JP2007196360A - Cutting tool with life sensor circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool with a reliable life sensor circuit used for cutting non-ferrous metals such as aluminum.
A cutting tool with a life sensor circuit having at least one insulating coating layer 2 on the surface of a conductive base material 3 and forming a circuit using the conductive hard layer 4 thereon. there are, together with at least one layer of the insulating covering layer 2 is a hard carbon film, the integrated intensity I _D of D band Raman spectrum of the hard carbon _film, the area intensity of G-band to the case of the I _G, The area intensity ratio R = ( _ID / _IG ) is set to 1.4 or less.
[Selection] Figure 2

Description

  The present invention relates to a cutting tool with a life sensor circuit used for cutting a work material having high weldability.

  In general, the tool life in cutting is determined based on the magnitude of flank wear of the cutting tool. However, directly observing tool wear during cutting is very difficult in the working environment. For this reason, conventionally, machining is interrupted in the middle of the cutting process, and visual confirmation of the wear state using a tool microscope or the like is a relatively easy confirmation means. However, such a confirmation means has to remove the tool from the machine once to interrupt the machining, and the working efficiency is remarkably lowered and the blade edge position accuracy is also lowered. Therefore, if the flank wear amount can be promptly estimated in-process during cutting, it is very effective in maintaining high-efficiency machining and high-precision machining. In fact, when you want to check the amount of wear in-process during cutting, other phenomena such as cutting force and vibration changes accompanying tool wear are detected by a sensor installed near the machining point on the machine tool. A method of estimating the wear amount by performing some signal conversion processing on the detection signal has already been disclosed. Among them, in the cutting work in which the work material is a non-ferrous metal such as aluminum, the degree of welding to the tool is large, so that wear determination is difficult, and in-process measurement is a very ideal method.

  However, in-process measurement has a problem that it is difficult to obtain a quantitative value of wear, and sufficient sensitivity and reliability cannot be obtained.

  On the other hand, a method has been proposed in which the tool life is automatically determined by directly detecting the wear amount of the cutting edge portion of the cutting tool. The technique disclosed in Patent Document 1 relates to a self-diagnosis method for tool life by detecting the amount of wear of such a cutting tool. As a method applied to a cutting tool made of a conductive base material, a conductive base material and In this case, a current is passed through a conductor track embedded in the vicinity of the cutting edge in a state insulated with an aluminum oxide film, and the limit wear is detected using a signal when the conductor track is interrupted due to wear during the cutting process as a trigger. It is.

In Patent Document 2, a cutting tool in which an insulating aluminum oxide film is coated on a conductive base material is used, a voltage is applied between the work material and the cutting tool, and the aluminum oxide film is formed. There has been proposed a tool life detection method in which a current flows when the conductive base material is exposed due to wear, that is, immediately before the service life. In any of these methods, the insulating state of the insulating layer is very important.
JP-A-62-88552 JP 59-81043 A

  However, although it is described that the insulating layer (described as a non-conductive layer) disclosed in Patent Document 1 can be manufactured by a CVD method or a PVD method, it has a thermal expansion coefficient such as that of a carbide substrate or a cermet substrate. When an aluminum oxide layer is formed on a different base material by a CVD method, an open crack leading to the base material is likely to occur in the aluminum oxide film after the film formation, and when a conductive sensor film is formed on the insulating layer, There is a problem that the conductive base material and the conductive sensor film are short-circuited through the crack. Further, the PVD method has a problem that defects such as open pinholes are easily formed in the aluminum oxide insulating film, and the conductive base material and the conductive sensor film are short-circuited through the pinholes. There is also a problem that conductive unreacted substances remain in the insulating layer depending on the state of the base material. Due to these problems, it has been very difficult to produce a circuit that can stably exhibit the sensor function.

  Further, in Patent Document 2, in order to obtain an insulating aluminum oxide film, at least a thickness of 10 μm to 100 μm is used in order to eliminate the influence of a short circuit caused by a very small chip or chip existing in the aluminum oxide film. It is stated that it is necessary to form an aluminum oxide film.

  For this reason, in the prior art, there are many defects that cause short circuits such as cracks, pinholes, and conductive particles that reach the substrate, so it cannot be used as a life-determination cutting tool for detecting the amount of wear. There was a problem. In addition, attempts have been made to increase the film thickness as a method for eliminating the effects of cracks and chips existing in the insulating layer, but the insulating layer has to be made thicker than necessary, leading to a reduction in cutting performance in recent years. Under severe cutting conditions, there is a problem that the chipping resistance is reduced by increasing the film thickness.

  In addition, a hard carbon film having high welding resistance is often applied as a coating film that is optimal for cutting of non-ferrous metals such as aluminum. Although the hard carbon film is also highly insulating, its performance varies greatly depending on the composition and manufacturing method, and problems such as cracks and chipping may occur as described above. In addition, since the residual stress is extremely high, the peel resistance is low, and generally a thin film specification is used, but it is worn out at an early stage and a sufficient effect cannot be obtained. From the above, it has not been put into practical use as a cutting tool with a life sensor circuit for processing non-ferrous metals such as aluminum.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a cutting tool with a life sensor circuit with high reliability used for cutting non-ferrous metals such as aluminum.

In order to solve the above-mentioned problems, the cutting tool with a life sensor circuit according to the present invention has at least one insulating coating layer on the surface of the conductive base material, and a circuit using the conductive hard layer is formed thereon. A cutting tool with a life sensor circuit, wherein at least one of the insulating coating layers is a hard carbon film, and the Raman spectrum of the hard carbon film has an area intensity in the D band of I _D and G band. When the area intensity at IG is I _G , the area intensity ratio R = (I _D / I _G ) is 1.4 or less.

With this configuration, even when processing a non-ferrous metal such as aluminum, the cutting tool with a life sensor circuit having excellent welding resistance can be obtained by using a hard carbon film as an insulating coating layer. If the area intensity ratio R = (I _D / I _G ) in the D band and the G band of the Raman spectrum of the hard carbon film is 1.4 or less, the diamond bond (sp3 bond) ratio having high insulation is high. Since it becomes higher and the hard carbon film has a denser structure, a highly reliable cutting tool with a life sensor circuit with few defects in the film can be obtained.

  In addition, when the film thickness of the hard carbon film is 0.05 to 0.1 μm, a stable hard carbon film that does not cause film peeling does not occur without reducing the insulating property of the hard carbon film. It is desirable because it can.

  Furthermore, the insulating coating layer has a multilayer structure in which two or more layers of the hard carbon film are laminated, even if an open defect occurs in a single insulating layer. By laminating the above insulating layers, it is desirable because a short circuit due to defects can be prevented and high insulation can be ensured.

Of the laminated hard carbon films, the area intensity ratio R _L = (I _DL / I _GL ) for the Raman spectrum of the hard carbon film on the inner layer side is directly above the hard carbon film on the inner layer side. By making the structure larger than the area intensity ratio R _H = (I _DH / I _GH ) for the Raman spectrum of the hard carbon film, it is required as a cutting tool that the outer layer side has high hardness and the inner layer side has high toughness. This is desirable because it can have both wear resistance and fracture resistance.

Furthermore, it is desirable that the difference between the area intensity ratio _RL and the area intensity ratio _RH is 0.1 or more in that the wear resistance performance and the fracture resistance performance can be further improved.

  Moreover, it is desirable that the total film thickness of the insulating coating layer is 0.2 to 1.0 μm in that both insulation and peel resistance can be achieved in an optimum state.

  Furthermore, providing a sensor circuit protective film made of a hard carbon coating layer on the life sensor circuit made of the conductive hard layer can prevent welding to a life sensor circuit when a non-ferrous metal such as aluminum is processed. At the same time, it is desirable because the life as a cutting tool with a life sensor circuit can be extended.

According to the cutting tool with a life sensor circuit of the present invention, even when processing a non-ferrous metal such as aluminum, by using a hard carbon film as an insulating coating layer, it has excellent welding resistance, and For the Raman spectrum, by setting the area intensity ratio R = (I _D / I _G ) in the D band and G band to 1.4 or less, the diamond bond (sp3 bond) ratio having high insulation is increased, and the hard carbon film is more Since it has a dense structure, a highly reliable cutting tool with a life sensor circuit can be obtained with few defects in the film.

  An example of an embodiment of a cutting tool with a life sensor circuit of the present invention will be described in detail with reference to the drawings. 2 to 3 show an embodiment of the present invention, and FIG. 2 shows the essentials of the cutting tool 1 with a throw-away tip type life sensor circuit (hereinafter sometimes simply referred to as a tool) according to the first embodiment. FIG. 3 is an enlarged sectional view of a main part of the tool according to the second embodiment, and FIG. 4 is a schematic view showing a method for investigating the electrical insulation of the tool of FIG.

  As shown in FIG. 2, the tool 1 of the first embodiment of the present invention includes a conductive insulating material layer 2 on the surface of a conductive base material 3, and a conductive material used as a life sensor circuit thereon. The hard layer 4 is provided.

  Here, a cemented carbide is used as the conductive base material 3. In general, a cemented carbide is composed of a hard phase and a binder phase, and the hard phase is tungsten carbide or a carbide of metals in groups 4, 5, and 6 of the periodic table containing 5 to 15% by weight of tungsten carbide. The binder phase is mainly composed of an iron group metal such as Co, and is contained in a total amount of 5 to 15% by weight, for example. Incidentally, it is desirable to use a K-type cemented carbide as a conductive base material in the case of cutting a non-ferrous metal such as aluminum from the viewpoint of welding resistance, and the embodiment of the present invention also uses a K-type cemented carbide. ing.

  In addition to the cemented carbide, the conductive base material 3 includes an aluminum oxide sintered body, a silicon nitride sintered body, a cermet, a cubic boron nitride sintered body (CBN / cubic Boron Nitride), and a diamond sintered body. Body (PCD / Polycrystalline Diamond), and any one of one, two or more carbides, nitrides, carbonitrides and oxides selected from Group 4, 5, 6 metals by PVD method and / or CVD method for the base material A coating tool coated with one hard film can be used.

The aluminum oxide sintered body is composed of 2 to 40% by weight of TiC, 0.01 to 5% by weight of at least one of oxides of Fe, Ni and Co, and the balance being Al ₂ O ₃ and inevitable impurities. An aluminum oxide sintered body can be used.

As a silicon nitride sintered body, Al is 1.5 to 10 mol% in terms of Al ₂ O ₃ , Ti carbide, nitride, carbonitride is 30 to 80 mol%, and the remainder is nitrided with silicon nitride and rare earth oxide. A silicon nitride sintered body having a ratio of 10 mol% or less with respect to silicon and 10 mol% or less of impurity oxygen in terms of SiO ₂ can be used.

  As the cermet, Ti is contained in a proportion of 50 to 80% by weight in terms of carbide, nitride or carbonitride, and a Group 6 element in the periodic table is contained in a proportion of 10 to 40% by weight in terms of carbide (nitrogen / carbon + nitrogen). ) TiCN group cermet comprising 70 to 90% by weight of a hard phase component having an atomic ratio in the range of 0.4 to 0.6 and 10 to 30% by weight of a binder phase component comprising an iron group metal. There is.

  As the coating film, a hard carbon film having a film thickness of 0.05 to 0.1 μm is used as a main component film, and a multilayer film is used. Otherwise, Ti carbide, nitride, carbonitride is 0.1 to 0.1%. 0.2 μm, Al oxide 0.1-0.2 μm, TiAl nitride 0.1-0.2 μm, etc. One or more of these hard films can be made of the above-mentioned cemented carbide, cermet It is coated on a base material such as ceramic.

  Further, as the insulating coating film 2 that insulates the conductive base material 3 and the life sensor circuit film 4, the hard carbon film that is the main constituent film of the present invention is formed by PCVD, ion plating, sputtering, vapor deposition, or the like. A film is formed by a PVD method or the like. When the insulating layer is formed into a multilayer film, the hard carbon films may be overlapped with each other, or the hard carbon film may be overlapped with another insulating film. These insulating films may be made of an insulating material such as aluminum nitride, silicon nitride, silicon oxide, or titanium oxide. However, in the processing of non-ferrous metals such as aluminum, which requires welding resistance, it is more desirable to use only one or more hard carbon films. By using only a hard carbon film, high welding resistance is expected. Further, by using ion implantation in combination with the film formation, it is possible to increase the film thickness in a state where the residual stress of the surface layer is relaxed.

  As the hard carbon film, a diamond film or an amorphous diamond-like carbon (DLC) film is suitable. However, lubricity, film forming cost, and film forming ease when formed on the surface of the cutting tool. From this point of view, a diamond-like carbon (DLC) film is used as an embodiment of the present invention.

Here in the present invention, the Raman spectrum in Raman spectroscopy of the hard carbon film (DLC), D-band (1390 cm ^-1 vicinity) the integrated intensity of _I D, the area intensity of G-band (1540 cm around ^-1) _{I G} In this case, the area intensity ratio R = (I _D / I _G ) is 1.4 or less.

Among the hard carbon films, in the case of diamond-like carbon (DLC) formed from sp3 structure (diamond structure) and sp2 structure (graphite structure), the G band (near 1540 cm ⁻¹ ) has a main peak, and D band ( An asymmetric Raman spectrum having a shoulder band in the vicinity of 1390 cm ⁻¹ is observed. Each of these Raman spectra is a Raman spectrum of carbon having an sp2 structure. However, the relative intensity of these Raman spectra is closely related to the sp3 bond ratio of the hard carbon film, and the area intensity ratio of both peaks R = ( When I _D / I _G ) is 1.4, the sp3 ratio is about 70%, and when it is less than that, the sp3 ratio increases. The insulating property of the hard carbon film varies greatly depending on the ratio of sp3 bonds, which are diamond bonds. If the ratio of diamond bonds having high insulating properties (sp3 bonds) exceeds 70%, the hard carbon film has a denser structure. As shown in FIG. 2, a highly reliable cutting tool with a life sensor circuit with few defects 5 such as cracks, pinholes, or conductive particles in the hard carbon film can be obtained. On the other hand, if the sp3 bond ratio is less than 70%, the insulation is lowered, and the function as a tool with a life sensor circuit cannot be sufficiently achieved.

  That is, when the area intensity ratio R exceeds 1.4, the insulating coating layer includes defects, and conductive foreign matters are mixed therein, so that the insulation is lost and the electric resistance value is reduced.

  As shown in FIG. 1, the insulating coating film 22 in the conventional cutting tool 21 with a life sensor has an open crack in the film, that is, a crack or pinhole having ends on the front and back surfaces of the film, conductive particles, and the like. When the conductive sensor circuit film 24 is formed on the insulating coating film 22, the conductive material penetrates into the defect or the like, and as a result The conductive base material 23 and the conductive sensor film 24 are short-circuited. For this reason, the sensor circuit cannot function normally and is not reliable as a sensor tool. On the other hand, when a hard carbon film such as the present invention, particularly a diamond-like carbon (DLC) film, is used as an insulating coating layer, the proportion of sp3 structure is large and an extremely dense structure is formed. It is possible to obtain a sensor tool with less insulation and high insulation.

  Here, the Raman spectroscopic analysis is an analysis method for estimating a molecular structure from a vibration energy level difference of atoms constituting molecules and crystals. More specifically, this is an analysis method in which a sample in a ground state is irradiated with visible light and an energy difference when returning to an excited state via an intermediate transition state is observed as Raman light.

  Next, after forming a hard carbon film (DLC) as the insulating coating layer 2, a conductive hard layer used as a life sensor circuit is formed. This conductive hard layer can be formed with a predetermined thickness on almost the entire tool surface by employing a CVD method, a PVD method such as ion plating, sputtering, vapor deposition, or a plating method. Thereafter, the conductive hard film formed on almost the entire surface of the tool is processed into a predetermined pattern as a life sensor circuit by laser processing. Specifically, the sensor pattern is formed on the rake face and the flank face of the blade edge so as to be parallel to the edge line of the blade edge. In general, the width of the sensor pattern may be 0.01 mm to 0.5 mm, but an arbitrary width may be given depending on the lifetime setting. Thereby, a sensor tool having good electrical insulation between the conductive base material and the conductive sensor film can be produced. As for the film thickness, when the film is thinner than 0.05 μm, the bonding to the surface of the base material is weakened and the electric resistance value of the sensor circuit is increased, so that the wear degree and chipping of the throw-away tip are accurately detected. May become difficult. If a conductive film exceeding 20 μm is formed, a large residual stress is generated in the conductive film during the formation, and the residual stress may weaken the bonding of the conductive film to the base material surface. There is.

Here, the conductive hard film is a metal material such as Ti, Zr, V, Nb, Ta, Cr, Mo, W, etc., Group 4, 5, 6 metal, Co, Ni, Fe, etc., or Al. 4, 5, 6 such as TiC, VC, NbC, TaC, Cr ₃ C ₂ , Mo ₂ C, WC, W ₂ C, TiN, VN, NbN, TaN, CrN, TiCN, VCN, NbCN, TaCN, CrCN, etc. It is formed of a group metal carbide, nitride, carbonitride, (Ti, Al) N or the like. Among these, TiN has a strong bonding force to the base material of the throw-away tip, does not react with the work material, and the electric resistance value of the sensor always shows a predetermined value, so that the work surface of the work material is damaged by a reaction product. Can be effectively prevented from forming, has excellent oxidation resistance, does not change the electrical resistance of the sensor circuit due to oxide formation, and accurately detects the wear degree of the throw-away tip and the presence or absence of defects It can be suitably used for the reason that it can be performed.

  Further, the insulating coating layer can achieve higher insulating properties by forming a multilayer structure in which two or more hard carbon films are laminated. A hard carbon film with a high sp3 ratio has a very dense structure, defects such as cracks and pinholes are extremely small, and there are very few open cracks with edges on the front and back surfaces of the film, so a single layer with high insulation However, it is desirable that the insulating film in the cutting tool with a life sensor circuit that requires higher insulation and higher reliability has a multilayer structure. Even if an open defect as described above exists in a single insulating layer, a part of the conductive material penetrates into the defect during the production of the conductive hard film as the life sensor circuit in the final process. This prevents a short circuit between the conductive base material and the conductive circuit, and a higher performance can be obtained as a cutting tool with a life sensor circuit. A conceptual diagram is shown in FIG. Even if there is an open defect at the time of forming the first insulating layer 12a, the defect 15a can be filled or covered with the second insulating layer 12b. Even if there is an open defect during the formation of the second insulating layer 12b, a short-circuiting factor component penetrates into the defect 15b during the production of the conductive sensor film, but the first insulating layer 12a A short circuit between the conductive base material 13 and the conductive sensor film 14 can be prevented. That is, a cutting tool with a life sensor circuit for non-ferrous processing such as aluminum having higher insulation and welding resistance by including at least one layer of hard carbon film and thus forming a multilayer film of two or more layers. Obtainable.

  The total thickness of the plurality of insulating coating layers is preferably 0.2 μm or more and 1.0 μm or less. This is because if the insulating coating layer thickness is less than 0.2 μm, the insulating property may be extremely lowered. Further, since it is predicted that a thick film will adversely affect cutting performance (particularly chipping resistance), the thickness of the insulating coating layer is preferably 1.0 μm or less, more preferably 0.5 μm or less. Further, when the number of insulating coating layers is increased to three or four layers, it is necessary to pay attention to the total thickness of the insulating coating layers. In particular, since the residual stress is high in a hard carbon film, there is a concern that the peel resistance may be lowered.

  Moreover, in order to improve the adhesion of the film, a method of reducing the internal stress by containing a metal element is known, but even when such a metal-containing adhesion-enhancing layer is disposed as the first layer, Non-conductivity can be maintained by the second layer.

Of the laminated hard carbon films, the area intensity ratio R _L = (I _DL / I _GL ) for the Raman spectrum of the hard carbon film on the inner layer side is the outer layer side directly above the hard carbon film on the inner layer side. By making the structure larger than the area intensity ratio R _H = (I _DH / I _GH ) for the Raman spectrum of the hard carbon film, the residual stress is lowered and the peeling resistance is lowered without impairing the insulating properties of the whole insulating film. Can be prevented. In particular, in the case of a hard carbon film, although the insulation property increases as the sp3 ratio increases, the residual stress also increases, so that sufficient attention must be paid to the decrease in peel resistance. Therefore, it is a more desirable insulating film configuration to form a hard carbon film having a low sp3 ratio and a high adhesion as an inner layer, and forming a hard carbon film having a high sp3 ratio and an extremely insulating property as an outer layer thereon. Moreover, it can have both the wear resistance and the fracture resistance required for a cutting tool, ie, the outer layer has high hardness and the inner layer has high toughness.

  As mentioned above, although the throw away tip type tool was demonstrated as embodiment of this invention, it cannot be overemphasized that application to another tool, for example, a drill etc. is also possible.

(Production method)
Next, the detailed manufacturing method of DLC as a hard carbon film is demonstrated.

  First, for example, when a tungsten carbide base cemented carbide is used as the conductive base material, cobalt is used as the binder phase, tungsten carbide is used as the hard layer, and carbides, nitrides, and carbonitrides of Group 4, 5 and 6 metals as other components. Then, the oxide powder is mixed and pulverized, and a molded body is produced by a known molding technique such as press molding and extrusion molding. The molded body is heated to 1300 to 1500 ° C. in an inert atmosphere such as a vacuum atmosphere or a nitrogen atmosphere. Firing at the firing temperature.

  The surface of the sintered body produced by firing is machined to produce a conductive base material.

  Moreover, you may form a hard coating layer on the surface by well-known film-forming techniques, such as PVD and CVD, if desired.

  Here, an insulating hard film made of a hard carbon film is formed on the surface of the conductive base material produced as described above.

  According to the present invention, the conductive base material can be formed by physical vapor deposition, plasma CVD, or the like, but according to the present invention, the film can be formed by sputtering. Thus, an insulating hard film having higher insulating properties can be obtained.

C ₂ H ₂ gas and solid carbon are used as raw materials for the hard carbon film.

By setting the temperature in the chamber to 100 to 300 ° C., sputtering the C ₂ H ₂ gas at a flow rate of 15 to 50 ml / min, solid carbon at 1 to 10 kw, and applying a bias voltage of 10 to 50 kV to the substrate. A film can be formed. The area intensity ratio R _H = (I _DH / I _GH ), that is, the sp3 ratio can be controlled by the ratio of the C ₂ H ₂ gas flow rate to the solid carbon sputtering rate, the bias voltage, and the substrate temperature. That is, by decreasing the C ₂ H ₂ gas flow rate and increasing the sputtering rate of the solid carbon, the amount of hydrogen in the hard carbon film is reduced, and the high hardness film, that is, the sp3 ratio is high and the area intensity ratio R _H = (I _A film having a low _DH / _IGH ) is obtained. However, in the case of a multi-layer film, it can be formed by increasing the gas flow rate to lower the solid carbon sputtering rate when forming the lower layer film and decreasing the gas flow rate to increase the solid carbon sputtering rate when forming the upper layer film. .

  The area intensity ratio can also be changed by controlling the bias voltage and temperature, and a hard carbon film as an insulating film of the sensor circuit can be produced even in a manufacturing method other than sputtering.

  After forming the insulating hard layer, a conductive hard film is formed by a well-known film forming technique such as PVD or CVD, and a sensor circuit pattern is formed by laser processing or polishing processing.

  Thereafter, if desired, in order to prevent the sensor circuit pattern from being damaged by chips and causing malfunction of the sensor, a hard coating layer may be formed as a protective film by a known film formation technique such as PVD or CVD. .

Example 1
As examples of the present invention, the following five samples 1 were produced. A K-type cemented carbide base material was used as the conductive base material. As an insulating film that insulates the conductive base material from the conductive sensor film, a hard carbon (DLC) film having a thickness of 0.1 μm was formed as the first layer by sputtering. For the Raman spectrum in the Raman spectroscopic analysis using Ar laser (output: 2 W, wavelength: 514.5 and 488.0 nm) in the hard carbon (DLC) film, the area intensity in the D band (near 1390 cm ⁻¹ ) is expressed as I _D the area intensity of G-band (1540 cm around ^-1) when the _{I G,} relative intensity _{R = (I D / I G} ) is 1.4, i.e. as sp3 ratio of about 70%, the furnace A film was formed under conditions of an internal temperature of 130 ° C., a flow rate of C ₂ H ₂ gas of 20 ml / min, solid carbon of 5.5 kw, and a bias voltage of 30 kV.

  The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

  Thereafter, TiN was formed by PVD as a conductive sensor film, and a sensor circuit pattern was produced by laser processing.

Five samples 2 below were produced as comparative samples. As the conductive base material, K-type cemented carbide was used. As an insulating film that insulates the conductive base material from the conductive sensor film, a hard carbon (DLC) film having a film thickness of 0.1 μm and a Raman spectrum area intensity ratio of 1.6 (sp3 ratio is approximately 60%) is formed by sputtering. A film was formed by sputtering at an internal temperature of 130 ° C., a C ₂ H ₂ gas flow rate of 60 ml / min, solid carbon at 7.0 kw, and a bias voltage of 30 kV. The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

  And TiN was formed into a film by PVD as a conductive sensor film, and the sensor circuit pattern was produced by laser processing.

For these samples 1 and 2, electrical insulation between the conductive base material and the conductive sensor film was performed using a commercially available tester. FIG. 4 is a schematic diagram showing a method for investigating electrical insulation, and Table 1 shows measurement results of electrical resistance values.

  In the sample 2 as a comparative example, the area intensity ratio of the Raman peak of the hard carbon (DLC) film constituting the insulating film is 1.4 or more, that is, the sp3 ratio is low, and thus the electric resistance value is low.

  On the other hand, Sample 1 which is an example of the present invention showed excellent electrical insulation properties.

  Furthermore, a mounting test was performed under the following cutting conditions to determine whether the life could be determined in actual cutting. Specifically, for sample 1 and sample 2 described above, a life determination sensor circuit pattern is prepared at a position of 0.2 mm from the cutting edge on the flank, and cutting is performed under the following conditions with a current signal flowing therethrough. Processing is performed, and a sudden change in electrical resistance value that occurs when the flank wear reaches 0.2 mm and the life determination sensor circuit pattern is disconnected is detected to stop the processing. The results are shown in Table 1.

(Cutting conditions)
Work material: A6061 Cylindrical tool shape: CNMM120408
Cutting speed: 200 m / min Feed speed: 0.2 mm / rev
Cutting depth: 1.0mm
As shown in Table 1, all the five samples 1 which are the products of the present invention were disconnected when the flank wear reached 0.2 mm, and the change in the electric resistance value generated at that time was observed. I was able to detect it. However, in sample 2 of the comparative product, insulation of the insulating coating layer is insufficient, so that even if the flank wear reaches 0.2 mm and the life determination sensor circuit pattern is disconnected, a change in the electrical resistance value is detected. I couldn't.

(Example 2)
As an example of the present invention, the following five samples 3 were produced. As the conductive base material, a K-type cemented carbide base material was used. As an insulating film that insulates the conductive base material and the conductive sensor film, a hard carbon (DLC) film having a thickness of 0.1 μm was formed as the first layer by sputtering. About the Raman spectrum in the Raman spectroscopic analysis performed in the same manner as in Example 1 on the hard carbon (DLC) film, the area intensity in the D band (near 1390 cm ⁻¹ ) is represented by I _D and the area in the G band (near 1540 cm ⁻¹ ). the strength when the _{I G,} relative intensity _{R = (I D / I G} ) is 1.4 (sp3 ratio is about 70%) furnace temperature of 130 ° so that the _flow rate of C 2 _{H 2} gas Was 20 ml / min, solid carbon was sputtered at 5.5 kw, and a film was formed at a bias voltage of 30 kV.

  The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

Next, a hard carbon (DLC) film having a thickness of 0.2 μm was formed by sputtering as the second layer. In order to enhance insulation, the sp3 ratio in the hard carbon (DLC) film is increased, that is, the furnace temperature is 130 ° C. and the C ₂ H is set so that the area intensity ratio of the Raman spectrum is 1.25 (sp3 ratio is 80%). Sputtering was performed at a flow rate of ₂ gases at 35 ml / min, solid carbon at 8.5 kw, and a film was formed at a bias voltage of 30 kV.

  The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

  Thereafter, TiN was formed by PVD as a conductive sensor film, and a sensor circuit pattern was produced by laser processing.

  Five samples 4 below were prepared as comparative samples. As the conductive base material, a K-type cemented carbide base material was used. As an insulating film that insulates the conductive base material from the conductive sensor film, a hard carbon (DLC) film having a thickness of 0.1 μm and a Raman spectrum area intensity ratio of 1.25 (sp3 ratio of 80%) was formed by sputtering. The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

Next, a hard carbon (DLC) film having an area intensity ratio of 1.6 (sp3 ratio of 80%) in the Raman spectrum is applied to the second layer by sputtering as in the case of the first layer. Sputtering was performed at a flow rate of C ₂ H ₂ gas of 60 ml / min, solid carbon at 7.0 kw, and a film was formed under a bias voltage of 30 kV.

  The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

  Thereafter, TiN was formed by PVD as a conductive sensor film, and a sensor circuit pattern was produced by laser processing.

And about these samples 3 and 4, similarly to Example 1, the electrical resistance value of the produced sensor circuit was measured with the commercially available tester. Table 2 shows the measurement results of the electrical resistance value.

  In the sample 4 for comparison, the Raman peak intensity ratio of the hard carbon (DLC) film is low, that is, the sp3 ratio is high, and high insulation is expected. However, due to the high residual stress, some peeling or cracking occurs. Energization has occurred.

  On the other hand, the sample 3 which is the product of the present invention has a structure in which the first layer having a low sp3 ratio compensates for the residual stress of the second layer having a high sp3 ratio and high insulation.

  Further, the first layer has a lower residual stress than the second layer, and therefore has a high adhesion to the base material, and the second layer has a relatively high adhesion to the first layer because the first layer is the same hard carbon film.

  As a result, a sensor tool with high adhesion and high insulation is obtained as a whole.

  Furthermore, the mounting confirmation by actual cutting was performed on the same conditions as Example 1. FIG. The results are shown in Table 2.

  As shown in Table 2, the sensor circuit pattern was disconnected at the stage where the flank wear reached 0.2 mm in all five samples 3 which were the products of the present invention, and the change in the electric resistance value generated at that time Was able to be detected. However, in the sample 4 as a comparative product, since the insulation of the insulating coating layer was insufficient, even if the flank wear reached 0.2 mm, a change in the electric resistance value could not be detected.

(Example 3)
Five samples 5 below were produced as examples of the present invention. As the conductive base material, a K-type cemented carbide base material was used. As an insulating film that insulates the conductive base material from the conductive sensor film, a hard carbon (DLC) film having a thickness of 0.05 μm was formed by sputtering as the first layer.

About the Raman spectrum in the Raman spectroscopic analysis performed in the same manner as in Example 1 on the hard carbon (DLC) film, the area intensity in the D band (near 1390 cm ⁻¹ ) is I _D and in the G band (near 1540 cm ⁻¹ ). the integrated intensity when the _{I G,} relative intensity _{R = (I D / I G} ) is 1.25 (sp3 ratio 70%) furnace temperature of 130 ° so that the _flow rate of C 2 _{H 2} gas Was 35 ml / min, solid carbon was sputtered at 8.5 kw, and a film was formed under a bias voltage of 30 kV.

  The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes. Next, a hard carbon (DLC) film having a thickness of 0.3 μm was formed by sputtering as the second layer.

In order to enhance insulation, the sp3 ratio in the hard carbon (DLC) film is increased, that is, the furnace temperature is 130 ° C. and the C ₂ H is set so that the area intensity ratio of the Raman spectrum is 1.25 (sp3 ratio is 80%). Sputtering was performed at a flow rate of ₂ gases at 35 ml / min, solid carbon at 8.5 kw, and a film was formed at a bias voltage of 30 kV.

  The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

  Thereafter, TiN was formed by PVD as a conductive sensor film, and a sensor circuit pattern was produced by laser processing.

  Five samples 6 below were produced as comparative samples. A K-type cemented carbide base material was used as the conductive base material.

The conductive base material and the conductive sensor film as an insulating film for insulating thickness by sputtering 0.05 .mu.m, relative intensity of Raman spectrum 1.6sp3 ratio 70% of the hard carbon film temperature in the furnace 130 _{degrees, C} 2 H Sputtering was performed at a flow rate of ₂ gases at 60 ml / min, solid carbon at 7.5 kw, and a film was formed under a bias voltage of 30 kV. The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

Next, a hard carbon film having a high film thickness of 0.05 μm by sputtering, that is, a Raman peak area intensity ratio of 1.25 (sp3 ratio of 80%), is heated to 130 ° C., C ₂ H ₂ gas. Was produced by sputtering at a flow rate of 20 ml / min, solid carbon at 7.0 kw, and a bias voltage of 30 kV.

  The sputtering apparatus was a high frequency sputtering apparatus, and pre-sputtering was performed for 3 minutes, the base material was etched for 12 minutes, the target was pre-sputtered for 15 minutes, and the film was formed for 60 minutes.

  And TiN was formed into a film by PVD as a conductive sensor film, and the sensor circuit pattern was produced by laser processing.

And about these samples 5 and 6, similarly to Example 1 and 2, the electrical resistance value of the produced circuit was measured with the commercially available tester. The electrical resistance results are shown in Table 3.

  In the comparative sample, the sp3 ratio of the hard carbon (DLC) film is high and high insulation is expected. However, since the total film thickness is as thin as 0.1 μm, energization occurs and a short circuit occurs. It was. In particular, when there is film formation unevenness or the like, an extremely low electric resistance value is obtained at the location, and the insulating film has low reliability. On the other hand, when the total film thickness is 2.0 μm or more, the residual stress becomes extremely high, and it is highly possible that the electrical resistance is greatly reduced due to the occurrence of cracks and peeling.

  Furthermore, the mounting confirmation by actual cutting was performed on the same conditions as Example 1 and 2. FIG. The results are shown in Table 3.

  As shown in Table 3, all the five samples 5 which are the products of the present invention were disconnected when the flank wear reached 0.2 mm, and the change in the electric resistance value generated at that time was observed. I was able to detect it. However, in the sample 6 of the comparative product, since the insulation of the insulating coating layer was insufficient, even if the flank wear reached 0.2 mm, a change in the electric resistance value could not be detected.

It is principal part sectional drawing of the cutting tool with a lifetime sensor circuit which concerns on a prior art. It is principal part sectional drawing of the cutting tool with a lifetime sensor circuit by 1st embodiment of this invention. It is principal part sectional drawing of the cutting tool with a lifetime sensor circuit by 2nd embodiment of this invention. It is the schematic which shows the method of investigating electrical insulation in the cutting tool with a lifetime sensor circuit of FIG.

Explanation of symbols

1: Cutting tool with life sensor circuit 2: Insulating coating layer 3: Conductive base material 4: Conductive hard layer (life sensor circuit)
5: Defects such as cracks, pinholes, conductive particles 9: Tester 11: Cutting tool with life sensor circuit 12a: First layer insulating coating layer 12b: Second layer insulating coating layer 13: Conductive base material 14 : Conductive hard layer (life sensor circuit)
15: Defects such as cracks, pinholes, conductive particles 21: Cutting tool with life sensor circuit 22: Insulating coating layer 23: Conductive base material 24: Conductive hard layer (life sensor circuit)
25: Defects such as cracks, pinholes, and conductive particles

Claims (7)

A cutting tool with a life sensor circuit, comprising a circuit using at least one insulating coating layer on a surface of a conductive base material and a conductive hard layer formed thereon, wherein the insulating coating layer with at least one layer of a hard carbon film, the Raman spectra for the integrated intensity of the D band I _D of the hard carbon _film, the area intensity of G-band to the case of the I _G, relative intensity R = (I A cutting tool with a life sensor circuit, wherein _D / I _G ) is 1.4 or less. The cutting tool with a life sensor circuit according to claim 1, wherein the hard carbon film has a thickness of 0.05 to 0.1 μm. The cutting tool with a life sensor circuit according to claim 1 or 2, wherein the insulating coating layer has a multilayer structure in which two or more hard carbon films are laminated. Of the laminated hard carbon films, the area intensity ratio R _L = (I _DL / I _GL ) for the Raman spectrum of the hard carbon film on the inner layer side is hard on the outer layer side immediately above the hard carbon film on the inner layer side. _{4. The} cutting tool with a life sensor circuit according to claim 3, wherein the area intensity ratio R _H = (I _DH / I _GH ) for the Raman spectrum of the carbon film is larger. The cutting tool with a life sensor circuit according to claim 4, wherein a difference between the area intensity ratio _RL and the area intensity ratio _RH is 0.1 or more. 6. The cutting tool with a life sensor circuit according to claim 3, wherein a total film thickness of the insulating coating layer is 0.2 to 1.0 [mu] m. 7. The cutting tool with a life sensor circuit according to claim 1, wherein a sensor circuit protective film made of a hard carbon coating layer is provided on the life sensor circuit made of the conductive hard layer.

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