A method for setting the fullerene content in machining oil and a cutting method using the same.

Abstract

To provide a method for setting the fullerene content in a processing oil composition and a cutting method using the same that reduce wear of tools and the like while suppressing the decrease in cutting performance.SOLUTION: Fullerene content is set within a range where a ratio of total speed, represented by the following formula: Ratio of Total Speed=(Ratio of Wear Speed) / (Ratio of Cutting Speed) (Formula 1), is 0.9 or less when determining the cutting speed at which material b is cut and the wear speed of material c, both when using a processing oil A, which contains fullerene, and a processing oil B, which does not contain fullerene in a case of cutting the material b by material a, using a tool made of the material c, which has a surface in contact with the material a, and using processing oils (where, Ratio of Wear Speed is defined as (the Wear Speed when using processing oil A) divided by (the Wear Speed when using the processing oil B), and Ratio of Cutting Speed is defined as (the Cutting Speed when using the processing oil A) divided by (the Cutting Speed when using the processing oil B)).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for setting the fullerene content in a machining oil containing fullerene, and a cutting method using the same. [Background technology]

[0002] In the manufacturing of semiconductor products, wire saws and band saws are used to process brittle materials such as silicon ingots. For example, a slurry in which loose abrasive grains are dispersed in processing oil is used in these processes.

[0003] Patent Document 1 relates to a processing oil for brittle materials that is suitable for use when cutting brittle materials with a wire saw using free abrasive grains, and discloses a processing oil for brittle materials that is formulated with (a) a base oil, (b) a nonionic surfactant that is an alkylene oxide adduct of a dihydric to hexahydric polyalcohol and has an added mole number of alkylene oxide of 2 to 50 and / or a nonionic surfactant that is a derivative of an alkylene oxide adduct of a dihydric to hexahydric polyalcohol and has an added mole number of alkylene oxide of 2 to 50, and (c) bentonite, in which the content of component (b) is 0.2 to 30 mass% and the content of component (c) is 0.1 to 10 mass% based on the total amount of the processing oil.

[0004] Fullerenes are also used as lubricant components that reduce wear. For example, Patent Document 2 discloses a lubricant composition that is capable of providing a lubricant composition with excellent wear resistance, and includes a base oil, fullerene, and a lubricant modifier, wherein the lubricant modifier is at least one selected from the group consisting of hydrindane, naphthalene, 1,2,3,4-tetrahydronaphthalene, tetrahydrodicyclopentadiene, decahydronaphthalene, cyclododecatriene, cyclododecane, dodecahydrofluorene, anthracene, phenanthracene, 9,10-dihydroanthracene, hexadecahydropyrene, and compounds in which at least one hydrogen atom of these compounds is substituted with a substituent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-203411 [Patent Document 2] International Publication No. 2020 / 137651 Summary of the Invention [Problem to be solved by the invention]

[0006] In cutting using a wire saw or the like as disclosed in the above-mentioned Patent Document 1, a processing oil containing loose abrasive grains is supplied to the workpiece, and the processing oil has the opportunity to come into contact with parts other than the workpiece (such as the saw wire and the processing oil circulation system, including pumps and piping), causing wear on these parts. However, using a processing oil that causes less wear reduces cutting performance. Therefore, it has been difficult to achieve both wear suppression and cutting performance.

[0007] The present inventors have conducted extensive research into this problem and have found that the fullerene content in the machining oil at which the fullerene's effect of suppressing wear (i.e., reducing cutting performance) becomes significant varies depending on the material.

[0008] Therefore, the present invention provides a method for setting the fullerene content in a cutting oil composition, which reduces wear on tools and the like while suppressing a decrease in cutting performance, and a cutting method using the same. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides the following means. [1] Using processing oil, A tool made of material c and having a surface that rubs against material a is used, When cutting material b using material a, A method for setting the fullerene content to be contained in the processing oil, comprising: When a processing oil containing fullerene (hereinafter referred to as "processing oil A") and a processing oil not containing fullerene (hereinafter referred to as "processing oil B") are used, the cutting speed at which material b is cut and the wear rate of material c are determined as follows: The following formula (1) Total speed ratio = (wear speed ratio) / (cutting speed ratio) ···(1) (however, Wear rate ratio = (wear rate when processing oil A is used) / (wear rate when processing oil B is used) Cutting speed ratio = (cutting speed when using processing oil A) / (cutting speed when using processing oil B) ) The method of setting the fullerene content in a range such that the overall velocity ratio expressed by the formula (1) is 0.9 or less. [2] Using processing oil A, A tool made of material c and having a surface that rubs against material a is used, A cutting method for cutting material b by material a, comprising: The fullerene content in the processing oil A is set by the method described in the preceding paragraph [1]. Cutting method. [3] The cutting method according to the preceding paragraph [2], wherein the tool is a wire saw or a band saw. [4] The cutting method according to the above item [2] or [3], wherein the material a is an abrasive grain or a cutting edge. [5] The cutting method according to any one of the above items [2] to [4], wherein the material a is at least one selected from silicon carbide, diamond, alumina, and hexagonal boron nitride. [6] The cutting method according to any one of the above items [2] to [5], wherein the material b is more brittle than the material c. [7] The cutting method according to the above item [6], wherein the material b is at least one selected from silicon, sapphire, silicon carbide, neodymium magnet material, quartz crystal, and glass. [8] The cutting method according to any one of the preceding items [2] to [7], wherein the material c is at least one selected from carbon tool steel, alloy tool steel, high-speed tool steel, carbon steel for machine structural use, high-carbon chromium bearing steel, spring steel, sulfur and sulfur composite free-cutting steel, and stainless steel. [9] A cutting method for cutting silicon with silicon carbide abrasive grains using a wire saw and processing oil, The saw wire of the wire saw is made of carbon tool steel, The processing oil contains 1 to 100 ppm by mass of fullerene. Cutting method.

[10] A cutting method for cutting silicon carbide with diamond abrasive grains using a wire saw and processing oil, The saw wire of the wire saw is made of carbon tool steel, The processing oil contains 10 to 300 ppm by mass of fullerene. Cutting method. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce wear on tools and the like while suppressing deterioration in cutting performance during cutting using a wire saw or the like. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing the relationship between the wear speed ratio, cutting speed ratio, and total speed ratio and the fullerene content in the processing oil in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes in detail the embodiments of the present invention. The embodiments are specifically described below to provide a better understanding of the gist of the invention, and unless otherwise specified, do not limit the present invention, and changes, additions, omissions, substitutions, etc. are possible with respect to the number, materials, quantities, shapes, values, ratios, positions, configurations, etc., within the scope of the gist of the present invention.

[0013] In this embodiment, a processing oil containing fullerene is used, a cutting tool or cutting device is provided with a member having a surface that rubs against material a, the rubbing surface is made of material c, and a content of fullerene to be contained in the processing oil is set in the case where material b is cut by material a. More specifically, when a processing oil containing fullerene (hereinafter referred to as "processing oil A") and a processing oil not containing fullerene (hereinafter referred to as "processing oil B") are used, the cutting speed at which material b is cut and the wear rate of material c are calculated, The following formula (2) Total speed ratio = (wear speed ratio) / (cutting speed ratio) ···(2) (however, Wear rate ratio = (wear rate when processing oil A is used) / (wear rate when processing oil B is used) Cutting speed ratio = (cutting speed when using processing oil A) / (cutting speed when using processing oil B) ) The fullerene content is set within a range in which the total speed ratio, expressed as follows: is 0.9 or less, preferably 0.5 or less, more preferably 0.3 or less, and even more preferably the lower limit of the total speed ratio. The lower limit of the total speed ratio can be determined from the minimum value shown in a graph of the total speed ratio, for example, as shown in Figure 1, which will be described later. The lower limit of the total speed ratio is better as close to 0 as possible, but may be 0.1 or 0.2 as a guideline.

[0014] The cutting method of this embodiment uses processing oil A containing the amount of fullerene set as described above, and uses a tool made of material c having a surface that rubs against material a, to cut material b with material a.

[0015] The material a may be an abrasive grain or a cutting edge, and preferably includes at least one selected from silicon carbide, diamond, alumina, and hexagonal boron nitride.

[0016] Examples of the tool include a wire saw and a band saw. When the tool is a wire saw, the part having a surface made of material c includes the saw wire and a processing oil circulation system such as a pump or piping if loose abrasive grains are used, and a pulley driving the saw wire if a saw wire with fixed abrasive grains is used. The cutting method of this embodiment can reduce wear on such tools and tool parts, thereby extending the life of the tool or reducing the frequency of replacing the tool parts.

[0017] The material b is a material that constitutes the workpiece, and examples thereof include at least one selected from silicon, sapphire, silicon carbide, neodymium magnet material (neodymium magnet before magnetization), quartz crystal, and glass.

[0018] The material c is a material used for tools, particularly for parts of tools that require wear resistance, and examples thereof include at least one steel selected from carbon tool steel, alloy tool steel, high-speed tool steel, carbon steel for machine structures, high-carbon chromium bearing steel, spring steel, sulfur and sulfur composite free-cutting steel, and stainless steel, which are listed in JIS standards and the like.

[0019] Generally, from the standpoint of wear resistance, material c used in tools is often a tougher material than material b constituting the workpiece. As shown in the examples and comparative examples described below, fullerenes exhibit wear resistance at relatively low concentrations against tough materials such as steel, and exhibit wear resistance (reduced cutting efficiency) at relatively high concentrations against brittle materials such as single-crystal silicon. Therefore, if material b is more brittle than material c, it is easier to find a range of fullerene content that suppresses tool wear and reduces the reduction in cutting efficiency of the workpiece, which is preferable.

[0020] The range of fullerene content depends on the combination of materials a to c. For example, when the tool is a wire saw, material c is carbon tool steel, material a is silicon carbide abrasive grains, and material b is silicon, the fullerene content in the range of 0.5 or less for the total speed ratio may be 1 to 100 ppm by mass. However, when material a is diamond abrasive grains and material b is silicon carbide, with the other conditions remaining the same, the fullerene content in the range of 0.5 or less for the total speed ratio may be 10 to 300 ppm by mass. Therefore, it is preferable to determine the fullerene content by conducting a preliminary test for each combination of tool and material.

[0021] From the viewpoint of accuracy in setting the fullerene content, it is preferable to carry out the preliminary test in the same manner as in actual cutting work to measure the wear rate and cutting speed. However, since this would make the preliminary test large-scale, from the viewpoint of simplifying the preliminary test, a simple test may be carried out, for example, using a pin-on-disk friction tester or a ball-on-disk friction tester as in the examples described below, to measure the wear rate of material c by material a and the wear rate (corresponding to the cutting speed) of material b by material a, and set the fullerene content. It is more preferable to first set the fullerene content in the simple test, and then set the fullerene content more accurately under conditions similar to those of actual cutting work.

[0022] In this embodiment, various fullerenes can be used. For example, C 60 or C 70 , and higher fullerenes, or mixtures thereof. Among fullerenes, C 60 and mixtures thereof are preferred. In the case of mixtures, C 60 It is more preferable that the content is 50% by mass or more. [Example]

[0023] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0024] (Evaluation of wear resistance) Using machining oil as the sample, a ball-on-disk friction tester was used, with the disk material being a high-carbon chromium bearing steel (SUJ2, 13mm square) equivalent to material c, and the ball material being silicon carbide (spherical, 6.35mm diameter) equivalent to material a, under the following conditions: load 20N, circular orbit with a sliding diameter of 8mm, sliding speed 25mm / sec, sliding time 100 minutes, and the ball material was slid over the disk material coated with the sample. After the sliding was completed, the sliding marks of the ball material on the surface of the disk material were observed with a laser microscope (manufactured by Keyence Corporation), and the wear cross-sectional area of ​​the sliding marks was measured.

[0025] From the obtained wear cross-sectional area, the following formula (3) Wear rate (μm 2 / min) = wear cross section (μm 2 ) / 100(minutes) ···(3) The wear rate was calculated using the formula:

[0026] (Evaluation of machinability) The disk material was single crystal silicon equivalent to material b, and the load was 2N and the sliding time was 1000 seconds, but the same operations and measurements were carried out as in the "Evaluation of wear properties" above, to obtain the wear cross-sectional area. From the obtained wear cross-sectional area, the following formula (4) Cutting speed (μm 2 / sec) = Wear cross section (μm 2 ) / 1000(seconds) ···(4) The cutting speed was calculated as

[0027] Examples 1 to 4 and Comparative Examples 1 to 3: 999.5 g of raw processing oil (PS-LW-11, water-insoluble cutting fluid, manufactured by Palace Chemical Co., Ltd.) and fullerene (nanom® mix ST, manufactured by Frontier Carbon Co., Ltd.) 60 Approximately 60% by mass, C 70 Approximately 25% by mass, C 70A processing oil composition containing 500 ppm by mass of fullerenes was obtained by mixing 0.5 g of a mixture containing about 15% by mass of higher fullerenes and stirring the mixture at room temperature for 48 hours using a magnetic stirrer. A portion of this mixture was diluted with raw processing oil to obtain the fullerene contents shown in Table 1, thereby obtaining processing oil compositions with each fullerene content. In Table 1, the processing oil with a fullerene content of 0 is the raw processing oil.

[0028] Next, for the processing oils having each fullerene content shown in Table 1, "evaluation of wear properties" and "evaluation of machinability" were performed to obtain the wear rate and cutting rate, and the wear rate ratio, cutting rate ratio, and total speed ratio were calculated using the above formula (2). The results are shown in Table 1 and Figure 1. [Table 1]

[0029] As shown in Table 1 and FIG. 1, by setting the fullerene content within an appropriate range, it is possible to improve the wear resistance and prevent the deterioration of cutting performance.

[0030] As shown in Figure 1, wear is significantly reduced in tough steel (SUJ2) when the fullerene content is 1 ppm by mass or more, but in single-crystal silicon, which is more brittle than steel, no significant reduction in wear (corresponding to a decrease in cutting performance) is observed up to a fullerene content of about 150 ppm by mass. In other words, it can be seen that by adjusting the fullerene content, it is possible to reduce wear on tools and other components while suppressing a decrease in cutting performance.

[0031] Specifically, assuming that the processing oil containing fullerene is used to cut single crystal silicon using a wire saw with a saw wire made of steel (SUJ2) and silicon carbide abrasive grains, the fullerene content in the processing oil is 0.13 to 450 mass ppm at which the total speed ratio is 0.9 or less, preferably 1 to 150 mass ppm at which the total speed ratio is approximately 0.4 or less, and more preferably 4 to 120 mass ppm at which the total speed ratio is approximately 0.3 or less. [Industrial Applicability]

[0032] The method of the present invention can be preferably applied to grinding using a processing oil containing fullerene.

Claims

1. Using processing oil, A tool made of material c and having a surface that rubs against material a is used, When cutting material b using material a, A method for setting the fullerene content to be contained in the processing oil, comprising: When a processing oil containing fullerene (hereinafter referred to as "processing oil A") and a processing oil not containing fullerene (hereinafter referred to as "processing oil B") are used, the cutting speed at which material b is cut and the wear rate of material c are determined as follows: The following formula (1) Total speed ratio = (wear speed ratio) / (cutting speed ratio) ... (1) (however, Wear rate ratio = (wear rate when processing oil A is used) / (wear rate when processing oil B is used) Cutting speed ratio = (cutting speed when processing oil A is used) / (cutting speed when processing oil B is used) It is.) The method of setting the fullerene content in a range such that the overall velocity ratio expressed by

2. Processing oil A was used, A tool made of material c and having a surface that rubs against material a is used, A cutting method for cutting material b with material a, comprising: The fullerene content in the processing oil A is set using the method according to claim 1, A processing oil containing the set fullerene content is used as the processing oil A, The processing oil A is applied to the surface of the material b that rubs against the material a. Cutting method.

3. The cutting method according to claim 2, wherein the tool is a wire saw or a band saw.

4. 4. The cutting method according to claim 2 or 3, wherein the material a forms an abrasive grain or a cutting edge.

5. 5. The cutting method according to claim 2, wherein the material a is at least one selected from the group consisting of silicon carbide, diamond, alumina, and hexagonal boron nitride.

6. The cutting method according to any one of claims 2 to 5, wherein the material b is more brittle than the material c.

7. 7. The cutting method according to claim 6, wherein the material b is at least one selected from the group consisting of silicon, sapphire, silicon carbide, neodymium magnet material, quartz crystal, and glass.

8. 8. The cutting method according to any one of claims 2 to 7, wherein the material c is at least one selected from carbon tool steel, alloy tool steel, high-speed tool steel, carbon steel for machine structure, high-carbon chromium bearing steel, spring steel, sulfur and sulfur composite free-cutting steel, and stainless steel.

9. The tool is a wire saw, The material a is silicon carbide and constitutes abrasive grains, the material b is silicon, The material c is a carbon tool steel, The content of the fullerene in the processing oil A is 1 to 100 ppm by mass. The cutting method according to any one of claims 2 to 8.

10. The tool is a wire saw, The material a is diamond and constitutes abrasive grains, The material b is silicon carbide, The material c is a carbon tool steel, The content of the fullerene in the processing oil A is 10 to 300 ppm by mass. The cutting method according to any one of claims 2 to 8.

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