阅读说明：本技术 涂层刀具及切削刀具 (Coated cutting tool and cutting tool ) 是由 胜间忠 于 2019-09-03 设计创作，主要内容包括：本发明的涂层刀具具备具有第一面的基体、和位于基体之上的涂层。涂层具有第一层和第二层。在测定出第一层的作为晶粒的晶面的{112}面的法线相对于第一层的表面的法线所成的倾斜角时,在以每隔0.25°的间距划分处于0～45°的范围内的测定倾斜角且将存在于各划分内的度数进行合计而成的倾斜角度数分布图表中,最高峰值存在于0～10°的范围内。存在于该范围内的度数的合计占度数整体的45％以上的比例。第一层在与第一面正交的剖面中具有多个空孔,该多个空孔以在沿着第一层和第二层的边界的方向上排列的方式配置,空孔在沿着界面的方向上的宽度的平均值比相邻的空孔的间隔的平均值小。(The coated cutting tool of the present invention has a substrate having a first face and a coating disposed on the substrate. The coating has a first layer and a second layer. When an inclination angle formed by a normal line of a {112} plane, which is a crystal plane of a crystal grain of a first layer, with respect to a normal line of a surface of the first layer is measured, a maximum peak value is present in a range of 0 to 10 DEG in an inclination angle degree distribution chart obtained by dividing the measured inclination angle in a range of 0 to 45 DEG at a pitch of 0.25 DEG and summing degrees present in each division. The total number of degrees present in this range accounts for 45% or more of the total number of degrees. The first layer has a plurality of holes arranged in a direction along a boundary between the first layer and the second layer in a cross section orthogonal to the first surface, and an average value of widths of the holes in the direction along the interface is smaller than an average value of intervals between adjacent holes.)

1. A coated cutting tool comprising:

a substrate having a first face; and

a coating on at least the first side of the substrate,

wherein the content of the first and second substances,

the coating has: a first layer located on the first face and containing a titanium compound; and a second layer which is located in contact with the first layer and contains alumina,

when an inclination angle formed by a normal line of a [112} plane, which is a crystal plane of the crystal grain, of the first layer with respect to a normal line of a surface of the first layer is measured, in an inclination angle frequency distribution chart obtained by dividing a measurement inclination angle in a range of 0 to 45 DEG at intervals of 0.25 DEG and summing up the degrees present in each division, a maximum peak value is present in a range of 0 to 10 DEG, and the total of the degrees present in the range of 0 to 10 DEG accounts for a proportion of 45% or more of the total degrees in the inclination angle frequency distribution chart,

the first layer has a plurality of pores arranged in a direction along a boundary between the first layer and the second layer in a cross section orthogonal to the first surface, and an average value of widths of the pores in the direction along the interface is smaller than an average value of intervals between adjacent pores.

2. The coated cutting tool of claim 1,

the first layer comprises titanium carbonitride and the second layer comprises alpha-alumina.

3. The coated cutting tool of claim 1 or 2,

in a cross section orthogonal to the first surface, an average value of widths of the voids in a direction parallel to the first surface is larger than an average value of heights of the voids in a direction orthogonal to the first surface.

4. The coated cutting tool according to any one of claims 1 to 3,

in a cross section orthogonal to the first surface, an average value of distances from the voids to the boundary is larger than an average value of heights of the voids in a direction orthogonal to the first surface.

5. The coated cutting tool of any of claims 1 to 4,

in a cross section orthogonal to the first surface, an average value of distances from the voids to the boundary is larger than an average value of intervals between adjacent voids.

6. A cutting tool, wherein,

the cutting tool has:

a shank which has a bar shape extending from a first end to a second end and has a blade groove located on the first end side; and

the coated cutting tool of any of claims 1-5, located within the pocket.

Technical Field

The present invention relates to a coated tool for cutting machining.

Background

As a coated tool used for cutting such as turning and milling, for example, a coated tool described in patent document 1 is known. The coated cutting tool described in patent document 1 is configured such that a coating layer including a layer containing a titanium (Ti) compound (titanium compound layer) and a layer containing alumina (Al) is formed on a surface of a substrate made of cemented carbide or the like₂O₃) Layer (aluminum oxide layer).

Patent document 1 describes that a titanium compound layer is oriented in the (112) plane and has excellent high-temperature strength. In patent document 2, a plurality of pores are formed at the interface between the titanium compound layer and the alumina layer. It is described that the impact relaxation effect can be obtained by using these plural voids.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-015426

Patent document 2: japanese patent laid-open publication No. 2015-182209

Disclosure of Invention

The coated cutting tool of the present invention includes a substrate having a first surface, and a coating layer on at least the first surface of the substrate. The coating has: a first layer located on the first face and containing a titanium compound; and a second layer which is located in contact with the first layer and contains alumina. When an inclination angle formed by a normal line of a {112} plane, which is a crystal plane of the crystal grains, of the first layer with respect to a normal line of a surface of the first layer is measured, a maximum peak value is present in a range of 0 to 10 DEG in an inclination angle degree distribution chart in which measurement inclination angles in a range of 0 to 45 DEG are divided at intervals of 0.25 DEG and degrees present in the respective divisions are summed. And a ratio of 45% or more of the total number of degrees in the inclination angle degree distribution chart in the total number of degrees existing in the range of 0 to 10 degrees. The first layer has a plurality of holes arranged in a direction along a boundary between the first layer and the second layer, in a cross section orthogonal to the first surface. An average value of widths of the voids in a direction along the interface is smaller than an average value of intervals of adjacent voids. The cutting tool of the present invention comprises: a shank which has a bar shape extending from a first end to a second end and has a blade groove located on the first end side; and a coated cutter located within the pocket.

Drawings

Fig. 1 is a perspective view showing a coated cutting tool of the present invention.

Fig. 2 is a cross-sectional view of the coated cutting tool shown in fig. 1, taken along the line a-a.

Fig. 3 is an enlarged view of the vicinity of the coating layer of the coated cutting tool shown in fig. 2.

Fig. 4 is an enlarged view showing an example of the region B1 shown in fig. 3.

Fig. 5 is an enlarged view showing another example of the region B1 shown in fig. 3.

Fig. 6 is a plan view showing the cutting tool of the present invention.

Fig. 7 is an enlarged view of the region B2 shown in fig. 6.

Detailed Description

Hereinafter, the coated cutting tool of the present invention will be described in detail with reference to the accompanying drawings. However, for convenience of explanation, the drawings referred to below simply show only the main members necessary for explaining the aspect of the present embodiment. Therefore, the coated cutting tool can be provided with any structural member not shown in the respective drawings to which reference is made. The dimensions of the members in the drawings do not faithfully represent the actual dimensions of the structural members, the dimensional ratios of the members, and the like.

< coated cutting tool >

As shown in fig. 1 and 2, the coated cutting tool 1 of the present invention includes a substrate 3 and a coating 5. The base body 3 has a first face 7 (upper face in fig. 2), a second face 9 (side face in fig. 2) adjacent to the first face 7, and a cutting edge 11 located at least in part of a ridge line where the first face 7 and the second face 9 intersect.

In the example shown in fig. 1, the base body 3 has a square plate shape, and the first surface 7 has a square shape. Thus, the number of second faces 9 is 4. At least a part of the first surface 7 is a so-called rake surface region, and at least a part of the second surface 9 is a so-called flank surface region. The shape of the base body 3 is not limited to the quadrangular plate shape, and the first surface 7 may be a triangular shape, a pentagonal shape, a hexagonal shape, or a circular shape, for example. The substrate 3 is not limited to a plate shape, and may be, for example, a columnar shape.

The coating 5 is located on at least a first side 7 of the substrate 3. The coating 5 may be provided only on the first surface 7, or may be provided on a surface other than the first surface 7 of the substrate 3. In the example shown in fig. 2, the coating 5 is also located on the second side 9 in addition to the first side 7. The coated tool 1 is provided with the coating 5 in order to improve characteristics such as wear resistance and chipping resistance during cutting.

As shown in fig. 3, the coating 5 has a first layer 13 and a second layer 15. The first layer 13 is located on the first face 7 and contains a titanium compound. The second layer 15 is in contact with the first layer 13 and contains alumina (Al)₂O₃)。

Examples of the titanium compound contained in the first layer 13 include carbides, nitrides, oxides, carbonitrides, oxycarbides, and oxycarbonitrides of titanium. The first layer 13 may have a structure containing only one of the compounds described above, or may have a structure containing a plurality of the compounds described above.

The first layer 13 may have a structure containing a titanium compound, and may have a single-layer structure or a structure in which a plurality of layers are stacked. For example, the first layer 13 may have a laminated structure of the titanium nitride layer 17 and the titanium carbonitride layer 19. In the case where the first layer 13 has the titanium nitride layer 17 as a layer in contact with the base body 3, the first layer 13 has higher bondability with the base body 3. The titanium nitride layer 17 and the titanium carbonitride layer 19 are mainly composed of titanium nitride and titanium carbonitride, respectively, and may contain other components. The "main component" refers to a component having the largest mass% value as compared with other components.

The coating 5 may be formed of only the first layer 13 and the second layer 15, or may have a layer other than these layers. For example, another layer may be present between the substrate 3 and the first layer 13, or another layer may be present on the second layer 15.

The titanium carbonitride layer 19 may have a structure in which a plurality of regions having different compositions are stacked. For example, the titanium carbonitride layer 19 may have a structure in which a so-called mt (mode temperature) -first region 19a and a so-called ht (high temperature) -second region 19b are stacked.

When the first layer 13 has the first region 19a and the second region 19b, the first layer 13 may further have an intermediate region 19c between the first region 19a and the second region 19 b. The boundaries of the layers and regions can be identified by, for example, observing an Electron Microscope photograph (SEM photograph or Transmission Electron Microscope photograph). This determination can be made based on the difference in the ratio of elements constituting each layer, the size of crystal, and the orientation.

Further, as alumina contained in the second layer 15, for example, α -alumina (α -Al) can be mentioned₂O₃) Gamma-alumina (gamma-Al)₂O₃) And kappa-alumina (kappa-Al)₂O₃). In the case where the second layer 15 contains α -alumina, among others, the heat resistance of the coated cutting tool 1 can be improved. The second layer 15 may have a structure containing only one of the compounds described above, or may have a structure containing a plurality of the compounds described above.

The alumina contained in the second layer 15 can be evaluated by analyzing the above-mentioned compounds by X-Ray Diffraction (XRD: X-Ray Diffraction), and observing the distribution of the peak values.

The content ratio of the titanium compound in the first layer 13 and the content ratio of the alumina in the second layer 15 are not limited to specific values. For example, the first layer 13 contains a titanium compound as a main component, and the second layer 15 contains alumina as a main component. The "main component" as used herein means a component having the largest mass% value as compared with other components, as described above.

The first layer 13 may contain a component other than a titanium compound, and the second layer 15 may contain a component other than alumina. For example, when the first layer 13 contains alumina and the second layer 15 contains a titanium compound, the adhesiveness between the first layer 13 and the second layer 15 is improved.

The first layer 13 is configured to show the following inclination angle degree distribution chart: when the inclination angle of the normal line of the {112} plane as the crystal plane of the crystal grain with respect to the normal line of the surface is measured, the total ratio of the degrees in which the highest peak of the inclination angle appears in the inclination angle division range of 0 to 10 DEG and in the inclination angle division range of 0 to 10 DEG is 45% or more of the entire degrees in the inclination angle degree distribution chart, whereby the high-temperature strength can be improved.

The measurement of the tilt angle can be evaluated by, for example, measurement using the back scattered Electron Diffraction (EBSD) method. An example of the measurement using the back scattered electron diffraction method is shown below.

First, the second layer 15 existing on the first layer 13 is removed by grinding, polishing, or the like, and the first layer 13 is exposed. Next, the surface on which the first layer 13 is exposed is polished to smooth the surface, and the measurement site is ion milled.

The surface of the first layer thus exposed, i.e., the polished surface, was irradiated with an electron beam at a thickness of about 40X 25 μm²In the range of (2), the tilt angle formed by the normal line to the {112} plane was measured at intervals of 0.1 μm. Then, it is preferable that the measurement tilt angle within the range of 0 to 45 ° among the measurement tilt angles is set to 0.25 ° or lessThe distances are divided.

In addition, the coating 5 of the present invention has voids 21 inside the first layer 13 as shown in fig. 4. Specifically, the coating 5 has a plurality of pores 21 arranged in the first layer 13 so as to be aligned in a direction along the boundary 16 between the first layer 13 and the second layer 15 in a cross section perpendicular to the first surface 7 of the base 3.

In a cross section orthogonal to the first surface 7, an average value of widths w1 of the holes 21 in a direction parallel to the first surface 7 is smaller than an average value of widths w2 of the adjacent holes 21, that is, the first portion X. In the coated cutting tool 1 having such a structure, it is possible to suppress a decrease in strength of the first portion X, and to obtain high impact resistance in the hollow 21.

Therefore, the effect of reducing the impact by the void 21 while suppressing the deterioration of the bondability between the first layer 13 and the second layer 15 can be obtained.

In the evaluation of the average value of the widths w1 of the holes 21 in the direction parallel to the first surface 7, it is not necessary to evaluate the widths w1 of all the holes 21 in the cross section perpendicular to the first surface 7, and the evaluation may be performed based on the average value of the widths w1 of about 10 holes 21 arranged in a row in the cross section. For example, a 10 μm square region including the boundary between the first layer 13 and the second layer 15 may be extracted in a cross section perpendicular to the first surface 7, and the width w1 of the hole 21 in the region may be measured. The average value of the width w2 of the first portion X may be evaluated based on the average value of the intervals between the 5 holes 21 arranged in the cross section.

The voids 21 may be present in the first layer 13. For example, the structure may be located not only in the first layer 13 as shown in fig. 4, but also in the first layer 13 and the second layer 15 as shown in fig. 5. In fig. 5, an imaginary line segment along the boundary between the first layer 13 and the second layer 15 is indicated by a one-dot chain line, and the void 21 located in the second layer 15 is arranged along the boundary between the first layer 13 and the second layer 15.

The arrangement of the voids 21 along the boundary between the first layer 13 and the second layer 15 means that the intervals from the plurality of voids 21 to the boundary between the first layer 13 and the second layer 15 are within ± 20% of the average value. In the case where the first layer 13 contains titanium carbonitride as a titanium compound and the second layer 15 contains α -alumina as alumina from the viewpoint of heat resistance and durability of the coated tool 1, when the plurality of pores 21 are located in the first layer 13, the durability of the coated tool 1 can be further improved.

This is because titanium carbonitride, although having a higher hardness than α -alumina, has a lower impact resistance, and therefore, when the pores 21 are located in the first layer 13, the first layer 13 can have an improved impact resistance due to the pores 21, and the durability of the coated cutting tool 1 can be further improved.

The size of the pores 21 is not particularly limited, and may be set to 20 to 200nm, for example. When the size of the void 21 is 20nm or more, the effect of relaxing the impact by the void 21 can be improved. In addition, when the size of the void 21 is 200nm or less, the strength of the first layer 13 is easily maintained. The size of the void 21 in the present embodiment is the maximum value of the width w1 of the void 21 in the cross section perpendicular to the first surface 7.

In addition, the shape of the void 21 is not particularly limited, but in a case where, in a cross section orthogonal to the first face 7, the width w1 in the direction parallel to the first face 7 is larger than the height h1 in the direction orthogonal to the first face 7, in other words, in a case where the average value of the width w1 in the direction parallel to the first face 7 of the void 21 is larger than the average value of the height h1 in the direction orthogonal to the first face 7 of the void 21, the ratio of the void 21 can be suppressed and the impact resistance can be further improved. This is for the following reason.

When a workpiece is cut to produce a cut product, a cutting load is easily applied to the coating 5 in a direction perpendicular to the first surface 7. At this time, in the case where the hole 21 has a shape in which the width w1 in the direction parallel to the first surface 7 is larger than the height h1 in the direction orthogonal to the first surface 7, the cutting load can be absorbed over a wide range of the hole 21 without increasing the size of the hole 21 more than necessary. Therefore, the ratio of the voids 21 can be suppressed and the impact resistance can be further improved.

Specifically, when the ratio of the average value of the width w1 of the hole 21 in the direction orthogonal to the first surface 7 to the average value of the height h1 of the hole 21 in the direction parallel to the first surface 7 is 1.2 or more, the cutting load is easily absorbed over a wide range of the hole 21. In addition, when the ratio is 2 or less, the deformation amount of the cavity 21 in the direction orthogonal to the first surface 7 is easily secured, and therefore the cutting load is easily and stably absorbed in the cavity 21.

When Rz is defined as the maximum height of the boundary between the first surface 7 and the second surface 9 in the cross section orthogonal to the first surface 7, when the average value of the heights h1 in the direction orthogonal to the first surface 7 of the pores 21 is smaller than Rz, the durability of the coating layer 5 is easily suppressed from decreasing.

The coated cutting tool 1 according to the invention has a high impact resistance due to the deformation of the first portion X of the first layer 13 between adjacent cavities 21 and of the plurality of cavities 21. Here, when the average value of the widths of the holes 21 in the direction orthogonal to the first surface 7 is smaller than Rz, the imaginary line connecting the adjacent holes 21 is represented by a zigzag shape bent to be larger than the width of the hole 21.

When the imaginary line is represented by the above-described shape, even if a crack is generated in one first portion X, the crack hardly progresses toward the first portion X located adjacent to the first portion X in which the crack is generated. Therefore, the durability of the coating 5 is difficult to be reduced.

In addition, in the cross section orthogonal to the first surface 7, even when the average value of the distance d1 from the void 21 to the boundary between the first layer 13 and the second layer 15 is larger than the average value of the width w2 of the first portion X, the durability of the coating layer 5 is less likely to decrease.

This is because, in the above case, the distance from the void 21 to the boundary between the first layer 13 and the second layer 15 can be sufficiently secured as compared with the first portion X, and therefore, even if a crack is generated in one first portion X, the crack is hard to reach the boundary between the first layer 13 and the second layer 15. Since the crack is hard to reach the boundary between the first layer 13 and the second layer 15, the bondability between the first layer 13 and the second layer 15 is hard to be reduced.

Voids 21 are located in first layer 13 and are located away from the boundary of first layer 13 and second layer 15. Here, in the case where the average value of the distance d1 from the void 21 to the boundary of the first layer 13 and the second layer 15 is larger than the average value of the height h1 of the void 21 in the direction orthogonal to the first surface 7 in the cross section orthogonal to the first surface 7, the impact resistance in the coating 5 is improved, and the adhesiveness of the first layer 13 and the second layer 15 is less likely to be reduced.

This is because the distance from the void 21 to the boundary between the first layer 13 and the second layer 15 can be sufficiently secured as compared with the size of the void 21, and therefore, even when the void 21 is deformed by absorbing the cutting load, the boundary between the first layer 13 and the second layer 15 is not deformed or the deformation amount becomes sufficiently small. Since the boundary between the first layer 13 and the second layer 15 is less likely to be deformed greatly, the bondability between the first layer 13 and the second layer 15 is less likely to be reduced.

Examples of the material of the substrate 3 include inorganic materials such as cemented carbide, cermet, and ceramics. The material of the substrate 3 is not limited to these materials.

Examples of the composition of the cemented carbide include WC (tungsten carbide) -Co, WC-TiC (titanium carbide) -Co, and WC-TiC-TaC (tantalum carbide) -Co. Herein, WC, TiC and TaC are hard particles, and Co is a binder phase. The cermet is a sintered composite material in which a metal and a ceramic component are combined. Specifically, examples of the cermet include compounds containing TiCN, TiC, or TiN (titanium nitride) as a main component.

The substrate 3 may have a through-hole 23 that penetrates the first surface 7 and a surface located on the opposite side of the first surface 7. The through hole 23 can be used to insert a fixing member for fixing the coated cutting tool 1 to the holder. Examples of the fixing member include a screw and a clamp member.

The size of the substrate 3 is not particularly limited, and for example, in the present embodiment, the length of one side of the first surface 7 is set to about 3 to 20 mm. The height from the first surface 7 to the surface opposite to the first surface 7 is set to be about 5 to 20 mm.

< manufacturing method >

Next, an example of a method for manufacturing the coated cutting tool 1 of the present invention will be described.

First, a metal powder, a carbon powder, and the like are appropriately added to an inorganic powder selected from carbide, nitride, carbonitride, oxide, and the like of a cemented carbide that can be formed into the matrix 3 by firing, and mixed to prepare a mixed powder. Next, the mixed powder is molded into a predetermined cutter shape by a known molding method to produce a molded body. Examples of the molding method include press molding, cast molding, extrusion molding, and cold isostatic press molding. The molded body is fired in a vacuum or in a non-oxidizing atmosphere to produce the substrate 3. If necessary, the surface of the base body 3 may be subjected to a grinding process and a honing process.

Next, the coating 5 is formed on the surface of the substrate 3 by a Chemical Vapor Deposition (CVD) method.

First, the titanium nitride layer 17 (underlayer) in the first layer 13 is formed. In the presence of hydrogen (H)₂) The gas is mixed with 0.5 to 10 vol% of titanium tetrachloride gas and 10 to 60 vol% of nitrogen gas to prepare a first mixed gas used as a reaction gas. Introducing the first mixed gas into the furnace chamber at a gas partial pressure of 10 to 20kPa, and forming a titanium nitride layer 17 at a temperature of 830 to 870 ℃.

Next, the first region 19a in the first layer 13 is formed. A second mixed gas is produced by mixing 0.5 to 10 vol% of titanium tetrachloride gas, 1 to 60 vol% of nitrogen gas, and 0.1 to 3.0 vol% of acetonitrile gas in hydrogen gas. This second mixed gas was introduced into the furnace and the acetonitrile gas was increased by 0.2 vol% per hour from the start of film formation. At this time, the second mixed gas is introduced into the furnace chamber at a gas partial pressure of 6 to 12kPa, and the first region 19a containing MT-titanium carbonitride is formed into a film at a temperature range of 830 to 870 ℃. By changing the amount of acetonitrile gas in this way, the coated cutting tool 1 of the present invention can be obtained.

Then, the intermediate region 19c is formed. In thatMixing 3 to 30 vol% of titanium tetrachloride gas, 3 to 15 vol% of methane gas, 5 to 10 vol% of nitrogen gas, and 0.5 to 5 vol% of carbon dioxide (CO)₂) Gas to produce a third mixed gas. Introducing the third mixed gas into the furnace chamber at a gas partial pressure of 6 to 12kPa, and forming a film in the intermediate region 19c having a thickness of about 50 to 300nm at a temperature of 980 to 1050 ℃. The third mixed gas contains carbon dioxide gas, and thereby the hollow holes 21 are formed in the intermediate region 19 c. If the above conditions are set, the following coated cutting tool 1 can be produced: in a cross section orthogonal to first surface 7, an average value of widths w1 of holes 21 in a direction parallel to first surface 7 is smaller than an average value of intervals w2 of adjacent holes 21.

In this case, since the thickness of the intermediate region 19c is as thin as about 50 to 300nm, the voids 21 formed in the intermediate region 19c can be arranged so as to be aligned in a direction along the boundary between the first layer 13 and the second layer 15.

Next, the second region 19b of the first layer 13 is formed. A fourth mixed gas is produced by mixing 1 to 4 vol% of titanium tetrachloride gas, 5 to 20 vol% of nitrogen gas, 0.1 to 10 vol% of methane gas, and 0.5 to 10 vol% of carbon dioxide gas in a hydrogen gas. Introducing the fourth mixed gas into the furnace chamber at a gas partial pressure of 5 to 45kPa, and forming a film of the second region 19b containing HT-titanium carbonitride having a thickness of about 0.3 to 3 μm at a temperature of 950 to 1050 ℃.

Next, the second layer 15 is formed. Setting the film forming temperature to 950-1100 ℃, setting the gas pressure to 5-20 kPa, and mixing 5-15 vol% of aluminum trichloride (AlCl) in hydrogen gas for the composition of the reaction gas₃) Gas, 0.5 to 2.5 vol% hydrogen chloride (HCl) gas, 0.5 to 5.0 vol% carbon dioxide gas, and 0 to 1 vol% hydrogen sulfide (H)₂S) gas to produce a fifth mixed gas. The fifth mixed gas is introduced into the furnace chamber to form the second layer 15.

Thereafter, if necessary, a portion of the cutting edge 11 on the surface of the coating 5 after film formation is polished. When such a grinding process is performed, the workpiece is easily prevented from adhering to the cutting edge 11, and therefore the coated tool 1 having more excellent chipping resistance is obtained.

The above-described manufacturing method is an example of a method for manufacturing the coated cutting tool 1 of the present invention. Therefore, it is needless to say that the coated cutting tool 1 of the present invention is not limited to the coated cutting tool manufactured by the above-described manufacturing method. For example, a third layer may be formed on the second layer 15.

In the case of producing the coated cutting tool 1 in which the average value of the width w1 in the direction parallel to the first surface 7 of the cross-sectional hollow hole 21 perpendicular to the first surface 7 is larger than the average value of the height h1 in the direction perpendicular to the first surface 7 of the hollow hole 21, it is desirable that the film is formed to a thickness of about 50 to 150nm by adjusting the time at the time of film formation of the intermediate region 19 c.

In the production of the coated cutting tool 1 in which the average value of the distance d1 from the void 21 to the boundary 16 in the cross section orthogonal to the first surface 7 is larger than the average value of the height h1 of the void 21 in the direction orthogonal to the first surface 7, it is desirable that the time adjustment is performed at the time of film formation of the intermediate region 19c, and after the film formation is performed to a thickness of about 50 to 150nm, the time adjustment is performed at the time of film formation of the second region 19b in the first layer 13, so that the second region 19b is formed to a thickness of about 0.5 to 3 μm.

In the production of the coated cutting tool 1 in which the average value of the distance d1 from the hole 21 to the boundary 16 in the cross section perpendicular to the first surface is larger than the average value of the interval w2 between adjacent holes 21, it is desirable that the second region 19b in the first layer 13 is formed with a thickness of about 0.5 to 3 μm by adjusting the time when forming the second region 19 b.

< cutting tool >

Next, the cutting insert 101 of the present invention will be described with reference to the drawings.

As shown in fig. 6 and 7, the cutting insert 101 includes: a shank 105 which is a rod-shaped body extending from a first end (upper in fig. 6 and 7) toward a second end (lower in fig. 6 and 7) and has a pocket 103 located on a first end side; and the above-described coated cutting tool 1, which is located in the pocket 103. In the cutting insert 101 of the present invention, the coated insert 1 is attached so that a portion of the ridge line used as a cutting edge protrudes from the tip of the shank 105.

The pocket 103 is a portion to which the coating cutter 1 is fitted, and has a seating surface parallel to the lower surface of the shank 105, and a constraining side surface inclined with respect to the seating surface. The pocket 103 is open at a first end side of the shank 105.

The coating tool 1 is located in the pocket 103. In this case, the lower surface of the coated cutting tool 1 may be in direct contact with the pocket 103, or a sheet may be sandwiched between the coated cutting tool 1 and the pocket 103.

The coating tool 1 is assembled such that a portion of the ridge line used as a cutting edge protrudes outward from the shank 105. The coating cutter 1 is mounted to the shank 105 by means of screws 107. That is, the coated cutting tool 1 is attached to the holder 105 by inserting the screw 107 into the through hole of the coated cutting tool 1, inserting the tip of the screw 107 into a screw hole (not shown) formed in the pocket 103, and screwing the screw portions together.

As the tool shank 105, steel, cast iron, or the like can be used. In particular, steel having high toughness is preferably used for these members.

In the examples shown in fig. 6 and 7, a cutting tool used in so-called turning is exemplified. Examples of the turning include inner diameter machining, outer diameter machining, and grooving. The cutting tool is not limited to use in turning. For example, the coated tool 1 of the present invention may also be used as a cutting tool for use in milling.

Description of reference numerals:

1. coating cutter

3. base

5. coating

7. first face

9. second face

11. cutting edge

13. first layer

15. second layer

16. boundary of first layer and second layer

17 titanium nitride layer

19. titanium carbonitride layer

19 a. first region

19 b. second region

19 c.intermediate region

21. hollow hole

23. through hole

101. cutting tool

103. knife groove

105. knife handle

107. set screw.