Cutting tool
By setting the corner wall inclination angle of 40 degrees or more on the cutting tool, the problem of insufficient chip cutting in the prior art is solved, and efficient finishing of the inner surface of the preset groove is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TUNGALOY CORP
- Filing Date
- 2023-07-11
- Publication Date
- 2026-07-31
AI Technical Summary
When existing cutting tools are used to finish the inner surface of a pre-set groove, the tilt angle of the chip breaker is too small, which results in the chips not being cut off sufficiently, thus affecting the machining efficiency.
A cutting tool is designed with a corner wall inclination angle greater than or equal to 40 degrees, including a first corner wall and a second corner wall. The inclination angle of the first corner wall relative to the boss surface is greater than or equal to 40 degrees, and the inclination angle of the second corner wall relative to the boss surface is less than that of the first corner wall. The corner wall protrudes in an arc shape toward the corner cutting edge, thereby enhancing the chip cutting capability of the chip breaker.
It effectively cuts off chips, improving the efficiency and quality of grooving, especially when finishing the inner surface of the pre-set groove, it can reliably cut off chips and reduce machining resistance.
Smart Images
Figure CN117773172B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to cutting tools for grooving. Background Technology
[0002] For example, as described in Patent Document 1 below, a cutting tool for grooving has multiple cutting edges, such as a front cutting edge and a corner cutting edge, configured to correspond to the shape of the inner surface of the groove. "Grooving" includes not only creating a new groove from scratch on the surface of the workpiece, but also finishing the inner surface of a pre-set groove in the workpiece.
[0003] Existing technical documents
[0004] Patent documents
[0005] Patent Document 1: US Patent Publication US2006 / 0269367A1 Specification
[0006] Technical issues
[0007] As described in Patent Document 1 above, the cutting tool has a chip breaker, which is used to cut the chips generated during machining. In order to reduce the resistance during machining, the inclination angle of the surface that performs the function of the chip breaker is generally set to be small.
[0008] However, if the tilt angle is too small, the chip breaker may not be able to fully perform its chip-cutting function. In particular, when finishing the inner surface of the preset groove, the chip breaker of the cutting tool described in Patent Document 1 may not be able to cut the chips sufficiently.
[0009] The purpose of this invention is to provide a cutting tool that can effectively cut chips while performing grooving. Summary of the Invention
[0010] The cutting tool provided by the present invention is used for grooving, including a front cutting edge, a pair of transverse cutting edges, a pair of angular cutting edges connecting the front cutting edge and the transverse cutting edges, an angular rake face extending from the angular cutting edge, and a protrusion protruding from the angular rake face and having a flat boss surface at the top; a corner wall surface is formed in the protrusion, the corner wall surface being a surface extending from the boss surface to the angular rake face; at least a portion of the corner wall surface has an inclination angle of greater than or equal to 40 degrees relative to the boss surface.
[0011] When finishing the inner surface of a pre-designed groove, the inner side of the groove is mainly machined by the angular cutting edge of the cutting tool. At this time, the direction of the chips generated from the angular cutting edge tends to become less consistent compared to creating a new groove from scratch. Therefore, as in the past, if the inclination angle of the surface that functions as the chip breaker is set too small, the chip breaker may not be able to adequately cut the chips.
[0012] Therefore, in the cutting tool with the above structure, the inclination angle of the corner wall that functions as a chip breaker, that is, the inclination angle of the corner wall relative to the boss surface, is set to be greater than or equal to 40 degrees. Thus, regardless of the direction in which the chip is generated from the corner cutting edge, the chip can be controlled and effectively cut off while grooving is performed.
[0013] Preferably, the corner wall includes a first corner wall and a second corner wall, the first corner wall being the portion on the boss side and the second corner wall being the portion on the front face side; the inclination angle of the second corner wall relative to the boss surface can be smaller than the inclination angle of the first corner wall relative to the boss surface.
[0014] Preferably, when viewed from a direction perpendicular to the boss surface, at least one of the first corner wall and the second corner wall can protrude in an arc shape toward the corner cutting edge.
[0015] Preferably, the first part is a part provided with a front cutting edge, a cross cutting edge, a corner cutting edge, a corner rake face and a protrusion, and the second part is a part held in the retainer of the cutting tool, and the first part and the second part are engaged with each other.
[0016] Preferably, the first part may be formed of a material containing cubic boron nitride.
[0017] This invention provides a cutting tool that can effectively cut chips while performing grooving. Attached Figure Description
[0018] Figure 1 This is a perspective view showing the structure of the cutting tool provided in this embodiment.
[0019] Figure 2 for Figure 1 A partially enlarged schematic diagram of the cutting tool shown.
[0020] Figure 3 To view from a direction perpendicular to the boss surface Figure 2 A schematic diagram of the part shown.
[0021] Figure 4 For along Figure 3 Observe the arrows in the middle Figure 3 A partial schematic diagram of the cutting tool shown.
[0022] Figure 5 This is a schematic diagram illustrating the groove machining method of the cutting tool provided in this embodiment.
[0023] Figure 6 This is a schematic diagram illustrating the groove machining method of the cutting tool provided in this embodiment.
[0024] Figure 7This is a schematic diagram illustrating the groove machining method of the cutting tool provided in this embodiment.
[0025] Explanation of main component symbols
[0026] Cutting tools 10
[0027] Blade 100
[0028] Front cutting edge 111
[0029] Angular cutting edge 112
[0030] Cross cutting edge 113
[0031] 122 Angle rake face
[0032] Protrusion 150
[0033] 160mm boss
[0034] Corner wall 180
[0035] First corner wall 181
[0036] Second corner wall 182
[0037] Main body 200 Detailed Implementation
[0038] The present embodiment will now be described with reference to the accompanying drawings. To facilitate understanding, the same components will be labeled with the same symbols as much as possible in the drawings, and repeated descriptions will be omitted.
[0039] The cutting tool 10 provided in this embodiment is mainly used for grooving. When grooving a workpiece, the cutting tool 10 is mounted and held in a cutting tool (not shown) and its cutting edge (such as the front cutting edge 111 described later) contacts the workpiece. The "grooving" performed by the cutting tool 10 includes not only creating a new groove from scratch on the surface of the workpiece, but also finishing the inner surface of a pre-existing groove in the workpiece. The cutting tool 10 is configured primarily for the latter type of grooving.
[0040] like Figure 1 As shown, the cutting tool 10 has a main body 200 and a cutting insert 100, which form a structure that is joined together (specifically, brazed).
[0041] The main body 200 is a portion held by a holder for a cutting tool (not shown). Figure 1The portion marked with the symbol "201" (hereinafter also referred to as "central portion 201") has arc-shaped recesses on its upper and lower sides. With the main body portion 200 held in place by the retainer of the cutting tool, a portion of the cutting tool enters these recesses, thereby fixing the main body portion 200. The main body portion 200 corresponds to the "second portion" in this embodiment.
[0042] The cutting tool 100 has a grooved portion formed because it directly contacts the workpiece being cut. The cutting tool 100 is entirely formed of a sintered body of cubic boron nitride (cBN) and is brazed to the main body 200. The cutting tool 100 corresponds to the "first part" in this embodiment. The material of the cutting tool 100 can be a material containing only cubic boron nitride as in this embodiment, or it can be a material containing other components besides cubic boron nitride.
[0043] Figure 2 for Figure 1 An enlarged schematic diagram of the blade 100 and its surrounding area. Figure 3 Viewed from a direction perpendicular to the boss surface 160 of the blade 100. Figure 2 A schematic diagram of the part shown. (As shown) Figure 2 , Figure 3 As shown, the insert 100 has a front cutting edge 111, a transverse cutting edge 113, and a corner cutting edge 112. These are all along the boundaries of the approximately cuboid insert 100. Figure 2 The edge of the upper surface shown extends to form this shape.
[0044] The front cutting edge 111 is a cutting edge that extends linearly along a direction perpendicular to the length direction of the main body 200 at the end of the front end side of the insert 100. The direction in which the front cutting edge 111 extends will also be referred to as the "width direction". The front cutting edge 111 is the portion opposite to the bottom surface of the groove during groove machining.
[0045] The transverse cutting edges 113 are a pair of cutting edges respectively disposed on both sides of the insert 100 in the width direction. Each transverse cutting edge 113 extends in a straight line from the front end portion where the front cutting edge 111 is located toward the central portion 201. Figure 3 As shown, the extending direction of each transverse cutting edge 113 is not perpendicular to the extending direction of the front cutting edge 111, but is slightly inclined. Therefore, the spacing between the transverse cutting edges 113 decreases slightly from the front end side to the central portion 201 side. The transverse cutting edges 113 are the portions that face the inner surface of the groove during groove machining.
[0046] The corner cutting edge 112 is an arc-shaped cutting edge that smoothly connects the front cutting edge 111 and the cross cutting edge 113. The corner cutting edge 112 is located at both ends of the front cutting edge 111. The corner cutting edge 112 is the portion opposite the corner between the bottom and inner surfaces of the groove during groove machining. Furthermore, as described later, the corner cutting edge 112 is also the portion used for finishing the inner and bottom surfaces of the groove.
[0047] The insert 100 has a rake face 121, rake faces 101, transverse rake face 123, transverse flank face 103, angular rake face 122, and angular flank face 102. The rake face 121 and rake faces 101 are surfaces corresponding to the front cutting edge 111. The rake face 121 is a flat surface extending from the front cutting edge 111 toward the central portion 201, and the rake faces 101 are flat surfaces extending from the front cutting edge 111 toward... Figure 2 A flat surface extending below the blade. In this embodiment, the front facet 121 is perpendicular to the front and rear facets 101.
[0048] A front cutting surface 124 is provided on the side of the central portion 201, adjacent to the front cutting surface 121. The front cutting surface 124 is an inclined surface, and the closer it is to the side of the central portion 201, the more inclined it becomes. Figure 2 The lower side is concave.
[0049] The transverse rake face 123 and the transverse clearance face 103 are faces that are provided corresponding to the transverse cutting edge 113. The transverse rake face 123 extends from the transverse cutting edge 113 towards... Figure 3 A flat surface extending from the center side in the left-right direction. The transverse rake face 103 extends from the transverse cutting edge 113 towards... Figure 2 A flat surface extending from the lower side of the blade. In this embodiment, the transverse front blade face 123 and the transverse rear blade face 103 form an acute angle with each other.
[0050] The angular rake face 122 and the angular clearance face 102 are surfaces corresponding to the angular cutting edge 112. The angular rake face 122 is a flat surface extending inward from the angular cutting edge 112, specifically towards the arm portion 151 described later. The angular rake face 122 connects the aforementioned front rake face 121 and the transverse rake face 123. The front rake face 121, the angular rake face 122, and the transverse rake face 123 form the same plane at the same height. The angular clearance face 102 extends from the angular cutting edge 112 towards... Figure 2 The lower side extends to form a curved shape corresponding to the shape of the angular cutting edge 112. In this embodiment, the angular rake face 122 and the angular clearance face 102 form an acute angle with each other.
[0051] like Figure 2 As shown, a protrusion 150 is provided on the surface of the cutting tool 100 where the angular rake face 122, etc., is located. The protrusion 150 extends from the angular rake face 122, etc., toward... Figure 2The upper side protrudes, and a flat boss surface 160 is provided at its top. The aforementioned front rake face 121, angular rake face 122, and transverse rake face 123 are all parallel to the boss surface 160. In such cases... Figure 3 As shown, when viewed from a direction perpendicular to the boss surface 160, a pair of arms 151 extending toward each corner cutting edge 112 are provided on the protrusion 150.
[0052] Each side of the protrusion 150 extending from the boss surface 160 toward the front rake face 121 is a wall surface that functions as a "chip breaker". The "chip breaker" is used to cut off the chips generated by the cutting edge.
[0053] A front wall surface 170, extending from the front end of the boss surface 160 toward the rake face 124, is disposed between a pair of arms 151, thus forming a recessed shape from the front cutting edge 111 side toward the central portion 201 side. The front wall surface 170 functions as a chip breaker, primarily used to cut chips generated by the front cutting edge 111. The central portion of the front wall surface 170 in the width direction connects to a recess 171 formed on the boss surface 160. The inclination angle of the recess 171 relative to the boss surface 160 is smaller than the inclination angle of the front wall surface 170 relative to the boss surface 160.
[0054] The corner wall 180 extending from the front end of the arm 151 toward the corner rake face 122 in the boss surface 160 functions as a chip breaker, mainly used to cut the chips generated by the corner cutting edge 112.
[0055] Figure 4 For along Figure 3 Arrow AR1 in the diagram shows a view of the corner wall 180 and its vicinity. (See diagram for reference.) Figure 4 As shown, the corner wall 180 has two protrusions formed by the first corner wall 181 and the second corner wall 182. Figure 4 Point P0 in the diagram represents the boundary position between the first corner wall 181 and the second corner wall 182. The first corner wall 181 is the portion of the corner wall 180 on the side of the boss surface 160, and the second corner wall 182 is the portion of the corner wall 180 on the side of the corner rake surface 122.
[0056] Figure 4 Point P1 shown represents a specific location in the first corner wall 181. Figure 4 The θ1 shown represents the inclination angle of the first corner wall 181 relative to the boss surface 160 at point P1. Specifically, the "inclination angle" refers to the angle between the tangent plane at point P1 that is tangent to the first corner wall 181 and the boss surface 160.
[0057] In the first corner wall 181, regardless of the location of point P1, the aforementioned tilt angle θ1 is greater than or equal to 40 degrees and less than or equal to 90 degrees. That is, the tilt angle θ1 of the entire region of the first corner wall 181 is greater than or equal to 40 degrees and less than or equal to 90 degrees. Optionally, the region where the tilt angle θ1 is greater than or equal to 40 degrees and less than or equal to 90 degrees may not be the entire first corner wall 181 but only a part of it. More preferably, the tilt angle θ1 is within the range of greater than or equal to 45 degrees and less than or equal to 90 degrees.
[0058] Figure 4 Point P2 shown represents a specific location in the second corner wall 182. Figure 4 The θ2 shown represents the tilt angle of the second corner wall 182 relative to the boss surface 160 at point P2. The definition of "tilt angle" is the same as above. That is, the tilt angle θ2 is the angle between the tangent plane at point P2 that is tangent to the second corner wall 182 and the boss surface 160.
[0059] The tilt angle θ2 of the second corner wall 182 is smaller than the tilt angle θ1 of the first corner wall 181. In this embodiment, the shape of the corner wall 180 is determined such that the relationship between the tilt angles θ1 and θ2 is not affected by the method of selecting the midpoint P1 of the first corner wall 181 or the method of selecting the midpoint P2 of the second corner wall 182. Optionally, in another embodiment, the second corner wall 182 has a region where the tilt angle θ2 is greater than or equal to the tilt angle θ1. However, in either case, preferably, the average value of the tilt angle θ2 of the entire second corner wall 182 is smaller than the average value of the tilt angle θ1 of the entire first corner wall 181. For example, the "average value of tilt angle θ2" can be obtained by dividing the sum of the maximum and minimum values of tilt angle θ2 by 2, or by dividing the value obtained by performing a surface integral on the value of the tilt angle θ2 of the entire second corner wall 182 by the surface area of the second corner wall 182. The same applies to the "average value of tilt angle θ1".
[0060] like Figure 3 As shown, when viewed from a direction perpendicular to the boss surface 160, the first corner wall 181 and the second corner wall 182 protrude in an arc shape toward the corner cutting edge 112. It is also possible that only one of the first corner wall 181 and the second corner wall 182 protrudes in an arc shape toward the corner cutting edge 112. The reason for setting the shapes of the first corner wall 181 and the second corner wall 182 in this way will be explained later.
[0061] return Figure 2Continuing the explanation, the transverse wall surface 190 extending from the outer end in the width direction toward the transverse rake face 123 within the boss surface 160 functions as a chip breaker, primarily used to cut chips generated by the transverse cutting edge 113. In this embodiment, the transverse wall surface 190 is inclined at a 90-degree angle relative to the boss surface 160.
[0062] The functions of each component of the cutting tool 10 during grooving will be explained below. An example of finishing the inner surface of a pre-set groove 31 on a workpiece 30 using the cutting tool 10 will be described below. For example... Figure 5 As shown, the groove 31 is a groove with an approximately rectangular cross-section formed when it is cut perpendicularly to its length direction. The groove 31 has a pair of inner surfaces 311 and 312 and a bottom surface 313 that are opposite to each other.
[0063] In addition, Figure 5 The area represented by the dashed line DL11 indicates the portion of the workpiece 30 that will be removed by finishing. For ease of illustration, [the area is shown in the diagram]. Figure 5 The description of this part's thickness is exaggerated; in reality, the thickness of the portion removed during finishing is greater than... Figure 5 The thickness shown is thin.
[0064] exist Figure 5 In this example, the distance from the inner surface 311 to the inner surface 312 (hereinafter also referred to as the "groove width" of the groove 31) is slightly smaller than the width dimension of the insert 100. In this case, while rotating the workpiece 30, the cutting tool 10 is moved in the direction of arrow AR11, thereby simultaneously finishing the inner surfaces 311 and 312. The finishing of the inner surfaces 311 and 312 is mainly performed by the corner cutting edges 112 located on both sides of the insert 100.
[0065] The chips generated by the corner cutting edge 112 immediately come into contact with the corner wall 180 after generation and deform along the surface shape of the corner wall 180. That is, the cross-section of the chip is bent and deformed relative to its length direction when it is cut perpendicularly. The chip deformed in this way is easily bent and cut off immediately when subjected to a force in the bending direction.
[0066] Thus, in this embodiment, by forming both the first corner wall 181 and the second corner wall 182 into a shape that protrudes in an arc toward the corner cutting edge 112, the chips generated during the finishing of the inner surfaces 311 and 312 can be reliably cut off.
[0067] Furthermore, the direction of the chips generated by the corner cutting edge 112 varies depending on the finishing conditions. For example, when the feed rate of the cutting tool 10 is high and the depth of cut is large, the chips tend to extend from the corner cutting edge 112 toward the first corner wall 181. Conversely, when the feed rate of the cutting tool 10 is slow and the depth of cut is small, the chips tend to extend from the corner cutting edge 112 toward the second corner wall 182. However, in either case, when finishing the groove 31 as in this embodiment, the direction in which the chips extend from the corner cutting edge 112 tends to become unpredictable.
[0068] Therefore, in the cutting tool 10 of this embodiment, the corner wall 180 that functions as a chip breaker is formed as a two-section protrusion consisting of a first corner wall 181 and a second corner wall 182, and a portion of the corner wall 180 has an inclination angle greater than 40 degrees relative to the boss surface 160. With this structure, the chip breaker's control over the chips is enhanced, thus enabling effective chip cutting while simultaneously performing groove machining.
[0069] Furthermore, under less demanding machining conditions, such as a slow feed rate of the cutting tool 10, the chips generated by the corner cutting edge 112 tend to extend slightly from the corner cutting edge 112 toward the corner wall 180, and then tend to extend in an unpredictable direction before reaching the corner wall 180. Therefore, in this embodiment, a second corner wall 182 with a smaller inclination angle θ2 is provided on the portion of the corner wall 180 on the side of the rake face 122. This shortens the distance from the corner cutting edge 112 to the corner wall 180, so the corner wall 180 can reliably restrain and cut off the chips generated by the corner cutting edge 112.
[0070] Even under low machining conditions, some chips generated by the corner cutting edge 112 may cross the second corner wall 182. In this case, the chips can be reliably cut off by the first corner wall 181 located on its inner side.
[0071] Furthermore, depending on the range of processing conditions employed, a second corner wall 182 may not be necessary. In this case, the tilt angle of all positions on the corner wall 180 relative to the boss surface 160 may be greater than or equal to 40 degrees and less than or equal to 90 degrees. That is, the entire corner wall 180 may be the first corner wall 181 of this embodiment.
[0072] exist Figure 5 In the example, the cutting tool 10 is moved in the direction of arrow AR11, and eventually the front cutting edge 111 reaches the bottom surface 313. Then, the bottom surface 313 is finished by the front cutting edge 111.
[0073] At this time, the chips generated by the front cutting edge 111 contact the corner wall 180 at both ends in the aforementioned width direction, and the chips are supported at two points, thus bending as a whole. The chips remain bent and contact the front wall 170, which acts as a chip breaker, and are cut off. At this time, friction may occur due to the contact between the chips and the rake face 124, but in this embodiment, since the rake face 124 is tilted downward and recessed, such friction is suppressed.
[0074] The finishing of groove 31 is not limited to Figure 5 Examples can also be made with Figure 6 Perform as shown. In Figure 6 In the example, the width of slot 31 is greater than the width dimension of blade 100. In this case, firstly as... Figure 6 As shown in (A), the cutting tool 10 is moved in the direction of arrow AR21. Thus, after finishing an inner surface 312 with the corner cutting edge 112, a portion of the bottom surface 313 is finished with the front cutting edge 111. The portion removed from the workpiece 30 by this machining... Figure 6 (A) is represented by the dashed line DL21.
[0075] Next, as Figure 6 As shown in (B), the cutting tool 10 is moved in the direction of arrow AR22. Thus, after finishing the other inner surface 311 via the corner cutting edge 112, the remaining portion of the bottom surface 313 is finished via the front cutting edge 111. The portion removed from the workpiece 30 by this machining... Figure 6 (B) is represented by the dashed line DL22. When the wider groove 31 is precision-machined, it can also function as... Figure 5 The example illustrates the same effect.
[0076] exist Figure 6 In the example, the width of slot 31 is less than or equal to twice the width dimension of blade 100. When the width of slot 31 exceeds twice the width dimension of blade 100, ... Figure 7 The method shown is used for finishing.
[0077] First, such as Figure 7 As shown in (A), the cutting tool 10 is moved in the direction of arrow AR31. Thus, after finishing an inner surface 312 with the corner cutting edge 112, a portion of the bottom surface 313 is finished with the front cutting edge 111. The portion removed from the workpiece 30 by this machining... Figure 7 (A) is represented by the dashed line DL31.
[0078] Next, as Figure 7As shown in (B), the cutting tool 10 is moved in the direction of arrow AR32. This allows for finishing of the other inner surface 311 via the corner cutting edge 112. Then, after the front cutting edge 111 reaches the bottom surface 313, the cutting tool 10 is moved in the direction of arrow AR33. This allows for finishing of the remaining portion of the bottom surface 313 via the front cutting edge 111. The portion removed from the workpiece 30 by this machining is... Figure 7 (B) is represented by the dashed line DL32.
[0079] When the cutting tool 10 moves in the direction of arrow AR33, the finishing of the bottom surface 313 is mainly performed by... Figure 7 The cutting edge 112 located on the left side of the center is used. At this time, the chips generated by the cutting edge 112, along with... Figure 5 The example described herein is the same, cut off by the first corner wall 181 and the second corner wall 182. Since the processing conditions are mostly set low at this time, the effect of setting the corner wall 180 as in this embodiment can be maximized.
[0080] The corner wall 180, which functions as a chip breaker, can also be used with cutting tools that have a structure different from that of this embodiment. For example, diamond can be used instead of cBN as the material for the insert 100. In addition, "polishing parts" or "finishing edges" can be formed on the flank face 102 and the area thereon.
[0081] The embodiments described above have been illustrated with reference to specific examples. However, this disclosure is not limited to these specific examples. Appropriate design modifications made by those skilled in the art to these specific examples, as long as they possess the features of this disclosure, are also included within the scope of this disclosure. The elements, their configurations, conditions, shapes, etc., of the above-described specific examples are not limited to the illustrated content and can be appropriately modified. As long as no technical contradiction arises, the elements of the above-described specific examples can be appropriately varied and combined.
Claims
1. A cutting tool for grooving, comprising: Front cutting edge; A pair of transverse cutting edges; A pair of angled cutting edges connecting the front cutting edge and the cross cutting edge; An angular rake face extending from the angular cutting edge; as well as A protrusion extending from the rake face and having a flat boss at its top; wherein, The surface of the boss is flat overall; A corner wall surface is provided in the protrusion, and the corner wall surface is a surface extending from the boss surface to the corner rake face; At least a portion of the corner wall surface has an inclination angle of 40 degrees or greater relative to the boss surface; The corner wall includes a first corner wall and a second corner wall, wherein the first corner wall is the portion on the side of the boss surface, and the second corner wall is the portion on the side of the corner rake surface; The inclination angle of the second corner wall relative to the boss surface is smaller than the inclination angle of the first corner wall relative to the boss surface; and The first corner wall extends continuously away from the corner rake face and toward the plane where the flat boss surface is located.
2. The cutting tool of claim 1, wherein, When viewed from a direction perpendicular to the boss surface, at least one of the first corner wall and the second corner wall protrudes in an arc shape toward the corner cutting edge.
3. The cutting tool according to claim 1, wherein, The first part is the portion provided with the front cutting edge, the cross cutting edge, the angular cutting edge, the angular rake face and the protrusion, and the second part is the portion held in the retainer of the cutting tool, and the first part and the second part are engaged with each other.
4. The cutting tool according to claim 3, wherein, The first part is formed of a material containing cubic boron nitride.
5. The cutting tool according to claim 1, wherein, The second corner wall is completely away from the corner facet and continuously inclined toward the plane containing the first corner wall and the flat boss surface.
6. The cutting tool according to claim 1, wherein, The second corner wall is located entirely between the corner cutting edge and the flat boss surface.