CN211413919U

CN211413919U - Cutting tool

Info

Publication number: CN211413919U
Application number: CN201922132550.XU
Authority: CN
Inventors: 岳国汉
Original assignee: Individual
Current assignee: Shenzhen Muji Superhard Technology Co Ltd
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2020-09-04
Anticipated expiration: 2029-11-29

Abstract

The utility model discloses a cutting tool, which comprises a tool apron, wherein an annular mounting surface arranged around the central axis of the tool apron is formed at the upper end of the tool apron, an annular boss is arranged on the inner side surface of the annular mounting surface, and the annular boss is arranged around the central axis of the tool apron; the annular blade is arranged on the mounting surface and surrounds the central axis of the tool apron, the annular blade is provided with a top surface and an outer side surface which are mutually connected, and the outer edge of the top surface is connected with the upper edge of the outer side surface to form a cutting edge; the annular chip guide surface is formed at the top of the outer side wall of the annular boss and surrounds the central axis of the cutter holder. The utility model discloses aim at increasing the face of leading bits to realize increasing the life of cutter.

Description

Cutting tool

Technical Field

The utility model relates to a cutter cutting technical field, in particular to cutting tool.

Background

When cutting a workpiece, chips are generated, and the chips are deformed and finally broken by the cutting force of the cutter, but sometimes the cutting force of the cutter is not enough to break the chips, especially for some materials which are difficult to break and have high strength, high plasticity and high toughness. When a cutter is used for cutting and processing the workpieces with thin thickness and hard materials, strip-shaped chips are easy to be left on the surfaces of the workpieces, so that the surfaces of the workpieces and the cutter are scratched, the appearance quality of the workpieces is affected, and the service life of the cutter is easy to reduce.

The above is only for the purpose of assisting understanding of the technical solutions of the present application, and does not represent an admission that the above is prior art.

SUMMERY OF THE UTILITY MODEL

The main object of the utility model is to provide a cutting tool aims at increasing the chip guide surface to realize increasing the life of cutter.

To achieve the above object, the present invention provides a cutting tool, including:

the upper end of the cutter holder is provided with an annular mounting surface arranged around the central axis of the cutter holder, and the inner side surface of the annular mounting surface is provided with an annular boss arranged around the central axis of the cutter holder;

the annular blade is arranged on the mounting surface, the annular boss is arranged around the central axis of the tool apron, the annular blade is provided with a top surface and an outer side surface which are mutually connected, and the outer edge of the top surface is connected with the upper edge of the outer side surface to form a cutting edge;

the annular chip guide surface is formed at the top of the outer side wall of the annular boss and surrounds the central axis of the cutter holder.

Optionally, the annular chip guide surface has an upper edge attached to the top wall of the annular boss and a lower edge attached to the inside edge of the top surface of the annular blade.

Optionally, on a cross section of the cutting tool, a top surface of the annular boss and the annular chip guide surface are arranged at an obtuse angle.

Optionally, the distance between the upper edge and the lower edge is 0.6mm to 1.0 mm.

Optionally, in a cross-section of the cutting tool, a height of the top surface of the annular insert gradually increases outward in a radial direction of the cutting tool.

Optionally, the mounting surface is spaced from the top surface of the ring blade by a distance of 5mm to 25 mm.

Optionally, the annular blade includes an inner side surface disposed opposite to the outer side surface, and a distance between the outer side surface and the inner side surface is 10mm to 30 mm.

Optionally, the tool apron includes a base and an installation platform, the base is arranged at the lower end of the tool apron, the installation platform is arranged on the base, and the installation surface is arranged on one side, far away from the base, of the installation platform.

Optionally, the base is a round table structure with a hole in the middle, the outer diameter of the upper end face of the base is larger than that of the lower end face of the base, and the mounting table is connected to the upper end face of the base.

Optionally, a positioning hole is formed in the middle of the tool apron and penetrates through the tool apron; and/or the blade is a cutting piece made of a superhard composite material.

The utility model discloses technical scheme's cutting tool includes blade holder, annular blade and annular chip guide face, and the blade holder plays fixed effect, and the top surface of blade holder is equipped with the installation face, and annular blade installs in the installation face, and annular blade encircles the blade holder the central axis sets up, and the outside edge of annular blade's top surface and the top edge of lateral surface are formed with the cutting edge, and the cutting edge sets up towards the outside of blade holder promptly for cut workpiece, blade holder still have annular boss, and annular boss locates the inboard surface of annular installation face, highly be higher than annular blade's inner edge height, annular chip guide face are formed at the top of the lateral wall of annular boss, bulge in annular blade's top promptly, are used for chip breaking and chip removal. When the annular cutting tool is used, the tool apron is fixed on a machine tool, and the cutting edge of the annular blade cuts a workpiece. Meanwhile, the annular chip guide surface can effectively play a chip breaking role when the cutting edge cuts a workpiece, when the annular blade cuts the workpiece, chips are subjected to the cutting force of the annular blade on the annular chip guide surface and the acting force of the annular chip guide surface to force the annular chip guide surface to be further curled and deformed, and when the chips collide with the workpiece, the chips are easily broken and discharged, the cutting effect cannot be influenced due to overlong chips, the precision and the appearance quality of the workpiece are ensured, and meanwhile, the service life and the efficiency of the cutter are also improved. Adopt the utility model discloses a but annular chip guide surface effectual rupture smear metal changes the length and the shape of smear metal, avoids the smear metal to cause the damage to machined surface and cutter, reaches the purpose that increases the life of cutter.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of the cutting tool of the present invention;

FIG. 2 is a schematic view of the tool holder shown in FIG. 1;

the reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				100	Cutting tool	121	The top surface
110	Tool apron	122	Outer side surface
				111	Mounting surface	123	Cutting edge
112	Boss	130	Annular chip guide surface
				113	Base seat	131	Upper edge
114	Mounting table	132	Lower edge
				120	Annular blade	115	Locating hole

The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

In the present application, unless expressly stated or limited otherwise, the terms "connected" and "fixed" are to be construed broadly, e.g., "fixed" may be fixedly connected or detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout is to include three juxtapositions, exemplified by "A and/or B," including either the A or B arrangement, or both A and B satisfied arrangement. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a cutting tool 100.

As shown in fig. 1 to 2, in the embodiment of the present invention, the cutting tool 100 includes:

the tool holder comprises a tool holder 110, wherein an annular mounting surface 111 arranged around the central axis of the tool holder 110 is formed at the upper end of the tool holder 110, an annular boss 112 is arranged on the inner side surface of the annular mounting surface 111, and the annular boss 112 is arranged around the central axis of the tool holder 110;

an annular insert 120, the annular insert 120 being mounted on the mounting surface 111, the annular insert 120 being disposed around the central axis of the insert seat 110, the annular insert 120 having a top surface 121 and an outer side surface 122 connected to each other, the top surface 121 having an outer edge connected to an upper edge 131 of the outer side surface 122 to form a cutting edge 123;

an annular chip guide surface 130, the height of the annular boss 112 is higher than the height of the inner edge of the annular blade 120, and the annular chip guide surface 130 is formed on the top of the outer side wall of the annular boss 112 and is arranged around the central axis of the tool holder 110.

The cutting tool 100 includes an annular insert 120 having a seat 110 disposed above a mounting surface 111 of the seat 110. The tool holder 110 is externally connected to a processing device (not shown) to drive the cutting tool to move and rotate. The tool holder 110 is substantially hollow and funnel-shaped, and the material of the base body may be cemented carbide or high-speed steel. In the embodiment, one end of the holder 110 forms a mounting surface 111, the diameter of the mounting surface 111 is larger than the diameter of the other portion of the holder 110, and the mounting surface 111 is used for mounting the annular insert 120. In the present embodiment, the annular blade 120 is directly soldered to the mounting surface 111 by brazing, but is not limited thereto. The annular blade 120 is substantially hollow and annular, has the same diameter as the mounting surface 111, and the annular blade 120 is attached to the mounting surface 111. The outer edge of the top surface 121 of the annular insert 120 is connected to the edge of the upper edge 131 of the outer side surface 122 to form a cutting edge 123, i.e., the cutting edge 123 is formed on the side of the annular insert 120 away from the central axis of the insert seat 110 (the outer side of the annular insert 120). In the present embodiment, the material of the annular blade 120 is Polycrystalline Diamond (PCD), but is not limited thereto.

As shown in FIG. 1, the annular insert 120 includes a top surface 121 on a side facing away from the tool holder 110, a connecting surface on a side adjacent to the mounting surface 111 of the tool holder 110, and an outer side surface 122 facing away from a central axis of the tool holder 110. The edge formed by connecting the outer edge of the top surface 121 and the upper edge 131 of the outer side surface 122 is the cutting edge 123. Cutting edge 123 is a cutting edge. The attachment surface is adapted to mate with the attachment surface 111 to attach the annular insert 120 to the tool holder 110. An annular boss 112 is further arranged on the mounting surface 111, and the annular blade 120 is arranged around the outer side wall of the annular boss 112. The annular boss 112 is provided with an annular chip guide surface 130 at the top, and the annular chip guide surface 130 is higher than the annular blade 120, and can also be understood as being arranged at the inner side of the annular blade 120, and is used for further cutting some high-strength, high-plasticity and high-toughness material workpieces which are difficult to break, so that the chips can be bent and broken again. The annular chip guide surface 130 is of an annular structure, so that the fitting degree of the annular chip guide surface 130 and a workpiece is increased, namely the breaking effect and the discharge effect of the annular chip guide surface 130 on chips are increased.

The annular chip guide surface 130 is formed by laser engraving, but is not limited thereto.

The utility model discloses technical scheme's cutting tool includes blade holder 110, annular blade 120 and annular chip guide surface 130, and blade holder 110 plays fixed effect, and the top surface 121 of blade holder 110 is equipped with installation face 111, and annular blade 120 installs in installation face 111, and annular blade 120 encircles blade holder 110 the central axis sets up, and the outside edge of the top surface 121 of annular blade 120 and the last 131 edge of lateral surface 122 are formed with cutting edge 123, and cutting edge 123 sets up towards the outside of blade holder 110 promptly, is used for cutting workpiece, and blade holder 110 still has annular boss 112, and annular boss 112 locates the interior side surface of annular installation face 111, highly be higher than annular blade 120's inner edge height, annular chip guide surface 130 is formed at the top of the lateral wall of annular boss 112, protrudes in annular blade 120's top promptly, is used for chip breaking and chip removal. In use, the tool holder 110 is fixed to a machine tool, and the cutting edge 123 of the annular blade 120 cuts a workpiece. Meanwhile, the annular chip guide surface 130 can effectively play a chip breaking role when the cutting edge 123 cuts, when the annular blade 120 cuts a workpiece, chips are forced to be further curled and deformed by the action force of the annular blade 120 and the action force of the annular chip guide surface 130 besides the cutting force acted on the chips by the annular blade 120, and when the chips collide with the workpiece, the chips are easily broken and discharged, so that the cutting effect cannot be influenced by overlong chips, the precision and the appearance quality of the workpiece are ensured, and meanwhile, the service life and the efficiency of the cutter are also improved. Adopt the utility model discloses a but annular chip guide surface 130 effectual rupture smear metal changes the length and the shape of smear metal, avoids the smear metal to cause the damage to machined surface and cutter, reaches the purpose that increases the life of cutter.

In this embodiment, the annular chip guide surface 130 has an upper edge 131 and a lower edge 132, the upper edge 131 being connected to the top wall of the annular boss 112, and the lower edge 132 being connected to the inner edge of the top surface 121 of the annular blade 120.

Specifically, the annular chip guide surface 130 has an inclined angle, is substantially arc-shaped, and is disposed adjacent to the annular blade 120. Because the annular blade 120 is in the cutting process, the cutter continuously rotates to cut workpieces at different angles, the cutter is in contact with the workpieces during cutting, and meanwhile, the cutter rotates, and the annular chip guide surface 130 is designed into an arc-shaped structure, so that the attachment degree of the annular chip guide surface 130 and the workpieces is favorably increased, namely, the chip breaking effect and the chip discharging effect of the annular chip guide surface 130 are increased. The upper edge 131 of the chip guide surface is connected to the end surface of the top end of the annular boss 112, and the lower edge 132 of the chip guide surface is connected to the inner side edge of the top surface 121 of the annular blade 120, so that a slope structure is formed, and chip breaking and chip removal are facilitated.

In this embodiment, in a cross-section of the cutting tool, the top surface 121 of the annular boss 112 and the annular chip guide surface 130 are disposed at an obtuse angle.

The whole cutting tool is of a columnar structure, namely the cross section of the cutting tool is of a circular structure, the top surface 121 of the boss 112 is in the circular structure, the included angle formed by the top surface 121 of the boss 112 and the chip guide surface is the included angle formed by the horizontal plane and the chip guide surface, the included angle is arranged at an obtuse angle, and the chip guide surface is connected to the top end surface of the boss 112, so that the chip guide surface which can be understood inclines towards the center direction of the cutting tool. In a cross-section of the cutting tool, the height of the top surface 121 of the annular insert 120 gradually increases outward in the radial direction of the cutting tool. It will be appreciated that the side of the insert located at the cutting edge 123 is inclined upwardly, i.e., the insert may be positioned higher than the mounting surface 111, which may increase the compactness of the cutting tool, allowing the insert to be recessed inwardly (the side closer to the central axis of the insert seat 110), reducing the diameter value of the cutting tool.

Specifically, the annular boss 112 is provided at a central position of the mounting surface 111. Since the annular blade 120 is disposed on the outer side wall of the annular boss 112 and the annular chip guide surface 130 is disposed on the top of the annular boss 112, the annular boss 112 is disposed at the center of the mounting surface 111, so that the stability of the annular blade 120 and the annular chip guide surface 130 during cutting can be enhanced. Meanwhile, the annular chip guide surface 130 is arranged on the annular boss 112 and above the annular blade 120 and is staggered with the annular blade 120, the annular chip guide surface 130 is arranged on the inner side of the annular blade 120 and is formed on the end surface of the tool holder 110, and the annular chip guide surface 130 is higher than the annular blade 120, namely, when the annular blade 120 is used for cutting, the annular chip guide surface 130 can be abutted against a workpiece, the acting force of the annular chip guide surface 130 and chips is increased, the chip cutting time is shortened, and the chip cutting and chip removing effects are increased.

In this embodiment, the distance between the upper edge 131 and the lower edge 132 is 0.6mm-1.0mm

The chip guide surface has a certain width because the chip guide surface is an obliquely arranged arc surface, and the upper edge 131 and the lower edge 132 are two upper and lower edges 132 of the chip guide surface. The width of leading the bits face influences the area of contact of leading bits face and smear metal, when leading the bits face too narrow, less with the contact surface of smear metal, will influence the smear metal effect, when leading bits face 130 broad, can cause the radian of leading the bits face less or great, can lead to the chip removal effect good, so set up the width of leading the bits face to be 0.6mm-1.0mm and be the preferred value, when the width of leading the bits face is 0.6mm, can reach the best smear metal effect, the chip removal effect is also better simultaneously, when the width of leading the bits face is 1.0mm, can reach the best chip removal effect, the smear metal effect is also better simultaneously.

In this embodiment, the distance between the mounting surface 111 and the top surface 121 of the annular blade 120 is 5mm to 25 mm.

The distance from the mounting surface 111 to the top surface 121 of the annular blade 120 is the thickness (also referred to as the width) of the cutting edge 123, and specifically refers to the height from the top to the bottom of the annular blade 120, the thickness of the cutting edge 123 affects the contact area between the annular blade 120 and a workpiece, when the cutting edge 123 is too narrow, the contact surface with the workpiece is small, which affects the chip removal effect, when the cutting edge 123 is wide, the radian of the cutting edge 123 is small or large, which results in a good chip removal effect, so the thickness of the cutting edge 123 is 5mm-25mm is a preferred value, when the width of the cutting edge 123 is 5mm, the best chip removal effect can be achieved, and simultaneously, when the width of the cutting edge 123 is 25mm, the best chip removal effect can be achieved, and the chip removal effect is also good. Of course, when the cutting edge 123 is an inclined edge, 5mm is a value at a position where the cutting edge 123 is thin, and 25mm is a value at a position where the cutting edge 123 is thick.

In this embodiment, the annular blade 120 includes an inner side surface opposite to the outer side surface 122, a distance between the outer side surface 122 and the inner side surface is 10mm to 30mm, and a height of the annular chip guide surface 130 is 0.8mm to 1.0 mm.

The distance between the outer side surface 122 and the inner side surface refers to the range of distances between the outer diameter and the inner diameter of the top surface 121 of the annular insert 120. The maximum height of the annular chip guide surface 130 (i.e., the depth of the annular chip guide surface 130) is in the range of 0.8 to 1.0 mm. In the present embodiment, the annular chip guide surface 130 has a maximum height of 1.0 mm. The shortest length of any point on the cutting edge 123 around the outer side of the protrusion from the annular chip guide surface 130 is 0.05 to 0.1 mm. In the present embodiment, 0.05 mm is preferable. During cutting, the generated chips enter the annular chip guide surface 130, are deformed in a curling manner, and are finally broken. The length of the annular chip guide surface 130 in the direction perpendicular to the tangent of the cutting edge 123, i.e., the width of the annular chip guide surface 130, ranges from 0.6mm to 1.2 mm. In the present embodiment, the width of the annular chip guide surface 130 is preferably 0.8 mm.

Optionally, the annular blade 120 is sleeved on the annular boss 112 and abuts against an outer side wall of the annular boss 112.

The annular blade 120 is a hollow annular structure, including being located the top surface 121 that deviates from blade holder 110 one side, being located the connection face that is close to blade holder 110 installation face 111 one side and being located the lateral wall that deviates from the blade holder 110 axis, the inboard butt of annular blade 120 is in the lateral wall of annular boss 112 promptly, because the annular blade 120 has certain thickness, although the annular blade 120 bottom is installed in installation face 111, but for the stability of guaranteeing annular blade 120 motion process, the stability of annular blade 120 upper portion can further be strengthened in the lateral wall butt of annular boss 112 in annular blade 120 inside wall.

In this embodiment, the tool holder 110 includes a base 113 and an installation platform 114, the base 113 is disposed at a lower end of the tool holder 110, the installation platform 114 is disposed on the base 113, and the installation surface 111 is disposed on a side of the installation platform 114 away from the base 113.

The base 113 is arranged at the lower part of the tool apron 110, the mounting table 114 is connected to the upper end of the base 113 and used for bearing the annular blade 120 and the annular chip guide surface 130, the base 113 is in a circular table-shaped structure, the upper part is larger than the lower part, namely the diameter of the joint of the mounting table 114 is larger, the mounting table 114 is in a circular ring structure, and the diameter of the mounting table 114 is equal to that of the upper end (the joint end with the base 113) of the base 113, so that the contact area between the cutting tool and a workpiece and the stability of the cutting tool can be enhanced.

In this embodiment, the base 113 is a circular truncated cone structure with an opening in the middle, the outer diameter of the upper end surface of the base 113 is greater than the outer diameter of the lower end surface of the base 113, and the mounting table 114 is connected to the upper end surface of the base 113.

The base 113 is substantially hollow round table-shaped, and the end with smaller diameter is disposed at the bottom of the tool apron 110 and connected to the machine tool, and the end with larger diameter (upper table top) is used for mounting the annular blade 120 to process the workpiece, meanwhile, the annular boss 112 and the annular chip guide surface 130 are both mounted on the upper table top, and the arrangement that the upper table top is larger than the lower table top can enhance the stability of the tool during cutting.

In this embodiment, a positioning hole 115 is formed in the middle of the tool holder 110, and the positioning hole 115 penetrates through the tool holder 110; and/or the annular blade 120 is a cutting member made of an ultrahard composite material.

The positioning hole 115 is disposed at a central position of the tool holder 110 and penetrates through the tool holder 110 along a thickness direction of the tool holder 110, a sectional structure of the positioning hole is a stepped structure, that is, an aperture of the positioning hole 115 is a structure with a large top and a small bottom, and the aperture of the positioning hole 115 is between 60mm and 100 mm. The positioning hole is used for being fixed with a lathe or a milling machine, and is inserted into the positioning hole through the rotating shaft to drive the tool apron 110 to rotate, so that the annular blade 120 rotates together, and the tool cuts a workpiece in the rotating process. Optionally, the annular blade 120 is a structural member made of an ultra-hard composite material.

The tool apron 110 is made of tungsten carbide (WC) materials, the annular blade 120 is supported by superhard composite materials, specifically polycrystalline diamond (PCD), Polycrystalline Cubic Boron Nitride (PCBN), tungsten carbide and the like, and mainly combines the PCD and the tungsten carbide, the tool apron 110 and the annular blade 120 are connected into a whole through fiber welding, so that the tool apron becomes a tool which can be used on a lathe or a boring machine, and the annular chip guide surface 130 is formed by machining on the tool apron 110 through electromachining.

The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structure changes made by the contents of the specification and the drawings under the inventive concept of the present invention, or the direct/indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A cutting tool, comprising:

the annular blade is arranged on the mounting surface and surrounds the central axis of the tool apron, the annular blade is provided with a top surface and an outer side surface which are mutually connected, and the outer edge of the top surface is connected with the upper edge of the outer side surface to form a cutting edge;

2. The cutting tool of claim 1, wherein the annular chip guide surface has an upper edge connected to the top wall of the annular boss and a lower edge connected to an inside edge of the top surface of the annular insert.

3. The cutting tool of claim 2, wherein, in a cross-section of the cutting tool, a top surface of the annular boss is disposed at an obtuse angle to the annular chip guide.

4. The cutting tool of claim 2, wherein the distance between the upper edge and the lower edge is 0.6mm to 1.0 mm.

5. The cutting tool of claim 1, wherein, in a cross-section of the cutting tool, the top surface of the annular insert has a height that gradually increases radially outward of the cutting tool.

6. The cutting tool of claim 1, wherein the mounting face is spaced from the top face of the ring blade by a distance of 5mm to 25 mm.

7. The cutting tool of claim 1, wherein the annular insert includes an inner side surface disposed opposite the outer side surface, the distance between the outer side surface and the inner side surface being 10mm to 30 mm.

8. The cutting tool of claim 1, wherein the tool holder includes a base disposed at a lower end of the tool holder and a mounting platform disposed above the base, the mounting surface being disposed on a side of the mounting platform remote from the base.

9. The cutting tool of claim 8, wherein the base is a centrally-apertured frustoconical structure, an outer diameter of an upper end surface of the base being greater than an outer diameter of a lower end surface of the base, the mounting table being attached to the upper end surface of the base.

10. The cutting tool according to any one of claims 1 to 9, wherein a positioning hole is formed in a middle portion of the holder, and the positioning hole is disposed through the holder;

and/or the blade is a cutting piece made of a superhard composite material.