge 30 has a first imaginary straight line LM1 including its first main point NJ1 and the third main point NJ3 and an elevated edge portion 62. The elevated edge portion 62 is located on one side of the first imaginary straight line LM1, and the insert boundary line BL is located on the other side of the first imaginary straight line LM1.

[0078] In some embodiments of the present invention, each raised edge portion 62 may extend to the first main point NJ1 of its associated main edge 30 .

[0079] Furthermore, in some embodiments of the present invention, each raised edge portion 62 may not extend to the third main point NJ3 of its associated main edge 30 .

[0080] like Figure 4 As shown, in the minor side view of the cutting insert 20 , the first minor point NN1 and the second minor point NN2 of each minor edge 32 define a minor side width SW measured parallel to the middle plane M.

[0081] In some embodiments of the present invention, the main side length SL of each main edge 30 may be greater than the secondary side width SW of each secondary edge 32 , that is, SL>SW.

[0082] like Figure 5 As shown, in a cross section taken in the middle plane M and intersecting the four corner surfaces 42 , the four corner surfaces 42 adjoin the two secondary side surfaces 28 a , 28 b at four corner points NC.

[0083] In addition, if Figure 5 As shown, the four corner points NC may define an imaginary parallelogram PL having a first pair of imaginary parallel sides S1 and a second pair of imaginary parallel sides S2.

[0084] In some embodiments of the present invention, the first pair of imaginary parallel sides S1 may be perpendicular to the main side length SL of each main edge 30 .

[0085] Furthermore, in some embodiments of the present invention, the first pair of imaginary parallel sides S1 and the second pair of imaginary parallel sides S2 may define an imaginary rectangle RT. Components of the first pair of sides S1 are shorter than components of the second pair of sides S2.

[0086] It should be understood that in some embodiments of the present invention, in a cross-section taken in any plane parallel to the middle plane M and intersecting the four corner surfaces 42, the four points where the four corner surfaces 42 are adjacent to the two secondary side surfaces 28a, 28b can define an imaginary parallelogram having a first pair of imaginary parallel sides and a second pair of imaginary parallel sides, and the first pair of imaginary parallel sides can be perpendicular to the main side length SL of each main edge 30.

[0087] like Figure 6 As shown, in a cross section taken in a first plane P1 intersecting one of the main cutting edges 34 and located along its associated second length portion L2 , the adjacent main rake surface 60 may be inclined toward the middle plane M while extending away from the one of the main cutting edges 34 .

[0088] In addition, if Figure 6 As shown, in a cross section taken in the first plane P1 , the one main cutting edge 34 may be further away from the middle plane M than its associated recessed center surface 58 .

[0089] In some embodiments of the present invention, the first plane P1 may be perpendicular to the middle plane M.

[0090] Furthermore, in some embodiments of the present invention, the first plane P1 may contain the second blade axis A2.

[0091] It should be understood that in some embodiments of the present invention, in a cross-section taken in any plane intersecting a main cutting edge 34 and positioned along its associated second length portion L2, the adjacent main rake face 60 may be inclined toward the middle plane M while extending away from the main cutting edge 34.

[0092] According to the present invention, Figure 3 As shown, in the main side view of the cutting insert 20, each raised edge 62 has a second main point NJ2 farthest from its associated first imaginary straight line LM1, which is located in the third length portion L3 of its associated main side length SL.

[0093] It will be appreciated that the term “furthest” as used in the preceding paragraph means that each second principal point NJ2 is further from its associated first imaginary straight line LM1 than any other point along its associated raised edge 62 .

[0094] In some embodiments of the present invention, each main cutting edge 34 may extend from its associated first main point NJ1 to its associated second main point NJ2.

[0095] Furthermore, in some embodiments of the present invention, each main edge 30 may include a non-cutting sub-portion 64 extending between its associated second main point NJ2 and its associated third main point NJ3 .

[0096] It will be appreciated that for embodiments of the invention in which each major cutting edge 34 extends from its associated first major point NJ1 to its associated second major point NJ2 in the third length portion L3 of its associated major side length SL, milling operations may advantageously be performed at large cutting depths.

[0097] like Figure 3 As shown, in the main side view of the cutting insert 20, each main edge 30 has an associated second imaginary straight line LM2 including its first main point NJ1 and second main point NJ2, which intersects with a minor cutting edge 36 at the projected intersection point NI.

[0098] By comparison Figure 3 and Figure 4 It can be seen that the projection intersection point NI is not collinear with the first principal point NJ1 and the second principal point NJ2 in the three-dimensional space.

[0099] It should be appreciated that in some embodiments of the present invention, end surfaces 22a, 22b may each have two projected intersection points NI associated therewith.

[0100] like Figure 7 As shown, in a cross section taken in a second plane P2 positioned between (passing through) the two main side surfaces 26a, 26b and containing a projected intersection point NI, the adjacent secondary land surface 40 can form an internal secondary cutting angle α1 with the adjacent secondary side surfaces 28a, 28b, and the secondary cutting angle α1 can be at least 65 degrees and at most 115 degrees, that is, 65°≤αl≤115°.

[0101] It should be understood that the term "interior angle" as used throughout the specification and claims refers to the angle between two surface features measured inside a component in which the two surface features are formed.

[0102] In some embodiments of the present invention, the second plane P2 may be perpendicular to the middle plane M.

[0103] Furthermore, in some embodiments of the invention, the second plane P2 may include two projected intersection points NI, namely one projected intersection point NI associated with each of the end surfaces 22a, 22b.

[0104] It should be understood that in some embodiments of the present invention, in a cross-section taken in any plane positioned between (passing through) the two major side surfaces 26a, 26b and intersecting with a minor cutting edge 36, the adjacent minor land surface 40 can form an internal minor cutting angle α1 with the adjacent minor side surfaces 28a, 28b, and the minor cutting angle α1 can be at least 65 degrees and at most 115 degrees, that is, 65°≤αl≤115°.

[0105] like Figure 8 As shown, in a cross section taken in a third plane P3 parallel to the first blade axis A1 and intersecting a reduced corner cutting edge 52, the adjacent reduced corner edge band surface 54 can form an internal lower cutting angle α2 with the peripheral side surface 24, and the lower cutting angle α2 can be at least 65 degrees and at most 115 degrees, that is, 65°≤α2≤115°.

[0106] like Fig. 9 As shown, in a cross section taken in a fourth plane P4 parallel to the first blade axis A1 and intersecting a raised corner cutting edge 50, the adjacent raised corner edge band surface 56 can form an internal raised cutting angle α3 with the peripheral side surface 24, and the raised cutting angle α3 can be at least 65 degrees and at most 115 degrees, that is, 65°≤α3≤115°.

[0107] like Figure 4 As shown, in the secondary side view of the cutting blade 20, the secondary side width SW of each secondary edge 32 is divided into equal first width portion W1, second width portion W2 and third width portion W3, wherein the boundary of the first width portion W1 is defined by the first secondary point NN1 and the boundary of the third width portion W3 is defined by the second secondary point NN2.

[0108] In some embodiments of the present invention, each projected intersection point NI may be located in the second width portion W2 of its associated secondary side width SW.

[0109] like Figure 2 As shown, in an end view of the cutting insert 20, each projected intersection point NI may coincide with the insert boundary line BL.

[0110] In addition, if Figure 2 As shown, in an end view of the cutting insert 20, each secondary edge 32 may coincide with the insert boundary line BL.

[0111] In some embodiments of the present invention, the secondary side surfaces 28a, 28b may each be perpendicular to the middle plane M.

[0112] It should be appreciated that, as opposed to having an outwardly inclined sub-surface extending away from the secondary edge 32, configuring the secondary side surfaces 28a, 28b to be perpendicular to the mid-plane M enables the cutting insert 20 to be oriented with a greater range of flexibility relative to the workpiece while providing sufficient clearance near the operative secondary cutting edge 36.

[0113] In other embodiments of the present invention (not shown), for example, wherein the secondary side surfaces 28a, 28b each include a transverse groove located at a midpoint between the end surfaces 22a, 22b and extending parallel to the second blade axis A2, in an end view of the cutting blade 20, each projected intersection point NI can be located outside the blade boundary line BL.

[0114] Furthermore, in other embodiments of the present invention, in an end view of the cutting insert 20, each secondary edge 32 may be located outside the insert boundary line BL.

[0115] like Figure 3 As shown, each projected intersection point NI may be further away from the middle plane M than its adjacent third principal point NJ3.

[0116] Each projected intersection point NI is configured to be further away from the middle plane M than its adjacent third main point NJ3 so that at least a portion of its associated secondary cutting edge 36 is closer to the middle plane M than the projected intersection point NI, which makes the cutting insert 20 suitable for performing ramping operations, also known as downhill or ramp milling operations.

[0117] In addition, if Figure 3 As shown, each projected intersection point NI is located at a first height H1 relative to the middle plane M, and each third principal point NJ3 is located at a second height H2 relative to the middle plane M.

[0118] In some embodiments of the present invention, the first height H1 may be at least 120% of the second height H2, ie, H1 ≥ 1.2*H2.

[0119] Furthermore, in some embodiments of the present invention, the first height H1 may preferably be at least 150% of the second height H2, ie, H1 ≥ 1.5*H2.

[0120] It should be appreciated that for embodiments of the present invention where the first height H1 is at least 150% of the second height H2, the cutting insert 20 may be used to perform ramping operations at increased ramping angles.

[0121] Further, in some embodiments of the present invention, the first height H1 may not exceed 220% of the second height H2, that is, H1≤2.2*H2.

[0122] In the secondary side view of the cutting insert 20, as shown Figure 4As shown, each secondary cutting edge 36 may include a scraping edge portion 66 adjacent its associated raised corner edge 46 , a ramping edge portion 68 adjacent its associated lowered corner edge 48 , and a convex engagement edge portion 70 extending between the scraping edge portion 66 and the ramping edge portion 68 .

[0123] like Figure 4 As shown, in a secondary side view of the cutting insert 20, each scraping edge 66 may be linear.

[0124] In addition, if Figure 4 As shown, in the secondary side view of the cutting blade 20, each ramp edge portion 68 may include a first ramp edge sub-portion 68a adjacent to its associated lowered corner edge 48, a third ramp edge sub-portion 68c adjacent to its associated engaging edge portion 70, and a concave second ramp edge sub-portion 68b extending between the first ramp edge sub-portion 68a and the third ramp edge sub-portion 68c.

[0125] In some embodiments of the present invention, each projected intersection point NI may be located on the third ramping edge sub-portion 68 c of its associated secondary cutting edge 36 .

[0126] It will be appreciated that each engagement edge 70 may operate as a "fourth" ramping edge sub-portion and participate in performing the ramping operation.

[0127] It should also be understood that each of the corner reducing cutting edges 52 may participate in performing a ramping operation.

[0128] In some embodiments of the present invention, each first ramping edge sub-portion 68a can be positioned overall closer to the median plane M than its associated recessed central surface 58 .

[0129] Furthermore, in some embodiments of the present invention, the end surfaces 22a, 22b may each include a secondary ramp surface 72 adjacent each first ramping edge sub-portion 68a.

[0130] It should be understood that in some embodiments of the present invention, for example Fig.10 As shown, each secondary ramp surface 72 may be spaced apart from its associated first ramping edge sub-portion 68 a by its associated secondary land surface 40 .

[0131] like Fig.10 As shown, in a cross section taken in a fifth plane P5 positioned between (passing through) the two main side surfaces 26a, 26b and intersecting a first ramp edge portion 68a, the adjacent secondary ramp surface 72 can be inclined away from the middle plane M while extending away from the first ramp edge portion 68a.

[0132] In some embodiments of the present invention, each secondary ramp surface 72 may be inclined toward its associated recessed central surface 58 while extending away from its associated first ramping edge sub-portion 68a.

[0133] Furthermore, in some embodiments of the present invention, the fifth plane P5 may be perpendicular to the middle plane M.

[0134] It will be appreciated that in some embodiments of the present invention, the secondary ramp surface 72 advantageously provides a compact and efficient mechanism for evacuating chips during ramping operations.

[0135] It should also be understood that in some embodiments of the present invention, in a cross-section taken in any plane positioned between (through) the two main side surfaces 26a, 26b and intersecting with a first ramp edge sub-portion 68a, the adjacent secondary ramp surface 72 can be inclined away from the middle plane M while extending away from the first ramp edge sub-portion 68a.

[0136] like Figure 2 and Figure 4 As shown, the major side surfaces 26a, 26b may each have a major outer surface 74 that is perpendicular to the first blade axis A1.

[0137] In some embodiments of the present invention, the two major outer surfaces 74 may define a maximum blade width W of the cutting insert 20. MAX .

[0138] like Figure 2 and Figure 4 As shown, a sixth plane P6 (“longitudinal blade plane”) containing the first blade axis A1 may be located at a midpoint between the major side surfaces 26 a , 26 b and at a midpoint between the two major outer surfaces 74 .

[0139] The sixth plane P6 can be defined by the intersection of the first blade axis A1 and the third blade axis A3 perpendicular to the first blade axis A1 and passing through the secondary side surfaces 28a, 28b. The third blade axis A3 can be included in the middle plane M. The third blade axis A3 can be perpendicular to the second blade axis A2. In addition, the second plane P2 and the fifth plane P5 can be parallel to the sixth plane P6.

[0140] In some embodiments of the present invention, the secondary side surfaces 28a, 28b may each include two secondary sub-surfaces 76a, 76b located on opposite sides of the sixth plane P6.

[0141] Furthermore, in some embodiments of the present invention, the two auxiliary sub-surfaces 76a and 76b may form an inner obtuse auxiliary abutment angle β1, and the auxiliary abutment angle β1 may be greater than 160 degrees, that is, β1>160°.

[0142] like Figures 1 to 4 As shown, the major side surfaces 26a, 26b may each include a major relief surface 78 proximate each of its associated major cutting edges 34.

[0143] like Figure 6 As shown, in a cross section taken in a seventh plane P7 intersecting one of the main cutting edges 34 , the adjacent main relief surface 78 may be inclined toward the middle plane M while extending away from the one of the main cutting edges 34 .

[0144] In some embodiments of the present invention, the seventh plane P7 may be perpendicular to the sixth plane P6.

[0145] Furthermore, in some embodiments of the present invention, the seventh plane P7 may coincide with the first plane P1 .

[0146] like Figure 6 As shown, in a cross section taken in the seventh plane P7 , the adjacent major relief surface 78 may be inclined away from the sixth plane P6 while extending away from its associated major cutting edge 34 .

[0147] It should be appreciated that, because each major relief surface 78 is inclined away from the sixth plane P6 while extending away from its associated major cutting edge 34 , each major relief surface 78 may be described as a “reverse relief surface”.

[0148] In some embodiments of the present invention, each major relief surface 78 may intersect one major outer surface 74 .

[0149] like Figures 1 to 4 As shown, each corner surface 42 may include a raised corner relief surface 80 proximate its associated raised corner cutting edge 50 .

[0150] It should be appreciated that each raised corner relief surface 80 may merge with its adjacent main relief surface 78 .

[0151] In some embodiments of the present invention, in the main side view of the cutting insert 20, as shown in FIG. Figure 3 As shown, each corner surface 42 may have an associated third imaginary straight line LM3 including its first principal point NJ1 and third principal point NJ3, and each third imaginary straight line LM3 may be inclined relative to the first blade axis A1.

[0152] It will be appreciated that for embodiments where each third imaginary straight line LM3 is inclined relative to the first insert axis A1 , the two major side lengths SL associated with each of the major side surfaces 26a , 26b may be offset from one another in a major side view of the cutting insert 20 .

[0153] like Figures 11 to 14As shown, another aspect of the present invention relates to a rotary cutting tool 82 rotatable about a tool axis AT in a rotational direction RT.

[0154] The rotary cutting tool 82 includes a cutting body 84 and at least one of the above-mentioned cutting inserts 20 , wherein each cutting insert 20 is removably fixed in a insert receiving slot 86 of the cutting body 84 .

[0155] like Fig.13 As shown, the tool axis AT defines a forward direction DF and a rearward direction DR, and each insert receiving slot 86 opens at a forward end surface 88 of the cutting body 84 .

[0156] In some embodiments of the present invention, the cutting body 84 may be cylindrical and have a circumferential wall 90 extending from the forward end surface 88 in the rearward direction DR.

[0157] Additionally, in some embodiments of the present invention, the rotating cutting tool 82 may be used for milling operations.

[0158] like Fig.12 As shown, the blade receiving slot 86 may have a seat surface 92 facing the rotational direction RT, a radially outward first slot wall 94 transverse to the seat surface 92 , and an axially forward second slot wall 96 transverse to the seat surface 92 .

[0159] In some embodiments of the present invention, the second groove wall 96 may intersect with the circumferential wall 90 .

[0160] Additionally, in some embodiments of the present invention, the seating surface 92 may include a threaded hole 98 extending along the bore axis AB.

[0161] like Figures 11 to 14 As shown, in the assembled position of the rotating cutting tool 82:

[0162] One of the two end surfaces 22a, 22b may be in contact with the seat surface 92;

[0163] One of the two main side surfaces 26a, 26b may be in contact with the first slot wall 94; and

[0164] One of the two secondary side surfaces 28 a , 28 b may be in contact with the second groove wall 96 .

[0165] In some embodiments of the present invention, the recessed central surface 58 of one of the end surfaces 22 a , 22 b may be in contact with the seat surface 92 .

[0166] Furthermore, in some embodiments of the present invention, the main outer surface 74 of one of the two main side surfaces 26 a , 26 b may be in contact with the first groove wall 94 .

[0167] Further, in some embodiments of the present invention, only one of the two subsidiary sub-surfaces 76 a , 76 b of one of the two subsidiary side surfaces 28 a , 28 b may be in contact with the second groove wall 96 .

[0168] Still further, in some embodiments of the present invention, a single secondary sub-surface 76 a , 76 b in contact with the second groove wall 96 may be adjacent to the primary side surfaces 26 a , 26 b that are not in contact with the first groove wall 94 .

[0169] like Figures 11 to 14 As shown, in the assembled position of the rotating cutting tool 82:

[0170] A clamping screw 100 may pass through the blade through hole 44 and threadedly engage with the threaded hole 98 .

[0171] In some embodiments of the invention, the second blade axis A2 may not be coaxial with the bore axis AB.

[0172] It should be understood that for embodiments of the present invention in which the first height H1 does not exceed 220% of the second height H2, the effective portion of the single auxiliary sub-surface 76a, 76b in contact with the second groove wall 96 can be positioned forward of the hole axis AB in the rotational direction to achieve stable clamping.

[0173] It should also be appreciated that for embodiments of the present invention where the second insert axis A2 is not coaxial with the bore axis AB, the insert throughbore 44 may be eccentric relative to the threaded bore 98 .

[0174] It should be further understood that when tightening the clamping screw 100, the eccentric relationship of the blade through hole 44 relative to the threaded hole 98 promotes contact between one of the two end surfaces 22a, 22b and the support surface 92 and contact between one of the two secondary side surfaces 28a, 28b and the second groove wall 96.

[0175] like Fig.13 As shown, the operative major cutting edge 34 of each cutting insert 20 may form a positive axial rake angle δ1 relative to the tool axis AT.

[0176] In some embodiments of the present invention, the operative major cutting edge 34, together with the adjacent raised corner cutting edge 50 and the scraping edge 66, may be configured to perform a shoulder milling operation in a workpiece (not shown).

[0177] like Fig.13 As shown, the operative minor cutting edge 36 of each cutting insert 20 may be located entirely axially forward of the forward end surface 88 .

[0178] It should be understood that for embodiments of the present invention in which each secondary cutting edge 36 extends along the entire length of its associated secondary edge 32 and the operative secondary cutting edge 36 of each cutting blade 20 is located entirely axially forward of the forward end surface 88, the rotating cutting tool 82 can be particularly suitable for performing ramping operations.

[0179] Although the present invention has been described to a certain degree of particularity, it should be understood that various substitutions and modifications could be made without departing from the spirit or scope of the invention as claimed herein.

Claims

1. A cutting insert (20), comprising: two opposite end surfaces (22a, 22b) interconnected by a peripheral side surface (24) and a first blade axis (A1) passing through the opposite end surfaces (22a, 22b), Each of the end surfaces (22a, 22b) has a concave central surface (58), The outer peripheral side surface (24) has two opposite main side surfaces (26a, 26b) and two secondary side surfaces (28a, 28b), A main edge (30) is formed at the intersection of each of the main side surfaces (26a, 26b) and each of the end surfaces (22a, 22b), and a main cutting edge (34) is formed along at least a portion of each of the main edges (30). A secondary edge (32) is formed at the intersection of each of the secondary side surfaces (28a, 28b) and each of the end surfaces (22a, 22b), and a secondary cutting edge (36) is formed along at least a portion of each of the secondary edges (32). A middle plane (M) is perpendicular to the first blade axis (A1) and intersects the peripheral side surface (24) to form a blade boundary line (BL), and Each of said end surfaces (22a, 22b) has two diagonally opposite raised corners (RC) and two diagonally opposite lowered corners (LC) relative to said median plane (M), Each of the raised corners (RC) has a convexly curved raised corner edge (46) formed at the intersection of the peripheral side surface (24) and the end surface (22a, 22b) associated therewith, each of the raised corner edges (46) adjoining one of the main edges (30) at a first main point (NJ1), and a raised corner cutting edge (50) is formed along at least a portion of each of the raised corner edges (46), Each of the lowering corners (LC) has a convexly curved lowering corner edge (48) formed at the intersection of the peripheral side surface (24) and the associated end surface (22a, 22b), each of the lowering corner edges (48) adjoining one of the main edges (30) at a third main point (NJ3), and a lowering corner cutting edge (52) is formed along at least a portion of each of the lowering corner edges (48), Wherein in the main side view of the cutting insert (20): The first main point (NJ1) and the third main point (NJ3) of each main edge (30) define a main side length (SL) measured parallel to the middle plane (M), the main side length (SL) being divided into equal first length portions (L1), second length portions (L2) and third length portions (L3), wherein the first length portion (L1) is bounded by the first main point (NJ1) and the third length portion (L3) is bounded by the third main point (NJ3), Each of the main edges (30) has a first imaginary straight line (LM1) including the association of the first main point (NJ1) and the third main point (NJ3) thereof, and a raised edge portion (62), the raised edge portion (62) being located on one side of the first imaginary straight line (LM1), and the blade boundary line (BL) being located on the other side of the first imaginary straight line (LM1), and Each of the raised edges (62) has a second main point (NJ2) located: (i) farthest from its associated first imaginary straight line (LM1) and (ii) within the third length portion (L3) of its associated major side length (SL).

2. The cutting insert (20) according to claim 1, wherein: In the main side view of the cutting insert (20): Each of the main cutting edges (30) has an associated second imaginary straight line (LM2) including its first principal point (NJ1) and the second principal point (NJ2), which intersects with one of the secondary cutting edges (36) at a projected intersection point (NI), and each of the projected intersection points (NI) is further away from the middle plane (M) than the third principal point (NJ3) adjacent thereto.

3. The cutting insert (20) according to claim 2, wherein: Each of the end surfaces (22a, 22b) includes a secondary land surface (40) adjacent to each of the secondary cutting edges (36) associated therewith, and In a cross section taken in a second plane (P2) located between the two major side surfaces (26a, 26b) and containing one of the projected intersection points (NI), the adjacent minor land surface (40) forms an inner minor cutting angle (α1) with the adjacent minor side surface (28a, 28b), and the minor cutting angle (α1) is at least 65 degrees and at most 115 degrees.

4. The cutting insert (20) according to claim 2, wherein: Each of said projected intersection points (NI) is located at a first height (H1) relative to said median plane (M), Each of the third principal points (NJ3) is located at a second height (H2) relative to the median plane (M), and the first height (H1) is at least 120% of the second height (H2).

5. The cutting insert (20) according to claim 4, wherein: The first height (H1) does not exceed 220% of the second height (H2).

6. The cutting insert (20) according to claim 3, wherein: In a cross section taken in any plane located between the two major side surfaces (26a, 26b) and intersecting with one of the minor cutting edges (36), the adjacent minor land surface (40) forms an inner minor cutting angle (α1) with the adjacent minor side surface (28a, 28b), and the minor cutting angle (α1) is at least 65 degrees and at most 115 degrees.

7. The cutting insert (20) according to claim 1, wherein: In an end view of the cutting insert (20), each of the secondary edges (32) coincides with the insert boundary line (BL) or is located outside the insert boundary line (BL).

8. The cutting insert (20) according to claim 1, wherein: Each of the secondary cutting edges (36) extends along the entire length of its associated secondary cutting edge (32).

9. The cutting insert (20) according to claim 1, wherein: The outer peripheral side surface (24) includes four convexly curved corner surfaces (42) alternating with the two main side surfaces (26a, 26b) and the two secondary side surfaces (28a, 28b).

10. The cutting insert (20) according to claim 9, wherein In a cross section taken in the median plane (M) and intersecting the four corner surfaces (42): The four corner surfaces (42) are adjacent to the two secondary side surfaces (28a, 28b) at four corner points (NC), The four corner points (NC) define an imaginary parallelogram (PL) having a first pair of imaginary parallel sides (S1) and a second pair of imaginary parallel sides (S2), and The first pair of imaginary parallel sides (S1) is perpendicular to the main side length (SL) of each of the main cutting edges (30).

11. The cutting insert (20) according to claim 1, wherein: In the secondary side view of the cutting insert (20), each of the secondary cutting edges (36) comprises: a scraping edge portion (66) adjacent its associated raised corner edge (46); a ramping edge portion (68) adjacent its associated lowered corner edge (48); and A convex engaging edge portion (70) extends between the scraping edge portion (66) and the ramping edge portion (68).

12. The cutting insert (20) according to claim 11, wherein In the secondary side view of the cutting insert (20), each of the ramping edge portions (68) comprises: a first ramping edge sub-portion (68a) adjacent its associated said lowered corner edge (48); a third ramping edge sub-portion (68c) adjacent its associated said engagement edge portion (70); and A concave second ramping edge sub-portion (68b) extends between the first ramping edge sub-portion (68a) and the third ramping edge sub-portion (68c).

13. The cutting insert (20) according to claim 12, wherein: Each of the end surfaces (22a, 22b) includes a secondary ramp surface (72) adjacent each of the first ramping edge sub-portions (68a), and In a cross section taken in a fifth plane (P5) located between the two main side surfaces (26a, 26b) and intersecting one of the first ramp edge sub-portions (68a), the adjacent secondary ramp surface (72) is inclined away from the middle plane (M) and simultaneously extends away from one of the first ramp edge sub-portions (68a).

14. The cutting insert (20) according to claim 13, wherein: In a cross section taken in any plane located between the two major side surfaces (26a, 26b) and intersecting one of the first ramp edge sub-portions (68a), the adjacent secondary ramp surface (72) is inclined away from the middle plane (M) and simultaneously extends away from one of the first ramp edge sub-portions (68a).

15. The cutting insert (20) according to claim 1, wherein The cutting insert (20) exhibits rotational symmetry about the first insert axis (A1).

16. The cutting insert (20) according to claim 1, wherein A second blade axis (A2) passes through the two major side surfaces (26a, 26b), and a blade through hole (44) extends along the second blade axis (A2) and intersects the two major side surfaces (26a, 26b).

17. The cutting insert (20) according to claim 16, wherein The cutting insert (20) exhibits rotational symmetry about the second insert axis (A2).

18. The cutting insert (20) according to claim 1, wherein Each of the raised edge portions (62) does not extend to the third main point (NJ3) of its associated main edge (30).

19. A rotary cutting tool (82) rotatable in a rotational direction (RT) about a tool axis (AT), comprising: a cutting body (84) having at least one blade receiving slot (86); as well as At least one cutting insert (20) according to claim 1 is removably secured in the insert receiving slot (86).

20. The rotary cutting tool (82) of claim 19, wherein: The tool axis (AT) defines a forward direction (DF) and a rearward direction (DR), Each of the blade receiving slots (86) opens at a forward end surface (88) of the cutting body (84), Each of the secondary cutting edges (36) extends along the entire length of its associated secondary edge (32), and the operative secondary cutting edge (36) of each cutting insert (20) is located entirely axially forward of the forward end surface (88).

21. The rotary cutting tool (82) of claim 19, wherein: The operative main cutting edge (34) of each cutting insert (20) forms a positive axial rake angle (δ1) relative to the tool axis (AT).

22. The rotary cutting tool (82) of claim 19, wherein: The blade receiving slot (86) has: a bearing surface (92) facing the direction of rotation (RT); a first groove wall (94) facing radially outwardly and transverse to the seat surface (92); and a second groove wall (96) facing forward in the axial direction and transverse to the seat surface (92), One of the two end surfaces (22a, 22b) is in contact with the seat surface (92), One of the two main side surfaces (26a, 26b) is in contact with the first groove wall (94), and One of the two secondary side surfaces (28a, 28b) is in contact with the second groove wall (96).

23. The rotary cutting tool (82) of claim 22, wherein: The seating surface (92) includes a threaded hole (98) extending along a hole axis (AB), A blade through hole (44) extending along the second blade axis (A2) intersects the two major side surfaces (26a, 26b) of the blade, and A clamping screw (100) passes through the blade through hole (44) and is threadedly engaged with the threaded hole (98).

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