JP2005279820A - Hard carbon film coated tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard carbon film coated tool, accurately discriminating between a used cutting edge and an unused cutting edge, and enough exhibiting excellent performance of a hard carbon film. <P>SOLUTION: This hard carbon film coated tool 1 has a rake face 6 and a flank 7, wherein at least one layer of hard carbon film 3 is deposited on the surface of a substrate 2 having a cutting edge ridge 8 at the intersecting part of the rake face 6 and the flank 7. A titanium compound film 4 is deposited on the outermost surface of the hard carbon film coated tool 1, and at least the titanium compound film 4 of the cutting edge ridge 8 is removed to expose the hard carbon film 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hard carbon film-coated tool having a hard carbon film coated on its surface, and more particularly to a hard carbon film-coated tool suitable as a cutting tool used for processing non-ferrous metals such as aluminum and titanium alloys.

  Hard carbon films such as diamond films and diamond-like carbon films have been used for sliding members and cutting tools because they have excellent slidability and wear resistance (see, for example, Patent Document 1).

  Further, in Patent Document 2, a TiN film and a TiAlN film are sequentially formed as an intermetallic compound film on the surface of a hard carbon film (diamond film), so that the work material and the diamond film are formed even if the iron-based material is cut. It is described that early wear and early peeling of the coating film can be prevented without contacting and reacting.

Patent Document 3 shows the color of amorphous carbon (diamond-like carbon), which is generally opaque in the visible light region and has a dark color such as black or dark brown, and is transparent in the visible light region and shows an interference color. It is described that the film hardness and heat resistance can be improved by using a color.
Japanese Patent No. 3339994 JP 2003-145309 A JP 2003-62708 A

  However, in the configuration of Patent Document 1, since the hard carbon film has a dark color when used as a cutting tool, it is difficult to determine whether or not a cutting blade has been used. There was a problem that it was difficult to stick.

  Moreover, in the tool of the structure which coat | covered the titanium nitride (TiN) film | membrane and the TiAlN film | membrane on the surface of the hard carbon film described in patent document 2, the effect of the low friction property of a hard carbon film | membrane will be impaired, and the said at the time of cutting The cutting resistance due to the contact between the TiN film or TiAlN film and the work material increases. As a result, the excellent slidability of the hard carbon film is not sufficiently exhibited. There is a problem that the chip has a high frictional resistance when the chips are discharged, and the chip disposal is deteriorated.

  The hard carbon film-coated tool of the present invention is for solving the above-mentioned problems, and its purpose is to easily and accurately distinguish between used cutting blades and unused cutting blades. Another object of the present invention is to provide a hard carbon film-coated tool that can sufficiently exhibit the sliding performance.

  In order to solve the above problems, the present inventor forms a titanium compound film on the outermost surface of a tool on which a hard carbon film is formed, and when used, the titanium compound film surely disappears and the color of the cutting edge changes. It is possible to easily and accurately recognize the presence or absence of use, and by exposing the hard carbon film of the part involved in cutting, the excellent sliding performance of the hard carbon film can be fully exhibited, and excellent processing It has been found that the tool has surface roughness and chip disposal.

  That is, the hard carbon film-coated tool of the present invention has a rake face and a flank face, and diamond and / or diamond-like carbon is formed on the surface of the substrate having a cutting edge at the intersection of the rake face and the flank face. In a hard carbon film coated tool in which at least one hard carbon film made of (DLC) is formed, a titanium compound film is formed on the surface of the hard carbon film, and at least the cutting edge ridge removes the titanium compound film The hard carbon film-coated tool is characterized in that the hard carbon film is exposed.

  Here, the titanium compound film on the entire surface of the rake face is removed and the hard carbon film is exposed. This improves the slidability on the rake face as a chip discharge path, and the flow of the chips. Is smooth and improves chip disposal, which is desirable in terms of further improving wear resistance by further reducing processing resistance and suppressing chipping and chipping caused by chips.

In addition, when the color tone display of the titanium compound film is based on JIS Z8729, the chromaticity a ^* : 0 to 10, b ^* : 20 to 50, and the lightness L ^* : 45 to 80 was used. At this time, the discoloration of the titanium compound film around the cutting edge becomes easy to understand, and it is desirable because it becomes easy to determine whether the cutting edge is used or not.

  Furthermore, it is desirable that the film quality of the titanium compound film is made of titanium nitride because discoloration when using a cutting blade becomes easier to understand and can exhibit excellent performance in wear resistance and slidability. .

  The hard carbon film-coated tool of the present invention is a hard carbon film-coated tool in which at least one layer of a hard carbon film is formed on the surface of a substrate, a titanium compound film is formed on the surface of the hard carbon film, and at least the above-mentioned Since the titanium compound film is removed at the cutting edge and the hard carbon film is exposed, the hard carbon film can contact the work material at the cutting edge related to cutting. Excellent cutting performance such as excellent slidability due to friction coefficient and high wear resistance due to extremely high hardness of hard carbon film can be fully exhibited, and the titanium compound film near the cutting edge turns black. In addition, the use or non-use of the cutting blade can be easily determined.

  A hard carbon film-coated tool (hereinafter simply referred to as a tool) 1 according to the present invention will be described with reference to FIG. 1 which is a schematic perspective view of an example thereof and FIG. 2 which is a schematic cross-sectional view of the tool of FIG. .

  According to FIG. 1, the tool of the present invention has a shape having a rake face 6 and a flank face 7 and a cutting edge ridge 8 at the intersection of the rake face 6 and the flank face 7.

  According to the present invention, the hard carbon film 3 is formed on the surface of the base 2 of the tool 1, the titanium compound film 4 is formed on the outermost surface, and the titanium compound film 4 is formed on the cutting edge ridge 8. The main feature is that the hard carbon film 3 is exposed to be removed, and with this configuration, the titanium compound film 4 existing in the vicinity of the cutting edge ridge 8 when being cut is peeled together with the cutting edge ridge 8 at the time of machining. The titanium compound in the immediate vicinity is damaged by cutting in the same way as the cutting edge even if the cutting edge ridge 8 cannot be observed directly because it discolors when it wears out and disappears and the hard coating film is exposed on the surface. By observing the state of the film 4, it is possible to determine the worn state of the cutting edge ridge 8 and to easily determine whether the cutting edge is used or not. Furthermore, since the hard carbon film 3 is exposed at the cutting edge 8 that most affects the cutting resistance, the hard carbon film 3 can come into contact with the work material during cutting, and the low friction of the hard carbon film 3 The excellent slidability and wear resistance due to the coefficient can be sufficiently exhibited during cutting, and the tool has excellent machined surface roughness and wear resistance.

  That is, if the titanium compound film 4 on the cutting edge 8 is removed and the hard carbon film 3 is not exposed, the surface of the cutting edge 8 becomes the titanium compound film 4 and comes into contact with the work material during cutting. Since the titanium compound film 4 is formed, the friction coefficient of the cutting edge 8 is increased, and the cutting resistance is increased, so that the machined surface roughness and wear resistance of the tool 1 are decreased.

  On the other hand, if the titanium compound film 4 is not formed on the outermost surface, the hard carbon film 3 existing on the outermost surface and the base 2 existing below the outer surface exhibit a dark color. It is difficult to visually confirm the state of the cutting edge 8 including the worn state, and it is difficult to determine whether the cutting edge 8 is used or not. Here, the thickness of the titanium compound film 4 is 0.1 to 2 μm in terms of prevention of film peeling and a bright color so that the use and non-use of the cutting edge 8 can be easily distinguished. A range is desirable.

Here, the titanium compound film 4 has chromaticity a ^* (red direction): 0 to 10, particularly 0 to 5, b ^* (yellow direction): 20 to 50, particularly 30 to 40, based on JIS Z8729. The brightness L ^* is preferably in the range of 45 to 80, and more preferably in the range of 55 to 70, and the appearance of the titanium compound film 4 existing on the surface becomes vivid by using a color within this range, and a cutting blade is used. Since the color change due to the disappearance of the titanium compound film 4 at this time can be clearly understood, it is desirable because it becomes easy to determine whether the cutting blade is used or not.

In addition, as the titanium compound film 4, titanium carbide, titanium nitride, titanium oxide, titanium carbonitride, titanium carbonate, titanium oxynitride, titanium carbonitride, or (Ti _x M _1-x ) (C _{1- yz} N _y O _z ) (where M is one or more of periodic group 4a, 5a and 6a metals other than Ti, Al, Si, 0.4 <x ≦ 1, 0 ≦ y ≦ 11) , 0 ≦ z ≦ 1). Among them, it is desirable to use titanium nitride because it exhibits a bright gold color and can easily identify the cutting edge used.

  According to the present invention, the hard carbon film 3 formed on the surface of the substrate 2 is a polycrystalline diamond film, an amorphous carbon film (diamond-like carbon (DLC)), or a tetrahedral amorphous carbon. It refers to a high-hardness carbon film such as (TAC). Further, the thickness of the hard carbon film 3 is 0.05 to 1 μm, particularly 0.1 to 0.6 μm from the viewpoint of preventing film peeling and maintaining wear resistance, and wear resistance, fracture resistance, etc. This is desirable because of its high cutting performance.

The base 2 in the tool 1 is a hard phase composed of tungsten carbide (WC) and, if desired, at least one selected from the group consisting of carbides, nitrides, and carbonitrides of Group 4a, 5a, and 6a metals of the periodic table. The periodic table 4a mainly composed of cemented carbide, titanium carbide (TiC), and titanium carbonitride (TiCN) bonded with a binder phase composed of an iron group metal such as cobalt (Co) and / or nickel (Ni). A hard phase composed of at least one selected from the group consisting of carbides, nitrides and carbonitrides of group 5a and 6a metals in a binder phase composed of an iron group metal such as cobalt (Co) and / or nickel (Ni) coupled to form the cermet, or silicon nitride _(Si 3 _{N 4)} and aluminum oxide _(Al 2 _{O 3)} ceramic sintered body consisting mainly of such news, cubic boron nitride (cBN), And, it is made of polycrystalline diamond (PCD) or the like hard material superhard sintered body consisting mainly of, or metal such as high speed steel, (using the cemented carbide in Figure 1). In particular, it is desirable to use a hard material as the material of the base body 2 in terms of wear resistance and chipping resistance.

  Furthermore, in order to improve wear resistance and fracture resistance, carbides, nitrides, and charcoal of group 4a, 5a, and 6a elements are used as an intermediate layer (not shown) between the titanium compound film 4 and the hard carbon film 3. A film made of nitride, carbonate, oxynitride, carbonitride, and metal such as Ti or Si may be formed.

  Further, between the hard carbon film 3 and the substrate 2, it is made of carbides, nitrides, carbonitrides, carbonates, oxynitrides, carbonitrides, and metals such as Ti and Si. Forming the film as the underlayer 5 is desirable in terms of improving the adhesion between the hard carbon film 3 and the substrate 2 and preventing the hard carbon film 3 from peeling off. In particular, it is desirable to use silicon carbide (SiC) and / or titanium nitride (TiN), as well as silicon (Si) or titanium (Ti), in terms of enhancing the adhesion between the substrate 2 and the hard carbon film 3.

  Further, according to the present invention, the titanium compound film 4 may be removed over the entire rake face 6 and the hard carbon film 3 may be exposed on the rake face 6. According to this configuration, the flow of chips on the rake face 6 becomes smooth, and the chip disposability is further improved. Therefore, wear resistance due to a further reduction in cutting resistance when machining chips extend. It is desirable because damage to the cutting edge 8 such as chipping and chipping due to improvement of chips and chips can be suppressed. Here, a part of the titanium compound film 4 on the flank 7 may be removed, but it is discriminated whether the cutting blade is used or not used by leaving the titanium compound film 4 near the cutting edge of the flank. It is necessary because it becomes easy to do.

(Production method)
In order to manufacture the hard carbon film-coated tool 1 described above, first, an inorganic powder such as a metal carbide, nitride, carbonitride, or oxide that can be formed by firing the hard material described above, a metal powder, a carbon powder, or the like. Are added and mixed as appropriate, and then molded into a predetermined tool shape by a known molding method such as press molding, cast molding, extrusion molding, or cold isostatic pressing, and then fired in a vacuum or non-oxidizing atmosphere. By doing so, the base body 2 made of the hard alloy described above is produced.

  In addition, when the base 2 is a hard alloy containing a large amount of iron group metal such as Co or Ni, the adhesion of the hard carbon film 3 to the base 2 is remarkably reduced, so acids such as sulfuric acid, hydrochloric acid, aqua regia, etc. It is desirable to remove the iron group metal on the surface of the substrate 2 by performing etching by plasma etching or heat treatment. Alternatively, instead of performing etching, the base layer 5 is formed between the base 2 and the hard carbon film 3 by chemical vapor deposition such as CVD or plasma CVD, or physical such as arc ion plating, ion plating, or sputtering. The film may be formed by a general thin film forming method such as a vapor deposition method.

  Next, after polishing the surface of the base 2 as desired, a hard carbon film 3 is formed on the surface. When a DLC film is formed as the hard carbon film 3, for example, a CVD method using a hydrocarbon (CmHn: m, n is a natural number) as an atmosphere gas, a plasma CVD method, carbon as a raw material, and a hydrocarbon gas as an atmosphere Sputtering and vacuum arc deposition are used. In particular, the sputtering method and the vacuum arc deposition method are preferable because the hydrogen ratio can be further controlled and the friction coefficient can be reduced.

  Further, when a diamond film is used as the hard carbon film 3, various diamond thin layer vapor phase synthesis methods such as a CVD method, a PVD method, a PCVD method, or a combination thereof can be used. Of these, various hot filament methods including the EACVD method, various direct current plasma CVD methods including the thermal plasma method, and microwave plasma CVD methods including the thermal plasma method can be preferably used.

  Next, the titanium compound film 4 is formed by chemical vapor deposition such as CVD or plasma CVD, or physical vapor deposition such as arc ion plating, ion plating, or sputtering. However, it is desirable to form the film by the method of forming the hard carbon film 3 because the manufacturing process can be shortened.

  Finally, as a method for removing the titanium compound film 4 on the cutting edge ridge 8 and the rake face 6, polishing is performed until the hard carbon film 3 is exposed by a polishing method such as an elastic grindstone, a brush, or a sand blast. As a processing method, polishing with a brush is particularly preferable because the surface roughness of the polishing surface can be uniformly and smoothly polished even if the rake surface has a large unevenness.

  In addition, this invention is not limited to the said embodiment, The thing produced by the other film-forming method may be used.

  80.0% by mass of WC powder with an average particle size of 1.5 μm, 3.0% by mass of TiC powder with an average particle size of 2 μm, 1.0% by mass of TaC powder with an average particle size of 2 μm, and an average particle size of 1.2 μm After adding and mixing Co powder at a ratio of 10.0% by mass and forming it into a cutting tool shape by press molding, it was subjected to binder removal treatment and fired at 1500 ° C. for 1 hour in a vacuum of 0.01 Pa. A cemented carbide was produced. Further, the prepared cemented carbide was subjected to blade edge processing (Honing R) by brushing. Further, in order to remove Co on the surface, plasma etching was performed for 1 hour to produce a cemented carbide substrate.

  On the surface of the cemented carbide substrate, an amorphous silicon carbide (SiC) film having a thickness of 0.1 μm was formed as a base layer by plasma CVD.

Further, a diamond-like carbon (DLC) film is formed on the surface of the underlayer by plasma CVD using a C ₂ H ₂ gas flow rate of 150 m / min, a bias voltage of 600 V, a discharge current of 15 A, and a substrate temperature of 450 ° C., and a film thickness of 0.1 μm. After that, a titanium nitride (TiN) film having a thickness of 0.1 μm was formed as a titanium compound layer on the surface by the same plasma CVD method as the DLC film.

  Next, the produced hard carbon film-coated tool was polished with a brush from the rake face to the cutting edge, and the TiN film at the edge of the cutting edge was polished until the DLC film was exposed. Also, the TiN film on the rake face was left in a polished form.

With respect to the flank face of the hard carbon film coated tool produced by the above method, the chromaticity (a ^* , b ^* ) and lightness (L ^* ) are measured based on JIS Z8729 for the portion of the TiN film coated on the surface ^. ) Was measured under the following conditions.

Reference light source: D65
Wavelength range: 360-740 nm
Field of view: 10 °
Measurement reflectance: Total reflectance mask: 5 × 7 mm (SAV)
Further, a cutting test was performed on the hard carbon film-coated tool under the following conditions.

<Cutting conditions>
Cutting method: Milling work material: ADC12
Cutting speed: 300 m / min
Feeding: 0.15mm / rev
Cutting depth: 5mm
Cutting state: The machined surface roughness Ra (arithmetic average roughness) at a wet cutting length of 36 m was measured, and the state of the cutting edge and the rake face was observed with a microscope.

As a result of the cutting test, the machined surface roughness Ra of the work material was 0.6 μm, which was a very smooth machined surface roughness. Further, regarding the state of the cutting edge and the rake face after cutting, welding of the work material was observed on the rake face, but no damage such as chipping was observed. Further, the spectrocolorimeter of the TiN film measured a ^* : 8.7, b ^* : 29.8, L ^* : 56.3, and after cutting, the TiN film near the cutting edge peeled off and turned black. Therefore, it was clearly confirmed that the cutting blade was used.

A hard carbon film-coated tool similar to Example 1 was prepared except that the TiN film on the rake face and the edge of the cutting edge was removed and the DLC film was exposed, and the same cutting test as in Example 1 was performed. Moreover, in the spectrocolorimeter measurement of the TiN film | membrane performed similarly to Example 1, they were a ^* : 7.9, b ^* : 30.8, L ^* : 60.2.

  As a result of the cutting test, the machined surface roughness Ra of the work material was 0.48 μm, which was a very smooth machined surface roughness. Further, the state of the cutting edge and the rake face after cutting was such that no damage such as welding or chipping of the work material was observed, and there was almost no crater wear. Furthermore, since the TiN film near the cutting edge peeled off and turned black, it was clearly confirmed that the cutting edge was used.

(Comparative Example 1)
A hard carbon film-coated tool was prepared in the same manner as in Example 1 except that the TiN film on the outermost surface of the hard carbon film-coated tool was not removed at all, and a cutting test was performed in the same manner as in Example 1. Similarly to Example 1, the color of the surface of the TiN film on the flank face was measured with a spectrocolorimeter. The results were a ^* : 6.9, b ^* : 33.0, and L ^* : 57.3.

  As a result of the cutting test, the nitrided TiN film in the vicinity of the cutting edge peeled off and turned black, so it was clearly confirmed that the cutting edge was used, but the machined surface roughness Ra of the work material was 1.2 μm. The surface roughness was slightly rough. Further, regarding the state of the cutting edge and the rake face after cutting, welding of the work material occurred on the rake face, and damage such as film peeling and chipping was observed.

It is a schematic perspective view which shows the external appearance of the hard carbon film coating tool of this invention. (A) is a schematic cross-sectional view of the hard carbon film-coated tool of the present invention from which only the TiN film on the cutting edge is removed, and (b) is the hard carbon film coating of the present invention from which only the nitrided TiN film on the cutting edge and the rake face is removed. It is a schematic sectional drawing of a tool.

Explanation of symbols

1: Hard carbon film coating tool 2: Substrate 3: Hard carbon film 4: Titanium compound film 5: Underlayer 6: Rake face 7: Relief face 8: Cutting edge 9: Intermediate layer

Claims (4)

A hard carbon film-coated tool having a hard carbon film formed on a surface of a substrate having a rake face and a flank face, and having a cutting edge at the intersection of the rake face and the flank face. A hard carbon film-coated tool, wherein a titanium compound film is formed on the outermost surface of the film-coated tool, and the hard carbon film is exposed by removing the titanium compound film at least at the cutting edge. The hard carbon film-coated tool according to claim 1, wherein the hard carbon film is exposed by removing the titanium compound film on the entire surface of the rake face. The titanium compound film has a chromaticity a ^* : 0 to 10, b ^* : 20 to 50, and a lightness L ^* : 45 to 80 in a color tone display based on JIS Z8729. 2. Hard carbon film-coated tool according to 2. The hard carbon film-coated tool according to claim 1, wherein the titanium compound film is made of a titanium nitride film.

Images