JP3719709B2 - Amorphous carbon coated tool and method for manufacturing the same - Google Patents

Description

【００５５】
【表２】

【００５６】
【表３】

【００５７】
表1、2の結果から、従来からのTiN膜(比較品6)、TiAlN膜(比較品7)、本発明で規定する範囲から外れる非晶質カーボン膜を形成した比較品(比較品1〜5)は、スラスト抵抗がノンコートとほぼ同等でかつ耐溶着性に劣る。これに対し、本発明例のドリル(本発明品1〜20)は、表1に示すように非晶質カーボン被膜の水素含有量がいずれも5原子％以下であった。そして、アルミ穴あけ加工において優れた耐摩耗性を有すると同時に、優れた耐溶着性を備えることがわかる。従って、穴開け加工後の穴加工精度も非常に高く、長寿命が可能であることがわかる。
【００５８】
(実施例2)
実施例1と全く同じ方法により、φ4mmの高速度鋼製リーマの表面に非晶質カーボン膜を被覆した(本発明品4の被膜)。比較品としてCVD法による水素化非晶質カーボン膜(比較品1)、膜厚が本発明の範囲外である非晶質カーボン膜(比較品2〜4)、雰囲気ガスにCH₄を添加して陰極アークイオンプレーティング法により作製した水素化非晶質カーボン膜(比較品5)、TiN膜(比較品6)、TiAlN膜(比較品7)を被覆した。次に、上記の方法により製造した各表面被覆リーマについて、表4の条件によるアルミダイキャスト(ADC12)の穴開け加工を行い、穴開け個数と刃先の状態を評価した。
【００５９】
【表４】

【００６０】
その結果、比較品1〜7は600穴あけたところで被削材の穴径にバラツキが生じたため、リーマの状態を調べたところ、刃先に摩耗が生じ、その先端でチッピングが認められた。
【００６１】
一方、本発明品4の非晶質カーボンを被覆したリーマでは9000穴あけた時点でも全く被削材の加工状況に問題がなく、リーマ刃先にも摩耗やチッピングは認められなかった。
【００６２】
(実施例3)
実施例1と全く同じ方法により、φ7mmの高速度鋼製エンドミルの表面に非晶質カーボン膜を被覆した(本発明品6の被膜)。比較品としてCVD法による水素化非晶質カーボン膜(比較品1)、膜厚が本発明の範囲外である非晶質カーボン膜(比較品2〜4)、雰囲気ガスにCH₄を添加して陰極アークイオンプレーティング法により作製した水素化非晶質カーボン膜(比較品5)、TiN膜(比較品6)、TiAlN膜(比較品7)を被覆した。次に、上記の方法により製造した各表面被覆エンドミルについて、表5の条件によるアルミダイキャスト(ADC12)のエンドミル加工を行い、被削の表面粗さの規格から外れるまでの切削長と刃先の状態を評価した。
【００６３】
【表５】

【００６４】
その結果、従来からの表面被覆切削エンドミルのうち、CVDの水素化非晶質カーボン膜(比較品1)は切削長さ20mで、膜厚が本発明の範囲外である非晶質カーボン膜(比較品2〜4)は切削長さ100mで、雰囲気ガスにCH₄を添加して陰極アークイオンプレーティング法により作製した水素化非晶質カーボン膜(比較品5)は切削長さ30mで、PVD法で形成した金属窒化物膜（比較品6及び7）はそれぞれ5m、6mの切削長さで表面粗さの規格から外れたため、工具の寿命と判断した。寿命になった表面被覆エンドミルの先端に溶着したアルミを除去して調べたところ、既に被覆した膜は存在せず、基材の高速度鋼が露出していた。
【００６５】
一方、本発明品6のエンドミルでは800m切削した時点でも被削材の表面粗さは規格内に維持できており、さらなる寿命延長が期待された。
【００６６】
ここで開示された実施例は全ての点で例示的であって制限的なものでないと考えるべきである。本発明の範囲は、以上の実施例の説明ではなく、特許請求の範囲によって示され特許請求の範囲と均等の意味および範囲内でのすべての修正や変形を含むものであることが意図させる。
【００６７】
以上、本発明の具体例について説明したが、本発明は他の形状の転削工具(ドリル、エンドミル、リーマなど)、フライス工具や旋削工具に使用される刃先交換型切削チップ、切断工具(カッター、ナイフ、スリッターなど)にも適用することができる。
【００６８】
【発明の効果】
以上説明したように、本発明の被覆工具によれば、基材の種類と非晶質カーボン膜の厚みを特定することで、耐摩耗性を維持し優れた耐溶着性を得ることができ、工具の切削・耐摩寿命を著しく延長させることができる。また、この工具は、被削材の凝着や刃先の欠損が生じ難く、さらに熱伝導性が高いので刃先の温度上昇が少なくドライ切削や高速加工といった過酷な切削環境下でも使用できる。特に、水素を実質的に含有しない非晶質カーボン膜とすることで、一層優れた耐摩耗性と耐溶着性を得ることができる。従って、転削工具(ドリル、エンドミル、リーマなど)、フライス工具や旋削工具に使用される刃先交換型切削チップ、切断工具(カッター、ナイフ、スリッターなど)への効果的な利用が期待される。
【図面の簡単な説明】
【図１】この発明工具の被膜形成に用いる成膜装置の概略図である。
【図２】この発明工具の刃先部の断面図である。
【図３】本発明の非晶質カーボン被覆膜のラマンスペクトルである。
【図４】従来の非晶質カーボン被覆膜のラマンスペクトルである。
【符号の説明】
１ 成膜装置
２、３ ターゲット
４ 基材保持具
５ ドリル
６ 基板加熱ヒーター
７，８ アーク電源
９ バイアス電源
10 供給口
11 排気口
20 非晶質カーボン
21 マクロパーティクル
22 グラファイト粒子
23 工具の刃先[0001]
BACKGROUND OF THE INVENTION
The present invention provides wear resistance and welding resistance to the surfaces of turning tools (drills, end mills, reamers, etc.), cutting edge exchangeable cutting tips used for milling tools and turning tools, and cutting tools (cutters, knives, slitters, etc.). The present invention relates to a tool in which an amorphous carbon film having properties is formed.
[0002]
[Prior art]
Conventionally, it has been possible to reduce tool surface damage for long life and high-efficiency machining, and to finish the work material (maintenance of surface shape, base metal hardness, dimensional accuracy, etc.) with high quality. It is required for cutting tools.
[0003]
In recent years, development of tools that reduce cutting resistance and tools that do not decrease life and cutting efficiency even if cutting fluids are reduced has been strongly demanded for environmental conservation and energy saving needs.
[0004]
In addition, in recent years, it has been used for soft metals such as aluminum alloys, non-ferrous metals such as titanium, magnesium and copper, organic materials, materials containing hard particles such as graphite, printed circuit board processing and iron-based materials and aluminum co-machining. The grades are versatile. Here, the co-machining means simultaneous cutting of a combination of an iron-based material and an aluminum alloy. When cutting the above materials, there is a problem that the work material adheres to the cutting edge portion of the cutting tool to increase the cutting resistance, or the cutting edge is lost in some cases. In these specific work materials, tool wear becomes more severe than other work materials.
[0005]
In addition, there is an urgent need from the metalworking site to drastically reduce costs without reducing performance.
[0006]
[Problems to be solved by the invention]
Conventionally, diamond tools have been used in specific applications for processing such aluminum and its alloys and organic materials. In a tool in which a diamond film is formed on a base material, the surface of the diamond film becomes uneven due to the polycrystalline structure of the diamond film. Therefore, it is necessary to polish the surface for use as a precision machining tool.
[0007]
However, since the diamond film is the hardest material among the existing materials, the diamond film is no less than the use of expensive diamond for polishing, which has been a significant cost increase factor.
[0008]
Further, a ceramic film such as TiN obtained by PVD (Physical vapor deposition) coating is usually 2 to 3 μm thick. On the other hand, in the case of a diamond film, since the crystal growth rate varies greatly depending on the crystal orientation, a thick film of 20 to 30 μm is required in advance to obtain a smooth polished surface. In addition, since the film is formed while etching away the graphite that grows simultaneously with the diamond growth, the film formation speed is very low, which is 1/10 or less of the normal ceramic film coating, and the manufacturing cost including the coating is very high. There was a problem of becoming.
[0009]
In addition, there is a problem that it is difficult to manufacture a tool having a complicated shape or a small diameter tool having a diameter of several millimeters with the tool for brazing the diamond sintered body to the base material.
[0010]
Therefore, Japanese Patent Laid-Open No. 2000-176705 proposes a tool member that is coated with a hard material containing TiN, TiCN, TiAlN, Al ₂ O ₃ or a combination thereof on a tool, and further coated with a hard carbon-based lubricating film. ing. Here, in order to form an inexpensive hard carbon-based lubricating coating having stable durability and suitable for mass production, the inventors have formed an intermediate layer composed of silicon and carbon or a component containing silicon, carbon and nitrogen. It is proposed to form a layer of silicon alone having a thickness of 0.02 μm to 0.5 μm in contact with the interface under the intermediate layer.
[0011]
However, the hard carbon film of the outermost layer in the present invention is formed by ion plating and plasma CVD (Chemical Vapor Deposition) using a hydrocarbon gas, so that hydrogen atoms are contained in the film. End up. Normally, hydrogen atoms in hard carbon are known to desorb from the film at a temperature of about 350 ° C. or higher in the atmosphere. After the hydrogen is desorbed, the hard carbon film transforms into graphite, and the hardness is extremely high. To drop. It must be said that such a coating is difficult to use in a severe cutting environment.
[0012]
Therefore, the main object of the present invention is soft metal, non-ferrous metal, organic material, material containing hard particles, printed circuit board, amorphous carbon for cutting such as co-machining of ferrous material and soft metal material It is to provide a coated tool. Another object of the present invention is to provide a method for producing an amorphous carbon-coated tool.
[0013]
[Means for Solving the Problems]
The present invention achieves the above object by specifying the type of substrate and the thickness of the amorphous carbon film.
[0014]
That is, the amorphous carbon-coated tool of the present invention includes a base material made of one type selected from high-speed steel, carbon tool steel, and alloy tool steel, and an amorphous carbon film that covers at least the cutting edge on the base material. An amorphous carbon-coated tool comprising: the amount of hydrogen in the amorphous carbon film is 5 atomic% or less, and the maximum thickness at the cutting edge of the amorphous carbon film is 0.05 μm to 0.5 μm It is characterized by being.
The amorphous carbon-coated tool of the present invention includes a base material made of one kind selected from high-speed steel, carbon tool steel, and alloy tool steel, and an amorphous carbon film that covers at least the cutting edge on the base material. The amorphous carbon film is formed by a physical vapor deposition method in an atmosphere substantially free of hydrogen using graphite as a raw material. The maximum thickness of the blade edge is 0.05 μm or more and 0.5 μm or less.
[0015]
The method for producing an amorphous carbon-coated tool according to the present invention includes a step of holding a base material made of one type selected from high-speed steel, carbon tool steel and alloy tool steel in a vacuum vessel, and zeroing the base material. Or applying a negative DC bias and evaporating graphite as a raw material to form an amorphous carbon film, and controlling the maximum thickness of the amorphous carbon film at the cutting edge to 0.05 to 0.5 μm It is characterized by.
[0016]
The constituent elements of the present invention will be described in detail below.
[0017]
(Steel substrate)
In the present invention, high-speed steel, carbon tool steel, or alloy tool steel is used for the base material. These steel materials have machinability and wear resistance necessary as a cutting tool, and are desirable for the base material of an amorphous carbon-coated tool. Moreover, since these steels have higher toughness and are cheaper than cemented carbide, it is possible to realize an amorphous carbon-coated tool that is highly reliable and inexpensive. Examples of the high speed steel include W type high speed steel such as JIS symbols SKH2, SKH5, and SKH10, and Mo type high speed steel such as SKH9, SKH52, and SKH56. Examples of the carbon tool steel include JIS symbols SK1, SK2, and SK3. Any alloy tool steel can be used as long as it is generally used for cutting, such as JIS symbols SKS1, SKS2, SKS5, SKS21, and SKS51. Among these, high speed steel is particularly desirable in terms of machinability and wear resistance.
[0018]
(Amorphous carbon film)
Amorphous carbon films include what are commonly called hard carbon films, diamond-like carbon films, DLC films, aC: H, i-carbon films, and the like. However, the amorphous carbon film of the present invention has the characteristics described below.
[0019]
<Film formation method>
In the present invention, an amorphous carbon film is formed by physical vapor deposition using graphite as a raw material in an atmosphere not containing hydrogen. This film has high hardness comparable to diamond and excellent wear resistance as a cutting tool. On the other hand, an amorphous carbon film made of hydrocarbon as a raw material contains hydrogen and is different from the amorphous carbon film of the present invention.
[0020]
This amorphous carbon film is composed of only carbon atoms, excluding impurities inevitably included during film formation. As a result, the proportion of sp ³ bonds is higher than that of the amorphous carbon film containing hydrogen, so that the hardness is increased and at the same time the oxidation resistance is improved to about 600 ° C., which is equivalent to that of diamond. Even if the film is formed in an atmosphere that does not substantially contain hydrogen, the resulting amorphous carbon film may contain a slight amount of hydrogen of about 5 atomic% or less. This is presumably because hydrogen and moisture remaining in the film formation apparatus are taken into the amorphous carbon film due to the degree of vacuum at the time of film formation.
[0021]
Among physical vapor deposition methods using graphite as a starting material, the cathode arc ion plating method, laser ablation method, sputtering method, etc., which are generally used industrially, have high film formation speeds and are problematic for diamond films. The problem of manufacturing cost is also eliminated. In particular, film formation by the cathodic arc ion plating method is preferable in terms of adhesion of the film and film hardness. In this cathodic arc ion plating method, since the ionization rate of the raw material is high, an amorphous carbon film is formed mainly by irradiating the substrate with carbon ions. Therefore, a dense and hard film having a high sp ³ bond ratio can be obtained, and the tool life can be greatly improved.
The temperature of the substrate during film formation is 50 ° C. to 200 ° C. This is because if the temperature of the substrate exceeds 350 ° C., graphite is likely to precipitate. At the time of film formation, the substrate is irradiated with carbon ions and amorphous carbon is formed. At this time, the temperature of the substrate rises. Therefore, even if the substrate is not heated by a heater, the temperature may rise to a level that does not hinder practical use. Further, the temperature of the substrate can be adjusted by heating or cooling.
The substrate temperature during film formation is more preferably 50 ° C. to 150 ° C.
[0022]
<Macro particle density>
Hard particles called macro particles exist on the surface of the amorphous carbon film formed by the cathodic arc ion plating method. The smaller the macroparticle density present on the film surface, the lower the cutting resistance, which is desirable. The macro particle density is 3 × 10 ⁵ particles / mm ² or less, more preferably 1.5 × 10 ⁵ particles / mm ² or less. Of course, it is needless to say that 0 piece / mm ² is optimal. When the density of the macro particles is larger than 3 × 10 ⁵ particles / mm ² , the work material is welded to the macro particles to increase the cutting resistance, which is not preferable.
[0023]
The density of the macro particles can be evaluated by SEM (Scanning Electron Microscope) observation. In SEM observation, in order to facilitate observation of macro particles, it is preferable to observe after vaporizing a noble metal such as Pt or Pd on the sample surface by ion sputtering or the like. It is advisable to obtain the density by taking a photograph of the sample surface at a magnification of at least 1000 times and counting the number of macro particles on the photograph.
[0024]
FIG. 2 is a cross-sectional view of the amorphous carbon coated surface 20 showing the process of generating the macro particles 21. Amorphous carbon 20 is coated on the cutting edge 23 of the tool. In the process, graphite particles 22 scatter and adhere to the coated surface. When the surface is viewed with an electron microscope, round particles 21 having various outer diameters can be observed. However, such particles are not desirable in the present invention. Since the graphite particles 22 are scattered during the film growth process, it is presumed that the graphite particles 22 exist at various thicknesses of the amorphous carbon 20 as shown in FIG.
Furthermore, in order to improve the surface roughness of the amorphous carbon film, it is possible to propose a method that uses, for example, a low-energy film formation or a magnetic field filter that prevents particulate scattering from the graphite raw material.
[0025]
<Surface roughness>
The surface roughness of the amorphous carbon film is desirably 0.002 μm or more and 0.05 μm or less in terms of Ra defined by JIS standard B0601. Here, when viewed as a cutting tool, the surface roughness Ra is desirably as small as possible. However, since it cannot actually be zero, as a result of various cutting tests, it was found that when Ra is 0.05 μm or less, the weldability at the cutting edge is improved and the cutting performance is improved. Moreover, it is also preferable that it is 0.02 μm or more and 0.5 μm or less in terms of Ry defined by JIS standard B0601. Here, if Ry exceeds 0.5 μm, the projections (microparticles) of the amorphous carbon film become the starting point of welding of the work material and cause an increase in cutting resistance, which is not preferable.
[0026]
<Thickness>
The reason for specifying the maximum film thickness of the amorphous carbon film at the tool edge as 0.05 μm to 0.5 μm is that if it is less than 0.05 μm, there is a problem with wear resistance, and if it exceeds 0.5 μm, the internal stress accumulated in the film This is because there is a problem that the film becomes large and is easily peeled off or the film is chipped. Also, by setting the film thickness to 0.5 μm or less, the size and density of the surface macro particles can be reduced, and the surface roughness can be suppressed to 0.05 μm or less in the Ra display and 0.5 μm or less in the Ry display. There is also an effect. The amorphous carbon film becomes thicker at the cutting edge of the tool, as indicated by T in FIG. When this thickness is thin, the performance is improved. Therefore, the maximum thickness T at the cutting edge part involved in cutting of the amorphous carbon film is preferably 0.05 μm or more and 0.25 μm or less from the viewpoint of less weldability.
[0027]
<Hardness>
The Knoop hardness of the amorphous carbon film is preferably 20 GPa or more and 50 GPa or less. If the hardness is less than 20 GPa, there is a problem in terms of wear resistance, and if it exceeds 50 GPa, the chipping resistance of the cutting edge is lowered. More preferably, the Knoop hardness of the amorphous carbon film is 25 GPa or more and 40 GPa or less.
[0028]
<Raman spectrum>
Since the amorphous carbon film is amorphous, it is very difficult to specify the film structure. As a result of evaluating various amorphous carbon films, it was found that there was a difference in the Raman spectrum obtained with the structural change when the Raman spectroscopic analysis was performed.
[0029]
FIG. 3 is a Raman spectrum of the amorphous carbon of the present invention, and FIG. 4 is a Raman spectrum of conventional amorphous carbon containing hydrogen. These were obtained by Raman spectroscopic analysis using an argon gas laser having a wavelength of 514.5 nm. In FIG. 4, the solid line shows the measurement result, 1340 cm ^{- 1} bulge near was observed, 700 cm ^{- 1} has no peak in the vicinity.
The background was then removed from the spectrum waveform to separate the resulting spectrum into two. Next, the spectrum with bulges was approximated by the nonlinear least squares method, assuming that two Gaussian functions were added, and separated into two peaks. The result is shown by a chain line. The height of the peak centered around 1340 cm ^{- 1} is denoted by I1340, and the height of the peak near 1560 cm ^{- 1} is denoted by I1560. In contrast, the Raman spectrum of the present invention, 1340 cm 3 ^{- 1} near bulge is hardly identified by the solid line, 700 cm ^- there is broad peak around ^1. The results of peak separation by the same method as described above are shown by chain lines in FIG. It can be seen that the peak height of I1340 is weaker than that of FIG. The peak height near 700 cm ^{- 1} is indicated by I700.
Similarly, a value obtained by integrating each peak is expressed as S700, for example. The amorphous carbon film of the present invention the tool, the wave number 400 cm ^{- 1} or 1000 cm ^{- 1} for less than, 1340 cm ^{- 1} and near 1560 cm ^{- 1} peak at a total of three places in the vicinity is observed. On the other hand, so far the wave number of the coating lower wavenumbers containing hydrogen of 400 cm ^{- 1} or 1000 cm ^{- 1} or less between the peak is not observed. By taking a film structure having a peak between the wave numbers of 400 cm ^{- 1 and} 1000 cm ^{- 1} , it is possible to increase hardness and improve wear resistance.
[0030]
Further, the wave number 400 cm ^{- 1} or 1000 cm ^{- 1} intensity of peaks present below (I700) and 1340 cm ^{- 1} peak intensity existing in the vicinity (I1340) and the intensity ratio of the (I700 / I1340) is 0.01 to 2.5 And wear resistance is improved. This is thought to be because the film hardness increases as the amount of fine sized graphite and sp ³ bonds with strain increases.
[0031]
Here is shown using the peak height, can also be organized in the peak integrated intensity ratio, the wave number 400 cm ^{- 1} or 1000 cm ^{- 1} integrated intensity of peaks present below (S700) and 1340 cm ^- present near ¹ The intensity ratio (S700 / S1340) to the peak integrated intensity (S1340) is preferably 0.01 or more and 2.5 or less. If the peak intensity ratio is less than 0.01, the wear resistance is equivalent to the conventional coating. As will be described later, various film formation experiments were performed, but in this experiment, a peak intensity ratio of 2.5 or more was not obtained.
[0032]
Further, 1560 cm ^{- 1} peak intensity existing near the (I1560) 1340cm ^- if the intensity of the peaks present in the vicinity of ¹ (I1340) and the intensity ratio of the (I1340 / I1560) is 0.1 or more and 1.2 or less, high wear It shows good sex. 1560 cm ^{- 1} peak intensity existing near the (I1560) 1340cm ^- the ratio of the intensity of the peaks present in the vicinity of ¹ and (I1340) is said to be sp ² / sp ^3, the presence of carbon bonding state of the inner coating Represents. Although these peak intensity ratios do not directly indicate the content of sp ² , the film structure can be classified relatively. It was found that the hardness increased when the intensity of the peak existing near 1560 cm ^{- 1} was high. That is, when the sp ³ bond is strong, the wear resistance is further improved. In addition to the peak intensity, the intensity ratio (S1340 / S1560) of the integrated intensity of the peak near 1560 cm ^{- 1} (S1560) and the integrated intensity of the peak near 1340 cm ^{- 1} (S1340) (S1340 / S1560) should be between 0.3 and 3. That's fine.
[0033]
Then, 1560 cm ^{- 1} peak present in the vicinity of 1560 or more 1580 cm ^- if present ¹ below high wear resistance can be realized. The peak position of the Raman spectrum is affected by the stress in the film. In general, when the stress in the coating is high on the compression side, the peak of the Raman spectrum shifts to the high wave number side, and conversely, when the stress on the tension side is high, the peak shifts to the low wave number side. It has been found that the wear resistance is improved when the stress of the coating is high on the compression side.
[0034]
<Interference color>
The amorphous carbon film used in the conventional technique is opaque in the visible light region and has a color tone from brown to black. The amorphous carbon film of the tool of the present invention is characterized by being transparent in the visible light region and exhibiting an interference color.
[0035]
Interference color means that the amorphous carbon film has many sp ³ bonding components, and its physical properties such as refractive index, optical band gap, and elastic modulus are closer to diamond than the conventional amorphous carbon film. Is shown. When such an amorphous carbon film is used as a tool, since the film hardness is high, excellent wear resistance and heat resistance are exhibited. Since the high-speed steel, carbon tool steel, and alloy tool steel, which are base materials of the tool of the present invention, are silver or gray close to silver, the tool of the present invention is characterized in that it exhibits an interference color.
[0036]
As the film thickness increases, the interference color of the amorphous carbon film is (1) brown → (2) magenta → (3) purple → (4) blue purple → (5) blue → (6) silver → (7 ) Yellow → (8) Red → (9) Blue → (10) Green → (11) Yellow → (12) Red, then repeat from (8) red to (12) red. These color changes are continuous with respect to the change in film thickness, and at each intermediate film thickness, an intermediate color is obtained.
[0037]
As a result of the study by the present inventors, when the maximum film thickness at the tool edge is specified as 0.05 μm to 0.5 μm, the coating film has a color between (2) magenta and (10) green. I found it. Moreover, the rainbow color which consists of a some color tone may be sufficient instead of a single color. Further, a conventional brown to black amorphous carbon film may be formed on these amorphous carbon films exhibiting interference colors.
[0038]
(Interface layer)
In the tool of the present invention, it is preferable to provide an interface layer between the base material and the amorphous carbon film in order to strengthen the adhesion of the amorphous carbon film.
[0039]
<Material>
This interfacial layer is at least one element selected from the group consisting of elements of Group IVa, Va, VIa, IIIb group elements and IVb group elements other than C, or at least one selected from these element groups A carbide of more than one element is preferred.
[0040]
Above all, at least one element selected from the group consisting of elements of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Si, or at least one element selected from this element group It is further desirable to be a carbide of Since these metal elements tend to form a strong bond with carbon, a stronger adhesion can be obtained by forming an amorphous carbon film on the interface layer of these metal elements or metal carbides.
[0041]
<Thickness>
The thickness of the interface layer is 0.5 nm or more and less than 10 nm. If the film thickness is thinner than this range, it does not play a role as an interface layer, and if it is thicker than this range, only the adhesion strength equivalent to that of the prior art can be obtained. By forming an extremely thin interface layer in this manner, an extremely strong adhesion force that cannot be achieved by the prior art can be obtained, and the tool life can be greatly improved. In particular, when an amorphous carbon film is formed on a steel substrate, it is difficult to obtain sufficient adhesion as a practical tool in the conventional technique, but in the present invention, it is practical by interposing an interface layer. Adequate adhesion as a tool is obtained.
[0042]
<Mixed composition layer / gradient composition layer>
If a mixed composition layer in which the composition of each film is mixed or a gradient composition layer in which the composition is continuously changed is interposed between the interface layer and the amorphous carbon film, a stronger adhesion can be obtained. desirable. The mixed layer and the gradient composition layer are not necessarily clearly distinguished. When the production conditions are switched from the formation of the interface layer to the formation of the amorphous carbon film, usually, the composition of the interface layer and the amorphous carbon film is slightly mixed. It is formed. These are difficult to confirm directly, but can be sufficiently estimated from results such as XPS: (X-ray Photo-electronic Spectroscopy) and AES: (Auger Electron Spectroscopy).
[0043]
(Use of tools)
The amorphous carbon-coated tool of the present invention is particularly suitable for a tool for processing aluminum and its alloys because of its wear resistance and welding resistance. Moreover, it is optimal to use it for non-ferrous materials such as titanium, magnesium and copper. Furthermore, it is effective for cutting materials such as graphite and materials containing hard particles, organic materials, printed circuit board processing, and co-machining processing of iron-based materials and aluminum. In addition, since the amorphous carbon film of the tool of the present invention has a very high hardness, it can be used not only for non-ferrous materials but also for processing of steel such as stainless steel and castings.
[0044]
(Specific examples of tools)
The amorphous carbon-coated tool according to the present invention comprises a group consisting of a drill, an end mill, an edge-changing tip for end milling, an edge-changing tip for milling, an edge-changing tip for turning, a metal saw, a toothing tool, a reamer, and a tap. It should be used for applications that include one selected.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Next, the amorphous carbon-coated tool of the present invention will be specifically described with reference to examples. However, it is not limited to the manufacturing method used here, and any method may be used as long as the film is formed by the PVD method using graphite.
[0046]
(Example 1)
As a base material, a φ8 mm steel drill was prepared. This base material consists of one type selected from high-speed steel, carbon tool steel, and alloy tool steel. The amorphous carbon-coated drill samples 1 to 20 of the present invention products shown in Tables 1 to 2 were prepared on the surface of the base material using the known cathodic arc ion plating method as described below. In Table 1, x in the chemical formula representing the interface layer represents the ratio of the nonmetallic element to the metallic element 1.
[0047]
That is, as shown in FIG. 1, a plurality of targets 2 and 3 are arranged in a film forming apparatus 1, and a steel drill 5 is attached to a base material holder 4 that rotates between targets around the center point of the target. To do. The cathode arc power supplies 7 and 8 are adjusted to change the discharge current of the vacuum arc to coat the amorphous carbon while controlling the evaporation amount of the target material.
[0048]
First, while heating to 100 ° C. using a substrate heating heater 6 degree of vacuum in the film forming apparatus 1 2 × 10 ^- was an atmosphere of ³ Pa. Then 2 × 10 argon gas was introduced ^- while maintaining the atmosphere of ¹ Pa, after argon plasma cleaning by applying a voltage of -1000V to the substrate holder 4 by bias power supply 9 was evacuated with argon gas . The gas is introduced into the film forming apparatus through the supply port 10 and exhausted through the exhaust port 11.
[0049]
Next, prior to the formation of amorphous carbon, metal is applied by applying a voltage of −1000 V to the substrate holder 4 by the bias power source 9 while evaporating and ionizing the targets of the group IVa, Va and VIa metal elements of the periodic table. Ion bombardment treatment was performed, and surface etching treatment was performed to improve the adhesion of the film.
[0050]
Furthermore, with or without introduction of hydrocarbon gas, a target selected from the group consisting of elements of group IVa, Va, VIa, IIIb and elements of group IVb other than C was evaporated by vacuum arc discharge. Ionization was performed, and a negative power of several hundred volts was applied to the substrate holder 4 by the bias power source 9 to form an interface layer of these metals or metal carbides. The formation of the amorphous carbon film from the interface layer is performed by switching the target and the atmosphere. At the time of switching, the composition of both layers is usually slightly mixed. From this, it is presumed that a mixed composition layer and a gradient composition layer of raw materials exist between both layers.
[0051]
Next, an amorphous carbon film is formed on the steel drill by evaporating and ionizing the graphite target by cathodic arc discharge while introducing argon gas into the film forming apparatus 1 at a rate of 100 cc / min. The At this time, the voltage by the bias power supply 9 was set to several hundreds of negative. The temperature of the steel drill as the base material was set to 100 ° C. during the formation of the amorphous carbon film.
[0052]
For comparison, coating drills of comparative products 1 to 8 shown in Tables 1 and 2 were also prepared. In comparative product 1, a hydrogenated amorphous carbon film was formed on the surface of the same steel drill as described above using a normal plasma CVD film forming apparatus using CH ₄ gas as a raw material. Comparative products 2 to 4 are obtained by forming an amorphous carbon film on the surface of the same steel drill by the cathodic arc ion plating method using graphite as a raw material, and the film thickness is outside the scope of the present invention. Comparative product 5 is a hydrogenated amorphous carbon film formed on the surface of the same steel drill as described above by adding CH ₄ to the atmospheric gas and using the cathodic arc ion plating method. It is outside the scope of the invention. Comparative products 6 and 7 are the same steel drill surfaces coated with TiN and TiAlN, respectively, by the cathodic arc ion plating method. Comparative product 8 is an uncoated drill.
[0053]
Next, for each drill manufactured by the above method, a drilling test under the conditions in Table 3 (wet condition by external lubrication) was performed, and the thrust reduction rate with respect to the non-coated drill (evaluated based on the thrust resistance of the comparative product 8) and The adhesion state at the cutting edge was measured. Tables 1 and 2 show the results of the above cutting tests. The amount of hydrogen in the formed amorphous carbon film was evaluated by ERDA (Elastic Recoil Detection Analysis). The film thickness at the blade tip was evaluated by SEM of the blade cross-section.
[0054]
[Table 1]

[0055]
[Table 2]

[0056]
[Table 3]

[0057]
From the results shown in Tables 1 and 2, the conventional TiN film (Comparative product 6), TiAlN film (Comparative product 7), and comparative product in which an amorphous carbon film outside the range specified in the present invention was formed (Comparative product 1 to In 5), the thrust resistance is almost the same as that of the non-coat and the welding resistance is inferior. In contrast, as shown in Table 1, in the drills of the present invention examples (the present invention products 1 to 20), the hydrogen content of the amorphous carbon coating was 5 atomic% or less. And it turns out that it has the outstanding abrasion resistance while having the outstanding abrasion resistance in an aluminum drilling process. Therefore, it can be seen that the drilling accuracy after drilling is very high and a long life is possible.
[0058]
(Example 2)
By the same method as in Example 1, an amorphous carbon film was coated on the surface of a φ4 mm high-speed steel reamer (the film of the product 4 of the present invention). As a comparative product, hydrogenated amorphous carbon film by CVD method (Comparative product 1), amorphous carbon film whose film thickness is outside the scope of the present invention (Comparative product 2-4), CH ₄ was added to the atmosphere gas. Then, a hydrogenated amorphous carbon film (Comparative product 5), a TiN film (Comparative product 6), and a TiAlN film (Comparative product 7) prepared by cathodic arc ion plating were coated. Next, each surface-coated reamer produced by the above method was subjected to aluminum die casting (ADC12) drilling under the conditions shown in Table 4, and the number of drilled holes and the state of the cutting edge were evaluated.
[0059]
[Table 4]

[0060]
As a result, in Comparative products 1 to 7, since the hole diameter of the work material varied when 600 holes were drilled, the state of the reamer was examined. As a result, the blade edge was worn and chipping was observed at the tip.
[0061]
On the other hand, in the reamer coated with amorphous carbon of the product 4 of the present invention, there was no problem in the processing condition of the work material even when 9000 holes were drilled, and no wear or chipping was observed in the reamer blade edge.
[0062]
(Example 3)
In the same manner as in Example 1, an amorphous carbon film was coated on the surface of a φ7 mm high-speed steel end mill (the film of the product 6 of the present invention). As a comparative product, hydrogenated amorphous carbon film by CVD method (Comparative product 1), amorphous carbon film whose film thickness is outside the scope of the present invention (Comparative product 2-4), CH ₄ was added to the atmosphere gas. Then, a hydrogenated amorphous carbon film (Comparative product 5), a TiN film (Comparative product 6), and a TiAlN film (Comparative product 7) prepared by cathodic arc ion plating were coated. Next, for each surface-coated end mill manufactured by the above method, end milling of aluminum die cast (ADC12) under the conditions of Table 5 is performed, and the cutting length and cutting edge state until the surface roughness of the workpiece is deviated Evaluated.
[0063]
[Table 5]

[0064]
As a result, among the conventional surface-coated cutting end mills, the CVD hydrogenated amorphous carbon film (Comparative Product 1) has a cutting length of 20 m and an amorphous carbon film whose film thickness is outside the scope of the present invention ( Comparative products 2 to 4) have a cutting length of 100 m, and hydrogenated amorphous carbon film (comparative product 5) prepared by cathodic arc ion plating with CH ₄ added to the atmospheric gas has a cutting length of 30 m. The metal nitride films (comparative products 6 and 7) formed by the PVD method deviated from the surface roughness standard at cutting lengths of 5 m and 6 m, respectively. When the aluminum deposited on the tip of the surface-coated end mill that had reached the end of its life was removed and examined, there was no film already coated and the high-speed steel of the base material was exposed.
[0065]
On the other hand, in the end mill of the product 6 of the present invention, the surface roughness of the work material could be maintained within the standard even when 800 m was cut, and further life extension was expected.
[0066]
The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. It is intended that the scope of the present invention is not limited to the above description of the embodiments, but is intended to include all modifications and variations within the meaning and scope shown by the claims and equivalent to the claims.
[0067]
Although specific examples of the present invention have been described above, the present invention relates to other shapes of rolling tools (drills, end mills, reamers, etc.), cutting edge exchangeable cutting tips used for milling tools and turning tools, cutting tools (cutters) , Knife, slitter, etc.).
[0068]
【The invention's effect】
As described above, according to the coated tool of the present invention, by specifying the type of the base material and the thickness of the amorphous carbon film, it is possible to maintain wear resistance and obtain excellent welding resistance, The cutting and wear life of the tool can be significantly extended. In addition, this tool is less likely to cause adhesion of the work material and chipping of the cutting edge, and further has high thermal conductivity, so that the temperature of the cutting edge is small and can be used even in severe cutting environments such as dry cutting and high-speed machining. In particular, by using an amorphous carbon film that does not substantially contain hydrogen, even more excellent wear resistance and welding resistance can be obtained. Therefore, it is expected to be effectively used for a cutting tool (drill, end mill, reamer, etc.), a cutting edge exchangeable cutting tip used for a milling tool or a turning tool, and a cutting tool (cutter, knife, slitter, etc.).
[Brief description of the drawings]
FIG. 1 is a schematic view of a film forming apparatus used for forming a film of the inventive tool.
FIG. 2 is a cross-sectional view of a cutting edge portion of the inventive tool.
FIG. 3 is a Raman spectrum of the amorphous carbon coating film of the present invention.
FIG. 4 is a Raman spectrum of a conventional amorphous carbon coating film.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Film-forming apparatus 2, 3 Target 4 Base material holder 5 Drill 6 Substrate heater 7, 8 Arc power supply 9 Bias power supply
10 Supply port
11 Exhaust port
20 Amorphous carbon
21 Macro particles
22 Graphite particles
23 Tool edge

Claims (22)

An amorphous carbon-coated tool comprising a base material made of one type selected from high-speed steel, carbon tool steel and alloy tool steel, and an amorphous carbon film covering at least the cutting edge on the base material. hand,
The amorphous carbon film is formed by physical vapor deposition,
The amount of hydrogen in the amorphous carbon film is 5 atomic% or less,
The maximum thickness at the cutting edge of this amorphous carbon film is 0.05 μm or more and 0.5 μm or less,
Amorphous carbon coated tool, wherein the density of the macro particles present in the amorphous carbon film surface is 3 × 10 ⁵ cells / mm ² or less. An amorphous carbon-coated tool comprising a base material made of one type selected from high-speed steel, carbon tool steel and alloy tool steel, and an amorphous carbon film covering at least the cutting edge on the base material. hand,
The amorphous carbon film is formed by physical vapor deposition under an atmosphere substantially free of hydrogen using graphite as a raw material,
The maximum thickness at the cutting edge of this amorphous carbon film is 0.05 μm or more and 0.5 μm or less ,
Amorphous carbon coated tool, wherein the density of the macro particles present in the amorphous carbon film surface is 3 × 10 ⁵ cells / mm ² or less.   3. The amorphous carbon-coated tool according to claim 1, wherein the amorphous carbon film is substantially composed only of carbon. The amorphous carbon-coated tool according to any one of claims 1 to 3 , wherein a maximum thickness at a cutting edge part involved in cutting of the amorphous carbon film is 0.05 µm or more and 0.25 µm or less. Amorphous carbon coated tool according to any one of claims 1 to 4, the surface roughness Ra of said amorphous carbon film is characterized in that at 0.05μm or less than 0.002 .mu.m. Amorphous carbon coated tool according to any one of claims 1 to 5, the surface roughness Ry of said amorphous carbon film is characterized in that at 0.5μm or less than 0.02 [mu] m. Amorphous carbon coated tool according to any one of claims 1 to 6, Knoop hardness of the amorphous carbon film is equal to or less than 50GPa least 20 GPa. The Raman spectrum obtained by Raman spectroscopic analysis using an argon ion laser having a wavelength of 514.5 nm has a peak at a wave number of 400 cm ^{- 1} or more and 1000 cm ^{- 1} or less, according to any one of claims 1 to 7 , Amorphous carbon coated tool. The intensity of the peaks present in the vicinity of ¹ (I1340) and the intensity ratio of the (I700 / I1340) is 0.02 to 2.5 ^- wavenumber 400 cm ^{- 1} or 1000 cm ^{- 1} peak intensity (I700) present below the 1340cm 9. The amorphous carbon-coated tool according to claim 8 , wherein Wavenumber 400 cm ^{- 1} or 1000 cm ^-1 integrated intensity of peaks present below (S700) and 1340 cm ^{- 1} present near the integrated intensity of the peaks (S1340) and the intensity ratio of (S700 / S1340) is 0.01 to 2.5 The amorphous carbon-coated tool according to any one of claims 8 to 9 , wherein 1560 cm ^{- claims 1} intensities of peaks present in the vicinity (I1340) and the intensity ratio of the (I1340 / I1560) is characterized in that 0.1 to 1.2 ^{- 1} exists near the intensity of peak (I1560) and 1340cm The amorphous carbon-coated tool according to any one of 8 to 10 . 1560 cm ^{- 1} present near the integrated intensity of the peaks (S1560) and 1340 cm ^- the integrated intensity of the peaks present in the vicinity of ¹ (S1340) and the intensity ratio of (S1340 / S1560) is characterized in that 0.3 to 3 The amorphous carbon-coated tool according to any one of claims 8 to 11 . The amorphous carbon-coated tool according to any one of claims 8 to 12 , wherein a peak existing in the vicinity of 1560 cm ^{- 1} is present at 1560 cm ^{- 1} or more and 1580 cm ^{- 1} or less. The amorphous carbon film is transparent in the visible light range, amorphous force one carbon coated tool according to any one of claims 1 to 13, characterized in that indicating an interference color. The amorphous carbon film according to claim 14 , wherein the amorphous carbon film exhibits one or more interference colors selected from among magenta, purple, violet, blue, silver, yellow, red, and green. Quality carbon coated tool. Comprising an interface layer between the substrate and the amorphous carbon film;
This interfacial layer is at least one element selected from the group consisting of elements of Group IVa, Va, VIa, Group IIIb and elements of Group IVb other than C, or at least one selected from these elements Consisting of carbides of more than seed elements,
16. The amorphous carbon-coated tool according to claim 1, wherein the thickness of the interface layer is 0.5 nm or more and less than 10 nm. The interface layer is at least one element selected from the element group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and Si, or at least one element selected from this element group 17. The amorphous carbon-coated tool according to claim 16 , wherein the amorphous carbon-coated tool is a carbide of the element. Between the interfacial layer and the amorphous carbon film, according to claim 16 or 17 gradient composition layer mixed composition layer or composition composition of each coating were mixed is continuously changed, characterized in that the intervening Amorphous carbon tool. The amorphous carbon tool is a tool for co-machining a soft metal material, a non-ferrous metal material, an organic material, a material containing hard particles, a printed circuit board, or a ferrous material and a soft metal material. The amorphous carbon-coated tool according to any one of claims 1 to 18 , wherein The amorphous carbon tool is a group consisting of a drill, a micro drill, an end mill, a tip replacement type tip for end milling, a tip replacement type tip for milling, a tip replacement type tip for turning, a metal saw, a toothing tool, a reamer, and a tap. The amorphous carbon-coated tool according to any one of claims 1 to 19 , wherein the tool is one selected from the above. Holding a base material made of one type selected from high-speed steel, carbon tool steel and alloy tool steel in a vacuum vessel;
Including applying a zero or negative DC bias to the substrate and evaporating graphite as a raw material in an atmosphere substantially free of hydrogen to form an amorphous carbon film,
Amorphous, characterized in that the maximum thickness of the amorphous carbon film at the cutting edge in the 0.05 to 0.5 [mu] m, the density of the macro particles present in the carbon film surface is controlled to be 3 × 10 ⁵ cells / mm ² or less A method for producing a carbon-coated tool. 22. The method for producing an amorphous carbon-coated tool according to claim 21 , wherein the step of forming the amorphous carbon film is performed by cathodic arc ion plating.

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