KR20200041947A - Cutting tool and its manufacturing method - Google Patents

Abstract

It is to provide a cutting tool having both good adhesion and smoothness and a method for manufacturing the same. A cutting tool made of a composite material comprising a ceramic phase and a metal phase, wherein the blade end portion of the cutting tool has a blade end ridge line and a blade end surface constituting the blade ridge line, and the blade end surface has the ceramic phase and the metal phase. The ceramic phase protrudes from the composite material layer, the ceramic phase intermittently exists, has a surface portion lacking the metal phase, and the surface roughness of the surface portion satisfies the arithmetic average roughness Ra≤0.1㎛, and asymmetry degree Rsk≤-0.01 A cutting tool and a manufacturing method therefor.

Description

Cutting tool and its manufacturing method

The present invention relates to a cutting tool having good durability and a method for manufacturing the same.

A composite alloy composed of a composite material composed of a hard phase represented by ceramics and a metal phase represented by Ni, Co, Fe, etc. is applied to the tool because of its excellent impact resistance at room temperature and high temperature. For example, this composite material is also applied to cutting blades for cutting paper, resin films, metal plates, and the like, and various studies have been made in the past. For example, in Citation Reference 1, at least one of the cutting blades selected from the group of Cr, V, and Ta contains 0.3 to 3.0% by mass and 8 to 15% by mass of Co in terms of carbide, and the cup It has been described for a cutting blade characterized by comprising a cemented carbide as WC particles with an addition average particle diameter of 0.1 to 0.5 µm.

In addition, the cited reference 2 is characterized in that the WC used for cutting or cutting such as a multilayer capacitor, a multilayer ceramic substrate, or a ceramic green sheet has a particle diameter of 1.0 µm or less, and is composed of a cemented carbide having a Co content of 8 to 20% as a bonding phase. It is described with respect to the thin cutting blade.

Japanese Patent Publication 2004-291137 Japanese Patent Publication No. 2002-86387

In the cutting tool made of a composite alloy as described above, when the material to be processed is a metal material or an amorphous thin ribbon, there is a problem that abrasion or blade deterioration occurs due to adhesion caused by contact between metals. there was. When this wear occurs at the tip of the blade, a burr is generated at the end of the workpiece to be cut due to a decrease in the degree of lifting of the knife, so that the precision required for the product cannot be achieved. Therefore, it is required to improve the adhesion resistance while maintaining the smoothness of the working surface of the cutting tool and the degree of knife lifting so as not to generate abrasive powder by attacking the workpiece according to the demand for better precision or use in a more severe environment. Is becoming. In response to such a request, the invention of Patent Document 1 described above is an excellent invention for increasing the hardness of the surface of a cemented carbide, but it is not described about suppression of surface state deterioration by removing Co, leaving room for examination. In addition, the invention of Patent Document 2 is an invention in which irregularities are formed on the surface in order to improve the adhesion of the diamond film, and there is a possibility that a desired surface quality may not be obtained, especially in a precision cutting tool. It is an object of the present invention to provide a cutting tool having good adhesion and smoothness and a method for manufacturing the same.

This invention is made | formed in view of the subject mentioned above.

That is, one aspect of the present invention is composed of a composite material including a ceramic phase and a metal phase, and is a cutting tool,

The blade end portion of the cutting tool has a blade end ridge and a blade end construction surface constituting the edge ridge,

The blade end construction surface has a surface portion where the ceramic phase intermittently exists and the ceramic phase is intermittent because the ceramic phase protrudes from the composite material layer having the ceramic phase and the metal phase,

The surface roughness of the surface portion is a cutting tool characterized in that it satisfies the arithmetic average roughness Ra≤0.1µm and the asymmetry degree Rsk≤-0.01.

Preferably, the surface portion of the cutting tool has an asymmetry of Rsk≤-1.0.

Preferably, the ceramic phase is WC or TiC, and the metal phase is at least one selected from Co, Ni, and Fe.

Preferably, at least one carbide, nitride, oxide, carbonitride, or boride film selected from the group of elements consisting of groups 4a, 5a, and 6a on the surface portion, or a diamond-like carbon film is at least one layer. It is characterized by being formed.

In addition, another aspect of the present invention is a method of manufacturing a cutting tool composed of a composite material comprising a ceramic phase and a metal phase,

The blade end portion of the cutting tool has a blade end ridge and a blade end construction surface constituting the edge ridge,

A shape processing step of grinding a portion of the tool base made of the composite material to be a blade end surface to adjust Ra ≤ 0.1 μm;

After the shape processing step, the part serving as the blade end surface of the tool substrate adjusted to Ra ≤ 0.1 µm is etched, and the metal phase of the part serving as the blade end surface is removed, so that the blade end surface is the ceramic phase and the metal phase. The ceramic phase is projected from the composite material layer, and the ceramic phase is intermittently present, and the metal phase is configured to have a surface part lacking, and the surface modification process having a surface roughness of Rsk≤-0.01 is provided. It is a manufacturing method of cutting tools.

Preferably, the surface modification process is wet etching using an acidic solution.

(Effects of the Invention)

According to the present invention, a cutting tool having both good adhesion and smoothness can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a mimetic diagram of a metal stand cutting device showing the slitter which is a cutting tool of this embodiment.
FIG. 2 is an enlarged schematic view of part A of the cutting tool of the present embodiment shown in FIG. 1.
It is a schematic diagram which expanded and observed part A in the conventional cutting tool or the cutting tool before a surface modification process.
4 is an enlarged photograph of both sides of a steel strip cut using the cutting tool of the present embodiment.
5 is a graph showing the amount of abrasive powder generated during cutting of the cutting tool of the present invention and the cutting tool of the comparative example.

The present invention will be described in detail below. However, the present invention is not limited to the embodiments listed herein, and combinations and improvements can be appropriately made without departing from the technical spirit of the invention.

The cutting tool of the present invention is a cutting tool composed of a composite material in which two phases of a ceramic phase (hereinafter also referred to as a hard phase) and a metal phase as a binder (bonding phase) are mixed. This cutting tool is characterized by having both a hard phase advantage (excellent strength) and a metal phase advantage (high ductility and toughness).

The ceramic phase of the cutting tool of the present invention is W (tungsten), Cr (chromium), Mo (molybdenum), V (vanadium), Zr (zirconium), Al (aluminum), Si (silicon), Nb (niobium), Ta It is preferable that it is at least one selected from carbides, nitrides, carbonitrides, oxides and borides of (tantalum) and Ti (titanium). More preferably, it is at least one selected from carbides, nitrides, carbonitrides, oxides and borides of W or Ti.

Further, the metal phase of the cutting tool of the present invention is preferably selected from at least one of Co (cobalt), Ni (nickel), Fe (iron), W (tungsten), and Mo (molybdenum). More preferably, it is at least 1 sort (s) selected from Co, Ni, and Fe.

Further, the cutting tool of the present embodiment is composed of a WC-Co composite material in which tungsten carbide (WC) is selected on the ceramic and Co is selected on the metal unless specifically described.

1 shows a schematic view of a cylindrical blade (hereinafter also referred to as a slit blade) as an example of the cutting tool of the present embodiment. The present invention can be used not only for the cylindrical blade, but also for shearing tools such as punches for knitting. In addition, it is applicable to a shearing tool having an acute angle with a sharp edge, such as a shear blade. The cylindrical blade of this embodiment is used for a slitter for cutting the metal strip 12 into a metal strip 13 of a desired width as shown in Fig. 1, and the cylindrical upper blade 1A and the cylindrical lower blade 1B are used. A certain clearance is formed and arranged, and the workpiece is cut by shearing the upper and lower blades. The cylindrical blade has a blade ridge (4) (solid white line) and a blade tip construction surface (6, 7) constituting the blade tip (hereinafter, if the blade construction surface 6 is circumferential, the blade construction surface 7 is also referred to as a side surface) ). 2 is an enlarged view of part A of the cutting tool in FIG. 1. The cutting tool of the present embodiment is composed of a composite material including a ceramic phase 2 and a metal phase 3, as shown in Fig. 2, and the blade ridge line 4 and the blade configuration surface constituting the blade end of the cutting tool ( In 6, 7), the ceramic phase 2 protrudes from the composite material layer so that the ceramic phase 2 exists intermittently (discontinuously) in the in-plane direction of the blade end surface 6, 7, and the metal phase 3 is It consists of a lacking surface part, and the surface roughness of the blade end surface 6, 7 is characterized by satisfying the arithmetic mean roughness Ra≤0.1㎛ and the asymmetry degree Rsk≤-0.01. Here, the term "surface portion where the ceramic phase is intermittently and lacks the metal phase" indicates that the metal phase is substantially absent. As in the embodiment of the manufacturing method to be described later, the blade ridge and the blade construction surface are produced by removing the metal phase from the portion which becomes the blade ridge and blade construction surface of the tool base as shown in FIG. 3 composed of a ceramic phase and a metallic phase. By the removal of the metal phase, the cutting edge ridge of the cutting tool of the present embodiment is formed with a concave portion 5 recessed into the center of the rotation axis rather than the portion in contact with the workpiece, thereby forming an intermittent cutting edge ridge. By having such a ridge edge, the cutting tool of the present embodiment improves the bite performance to the work piece, and suppresses the decrease in shear stress caused by the work piece sliding near the cutting edge to improve the cut performance. It is possible. In addition, the blade end configuration surface is similar to the blade ridge, and the ceramic phase is intermittently present, and the metal phase that is soft and easy to adhere to the workpiece by having the metal phase lacks a surface that does not exist on the blade ridge and blade end surface of the cutting tool. Since it is possible to improve the adhesion resistance of the cutting tool. In addition, it is possible to perform good cutting without causing defects in the cutting surface of the secondary shear surface or excessive burrs in the cutting surface of the workpiece. Moreover, since the unevenness is appropriately formed on the blade end surface, the tool tends to be easily pulled out of the workpiece during cutting. As a result, it is possible to expect the effect of suppressing the curling of the burrs generated in the workpiece to reduce the mixing of the broken burrs into the product. In addition, although the cutting edge ridge of the cutting tool in this embodiment is discontinuous as described above, the ceramic phase forming the cutting edge ridge is intermittent as shown in Fig. 2, but can be smoothly connected by a straight line and a curve of constant curvature. (The dotted line portion 5a is a virtual edge ridge). The shape of the blade can improve the bite performance of the blade and perform smooth shearing.

In the present embodiment, it is said that the metal phase is not substantially present because the part that is not completely removed may be present in the removal of the metal phase described above. Compared to most parts (base parts) of the cutting tool composed of the ceramic phase and the metal phase, the amount of the metal phase in the blade ridge and the blade construction surface is clearly different, and is composed of a ceramic phase in which there is substantially no metal phase. It is easy to specify the part that is made. In addition, the blade end ridge line and the blade end surface may be made of a material other than the ceramic phase and the voids, or a metal phase filling the ceramic phase and the voids. The voids are formed by removing the metal phase, and may be left as voids, or the voids may be filled with a material other than the metal phase. For example, by filling a void with a resin-based material containing polytetrafluoroethylene as a main component, it is possible to prevent the exposure of the metal layer and suppress the drop of hard particles. In addition, by filling the resin-based material as described above, the effect of suppressing the curling of the burrs generated in the work material can also be expected. Of course, some voids may remain.

It is preferable that the portion (surface portion) formed by protruding the ceramic image of the present embodiment is formed at least in the range of 0.2 µm in the depth direction from the blade end construction surface. Thereby, the above-described adhesion resistance can be further improved (hereinafter, the layer-shaped portion formed along the in-plane direction of the blade end constitutional surface composed of the ceramic phase from which the metal phase is removed is also referred to as a hard reinforcing layer). The thicker the hardened layer is, the more advantageous the above-described advantageous effect can be obtained for a long period of time, so it is more preferably formed in the depth direction (direction perpendicular to the blade configuration surface) to a range of 0.5 µm, and formed to a range of 1 µm. It is more preferable to be. Further, as described later, a coating layer may be formed on the blade end surface. Further, in this case, the range in the depth direction of the surface portion (hard reinforcement layer) indicates the depth from the blade end surface in the absence of the coating layer. In addition, it is preferable that the diameter of the ceramic phase is 1 µm or more in order to make it easier to form voids formed in the hard reinforcement layer. In addition, the diameter of the ceramic phase can be obtained, for example, by observing the surface and the cross-section of the cutting tool at a magnification of 3000 to 20,000, and calculating the average value of the equivalent circle of the ceramic phase present in the field of view. The upper limit of the thickness of the hard reinforcing layer is not particularly limited, but may be about 15 μm in production. In addition, according to the manufacturing method of the present invention to be described later, since the hardened layer is formed almost uniformly on the entire surface of the blade ridge line and the blade surface by etching, a cross section of the blade surface, for example, using a measuring device such as a scanning electron microscope (SEM) It is good to check the range of about 10 µm to 20 µm in the in-plane direction.

Further, when the ratio of the area of the ceramic phase to the sum of the area of the ceramic phase and the area of the metal phase as the area ratio by cross-sectional observation is called the ceramic phase ratio, the ceramic of the hardened layer is harder than the ceramic phase ratio of the main part of the cutting tool described above. It is preferable that the phase ratio is high and the ceramic phase ratio of the hard reinforced layer is 99% or more. An example of a method for measuring this ceramic phase ratio is shown. First, the cutting edge of the cutting tool is cut toward a direction perpendicular to the surface, and a photograph is taken at a predetermined magnification using a scanning electron microscope (SEM) so that the cutting edge of the cutting edge enters the field of view. A line B having a substantially flat-shaped or curved-shaped blade end surface that is a contact surface with the workpiece is connected to the line A, and the line B parallel to the depth direction of the cutting tool at a position of at least 0.2 μm in the depth direction from the blade end surface. To write. The ratio of the area ratio of the ceramic phase when the area ratio excluding the voids from the area surrounded by the line A, the line B, and the photo end portion is 100% is taken as the ceramic phase ratio. In addition, the "approximate plane" in the present embodiment refers to a shape that can be regarded as a plane as a whole except for minute irregularities present on the upper surface of the ceramic phase serving as the contact surface.

In the cutting tool of this embodiment, it is also important that the roughness of the blade end surface is arithmetic average roughness Ra (according to JIS-B-0601-2001) of 0.1 µm or less, and the asymmetry Rsk is -0.01 or less. As a result, in the cutting tool of the present invention, since the roughness curve of the blade end surface in contact with the workpiece is wider on the convex portion and can suppress the formation of a sharp convex portion, wear from the convex portion of the contact surface as a starting point However, it is possible to significantly suppress the occurrence of goling and to exhibit good sliding characteristics. In addition, for example, when the contact surfaces of the cutting tool and the workpiece are smooth, and lubricant is used at the time of cutting, it is difficult to impregnate the lubricating oil in the places where the contact surfaces are in contact with each other, but in the present invention, Rsk is -0.01. It is possible to improve the impregnation properties of the lubricating oil by exposing a suitable recess (hereinafter, also referred to as an air gap) on the working surface of the cutting tool as below and to exhibit good sliding properties. In addition, when the working surfaces of the cutting tool and the workpiece are smooth, there is a possibility of vacuum adhesion, but the contact surface between the cutting tool and the workpiece can be prevented from becoming a vacuum by the above-described concave portion. It is thereby possible to obtain good sliding characteristics. It is preferable that Rsk of the present invention is -1.0 or less in order to obtain the above-described effect more reliably. In addition, it is preferable that the blade ridge of the present embodiment also has a roughness curve similar to that of the blade construction surface. The present invention exerts an effect when the material to be processed is made of a metal material. In particular, according to the cutting tool of the present invention, stable cutting processing can be expected even for an amorphous alloy thin ribbon which has been difficult to process conventionally.

The cutting tool of this embodiment has at least one carbide, nitride, oxide, carbonitride, or boride selected from the group of elements consisting of groups 4a, 5a, and 6a on the blade ridge and the surface portion to further improve wear resistance. A film composed of may be formed. Preferably, a coating made of Cr-based nitride, Ti-based nitride or Ti-based carbonitride is applied. More preferably, a coating made of TiCN, AlCrN, TiSiN, TiAlN, AlCrSiN, TiAlSiN, TiAlCrSiN is applied. When AlCrSiN is applied, the composition formula of Al _x Cr _y Si _z (x + y + z = 100) is controlled by 20 <x <75, 25 <y <75, and 0 <z <10 in order to further improve wear resistance. It is preferable, and it is more preferable to control with 50 <x <55, 45 <y <50, and 0.1 <z <1. In addition, when TiAlSiN is applied to the coating, the composition formula of Ti _x Al _y Si _z (x + y + z = 100) enters the range of 25 <x <75, 20 <y <75, 0.0 <z <10. Control. The film preferably has a thickness of 0.1 µm to 5.0 µm, and more preferably 0.5 µm to 2.0 µm. This is because if the film thickness is too thick, there is a possibility that the ceramic convex portions cannot be traced, so that advantageous effects such as adhesion resistance described above may not be exerted. If the film thickness is too thin, there is a possibility that the wear resistance improving effect may not be sufficiently obtained. . Here, when the Al _x Cr _y Si _z N film is used, the x value increases from the substrate side toward the film surface side, and may have a gradient composition in which the y value decreases. Thereby, the adhesive strength with a base material can further be improved.

Further, it is preferable that the surface roughness of the film is 0.06 µm or less with an arithmetic average roughness Ra and 1.0 µm or less with a maximum height Rz. Thereby, the unevenness | corrugation on a film surface can be suppressed as a starting point of abrasion, and abrasion resistance can further be improved.

The cutting tool of this embodiment can also apply a diamond-like carbon film (hereinafter also referred to as a DLC film) in addition to the above-described film. This DLC film can also improve the abrasion resistance of the cutting tool, and since the DLC film is formed on the surface of the film so as to follow the unevenness of the surface of the hard reinforcing layer, it can be expected to exert the advantages of forming the above-mentioned pores. . In order to obtain higher hardness and to improve adhesion with a cutting tool, the content of hydrogen atoms on the surface of the DLC film should be 0.5 atomic% or less, and the nitrogen content should be 2 atomic% or less. You can. In addition, better abrasion resistance can be expected to be improved by setting the hydrogen content at the interface side of the DLC film with the hard reinforcing layer to 0.7 atomic% or more and 7 atomic% or less and the nitrogen content to 2 atomic% or more and 10 atomic% or less. The content of this hydrogen atom can be determined, for example, by an elastic semiconducting particle detection method (ERDA analysis). In addition, the content of the nitrogen atom can be determined, for example, by Auger electron spectroscopy (AES analysis).

DLC coatings may contain metal (including semi-metal) elements to impart properties such as wear resistance and heat resistance, and may be contained in the form of compounds such as metals, alloys, carbides, nitrides, carbonitrides, carbonitrides, and borides It is good. Preferably, the content ratio (atom%) of the metal (including semimetal) element is 2% or more, and more preferably 5% or more. However, when the content ratio of the metal (including semi-metal) element increases, the sliding property tends to decrease. Therefore, the content ratio (atom%) of the metal (including semimetal) element can be set to 20% or less, more preferably 10% or less. In addition, the thickness of the DLC film can be set to 0.1 µm to 1.5 µm to further improve durability or adhesion to the mold, and may be set to 0.1 µm to 1.2 µm, and the film of the DLC film is provided to provide sufficient wear resistance to the mold. The thickness may be set to 0.2 µm or more. In order to achieve smooth surface roughness and excellent wear resistance at the same time, the film thickness of the DLC film may be set to 0.6 µm to 1.2 µm. The surface roughness of this DLC film is also preferably 0.06 µm or less in arithmetic average roughness Ra and 1.0 µm or less in maximum height roughness Rz. More preferably, when Ra has a smoothness of 0.03 µm or less and Rz of 0.5 µm or less, it is possible to reduce surface defects as a starting point for welding of the workpiece. More preferably, Ra is 0.02 µm or less and Rz is 0.3 µm or less.

Next, the manufacturing method of the present invention will be described.

The manufacturing method of the present invention includes a shape processing process in which a portion serving as a blade end surface of a tool base material composed of a composite material containing a ceramic phase and a metal phase is Ra ≤ 0.1 μm, and after the shape processing process, Ra ≤ 0.1 μm. It is characterized by having a surface modification process for etching the surface of the adjusted tool substrate and removing a metal layer near the surface. The tool base made of this composite material can be produced by an existing method, for example, after pressing and molding a mixed powder of ceramic powder and metal powder into a predetermined shape, at a temperature of 1250 to 1550 ° C under a vacuum atmosphere. It can be obtained by sintering. In addition, in order to further improve the strength of the cutting tool, when the total volume of the ceramic powder and the metal powder is 100%, the volume ratio of the metal powder is 3% to 30%. desirable. In addition, the ceramic powder is W (tungsten), Cr (chromium), Mo (molybdenum), V (vanadium), Zr (zirconium), Al (aluminum), Si (silicon), Nb (niobium), Ta (tantalum) And one of Ti (titanium) carbides, nitrides, carbonitrides, oxides and borides, more preferably W or Ti carbides, nitrides, carbonitrides, oxides and borides. The metal powder is preferably selected from at least one of Co (cobalt), Ni (nickel), Fe (iron), W (tungsten), and Mo (molybdenum), and selected from at least one of Co, Ni, and Fe. It is more preferable.

<Shape processing process>

In the manufacturing method of the present invention, a shape processing step is performed in which the surface of the portion serving as the blade end surface of the prepared tool base material is adjusted to Ra ≤ 0.1 μm by grinding, polishing, cutting and electric discharge machining. By smoothing the surface of the cutting tool, in particular, the blade end constituting surface, which is the working surface, by this shape processing step, a smooth and suitable recess is formed in the cutting tool formed through the subsequent surface modification process, Ra≤0.1㎛, and asymmetry Rsk≤ A hard reinforced layer having a surface roughness of -0.01 can be formed. The upper limit of more preferred Ra is 0.05 µm, and the upper limit of more preferred Ra is 0.02 µm. The lower limit is not particularly limited, but may be set to, for example, 0.005 μm in consideration of mass productivity. Here, the shape processing step may be a combination of a plurality of steps, or may be adjusted to Ra ≤ 0.1 μm, for example, after roughing in grinding and finishing in polishing. Existing grinding methods can be used for polishing at this time, but buff polishing using a diamond paste may be performed to reliably obtain a desired surface roughness.

<Surface modification process>

Subsequently, in the manufacturing method of the present invention, after the shape processing step, the tool base whose portion is the blade end surface is adjusted to Ra ≤ 0.1 µm is etched, and a surface modification step of removing the metal phase near the surface is performed. 3 shows an enlarged schematic view of the tool base before the surface modification step. As the metal phase 3 is removed by the above-described surface modification step, the ceramic phase is projected from the ceramic phase as shown in Fig. 2 and the composite material layer having the metal phase, and the ceramic phase intermittently exists. It can be made into the structure which lacks a metal phase. In the present invention, etching is applied to this surface modification process, and wet etching using an acidic solution or an alkaline solution or dry etching using an electric discharge plasma can be used for the etching. More preferably, wet etching, which is easy to thickly form a hard reinforcing layer composed of a ceramic phase, and easily adjusts Rsk to a negative value, is used. In this case, Ra of the blade end surface may be larger than that of the shape processing step by this surface modification step. However, since the fine processing debris bitten by the machining surface can be removed by etching during grinding, the smoothness is improved and Ra is reduced. There are cases.

In the present embodiment, when wet etching is applied to the surface modification process, an acidic solution such as hydrochloric acid, nitric acid, or aqueous water can be used as the etching solution, but it is preferable to use an aqueous solution having a high removal ability of the metal phase and easy to form a hard strengthening layer. desirable. Here, when aqua regia is used for wet etching, it is preferable that the etching treatment time is more than 30 seconds in order to reliably adjust Rsk to a value of -1.0 µm or less. The more preferable treatment time is 60 seconds or more, and the more preferable treatment time is 90 seconds or more. When dry etching is applied to the surface modification process, an existing method can be applied. In the embodiment, a cutting tool having a desired hard reinforcing layer is formed by, for example, setting the inside of a chamber generating plasma to a reduced pressure Ar atmosphere of about 2 Pa, plasmating Ar gas, and etching by applying a bias of -300 V to the substrate. Can be obtained. In addition, if the above-described processing is performed on the blade end surface, the blade end ridge can also be formed discontinuously.

In the manufacturing method of the cutting tool of the present invention, in order to further improve wear resistance, at least one kind of carbide, nitride, oxide, or boride selected from the group of elements consisting of groups 4a, 5a, and 6a on the blade ridge and the blade construction surface The film formed may be coated. Preferably, a coating made of Cr-based nitride, Ti-based nitride or Ti-based carbonitride is applied. More preferably, a coating made of TiCN, AlCrN, TiSiN, TiAlN, AlCrSiN, TiAlSiN, TiAlCrSiN is applied. When AlCrSiN is applied, in order to further improve wear resistance, the range of 20 <x <75, 25 <y <75, 0 <z <10 in the composition formula of Al _x Cr _y Si _z (x + y + z = 100) It is preferable to control to enter, and it is more preferable to control to enter the range of 50 <x <55, 45 <y <50, and 0.1 <z <1. In addition, when TiAlSiN is applied to the coating, the composition formula of Ti _x Al _y Si _z (x + y + z = 100) enters the range of 25 <x <75, 20 <y <75, 0.0 <z <10. Control. The PVD method can be used as a film forming method, but it is preferable to form a film using a sputtering method, which has fewer droplets and can obtain a smoother film surface. In the case of using the sputtering method, it is more preferable to set the bias voltage applied to the substrate to 40 to 150 V because the adhesion between the cutting tool and the film is improved while further improving the surface smoothness.

Moreover, in the manufacturing method of the cutting tool of this embodiment, in order to further improve abrasion resistance, the DLC film can be coated on the blade ridge line and the edge construction surface. Existing film forming methods such as sputtering or plasma CVD can be employed for coating the DLC film, but if the filtered arc ion plating method is used, it can be expected to coat a more smooth DLC film with fewer droplets. In addition, in order to form a DLC film having a high hardness and high adhesion to a cutting tool, in this embodiment, coating the DLC film while reducing the flow rate of a gas containing hydrogen such as nitrogen gas and / or hydrocarbon introduced into the furnace It tends to be desirable. Here, instead of introducing a hydrogen-containing gas, gas bombard treatment using a mixed gas containing hydrogen is used to remove the oxide film or contamination existing on the surface of the hard reinforced layer while containing hydrogen on the surface of the DLC film on the side of the hard reinforced layer. You may do it. The hydrogen mixed gas at this time is more preferably a mixed gas containing 4% by mass or more of hydrogen gas with respect to the total mass of the argon gas and the mixed gas.

Example

(Example 1)

A slit blade composed of a composite material selected from WC on a ceramic and Co on a metal was prepared. The volume ratio of the ceramic powder and the metal powder in this composite material was 82:18. After the portion serving as the blade tip construction surface of the cutting tool was ground to Ra = 1.5 µm with a grinding tool, the blade tip construction surface was polished to Ra = 0.005 µm by buffing using a diamond paste. Thereafter, a sample of the present invention was prepared by immersing the cutting tool after polishing in aqua regia for 60 seconds to remove Co (metal phase) to form a hard strengthening layer. Slit processing was actually performed using the obtained cutting tool, and the surface of the cutting tool after processing was observed. The material to be processed is a 13Cr stainless steel strip of the SUS420J2 system, and steel strips having different thicknesses in a range of 0.075 µm to 0.4 µm were cut in total to about 3500 m. The mailing speed of the steel strip at this time is about 60 m / min.

(Measurement of surface roughness)

The surface roughness of the blade end surface was measured for the sample of the present invention. To measure the surface roughness, TOKYO SEIMITSU CO., LTD. Stylus roughness machine (SURFCOM) was used. The measurement conditions were 4 mm evaluation length, 0.3 mm / s measurement speed, 0.8 mm cutoff value, and Gaussian filter type. As a result of the measurement, it was confirmed that the sample of the present invention has a smooth surface and few convex portions. In particular, Rsk has a negative value of -1.8. This indicates that the concave portion in the roughness curve of the working surface is formed to a deep position, and from this point, it can be estimated that the hard reinforcing layer of the present invention is formed deep.

Fig. 4 shows enlarged photographs of both sides of the steel strip cut by the slit blade of the present invention. It was confirmed from FIG. 4 that the cut surface of the steel strip cut by the slit blade of the example of the present invention shows a good cut surface in which no secondary burrs or excessive burrs are generated despite cutting in large quantities.

(Example 2)

Cutters of the present invention examples and comparative examples were prepared, and 13Cr stainless steel (0.1 mm in thickness) of the SUS420J2 system was cut to the same length. The surface modification cutter used in Example 1 was used in the present invention example, and a conventional cutter having a continuous edge ridge as shown in Fig. 3 was used in the comparative example without performing the treatment of the present invention. As a result of checking the side surface of the steel strip after cutting, the steel strip cut using the cutter of the comparative example had a maximum burr height of 3 µm at the end of cutting, while the maximum burr height at the start of cutting was 1 µm. On the other hand, it was confirmed that the steel strip cut using the cutter of the present invention example has a maximum burr height of 1 µm even at the start of the steel strip even at the end of cutting. From these results, it was confirmed that the cutter of the present invention enables better cutting than the comparative example, and even better continuous cutting is possible.

(Example 3)

Subsequently, the material to be processed was changed to a Ni alloy, and the same length as the cutter of the example of the invention and the cutter of the comparative example was cut to confirm the performance difference. Since the Ni alloy is soft, burrs are likely to be generated at the time of slit, and the generated burrs tend to break and fall out, thereby tending to form metal powder. The amount of metal powder generated was used as an index indicating the effect of suppressing the burr of the cutter. Fig. 5 shows the counting result of the abrasive powder. As shown in Fig. 5, it was confirmed that the number of counts of metal powder generated during the use of the cutter of the present invention is about 35% less than the number of counts of metal powder generated during the use of the cutter of the comparative example. Particularly, the number of metal powder counts having a maximum diameter of 100 µm or more, which tends to be a factor of deterioration in product quality, is also shown to be about 50% of the comparative example, and the cutter of the inventive example is excessively formed in the workpiece than the comparative example cutter. It was confirmed that it is possible to cut a stable material due to a small number of burrs.

1, 1A, 1B cutting tool 2 ceramic phase
3 Metal phase 4 Edge ridge
5 recess 5a virtual blade ridge
6, 7 blade end surface 12 metal stand
13 metal strips

Claims (7)

A cutting tool composed of a composite material comprising a ceramic phase and a metal phase,
The blade end portion of the cutting tool has a blade end ridge and a blade end construction surface constituting the edge ridge,
The blade end construction surface has a surface portion where the ceramic phase intermittently exists and the ceramic phase is intermittent because the ceramic phase protrudes from the composite material layer having the ceramic phase and the metal phase,
A cutting tool characterized in that the surface roughness of the surface portion satisfies the arithmetic average roughness Ra≤0.1µm and asymmetry degree Rsk≤-0.01. According to claim 1,
Cutting tool characterized in that the surface portion has an asymmetry of Rsk≤-1.0. The method of claim 1 or 2,
The ceramic phase is WC or TiC, the metal phase is a cutting tool, characterized in that at least one selected from Co, Ni, Fe. The method according to any one of claims 1 to 3,
At least one carbide, nitride, oxide, carbonitride, or boride film selected from the group of elements consisting of Groups 4a, 5a, and 6a on the surface portion, or a diamond-like carbon film formed of one or more layers. Cutting tool characterized in that. The method according to any one of claims 1 to 4,
A cutting tool characterized in that a material other than the metal phase is disposed between the ceramic phases in the surface portion. A method of manufacturing a cutting tool composed of a composite material comprising a ceramic phase and a metal phase,
The blade end portion of the cutting tool has a blade end ridge and a blade end construction surface constituting the edge ridge,
A shape processing step of grinding a portion of the tool base made of the composite material to be a blade end surface to adjust Ra ≤ 0.1 μm;
After the shape processing step, the part serving as the blade end surface of the tool substrate adjusted to Ra≤0.1 μm is etched, and the metal phase of the part serving as the blade end surface is removed to form the ceramic phase and the metal phase. The ceramic phase is projected from the composite material layer, and the ceramic phase intermittently exists, and the metal phase is configured to have a surface part lacking, and the surface modification process having a surface roughness of Rsk≤-0.01 is provided. Method of manufacturing cutting tools. The method of claim 6,
The surface modification process is a method of manufacturing a cutting tool, characterized in that wet etching using an acidic solution.

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