JP2007245269A - Coated cermet throwaway cutting tip having hard coating layer exerting excellent anti-chipping performance in high-speed cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated cutting tip whose hard coating layer exerts excellent anti-chipping performance in high-speed cutting. <P>SOLUTION: The coated cutting tip is structured so that the hard coating layer consisting of a Ti compound layer as lower layer and an α-type Al<SB>2</SB>O<SB>3</SB>layer as upper layer is formed by means of evaporation on the surface of the base of the tip, wherein the surface of the α-type Al<SB>2</SB>O<SB>3</SB>layer as the upper layer is polished by jetting a polishing liquid containing Al<SB>2</SB>O<SB>3</SB>particulates as a jet polishing material by means of wet blasting in the condition that the polishing material layer structured so that two or more TiN layers and TiCN layers having a mean thickness of 0.1-2.5 μm are laminated alternately and having an overall mean thickness of 0.4-5 μm is formed by evaporation on the whole surface of the Al<SB>2</SB>O<SB>3</SB>layer as the upper layer, wherein the surface roughness Ra should be no more than 0.2 μm, and a pattern where the hard coating layer residual stress is reduced is formed on the surface to be polished by means of irradiation with laser beam. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface-coated cermet cutting throwaway tip (hereinafter referred to as a coated cutting tip) that exhibits excellent chipping resistance with a hard coating layer, particularly when used for high-speed cutting of various types of steel and cast iron. Is.

Conventionally, generally, for example, as illustrated in a schematic perspective view in FIG. 10, a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet, and a central portion A cermet base (hereinafter referred to collectively as a chip base) having a tool mounting bolt through hole (in the case where the mounting is performed by clamping with a clamp piece, the bolt through hole does not exist). ) On the entire rake face and flank face including the cutting edge ridge
(1) As a lower layer, a titanium carbide (hereinafter referred to as TiC) layer, a titanium nitride (hereinafter also referred to as TiN) layer, a titanium carbonitride (hereinafter referred to as TiCN) layer, a titanium carbonate (hereinafter referred to as TiCO). A Ti compound layer consisting of one or two or more of the layers shown below and a titanium carbonitride oxide (hereinafter referred to as TiCNO) layer and having an overall average layer thickness of 3 to 20 μm,
(2) As an upper layer, an aluminum oxide layer (hereinafter referred to as an α-type Al ₂ O ₃ layer) having an average layer thickness of 1 to 15 μm and having an α-type crystal structure in a state of chemical vapor deposition,
A coated cutting tip formed by vapor-depositing the hard coating layer constituted by the above (1) and (2) is known, and this coated cutting tip is used for continuous cutting and intermittent cutting of various steels and cast irons, for example. It is well known to be used.

In the above-mentioned coated cutting tip, the constituent layer of the hard coating layer generally has a granular crystal structure, and the TiCN layer constituting the Ti compound layer as the lower layer is intended to improve the strength of the layer itself. In a normal chemical vapor deposition apparatus, a gas mixture containing organic carbonitrides is used as a reaction gas, and it is formed by chemical vapor deposition at an intermediate temperature range of 700 to 950 ° C. so that it has a vertically grown crystal structure. It is also known to do.
Furthermore, it is also known that the surface of the α-type Al ₂ O ₃ layer (upper layer) constituting the hard coating layer of the above-described coated cutting tip is smoothed by wet blasting for the purpose of improving cutting performance. Yes.
Japanese Unexamined Patent Publication No. 6-31503 Japanese Patent Laid-Open No. 6-8010 JP-A-8-276305

  In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and along with this, cutting has been on the trend of higher speed. The coated cutting tip has no problem when it is used for continuous cutting or intermittent cutting under normal conditions such as steel or cast iron, but the cutting speed is 400 m / min. When used for cutting at the above high speed, chipping (small chipping) is likely to occur in the hard coating layer, and as a result, the service life is reached in a relatively short time.

Therefore, the present inventors, from the above viewpoint, paying attention to the above-mentioned conventional coated cutting tip, and as a result of conducting research to improve the chipping resistance of the hard coating layer in particular,
(A) The smoothness of the deposition surface of the α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer in the above-mentioned conventional coated cutting tip is not sufficiently satisfactory, and the deposition surface is not wet blasted. Then, as a jetting abrasive, a polishing liquid containing 15 to 60% by mass of aluminum oxide fine particles (hereinafter referred to as Al ₂ O ₃ fine particles) in a proportion of the total amount with water is jetted and polished, The α-type Al ₂ O ₃ layer is a measurement based on the compliant standard JIS B0601-1994 (the following surface roughness is all measured based on the compliant standard), and Ra: 0.3 to 0.6 μm The coated cutting tip having the α-type Al ₂ O ₃ layer with the surface roughness Ra: 0.3 to 0.6 μm as the upper layer of the hard coating layer is used. However, the cutting speed is 400 m / min. The above high-speed cutting cannot satisfactorily suppress chipping at the cutting edge.

(B) On the other hand, as illustrated in a schematic perspective view in FIG. 8, a rake face including the cutting edge ridge line portion of the α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer in the conventional coated cutting tip and On the entire surface of the flank, an ordinary chemical vapor deposition apparatus is used, and titanium nitride (hereinafter referred to as TiN hereinafter) having an average layer thickness of 0.1 to 2.5 μm under normal conditions, for example, conditions shown in Table 3. ) Layer and a titanium carbonitride (hereinafter referred to as TiCN) layer of two or more layers alternately deposited in an overall average layer thickness of 0.4 to 5 μm,
As in the above (a), when a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles as a spray abrasive is mixed with water as a spray abrasive, the TiN layer and Two or more alternating layers of TiCN layers (hereinafter referred to individually as a TiN abrasive layer and a TiCN abrasive layer, and these are shown as TiN / TiCN abrasive layers) are pulverized and atomized by the Al ₂ O ₃ granules. , TiN fine particles and TiCN fine particles that act as an abrasive in the presence of the Al ₂ O ₃ fine particles, and as illustrated in a schematic perspective view in FIG. 9, α-type Al ₂ constituting the upper layer of the hard coating layer The surface of the O ₃ layer is polished, and high-speed cutting is performed using a coated cutting tip in which the surface of the α-type Al ₂ O ₃ layer, which is the upper layer, is smoothed to a surface roughness of Ra: 0.2 μm or less. 350m when processed / Min. Although the occurrence of chipping at the cutting edge portion is remarkably suppressed even at the front and rear cutting speeds, the cutting speed is further 400 m / min. When the above-mentioned one-stage high-speed machining is performed, the chipping resistance is not necessarily exhibited.

(C) On the other hand, the hard coating layer in the above-mentioned conventional coated cutting chip is formed by being deposited on the surface of the chip substrate at a reaction temperature of about 1000 ° C. and cooled to room temperature by a chemical vapor deposition apparatus. In the cooling process, since the thermal expansion coefficient of the hard coating layer is relatively larger than the thermal expansion coefficient of the chip base, tensile stress remains in the hard coating layer, The residual tensile stress in the hard coating layer is such that the cutting speed is 400 m / min. In the above high-speed cutting, it acts to promote chipping.

(D) On the other hand, a single basic shape mark, for example, a single basic shape mark such as a circle, a triangle, and a quadrangle, or a similar shape thereof, is used for either the rake face or the flank face of the chip base, or these The single basic shape mark and the single basic shape, as shown in the embodiment in which the single basic shape mark is circular, for example, in FIGS. One or both of the mark set marks are distributed and distributed (in this case, the layers shown in FIGS. 1 to 3 have a relatively thin hard coating layer, and are shown in FIGS. 4, 5 and 6 and 7). The distribution form in the case where the layer thickness becomes thicker is shown) and the single basic shape mark is a dug surface where any one of the constituent layers of the hard coating layer is exposed (in this case) Said single group of The digging depth of the exposed surface of the shape mark is individually adjusted according to the layer thickness of the hard coating layer, but in order to reduce the residual stress efficiently, the depth corresponding to 5 to 20% of the layer thickness When the laser beam irradiation pattern is formed, the residual stress of the hard coating layer is remarkably reduced. By forming this hard coating layer residual stress reduction pattern, the hard coating layer during high-speed cutting is formed. In combination with the fact that the occurrence of chipping due to residual stress in the inside is remarkably suppressed and the surface of the α-type Al ₂ O ₃ layer as the upper layer is smoothed to a surface roughness of Ra: 0.2 μm or less, 400 m / min. The occurrence of chipping in the above high-speed cutting processing is to be prevented.
The research results shown in (a) to (d) above were obtained.

The present invention has been made based on the above research results, and the entire rake face and flank face including the cutting edge ridge line portion of the chip base composed of the WC-based cemented carbide or TiCN-based cermet,
(1) A Ti compound layer consisting of one or more of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer as a lower layer, and having an overall average layer thickness of 3 to 20 μm,
(2) As an upper layer, an α-type Al ₂ O ₃ layer having an average layer thickness of 1 to 15 μm,
In the coated cutting tip formed by vapor-depositing the hard coating layer composed of (1) and (2) above,
(A) _Two layers of a TiN abrasive layer and a TiCN abrasive layer each having an average layer thickness of 0.1 to 2.5 μm on the entire surface of the α-type Al ₂ O ₃ layer which is the upper layer of the hard coating layer In a state where the TiN / TiCN abrasive material layer formed by the above alternate lamination and having an overall average layer thickness of 0.4 to 5 μm is formed by vapor deposition,
In wet blasting, as a spraying abrasive, a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles in a proportion of the total amount with water is sprayed,
Α-type constituting the upper layer of the hard coating layer in the presence of pulverized TiN fine particles and pulverized TiCN fine particles by wet blasting of the TiN / TiCN abrasive layer and Al ₂ O ₃ fine particles as a spray abrasive Grind the rake face portion and the flank face portion including at least the cutting edge ridge line portion of the Al ₂ O ₃ layer, and set the surface roughness of these polished surfaces to Ra: 0.2 μm or less,
(B) Furthermore, either or both of the rake face and the flank face of the polishing surface, or the single basic shape mark and the collective mark of the single basic shape mark are distributed over both surfaces. A hard coating layer residual stress reduction pattern is formed by irradiating a laser beam with the single basic shape mark as a dug surface where any one of the constituent layers of the hard coating layer is exposed. ,
The hard coating layer is characterized by a coated cutting tip that exhibits excellent chipping resistance in high-speed cutting.

The reason why the hard coating layer and the abrasive layer of the coated cutting chip of the present invention and the Al ₂ O ₃ fine particles of the polishing liquid used in wet blasting are limited numerically as described above will be described below.
(A) Hard coating layer (a-1) Ti compound layer of lower layer The Ti compound layer exists as a lower layer of the α-type Al ₂ O ₃ layer, and the hard coating layer has a high temperature due to its excellent high temperature strength. In addition to contributing to strength improvement, it has a function of firmly adhering to both the chip base and the α-type Al ₂ O ₃ layer, thereby improving the adhesion of the hard coating layer to the chip base, but the overall average layer thickness is If the thickness is less than 3 μm, the above-mentioned effect cannot be sufficiently exerted. On the other hand, if the total average layer thickness exceeds 20 μm, it becomes easy to cause thermoplastic deformation particularly in high-speed cutting accompanied by generation of high heat. Since it becomes a cause, the whole average layer thickness was set to 3-20 micrometers.

(A-2) α-type Al ₂ O ₃ layer of the upper layer The α-type Al ₂ O ₃ layer has excellent high-temperature hardness and heat resistance, and contributes to improving the cutting performance of the coated cutting tip. If the average layer thickness is less than 1 μm, the desired excellent cutting performance cannot be exhibited over a long period of time. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. The average layer thickness was set to 1 to 15 μm.

(B) TiN / TiCN abrasive material layer As described above, the TiN / TiCN abrasive material layer is pulverized and atomized by Al ₂ O ₃ fine particles blended as an abrasive material into the polishing liquid during wet blasting, and TiN fine particles and TiCN fine particles It acts as an abrasive in the coexistence with the Al ₂ O ₃ fine particles, and polishes the surface of the α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer. If the average layer thickness is less than 0.1 μm, or the overall average layer thickness of the TiN / TiCN abrasive layer is less than 0.4 μm, the ratio of pulverized TiN particles and pulverized TiCN particles during wet blasting Too little, the polishing function cannot be fully exerted. On the other hand, the average layer thickness of each abrasive layer exceeds 2.5 μm, or the total average layer thickness of the TiN / TiCN abrasive layer is 5 μm. When Etari, in unbalanced and Al ₂ O ₃ fine formulated as injection abrasive in the polishing liquid, too many relatively, again become the polishing function is rapidly reduced, in any case Because the surface of the α-type Al ₂ O ₃ layer cannot be polished to a surface roughness of Ra: 0.2 μm or less, the average thickness of each abrasive layer is 0.1 to 2.5 μm, The overall average layer thickness was determined to be 0.4-5 μm.

The Al ₂ O ₃ fine fraction polishing liquid Al ₂ O ₃ fine of (c) polishing liquid, in a state where at the time of wet blast coexists with pulverized TiN atomization and pulverization TiCN fine of TiN / TiCN abrasive layer, alpha The surface of the type Al ₂ O ₃ layer has an action of polishing, but even if the ratio is less than 15% by mass or more than 60% by mass with respect to the total amount with water, the polishing function seems to be drastically reduced. Therefore, the ratio was determined to be 15 to 60% by mass.

In the coated cutting tip of the present invention, the rake face portion and the flank portion including at least the cutting edge ridge line portion of the α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer have a surface roughness of Ra: 0.2 μm or less. Chipping of the hard coating layer by the hard coating layer residual stress reduction pattern formed by laser beam irradiation over one of the rake surface and the flank surface of the polished surface or the entire surface of both surfaces. And the cutting speed of various steels and cast irons is 400 m / min. Even when used for the above high speed, chipping does not occur in the hard coating layer, it exhibits excellent cutting performance over a long period of time, and it is possible to further extend the service life. .

  Next, the coated cutting tip of the present invention will be specifically described with reference to examples.

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders were blended into the composition shown in Table 1, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and pressed into a green compact with a predetermined shape at a pressure of 98 MPa. The green compact was vacuum sintered at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa. After sintering, the cutting edge portion was R: 0.07 mm honing By processing, chip bases A to F made of a WC-based cemented carbide having a throwaway tip shape defined in ISO · CNMG120408 were manufactured.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and pressed into a compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after the sintering, the cutting edge portion was subjected to a honing process of R: 0.07 mm. TiCN base cermet chip bases a to f having a standard / CNMG12041 chip shape were formed.

Next, each of these chip bases A to F and chip bases a to f is charged into a normal chemical vapor deposition apparatus,
(A) First, Table 3 (the 1-TiCN layer in Table 3 shows the conditions for forming a TiCN layer having a vertically grown crystal structure described in JP-A-6-8010; In the conditions shown in Table 5), the Ti compound layer and the α-type Al ₂ O ₃ layer having the target layer thicknesses shown in Table 5 are used as the lower and upper layers of the hard coating layer. Vapor deposition,
(B) Next, as shown in Table 6, the TiN / TiCN abrasive layer was formed under the same conditions as shown in Table 3 for forming the TiN abrasive layer and TiCN abrasive layer. (See FIG. 8)
(C) Subsequently, the coated cutting tip for forming the TiN / TiCN abrasive layer is subjected to wet blasting under the blasting conditions shown in Table 4 and in the combinations shown in Table 6, and the peripheral part of the tool mounting hole is formed. In the state where the TiN / TiCN abrasive layer is present, the rake face portion and the flank portion including the cutting edge ridge line portion of the α-type Al ₂ O ₃ layer (upper layer) are also shown in Table 6 below. (See FIG. 9)
(C) Furthermore, using a laser beam irradiation device, the hard coating layer,
Laser beam output: 10W
The shape of a single basic shape mark: a circle with a diameter of 0.5 mm,
Hard coating layer residual stress reduction pattern: any one of the implementation patterns shown in FIGS. 1 to 7 is applied in the combination shown in Table 6.
Depth of exposed surface of single basic shape mark: Depth shown as a percentage of total target layer thickness in Table 6,
The coated cutting chips 1 to 13 of the present invention were manufactured by forming a hard coating layer residual stress reduction pattern under the conditions described above.

(A) Also, for the purpose of comparison, as shown in Table 7, the Ti compound layer and the α-type Al ₂ O ₃ layer are hard coating layers under the same conditions as the above-described cutting chips 1 to 13 of the present invention. As a lower layer and an upper layer, vapor deposition is formed (see FIG. 10).
(B) Subsequently, a rake face including the cutting edge ridge line portion of the α-type Al ₂ O ₃ layer (upper layer) by performing wet blasting under the blasting conditions shown in Table 4 and in the combination shown in Table 7 Conventionally, the coated cutting chips 1 to 13 were manufactured by polishing the portion and the flank portion to the surface roughness similarly shown in Table 7.

  Moreover, when the thickness of the structural layer of the hard coating layer of the said invention cutting chip 1-13 of this invention and the conventional coating cutting chip 1-13 was measured using the scanning electron microscope (longitudinal section measurement), all were target. The average layer thickness (average value of 5-point measurement) substantially the same as the layer thickness was shown.

Next, for the various coated cutting chips of the present invention coated cutting chips 1 to 13 and the conventional coated cutting chips 1 to 13 described above, all of them are screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS · SCM430 lengthwise equidistant 4 round bars with vertical grooves,
Cutting speed: 410 m / min,
Incision: 1.5mm,
Feed: 0.2mm / rev,
Wet intermittent high-speed cutting test (normal cutting speed is 200 m / min) of alloy steel under the above conditions (referred to as cutting condition A),
Work material: JIS · S45C lengthwise equal 4 round grooved round bars,
Cutting speed: 420 m / min,
Cutting depth: 2mm,
Feed: 0.25mm / rev,
Wet intermittent high-speed cutting test (normal cutting speed is 200 m / min) of carbon steel under the conditions (referred to as cutting conditions B),
Work material: JIS / FC250 round bar,
Cutting speed: 450 m / min,
Incision: 1.5mm,
Feed: 0.2mm / rev,
The dry continuous high-speed cutting test (normal cutting speed is 200 m / min) of cast iron under the above conditions (referred to as cutting condition C). The cutting time until reaching 0.3 mm, which is regarded as a standard for the measurement, was measured. The measurement results are shown in Table 7.

From the results shown in Tables 5 to 8, each of the present coated cutting chips 1 to 13 includes a rake face portion including at least the cutting edge ridge portion of the α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer, and The flank portion is polished to a surface roughness of Ra: 0.2 μm or less, and further, the residual tensile stress in the hard coating layer is formed by the hard coating layer residual stress reduction pattern formed by laser beam irradiation over the entire polished surface. Is remarkably reduced, high-speed cutting of steel and cast iron is performed at a cutting speed of 400 m / min. Even when performed at the above high speed, chipping does not occur and excellent cutting performance is demonstrated over a long period of time, whereas the surface roughness of the α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer is Ra: 0.3 to 0.6 μm, and the conventional coated cutting tips 1 to 13 having no hard coating layer residual stress reduction pattern are all 400 m / min. In the above high-speed cutting, it is clear that chipping occurs in the hard coating layer and the service life is reached in a relatively short time.

  As described above, the coated cutting tip of the present invention has a cutting speed of 400 m / min. As well as continuous cutting and intermittent cutting under normal conditions such as various steels and cast iron. It exhibits excellent chipping resistance even when performed at high speeds as described above, and exhibits excellent cutting performance over a long period of time. It can cope with cost reduction sufficiently.

It is a schematic perspective view of this invention coating cutting tip which formed the hard coating layer residual stress reduction pattern as an Example by laser beam irradiation formation. FIG. 2 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reducing pattern as an embodiment other than FIG. 1 is formed by laser beam irradiation. FIG. 3 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reducing pattern as an embodiment other than FIGS. FIG. 4 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reduction pattern as an embodiment other than FIGS. FIG. 5 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reducing pattern as an embodiment other than FIGS. FIG. 6 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reduction pattern as an embodiment other than FIGS. FIG. 7 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reducing pattern as an embodiment other than FIGS. 1 to 6 is formed by laser beam irradiation. It is a schematic perspective view which shows the state which formed the abrasive material layer in the whole surface of the conventional coated cutting chip. It is a schematic perspective view which shows the state after giving wet blast in the state which formed the abrasive material layer. It is a schematic perspective view of the conventional coated cutting tip.

Claims (1)

On the entire rake face and flank face including the cutting edge ridge line portion of the cermet base composed of tungsten carbide base cemented carbide or titanium carbonitride base cermet,
(1) As a lower layer, it is composed of one or more of a titanium carbide layer, a titanium nitride layer, a titanium carbonitride layer, a carbonated titanium layer, and a titanium carbonitride oxide layer, and has an overall average of 3 to 20 μm. A Ti compound layer having a layer thickness,
(2) As an upper layer, an aluminum oxide layer having an average layer thickness of 1 to 15 μm and having an α-type crystal structure in a state of chemical vapor deposition,
In the cutting throwaway tip made of surface-covered cermet formed by vapor-depositing the hard coating layer composed of (1) and (2) above,
(A-1) Alternation of two or more layers of titanium nitride layer and titanium carbonitride layer each having an average layer thickness of 0.1 to 2.5 μm on the entire surface of the aluminum oxide layer which is the upper layer of the hard coating layer In a state in which an abrasive layer having a total average layer thickness of 0.4 to 5 μm is formed by vapor deposition,
(A-2) In wet blasting, as a spray abrasive, a polishing liquid containing 15 to 60% by mass of aluminum oxide fine particles in a ratio to the total amount with water is sprayed.
In the coexistence of the ground titanium nitride fine particles and the ground titanium carbonitride fine particles by wet blasting of the abrasive layer and the aluminum oxide fine particles as the spray abrasive, the aluminum oxide layer constituting the upper layer of the hard coating layer Polishing at least the rake face portion and the flank portion including the cutting edge ridge line portion, and measuring the surface roughness of these polished surfaces based on compliant standard JIS B0601-1994, Ra: 0.2 μm or less,
(B) Furthermore, either or both of the rake face and the flank face of the polishing surface, or the single basic shape mark and the collective mark of the single basic shape mark are distributed over both surfaces. A hard coating layer residual stress reducing pattern formed by irradiating with a laser beam by forming the single basic shape mark as a dug surface in which any one of the constituent layers of the hard coating layer is exposed,
A surface-coated cermet cutting throwaway tip with a hard coating layer that exhibits excellent chipping resistance in high-speed cutting.

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