Surface treatment method for tool, tool, and soft material processing method

Abstract

A surface treatment method for a tool according to the present invention comprises a coating step (S12) for coating an organic solvent onto a die having a first hard coating, which contains carbon, on a surface of a die base material.

Description

Surface treatment method for jig / tool, jig / tool, and soft material processing method

[0001] The present disclosure relates to a surface treatment method for a tool, a tool, and a method for processing a soft material.

[0002] The mold described in Patent Document 1 includes a mold body and a diamond-like carbon film. The diamond-like carbon film covers the surface of the mold body. The diamond-like carbon film is formed by ion plating using a three-color ion source.

[0003] Japanese Patent Application Publication No. 8-90092

[0004] In the mold described in Patent Document 1, the presence of a diamond-like carbon film can prevent adhesion between the mold and the soft material to be processed by the mold. However, in an environment with low relative humidity, the adhesion prevention effect cannot be sufficiently obtained, and there is a risk that the soft material will adhere to the mold.

[0005] In order to solve the above problems, the present disclosure provides a surface treatment method for a tool, which includes a coating step of coating an organic solvent onto a tool having a substrate surface on which a hard coating containing carbon is formed. Also, in order to solve the above problems, the present disclosure provides a surface treatment method for a tool, which includes a substrate and a hard coating covering the surface of the substrate, the hard coating containing carbon, and which is characterized by Sp containing C—C bonds and C—H bonds when the surface is analyzed by narrow scan X-ray photoelectron spectroscopy. ３ Sp containing hybrid orbitals, C-C bonds and C-H bonds ２ Of the four types of hybrid orbitals, C=O bonds, and C-O bonds, Sp ３ The peak area ratio of hybrid orbitals is 70% or more.

[0006] In addition, in order to solve the above-mentioned problems, the present disclosure provides a method for processing soft materials, including: a coating step of applying an organic solvent to a tool having a substrate surface on which a hard coating containing carbon is formed; and a processing step of, after the coating step, bringing the tool into contact with a soft material that is softer than the substrate and processing the tool.

[0007] According to the above configuration, adhesion between the jig and the soft material can be suppressed.

[0008] Fig. 1 is a schematic diagram of a jig and tool. Fig. 2 is a flowchart showing a series of steps in a method for processing soft materials. Fig. 3 is a graph showing the results of a friction test. Fig. 4 is a graph showing a C1s spectrum by XPS. Fig. 5 is a graph showing the peak area ratio of a C1s spectrum by XPS.

[0009] Hereinafter, an embodiment of a machining apparatus having a jig and tool will be described with reference to the drawings. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from those in the actual drawings or from those in other drawings.

[0010] 1, the processing apparatus 10 includes a die 20 as a jig or tool, a blank holder 30, and a punch 40 as a jig or tool. The processing apparatus 10 is used for press working, specifically deep drawing.

[0011] The die 20 has a mold substrate 21 and a first hard coating 22. In Fig. 1, the first hard coating 22 is shown by a thick line. The mold substrate 21 has a cylindrical shape as a whole. That is, the mold substrate 21 has a machined hole 21A in the center. The mold substrate 21 is made of a material such as carbon tool steel or cemented carbide.

[0012] The first hard coating 22 covers the peripheral surface of the machined hole 21A in the mold substrate 21 and one end face of the mold substrate 21. That is, the first hard coating 22 covers a portion of the surface of the mold substrate 21. The first hard coating 22 contains carbon. In this embodiment, the first hard coating 22 is a diamond-like carbon film. The diamond-like carbon film is an amorphous film made of carbon atoms. An organic solvent having a hydroxyl group is applied onto the first hard coating 22. Examples of the organic solvent include isopropanol (hereinafter referred to as IPA) and perfluoropolyether (hereinafter referred to as PFPE) having a hydroxyl group.

[0013] The dynamic friction coefficient of the surface of the die 20 where the organic solvent is applied is 0.16 or less. The surface is also subjected to narrow scan analysis by X-ray photoelectron spectroscopy. In this case, Sp ３ Sp containing hybrid orbitals, C-C bonds and C-H bonds ２ Of the four types of hybrid orbitals, C=O bonds, and C-O bonds, Sp ３ The peak area ratio of hybrid orbitals is 70% or more. The method for measuring the dynamic friction coefficient and the narrow scan analysis will be described in detail later.

[0014] The blank holder 30 is substantially annular. That is, the blank holder 30 has a hole 31. The diameter of the hole 31 in the blank holder 30 is larger than the diameter of the machined hole 21A in the mold substrate 21. The blank holder 30 is placed on the end face of the mold substrate 21 on the side where the first hard coating 22 is applied. In this state, the central axis of the hole 31 in the blank holder 30 coincides with the central axis CL of the machined hole 21A in the mold substrate 21.

[0015] The punch 40 has a punch substrate 41 and a second hard coating 42. In FIG. 1, the second hard coating 42 is indicated by a thick line. The punch substrate 41 is cylindrical. The material of the punch substrate 41 is the same as that of the mold substrate 21. The diameter of the punch substrate 41 is smaller than the diameter of the machining hole 21A of the mold substrate 21. The punch 40 is connected to a driving device (not shown). The punch 40 can reciprocate on and along the central axis CL of the die 20 based on the driving force from the driving device. In other words, the die 20 can be inserted into and removed from the machining hole 21A of the mold substrate 21.

[0016] The second hard coating 42 covers the surface of the punch substrate 41. The material of the second hard coating 42 is the same as the material of the first hard coating 22. An organic solvent having a hydroxyl group is applied onto the second hard coating 42. Examples of the organic solvent include IPA and PFPE having a hydroxyl group.

[0017] The dynamic friction coefficient of the surface of the punch 40 where the organic solvent is applied is 0.16 or less. The surface is also subjected to narrow scan analysis by X-ray photoelectron spectroscopy. In this case, Sp ３ Sp containing hybrid orbitals, C-C bonds and C-H bonds ２ Of the four types of hybrid orbitals, C=O bonds, and C-O bonds, Sp ３ The peak area ratio of hybrid orbitals is 70% or more. The method for measuring the dynamic friction coefficient and the narrow scan analysis will be described in detail later.

[0018] <Method for Processing Soft Material> Next, a method for processing a soft material 50 using the processing device 10 will be described. The processing device 10 is used for drawing the soft material 50. The soft material 50 is softer than the materials of the die substrate 21 and the punch substrate 41. Specifically, the hardness of the soft material 50 is lower than the hardness of the materials of the die substrate 21 and the punch substrate 41. For example, the soft material 50 is aluminum. The hardness is measured, for example, by a hardness test in accordance with ISO 6506.

[0019] 2, the method for processing the soft material 50 includes a preparation step S11, an application step S12, and a processing step S13. First, in the preparation step S11, a tool having a first hard coating 22 containing carbon on the surface of a mold substrate 21 is prepared. Also, in the preparation step S11, a tool having a second hard coating 42 containing carbon on the surface of a punch substrate 41 is prepared. In other words, the tool referred to here is the die 20 and punch 40 described above, on whose surfaces no organic solvent has been applied.

[0020] Next, the coating step S12 is performed. In the coating step S12, an organic solvent is applied to the jig or tool. Specifically, in the coating step S12, an organic solvent having a hydroxyl group is applied to the surface of the first hard coating 22 and the surface of the second hard coating 42. Thereafter, the resulting mixture is left to stand, thereby volatilizing excess organic solvent from the surface of the first hard coating 22 and the surface of the second hard coating 42. The coating step S12 is one step in a surface treatment method for a jig or tool.

[0021] Next, the processing step S13 is performed. In the processing step S13, a blank holder 30 is used in addition to the jig tool. In the processing step S13, the jig tool is brought into contact with a soft material 50, which is softer than the die substrate 21 and the punch substrate 41, in an environment with a relative humidity of 8% or less, to perform processing. Specifically, first, the soft material 50 is placed on one end surface of the die 20. Then, the blank holder 30 presses the soft material 50 with a constant pressure from above the soft material 50. This positions the soft material 50, which is the object to be processed, between the blank holder 30 and the die 20. Then, the drive device is driven to insert the punch 40 into the processing hole 21A of the die 20. As a result, the soft material 50 deforms to conform to the shape of the processing hole 21A.

[0022] <Adhesion Test> Four types of jig and tool samples with different surface treatment methods were prepared, and an aluminum adhesion test was performed on each sample. In the adhesion test, first, each jig and tool sample was fixed. Next, an aluminum ball was brought into point contact with the sample. Then, in an environment with a relative humidity of 8% or less, the ball was slid over the jig and tool sample while a constant load was applied. In the adhesion test, the ball was slid over the sample 5,000 times, and whether or not aluminum had adhered to the sample was determined by observing the appearance.

[0023] The first sample was a carbon tool steel having a hard coating on its surface, to which no organic solvent was applied. The hard coating referred to here is the same as the first hard coating 22 described above, and will be referred to as the first hard coating 22 below for convenience. The second sample was a carbon tool steel having the first hard coating 22 on its surface, to which isoparaffin (hereinafter referred to as IP), an organic solvent without a hydroxyl group, was applied. The third sample was a carbon tool steel having the first hard coating 22 on its surface, to which PFPE was applied as an organic solvent with a hydroxyl group. The fourth sample was a carbon tool steel having the first hard coating 22 on its surface, to which IPA, an organic solvent with a hydroxyl group, was applied.

[0024] In this adhesion test, adhesion of aluminum to the first sample, which was not coated with an organic solvent, was observed. In the second sample, which was coated with IP, no adhesion of aluminum to the sample was observed. In the third sample, which was coated with PFPE, no adhesion of aluminum to the sample was observed. In the fourth sample, which was coated with IPA, no adhesion of aluminum to the sample was observed.

[0025] The results of the adhesion test showed that applying an organic solvent to the first hard coating 22 suppressed aluminum adhesion more effectively than not applying an organic solvent to the first hard coating 22. Furthermore, it was found that the effect of the organic solvent in suppressing aluminum adhesion was exerted even in an extremely dry environment with a relative humidity of 8% or less.

[0026] <Friction Test> Four types of jig and tool samples with different surface treatment methods were created, and a wear test was performed on each sample. In the friction test, first, each jig and tool sample was fixed. An aluminum ball was brought into point contact with the sample. Then, while applying a constant load, the ball was slid on the sample to measure the dynamic friction coefficient. This dynamic friction coefficient was measured every time the aluminum ball was slid, and the measurement was repeated 100 times.

[0027] The first sample was a carbon tool steel having a hard coating on its surface to which no organic solvent was applied. Note that the hard coating referred to here is the same as the first hard coating 22 described above, and will therefore be referred to as the first hard coating 22 below for convenience. The second sample was a carbon tool steel having the first hard coating 22 on its surface to which PFPE was applied as an organic solvent having a hydroxyl group. The third sample was a carbon tool steel having the first hard coating 22 on its surface to which IP was applied. The fourth sample was a carbon tool steel having the first hard coating 22 on its surface to which IPA was applied as an organic solvent having a hydroxyl group.

[0028] As shown in Figure 3, the dynamic friction coefficient of the first sample, which was not coated with an organic solvent, increased overall as the number of slides increased from 1 to 20. Furthermore, the dynamic friction coefficient of the first sample was 0.5 or higher from 21 to 100 slides. The minimum dynamic friction coefficient of the first sample was approximately 0.17. The maximum dynamic friction coefficient of the first sample was approximately 0.69.

[0029] The dynamic friction coefficient of the second sample coated with PFPE was approximately 0.15 between 1 and 10 slides. The dynamic friction coefficient of the second sample gradually decreased as the number of slides increased between 11 and 100 slides. The minimum dynamic friction coefficient of the second sample was approximately 0.11. The maximum dynamic friction coefficient of the second sample was approximately 0.16.

[0030] The dynamic friction coefficient of the third sample coated with IP decreased as the number of sliding cycles increased from 1 to 4. The dynamic friction coefficient of the third sample was approximately 0.08 from 4 to 100 sliding cycles.

[0031] The dynamic friction coefficient of the fourth sample coated with IPA decreased as the number of slides increased from 1 to 3. The dynamic friction coefficient of the fourth sample also decreased gradually as the number of slides increased from 4 to 50. The dynamic friction coefficient of the fourth sample also increased gradually as the number of slides increased from 51 to 100. The minimum dynamic friction coefficient of the fourth sample was approximately 0.02. The maximum dynamic friction coefficient of the fourth sample was approximately 0.09.

[0032] The results of this friction test showed that the kinetic friction coefficient of the sample coated with an organic solvent was smaller than that of the sample not coated with an organic solvent. Specifically, the minimum kinetic friction coefficient of the sample not coated with an organic solvent was 0.17, while the maximum kinetic friction coefficient of the sample coated with an organic solvent was 0.16. Thus, when an organic solvent is applied to the surface of the first hard coating 22, the kinetic friction coefficient of the surface can be reduced.

[0033] <Peak Area Ratio Measurement Test> Four types of jig and tool samples with different surface treatment methods were prepared, and the surfaces of each sample were subjected to narrow scan analysis using X-ray photoelectron spectroscopy (hereinafter referred to as XPS). The samples were prepared as follows. First, four carbon tool steel test pieces were prepared. Each test piece was coated with a hard coating. Note that the hard coating here is the same as the first hard coating 22 described above. The surfaces of each test piece were then rubbed against each other. Specifically, the surfaces of each test piece were rubbed against each other 200 times.

[0034] The first sample was prepared by applying PFPE as an organic solvent having hydroxyl groups to the surface of one test specimen. The second sample was prepared by applying IPA as an organic solvent having hydroxyl groups to the surface of one test specimen. The third sample was prepared by applying IP as an organic solvent without hydroxyl groups to the surface of one test specimen. The fourth sample was prepared by leaving the surface of one test specimen uncoated.

[0035] The surface of each sample was subjected to narrow scan analysis using an X-ray photoelectron spectrometer (manufactured by ULVAC-PHI, Inc.). The analysis depth was several nanometers. As shown in Figure 4, four peaks of components were observed in the C1s spectrum measured by XPS when irradiated with X-rays. Specifically, at a binding energy of 283.9 eV, the peaks of four components were observed. ２ The peaks of hybrid orbital components were observed. At a binding energy of 284.8 eV, the peaks of Sp containing C-C and C-H bonds were observed. ３A peak due to a hybrid orbital component was observed. A peak due to a C—O bond component was observed at a binding energy of 286.2 eV. A peak due to a C═O bond component was observed at a binding energy of 287.5 eV.

[0036] As shown in FIG. 5, the peaks of each component were separated, and the Sp ３ Sp containing hybrid orbitals, C-C bonds and C-H bonds ２ The areas of four peaks, namely hybrid orbitals, C═O bonds, and C—O bonds, were calculated.

[0037] In the first sample coated with PFPE, Sp ３ The peak area ratio of hybrid orbitals was about 78%. In the first sample, Sp ２ The peak area ratio of the hybrid orbital was about 15%.

[0038] In the second sample coated with IPA, the Sp ３ The peak area ratio of hybrid orbitals was about 79%. In the second sample, Sp ２ The peak area ratio of the hybrid orbital was about 18%.

[0039] In the third sample coated with IP, the Sp ３ The peak area ratio of hybrid orbitals was about 65%. In the third sample, Sp ２ The peak area ratio of the hybrid orbital was about 32%.

[0040] In the fourth sample without organic solvent, Sp ３ The peak area ratio of hybrid orbitals was about 64%. In the fourth sample, Sp ２ The peak area ratio of the hybrid orbital was about 30%.

[0041] From the test results of the narrow scan analysis, the samples coated with organic solvents having hydroxyl groups, in other words, PFPE and IPA, showed a higher Sp ３Specifically, in the sample coated with an organic solvent having a hydroxyl group, the proportion of the hybrid orbital component was high. ３ The peak area ratio of hybrid orbitals was 70% or more.

[0042] <Effect of Organic Solvent> The surface condition of the first hard coating 22 is altered by reacting with the organic solvent. Specifically, it is presumed that a lubricating layer containing organic solvent components and first hard coating 22 components is formed on the surface of the first hard coating 22. This lubricating layer can prevent the die 20 from adhering to the soft material 50. In addition, the first hard coating 22 reacts with the hydroxyl groups of the organic solvent, and a part of the surface side of the first hard coating 22 becomes Sp ３ It is presumed that the first hard coating 22 is transformed into a passive film composed of hybrid orbital carbon atoms and components of the organic solvent. When a passive film is formed in this manner, even if the lubricating layer is reduced by friction, the passive film still remains on the first hard coating 22. It is presumed that the presence of this passive film prevents the dynamic friction coefficient of the first hard coating 22 from increasing. Note that although the first hard coating 22 has been described above, the same applies to the second hard coating 42.

[0043] <Effects of this embodiment> (1) The surface treatment method of the jig / tool ​​of the above embodiment includes a coating step S12 in which an organic solvent is applied to a die 20 having a first hard coating 22 containing carbon on the surface of a die substrate 21. In addition, in the coating step S12, the organic solvent is applied to a punch 40 having a second hard coating 42 containing carbon on the surface of a punch substrate 41. According to this configuration, the surface of the jig / tool ​​can be made to be in a state in which the soft material 50 is less likely to adhere.

[0044] (2) In the above embodiment, the dynamic friction coefficient of the surface of the tool where the organic solvent is applied is 0.16 or less. As described above, a tool formed by applying an organic solvent can have a lower dynamic friction coefficient of the surface than a tool not coated with an organic solvent. Specifically, by applying an organic solvent, the dynamic friction coefficient of the surface of the first hard coating 22 and the surface of the second hard coating 42 can be reduced to 0.16 or less. If the surface dynamic friction coefficient is within this range, adhesion of the soft material 50 to the first hard coating 22 and the second hard coating 42 can be suppressed.

[0045] (3) In the above embodiment, when the surface was analyzed by narrow scan X-ray photoelectron spectroscopy, Sp ３ Hybrid orbit, Sp ２ Of the four types of hybrid orbitals, C=O bonds, and C-O bonds, Sp ３ The peak area ratio of hybrid orbitals is 70% or more. On the other hand, the peak area ratio of Sp observed on the surface coated with an organic solvent without a hydroxyl group and on the surface not coated with an organic solvent is 70% or more. ３ The peak area ratio of the hybrid orbital is less than 70%. Therefore, according to the configuration of the above embodiment in which the organic solvent having a hydroxyl group is applied, it is expected that the effect of preventing the soft material 50 from adhering to the surface of the jig or tool can be maintained for a longer period of time.

[0046] (4) The method for processing the soft material 50 of the above embodiment includes a processing step S13. The processing step S13 is performed in an environment with a relative humidity of 8% or less. As can be seen from the above friction test, the tool of the above embodiment can prevent the soft material 50 from adhering even in a special processing environment with a relative humidity of 8% or less. In other words, an environment with a relative humidity of 8% or less is suitable as an environment for using the tool of the above embodiment.

[0047] <Modifications> The above embodiment and the following modifications can be implemented in combination with each other within the scope of technical compatibility.

[0048] The processing device 10 is not limited to a device for deep drawing. The processing device 10 may be any device that processes a soft material 50 that is softer than the base material by bringing a tool into contact with the soft material 50. For example, the processing device 10 may be a device for shearing. Furthermore, the tool provided in the processing device 10 may be a tool other than the die 20 and the punch 40. For example, the tool may be a cutting blade for shearing the soft material 50.

[0049] In the above embodiment, the material of the soft material 50 may be changed as appropriate as long as it is softer than the die substrate 21 and the punch substrate 41. For example, the soft material 50 may be a soft metal such as Cu or Mg, or a soft ceramic.

[0050] In the above embodiment, the material of the mold substrate 21 is not limited to the example in the above embodiment. The material of the mold substrate 21 can be changed as appropriate as long as it is suitable for processing the soft material 50. The same applies to the material of the punch substrate 41. In addition, the material of the mold substrate 21 may be different from the material of the punch substrate 41.

[0051] In the above embodiment, the first hard coating 22 is not limited to a diamond-like carbon film. The first hard coating 22 may be any hard coating containing carbon. For example, the first hard coating 22 may be a film made of polycrystalline sintered diamond. Furthermore, the first hard coating 22 is not limited to a film formed by processing the mold substrate 21. The same applies to the second hard coating 42. Furthermore, the composition of the first hard coating 22 may be different from the composition of the second hard coating 42.

[0052] In the above embodiment, the dynamic friction coefficients of the surfaces of the first hard coating 22 and the second hard coating 42 may be greater than 0.16. Even if the dynamic friction coefficients of the surfaces of the first hard coating 22 and the second hard coating 42 are greater than 0.16, the application of an organic solvent can prevent the soft material 50 from adhering to the surface of the jig or tool.

[0053] The organic solvent does not have to have a hydroxyl group, as in the case of isoparaffin described in the above embodiment. Applying an organic solvent can provide the effect of suppressing adhesion of the soft material 50 to the first hard coating 22 and the second hard coating 42.

[0054] In the above embodiment, the type of organic solvent is not limited to the example in the above embodiment. For example, the organic solvent may be an alcohol-based organic solvent such as ethanol or methanol, or an aromatic organic solvent such as phenol.

[0055] In the above embodiment, the processing step S13 does not have to be performed in an environment with a relative humidity of 8% or less. For example, even when the processing step S13 is performed in a normal environment with a relative humidity of 60%, adhesion between the tool and the soft material 50 can be suppressed. However, according to the configuration of the above embodiment, adhesion between the tool and the soft material 50 can be suppressed even in a very dry environment with a relative humidity of 8% or less.

[0056] <Supplementary Notes> The technical concepts that can be derived from the above-described embodiments and modifications are described below. [1] A surface treatment method for a tool, comprising a coating step of coating an organic solvent onto a tool having a substrate surface with a hard coating containing carbon.

[0057] [2] The method for surface treatment of a tool according to [1], wherein the organic solvent has a hydroxyl group. [3] The method for surface treatment of a tool according to [1], further comprising: a substrate; and a hard coating covering a surface of the substrate, the hard coating containing carbon, and when the surface is analyzed by narrow scan X-ray photoelectron spectroscopy, Sp containing C-C bonds and C-H bonds. ３ Sp containing hybrid orbitals, C-C bonds and C-H bonds ２ Of the four types of hybrid orbitals, C=O bonds, and C-O bonds, Sp ３ A tool in which the peak area ratio of hybrid orbitals is 70% or more.

[0058] [4] The tool according to [3], wherein the coefficient of dynamic friction of the surface of the hard coating is 0.16 or less. [5] A method for processing soft materials, comprising: a coating step of coating an organic solvent onto a tool having a substrate surface with a hard coating containing carbon, and a processing step of bringing the tool into contact with a soft material softer than the substrate after the coating step.

[0059] [6] The method for processing a soft material according to [5], wherein the processing step is carried out in an environment with a relative humidity of 8% or less.

[0060] S11: Preparation step S12: Application step S13: Processing step 10: Processing device 20: Die 21: Mold substrate 22: First hard coating 30: Blank holder 40: Punch 41: Punch substrate 42: Second hard coating 50: Soft material

Claims

1. A surface treatment method for a tool, comprising a coating step of coating an organic solvent onto a tool having a base material on the surface of which is a hard coating containing carbon.

2. The surface treatment method for a tool according to claim 1, wherein the organic solvent has a hydroxyl group.

3. A hard coating comprising a substrate and a hard coating covering a surface of the substrate, the hard coating containing carbon, and a surface of the substrate being subjected to narrow scan analysis by X-ray photoelectron spectroscopy, the hard coating containing a C-C bond and a C-H bond. ３ Sp including hybrid orbitals, C-C bonds and C-H bonds ２ Of the four types of hybrid orbitals, C=O bonds, and C-O bonds, Sp ３ The peak area ratio of the hybrid orbital is 70% or more.

4. The tool according to claim 3, wherein the dynamic friction coefficient of the surface of the hard coating is 0.16 or less.

5. A method for processing a soft material, comprising: a coating step of coating an organic solvent onto a tool having a substrate surface on which a hard coating containing carbon is formed; and a processing step of, after the coating step, bringing the tool into contact with a soft material that is softer than the substrate, thereby processing the tool.

6. The method for processing a soft material according to claim 5, wherein the processing step is carried out in an environment with a relative humidity of 8% or less.

Images