阅读说明：本技术 包括具有前缘和后缘部件切削刃的***切削刃的切削刀片 (Cutting insert including a split cutting edge having leading and trailing component cutting edges ) 是由 希蒙·阿萨德 于 2018-04-25 设计创作，主要内容包括：一种切削刀片(24)包括在刀片前表面(28)和刀片上表面(34)的相交处形成的分裂式切削刃(46),该分裂式切削刃(46)包括轴向前缘切削刃(48)和轴向后缘切削刃(50)。底切部(52)位于刀片前表面中并且在前缘切削刃(48)和后缘切削刃(50)之间延伸的底切部刃部(54)处使分裂式切削刃(46)断开。底切部刃部(54)在后缘切削刃(50)的直后缘切削刃部(60)处过渡到轴向后缘切削刃(50)中。(A cutting insert (24) includes a split cutting edge (46) formed at an intersection of an insert forward surface (28) and an insert upper surface (34), the split cutting edge (46) including an axial forward edge cutting edge (48) and an axial rearward edge cutting edge (50). An undercut (52) is located in the insert forward surface and breaks the split cutting edge (46) at an undercut edge portion (54) extending between the leading edge cutting edge (48) and the trailing edge cutting edge (50). The undercut edge portion (54) transitions into the axial trailing edge cutting edge (50) at a straight trailing edge cutting edge portion (60) of the trailing edge cutting edge (50).)

1. A cutting insert (24) having a cutting insert body defining opposing forward directions (D)_F) And a rear direction (D)_R) The cutting insert (24) comprising:

axially opposed insert front and rear surfaces (28, 30) and an insert peripheral surface (32) extending therebetween, the insert peripheral surface (32) including opposed upper and lower insert surfaces (34, 36) and opposed side surfaces (38) connecting the upper and lower insert surfaces (34, 36);

a blade transverse axis (B) perpendicular to the blade axis (A), a blade vertical axis (C) perpendicular to the blade axis (A) and the blade transverse axis (B) and intersecting the blade upper surface (34) and the blade lower surface (36), a first vertical plane (P1) defined by the blade axis (A) and the blade vertical axis (C), and a second vertical plane (P2) defined by the blade transverse axis (B) and the blade vertical axis (C);

a split cutting edge (46) formed at an intersection of the insert front surface (28) and the insert upper surface (34) and including a leading edge cutting edge (48) and a trailing edge cutting edge (50), the leading edge cutting edge (48) being axially forward of the trailing edge cutting edge (50); and

an undercut (52) in the insert forward surface (28) and breaking the split cutting edge (46) at an undercut edge portion (54), the undercut edge portion (54) extending between the leading edge (48) and the trailing edge (50), wherein:

the trailing edge cutting edge (50) comprises a straight trailing edge cutting edge portion (60);

in a top view of the cutting insert (24), an imaginary line (L) parallel to the insert axis (a) tangentially contacts and intersects the split cutting edge (46) at a tangent point (T) and an intersection point (I) defining an axial extent of the undercut edge portion (54); and is

The intersection point (I) is an endpoint of the straight trailing edge cutting edge portion (60).

2. The cutting insert (24) according to claim 1, wherein:

the undercut edge portion (54) comprising a straight undercut edge portion (62), the straight undercut edge portion (62) being collinear with the straight trailing edge cutting edge portion (60); and is

The intersection point (I) is an endpoint of the straight undercut edge (62).

3. The cutting insert (24) according to claim 1 or 2, wherein the tangent point (T) is an endpoint of a convexly curved leading edge cutting edge portion (64) of the leading edge cutting edge (48).

4. The cutting insert (24) according to any one of claims 1-3, wherein the tangent point (T) is an end point of a convexly curved undercut edge portion (66) of the undercut edge portion (54).

5. The cutting insert (24) according to any one of claims 1-4, wherein:

the insert forward surface (28) including a leading relief surface (72) and a trailing relief surface (74);

the insert upper surface (34) includes a leading rake surface (76) and a trailing rake surface (78); and is

The leading edge cutting edge (48) and the trailing edge cutting edge (50) are formed at an intersection of the leading edge relief surface (72) and the leading edge rake surface (76) and an intersection of the trailing edge relief surface (74) and the trailing edge rake surface (78), respectively.

6. The cutting insert (24) according to claim 5, wherein:

the leading rake surface (76) is defined by a leading rake plane (P)_L) Is defined and the trailing edge rake surface (78) is defined by a trailing edge rake plane (P)_T) Defining; and is

The leading edge rake plane (P)_L) And the trailing edge rake plane (P)_T) Parallel to each other and spaced apart from each other by a rake plane distance D.

7. The cutting insert (24) according to claim 6, wherein the rake plane distance D is in the range of 0.2mm ≦ D ≦ 0.3 mm.

8. The cutting insert (24) according to any one of claims 5-7, wherein the leading edge rake plane (P)_L) And the trailing edge rake plane (P)_T) In the rear direction(D_R) And is inclined upwards.

9. The cutting insert (24) according to any one of claims 5-8, wherein:

the opposing insert side surface (38) including a leading side surface (56) and a trailing side surface (58), the leading side surface being closer to the leading edge (48) than to the trailing edge (50), the trailing side surface (58) being closer to the trailing edge (50) than to the leading edge (48); and is

The leading rake surface (76) includes a laterally sloping surface (80) extending upwardly from the trailing rake surface (78) in a direction toward the leading side surface (56).

10. The cutting insert (24) according to claim 9, wherein the transversely inclined surface (80) is in the forward direction (D)_F) Up to the undercut edge portion (54).

11. The cutting insert (24) according to claim 9 or 10, wherein the transverse sloping surface (80) extends to a chip control structure (84) on the leading rake surface (76) and forms an edge (88) at the chip control structure (84).

12. The cutting insert (24) according to any one of claims 5-11, wherein the leading rake surface (76) and the trailing rake surface (78) each include a chip control structure (84) spaced apart from the split cutting edge (46).

13. The cutting insert (24) according to claim 12, wherein each chip-control structure (84) is a chip-control recess recessed into the respective rake surface (76, 78).

14. The cutting insert (24) according to any one of claims 1-13, wherein the cutting insert (24) comprises only one undercut (52) located in the insert front surface (28) and interrupting the split cutting edge (46).

15. The cutting insert (24) according to any one of claims 1-14, wherein the straight trailing edge cutting edge portion (60) is perpendicular to the insert axis (a) in a top view of the cutting insert (24).

16. The cutting insert (24) according to any one of claims 1-15, wherein, in a front view of the cutting insert (24), the straight trailing edge cutting edge portion (60) is parallel to the insert transverse axis (B).

17. The cutting insert (24) according to any one of claims 1-16, wherein the leading edge cutting edge (48) comprises a straight leading edge cutting edge portion (70).

18. The cutting insert (24) according to claim 17, wherein the straight leading edge cutting edge portion (70) and the straight trailing edge cutting edge portion (60) are parallel to each other in a top view of the cutting insert (24).

19. The cutting insert (24) according to claim 18, wherein the straight leading edge cutting edge portion (70) and the straight trailing edge cutting edge portion (60) are perpendicular to the insert axis (a) in a top view of the cutting insert (24).

20. The cutting insert (24) according to any one of claims 17-19, wherein the straight leading edge cutting edge portion (70) and the straight trailing edge cutting edge portion (60) are parallel to each other in a front view of the cutting insert (24).

21. The cutting insert (24) according to claim 20, wherein, in a front view of the cutting insert (24), the straight leading edge cutting edge portion (70) and the straight trailing edge cutting edge portion (60) are parallel to the insert transverse axis (B).

22. The cutting insert (24) according to claim 21, wherein the straight leading edge cutting edge portion (70) and the straight trailing edge cutting edge portion (60) are aligned with each other in a front view of the cutting insert (24).

23. The cutting insert (24) according to any one of claims 1-22, wherein, measured in a direction along the insert transverse axis (B):

the leading edge cutting edge (48) has a leading edge cutting edge length L_L；

The trailing edge cutting edge (50) has a trailing edge cutting edge length L_T(ii) a And is

The length L of the leading edge cutting edge_LL is more than or equal to 75 percent_TLess than or equal to 125 percent.

24. The cutting insert (24) according to any one of claims 1-23, wherein the split cutting edge (46) comprises only a single leading edge cutting edge (48) and a single trailing edge cutting edge (50) between the opposing side surfaces (38).

25. The cutting insert (24) according to any one of claims 1-24, wherein, in a top view of the cutting insert (24), the cutting insert (24) has no mirror symmetry about the first perpendicular plane (P1).

Technical Field

The subject matter of the present application relates to cutting inserts, and more particularly, to cutting inserts having chip-splitting structures.

Background

The cutting insert may have a chip-splitting structure to split chips during a metal cutting operation. Typically, the chip-dividing structure is formed by at least two spaced-apart main cutting edges.

In such cutting inserts designed for grooving and/or parting cutting operations, at least two major cutting edges may be spaced apart in the axial direction. Examples of such cutting inserts are disclosed in, for example, CN101698243A and US5,975,812.

It is an object of the subject matter of the present application to provide a new and improved cutting insert.

It is another object of the subject matter of the present application to provide a cutting insert having a new and improved chip-dividing structure.

It is a further object of the subject matter of the present application to provide a cutting insert that reduces wear of the cutting edge during cutting operations.

Disclosure of Invention

According to a first aspect of the subject matter of the present application, there is provided a cutting insert having an insert axis defining opposite forward and rearward directions, the cutting insert comprising:

axially opposed insert front and rear surfaces and an insert peripheral surface extending therebetween, the insert peripheral surface including opposed insert upper and lower surfaces and opposed insert side surfaces connecting the insert upper and lower surfaces;

a blade lateral axis perpendicular to the blade axis, a blade vertical axis perpendicular to the blade axis and the blade lateral axis and intersecting the blade upper surface and the blade lower surface, a first vertical plane defined by the blade axis and the blade vertical axis, and a second vertical plane defined by the blade lateral axis and the blade vertical axis;

a split cutting edge formed at an intersection of the insert front surface and the insert upper surface and including a leading edge cutting edge and a trailing edge cutting edge, the leading edge cutting edge being axially forward of the trailing edge cutting edge; and

an undercut in the insert forward surface and breaking a split cutting edge at an undercut edge portion extending between the forward edge cutting edge and the rearward edge cutting edge, wherein:

the trailing edge cutting edge comprises a straight trailing edge cutting edge part;

in a top view of the cutting insert, an imaginary line parallel to the insert axis tangentially contacts and intersects the split cutting edge at a tangent point and an intersection point, the tangent point and the intersection point defining an axial extent of the undercut edge portion; and is

The intersection point is the end point of the straight trailing edge cutting edge portion.

It should be understood that the above is a summary and that the features described below may be applied to the subject matter of the present application in any combination, e.g. any of the following features may be applied to a cutting insert:

the undercut edge portion may comprise a straight undercut edge portion that is collinear with the straight trailing edge cutting edge portion. The intersection point may be the end point of the straight undercut edge.

The tangent point may be an endpoint of a convexly curved leading edge cutting edge portion of the leading edge cutting edge.

The tangent point may be an endpoint of a convexly curved undercut edge of the undercut edge.

The insert forward surface may include a leading relief surface and a trailing relief surface. The blade upper surface may include a leading rake surface and a trailing rake surface. The leading and trailing cutting edges may be formed at the intersection of the leading and trailing relief surfaces with the leading and trailing rake surfaces, respectively.

The leading rake surface may be defined by a leading rake plane and the trailing rake surface may be defined by a trailing rake plane. The leading edge rake plane and the trailing edge rake plane may be parallel to each other and spaced apart from each other by a rake plane distance.

The plane distance of the front cutter can be within the range that D is more than or equal to 0.2mm and less than or equal to 0.3 mm.

The leading edge rake plane and the trailing edge rake plane may be inclined upwardly in the rearward direction.

The opposing insert side surfaces include a leading edge side surface that is closer to the leading edge than to the trailing edge and a trailing edge side surface that is closer to the trailing edge than to the leading edge. The leading rake surface may include a laterally sloping surface extending upwardly from the trailing rake surface in a direction toward the leading flank surface.

The laterally inclined surface may extend in a forward direction to the undercut edge.

The laterally inclined surface may extend to and form an edge at a chip control structure located on the leading rake surface.

The leading rake surface and the trailing rake surface may each include a chip control structure spaced apart from the split cutting edge.

Each chip-control structure may be a chip-control recess recessed into the respective rake surface.

The cutting insert may comprise only one undercut in the insert front surface and interrupting the split cutting edge.

The straight trailing edge cutting edge portion may be perpendicular to the insert axis in a top view of the cutting insert.

In a front view of the cutting insert, the straight trailing edge cutting edge portion may be parallel to a transverse axis of the insert perpendicular to the insert axis.

The leading edge cutting edge may comprise a straight leading edge cutting edge portion.

The straight leading edge cutting edge portion and the straight trailing edge cutting edge portion may be parallel to each other in a top view of the cutting insert.

The straight leading edge cutting edge portion and the straight trailing edge cutting edge portion may be perpendicular to the insert axis in a top view of the cutting insert.

In a front view of the cutting insert, the straight leading edge cutting edge portion and the straight trailing edge cutting edge portion may be parallel to each other.

In a front view of the cutting insert, the straight leading edge cutting edge portion and the straight trailing edge cutting edge portion may be parallel to the insert transverse axis.

The straight leading edge cutting edge portion and the straight trailing edge cutting edge portion may be aligned with each other in a front view of the cutting insert.

The leading edge cutting edge may have a width measured in a direction along the transverse axis of the bladeThere is a leading edge cutting edge length. The trailing edge cutting edge may have a trailing edge cutting edge length. The length of the front edge cutting edge can be more than or equal to L of 75 percent_TLess than or equal to 125 percent.

The split cutting edge includes only a single leading edge and a single trailing edge between the opposing side surfaces.

In a top view of the cutting insert, the cutting insert may not have mirror symmetry about a first perpendicular plane.

Drawings

For a better understanding of the present application and to show how the same may be carried into effect in practice, reference will now be made to the accompanying drawings, in which:

FIG. 1 is a partial perspective view of a cutting tool;

FIG. 2 is an exploded perspective view of the cutting tool shown in FIG. 1;

fig. 3 is a perspective view of a cutting insert according to an embodiment of the present application;

FIG. 4 is a top view of the cutting insert shown in FIG. 3;

FIG. 5 is a side view of the cutting insert shown in FIG. 3;

FIG. 6 is a front view of the cutting insert shown in FIG. 3;

FIG. 7 is a detail of FIG. 4;

FIG. 8 is a detail of FIG. 7;

FIG. 9 is a detail of FIG. 5; and is

Fig. 10 is a partial cross-sectional view taken along line X-X shown in fig. 4.

It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity, or several physical components may be included in one functional block or element. Where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

Detailed Description

In the following description, various aspects of the subject matter of the present application will be described. For purposes of explanation, specific configurations and details are set forth in sufficient detail to provide a thorough understanding of the subject matter of the present application. It will be apparent, however, to one skilled in the art that the subject matter of the present application may be practiced without the specific configurations and details presented herein.

Attention is first drawn to fig. 1 and 2, which show a cutting tool 20 for chip removal. In this non-limiting example shown in the drawings, the cutting tool 20 is a nicking/severing tool. However, the subject matter of the present application is not limited to grooving/parting tools only, but may also be applied to, for example, but not limited to, milling tools. The cutting tool 20 has a tool holder 22, which may be typically made of steel. The cutting tool 20 also has at least one cutting insert 24 that is removably attached to the tool holder 22. In this non-limiting example shown in the drawings, the cutting insert 24 is resiliently retained in an insert pocket 26 of the tool holder 22. Thus, the cutting insert 24 does not have a screw hole for positioning a set screw therein. The cutting insert 24 may be generally made of cemented carbide.

Referring now to fig. 3-6, a cutting insert 24 according to the subject matter of the present application is shown. The cutting insert 24 comprises a unitary, integral, one-piece construction. The cutting insert 24 has an insert axis A defining an opposite forward direction D_FAnd a rear direction D_R. As shown in fig. 1, in the case of a grooving/parting tool, the insert axis a may be co-directional with the feed direction F of the cutting tool 20. The cutting insert 24 includes axially opposed insert front and rear surfaces 28, 30 and an insert peripheral surface 32 extending therebetween. The insert front surface 28 is located at the front end of the cutting insert 24, while the insert rear surface 30 is located at the rear end of the cutting insert 24.

It should be appreciated that throughout the description and claims, the use of the words "front" and "rear" refer to the relative positions in fig. 4 and 5 in the left and right directions of the blade axis a, respectively.

The insert peripheral surface 32 extends peripherally along the insert axis a. Thus, the insert axis a intersects the insert front surface 28 and the insert rear surface 30. The insert peripheral surface 32 includes opposing insert upper and lower surfaces 34, 36 and opposing insert side surfaces 38 connecting the insert upper and lower surfaces 34, 36.

In this non-limiting example shown in the drawings, the insert lower surface 36 may be stepped in a direction from the insert front surface 28 toward the insert rear surface 30, as best shown in fig. 5. In such a configuration, the insert lower surface 36 may include a lower front surface 40 adjacent the insert front surface 28, a lower rear surface 42 adjacent the insert lower surface 36, and a lower intermediate surface 44 extending laterally between the lower front surface 40 and the lower rear surface 42. From the foregoing, it can be seen that the cutting insert 24 can only be retained in the insert pocket in one orientation, and thus the cutting insert is not indexable.

Referring to fig. 5, the insert upper surface 34 may be parallel to the insert axis a. The cutting insert 24 also has an insert transverse axis B perpendicular to the insert axis a and intersecting the insert side surface 38. In particular, the insert side surface 38 may be perpendicular to the insert lateral axis B. The insert transverse axis B defines an opposite first transverse direction D_L1And a second transverse direction D_L2. The cutting insert 24 also has an insert vertical axis C that is perpendicular to the insert axis a and the insert lateral axis B and intersects the insert upper surface 34 and the insert lower surface 36. The insert axis a, the insert lateral axis B, and the insert vertical axis C are all perpendicular to one another. The insert vertical axis C defines an opposite upper direction D_UAnd a lower direction D_D. Referring to fig. 4 and 6, the insert axis a and the insert vertical axis C each extend midway between the insert side surfaces 38. The insert side surface 38 may be parallel to the insert axis a and the insert perpendicular axis C. The insert axis a and the insert vertical axis C define an imaginary first vertical plane P1 that is perpendicular to the transverse axis B. The blade transverse axis B and the blade vertical axis C define a second vertical plane P2 that is perpendicular to the blade axis a.

It should be appreciated that throughout the specification and claims, the use of the term "transverse" refers to the relative positions in fig. 6 in the left and right directions of the blade transverse axis B, respectively. Also, throughout the description and claims, the use of the terms "upper" and "lower" refer to the relative positions in fig. 5 and 6 in the top and bottom facing directions of the blade vertical axis C, respectively. Further, the front view of the cutting insert 24 is a view of the front of the insert front surface 28 along the insert axis a. The side view of the cutting insert 24 is a view of the front of one of the insert side surfaces 38 along the insert transverse axis B. The top view of the cutting insert 24 is a view of the front of the insert's upper surface 34 along the insert's vertical axis C.

Referring to fig. 3 and 4, the cutting insert 24 includes a cutting edge 46 formed at the intersection of the insert front surface 28 and the insert upper surface 34. The cutting edge 46 is split in the width direction of the insert (i.e., along the insert transverse axis B) and includes a leading edge cutting edge 48 and a trailing edge cutting edge 50 spaced apart from each other along the insert axis a. The leading edge cutting edge 48 is axially forward of the trailing edge cutting edge 50 with respect to the insert axis a and with respect to the insert transverse axis B. Thus, the leading edge cutting edge 48 and the trailing edge cutting edge 50 are staggered in the axial direction.

The leading edge 48 and the trailing edge 50 are in the transverse direction D_L1、D_L2There is no overlap. However, as shown in the front view (fig. 6) of the cutting insert 24, the split cutting edge 46 extends the entire width between the opposing insert side surfaces 38 due to the configuration of the leading edge cutting edge 48 and the trailing edge cutting edge 50. As shown, the split cutting edge 46 includes only a single leading edge 48 and a single trailing edge 50 between the opposing side surfaces 38. As shown in fig. 7, according to some embodiments of the subject matter of the present application, the leading edge cutting edge 48 has a leading edge cutting edge length L, measured in a direction along the blade transverse axis B_LThe trailing edge cutting edge 50 has a trailing edge cutting edge length L_T. Length L of leading edge cutting edge_LCan be more than or equal to 75 percent L_TLess than or equal to 125 percent. Preferably, the trailing edge cutting edge length L_TMay be less than the leading edge cutting edge length L_L。

The cutting insert 24 includes an undercut 52 in the insert front surface 28. Advantageously, because the undercut 52 is located in the insert front surface 28, e.g., opposite the insert upper surface 34, the cutting insert 24 may be manufactured without the need for additional grinding processes. The undercut 52 breaks the split cutting edge 46 at an undercut edge portion 54. Due to the undercut portion 52, in a front view (i.e., drawing) of the cutting insert 246) A portion of the middle insert front surface 28 is not visible. As shown in fig. 7, the undercut edge portion 54 extends between the leading edge cutting edge 48 and the trailing edge cutting edge 50. Note that a portion of the leading edge cutting edge 48 is in the transverse direction D_L2Fully overlapping the undercut edge portion 54. Accordingly, the undercut edge portion 54 is a non-cutting edge. That is, the undercut edge portion 54 does not provide any cutting of the workpiece, but rather serves to provide a chip-splitting structure for the cutting insert 24.

For clarity, in a top view of the cutting insert 24 (i.e., fig. 4), the undercut edge portion 54 may be defined with reference to an imaginary line L that is parallel to the insert axis a. In this view, the imaginary line L tangentially contacts and intersects the split cutting edge 46 at the tangent point T and the intersection point I. The tangent line T and the intersection point I define the axial extension of the undercut edge portion 54. The undercut edge portion 54 transitions into the leading edge 48 at a tangent point T and into the trailing edge 50 at an intersection point I.

Because the leading edge cutting edge 48 and the trailing edge cutting edge 50 are axially offset and also because of the undercut 54, the cutting insert 24 may not have mirror symmetry about the first vertical plane P1 in top view.

Referring now to fig. 7, the trailing edge cutting edge 50 includes a straight trailing edge cutting edge portion 60. Typically, the majority of the trailing edge cutting edge length L_TMay be formed by a straight trailing edge cutting edge portion 60. The intersection point I is the end point of the straight trailing edge cutting edge portion 60. Referring now to FIG. 8, in accordance with some embodiments of the subject matter of the present application, the undercut edge 54 may comprise a straight undercut edge 62. Intersection point I may be the end point of straight undercut edge 62. That is, the straight undercut edge portion 62 and the straight trailing edge cutting edge portion 60 transition into each other at the intersection point I. The straight undercut edge portion 62 may be collinear with the straight trailing edge cutting edge portion 60. Thus, the intersection point I may be located at a non-end point of a continuous straight edge portion, a portion of which serves as a cutting edge (i.e., the straight trailing edge cutting edge portion 60) for cutting a workpiece, and another portion of which does not serve as a cutting edge (i.e., the straight undercut edge portion 62) for cutting a workpiece. In accordance with some embodiments of the subject matter of the present application, the straight undercut edge 62 may transition to a concavely curved undercut edge at the end opposite the straight trailing edge cutting edge 6067 (c).

In accordance with some embodiments of the subject matter of the present application, the leading edge 48 may include a convexly curved leading edge cutting edge portion 64. The undercut edge portion 54 may include a convexly curved undercut edge portion 66. The tangent point T may be the end point of the convexly curved leading edge cutting edge portion 64. Tangent point T may be the end point of convexly curved undercut edge portion 66. In other words, the convexly curved leading edge cutting edge portion 64 and the convexly curved undercut edge portion 66 may transition into each other at the tangent point T. The tangent point T being the change in the transverse direction D of the split cutting edge 46_L1、D_L2Point (2) of (c).

The undercut edge portion 54 may include a straight central undercut edge portion 68 extending between a convexly curved undercut edge portion 66 and a concavely curved undercut edge portion 67. As shown in fig. 8, the straight central undercut edge portion 68 and the straight trailing edge cutting edge portion 60 form an external angle α. The external angle can be within the range of alpha being more than or equal to 60 degrees and less than or equal to 70 degrees.

In accordance with some embodiments of the subject matter of the present application, the leading edge 48 may include a straight leading edge cutting edge portion 70. Typically, a majority of the leading edge cutting edge length L_LMay be formed by a straight leading edge cutting edge portion 70. In a top view of the cutting insert 24 (i.e., fig. 4), the straight leading edge cutting edge portion 70 and the straight trailing edge cutting edge portion 60 may be parallel to each other. Further, the straight leading edge cutting edge portion 70 may be perpendicular to the insert axis a. Likewise, the straight trailing edge cutting edge portion 60 may be perpendicular to the insert axis a. In a front view of the cutting insert 24 (i.e., fig. 6), the straight leading edge cutting edge portion 70 and the straight trailing edge cutting edge portion 60 may be parallel to each other. Further, the straight leading edge cutting edge portion 70 may be parallel to the insert transverse axis B. Likewise, the straight trailing edge cutting edge portion 60 may be parallel to the insert transverse axis B. The straight leading edge cutting edge portion 70 and the straight trailing edge cutting edge portion 60 may be aligned with each other.

The insert side surface 38 includes a leading side surface 56 and a trailing side surface 58, the leading side surface 56 being closer to the leading edge 48 than to the trailing edge 50, and the trailing side surface 58 being closer to the trailing edge 50 than to the leading edge 48. According to some embodiments of the subject matter of the present application, the cutting insert 24 includes only one undercut portion 52 located in the insert front surface 28 and interrupting the split cutting edge 46. Thus, the split cutting edge 46 may include only one undercut edge portion 54. In this configuration, the leading edge 48 extends to a leading side surface 56 and the trailing edge 50 extends to a trailing side surface 58.

The insert forward surface 28 includes a leading relief surface 72 and a trailing relief surface 74 extending from the leading cutting edge 48 and the trailing cutting edge 50, respectively. In accordance with some embodiments of the present subject matter, the undercut 52 may be located between the leading and trailing relief surfaces 72, 74. In this non-limiting example shown in the drawings, the leading and trailing edge surfaces 72 may have a trapezoidal basic shape with a varying width that decreases in a direction toward the insert lower surface 36 in a front view of the cutting insert 24 (i.e., fig. 6).

The insert upper surface 34 includes a rearward direction D_RA leading rake surface 76 and a trailing rake surface 78 extending from the leading edge cutting edge 48 and the trailing edge cutting edge 50, respectively. The leading edge 48 and trailing edge 50 cutting edges are formed at the intersection of leading 72 and trailing 74 relief surfaces and leading 76 and trailing 78 relief surfaces, respectively. According to some embodiments of the subject matter of the present application, the leading rake surface 76 may be defined by a leading rake plane P_LThe trailing edge rake surface 78 may be defined by a trailing edge rake plane P_TAnd (4) limiting. As shown in the side view of FIG. 5 of the cutting insert 24 (or a detail thereof, e.g., FIG. 9), the leading edge rake plane P_LAnd trailing edge rake plane P_TMay be parallel to each other and spaced apart from each other by a rake plane distance D. The distance D of the plane of the front cutter can be within the range that D is more than or equal to 0.2mm and less than or equal to 0.3 mm. Front edge rake plane P_LAnd trailing edge rake plane P_TMay be in the rear direction D_RAnd is inclined upwards. In other words, the leading edge rake plane P_LAnd trailing edge rake plane P_TMay follow them in the rear direction D_RExtend from the respective cutting edge 48, 50 at increasing distances from the insert axis a. The leading rake surface 76 may include a laterally sloped surface 80 that extends upwardly from the trailing rake surface 78 in a direction toward the leading side surface 56. The laterally inclined surface 80 may be in the forward direction D_FUp to the undercut edge portion 54. Leading rake surface 76 and trailingThe rake surface 78 may be in the rear direction D_RUp to a chip deflecting protrusion 82 oriented transversely to the insert axis a.

In accordance with some embodiments of the subject matter of the present application, the leading rake surface 76 and the trailing rake surface 78 may each include a chip control structure 84 spaced apart from the split cutting edge 46. Each chip-control structure 84 may include a chip-control recess 86 recessed into the respective rake surface 76, 78. The chip control structures 84 associated with the leading rake surface 76 and the trailing rake surface 78 may not be identical. Each chip control structure 84 may be in the rearward direction D_RAnd an upper longitudinal extension. As taken in a plane perpendicular to the insert axis A and in the forward direction D_FAs shown in the top-view cross-sectional view (e.g., fig. 10), the laterally sloped surface 80 may extend to a chip control structure 84 located on the leading rake surface 76, thereby forming an edge 88 at the chip control structure 84.

It should be noted that the trailing edge cutting edge may have a concavely curved axial leading edge portion (although with a relatively small curvature) as shown in the prior art. The concavely curved portion is the first portion of the trailing edge cutting edge to meet the workpiece during a cutting operation and is susceptible to wear. Wear of the trailing edge 50 is detrimental to its chip forming ability and also shortens tool life. Thus, because the intersection point I is the end point of the straight trailing edge cutting edge portion 60, the split cutting edge 46, or more specifically the trailing edge cutting edge 50, experiences less wear.

Although the subject matter of the present application has been described with a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the spirit or scope of the invention as hereinafter claimed.