JP2007222987A - Lapping method and lapping apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lapping method and a lapping apparatus, improving the lapping efficiency. <P>SOLUTION: The lapping method laps the surface of a machining sample 10 formed of ceramics by using a grinding wheel 6, and the grinding wheel 6a contains abrasive grains having higher hardness than that of the machining sample 10. A working fluid 5 containing particles causing tribo-chemical reaction in the machining sample 10 is supplied between the machining sample 10 and the grinding wheel 6 to perform lapping. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lapping method and a processing apparatus, and more particularly to a lapping method and a processing apparatus for lapping a surface of a workpiece made of ceramics with an abrasive material.

  Since silicon nitride ceramics and sialon ceramics have excellent mechanical properties such as high strength, high hardness, high heat resistance, and high corrosion resistance, they are used as mechanical parts such as bearings and engine parts. On the other hand, since it has excellent mechanical strength as described above, silicon nitride ceramics and sialon ceramics have difficult-to-grind properties when viewed from the processed surface. For this reason, grinding stones such as silicon nitride ceramics and sialon ceramics use high-hardness grindstones and abrasive grains such as diamond and CBN, and their processing efficiency and processing speed are not so fast.

  As a technique for improving machining efficiency without causing a fatal defect in a ceramic material, Japanese Patent Laid-Open No. 7-132448 (Patent Document 1) discloses a technique for optimizing the peripheral speed and feed speed of the working surface of a grinding wheel. It is disclosed. Specifically, a technique is disclosed in which the peripheral speed of the working surface of the grinding wheel is 50 to 300 m / sec and the feed speed of the working surface of the grinding wheel in the working direction is 50 to 200 m / min.

  However, for example, when a final lapping process is performed on a ceramic material, a relatively slow condition in which the relative speed between the grindstone and the workpiece is 250 m / min or less is applied. Since the technique of the above-mentioned patent document 1 assumes the case of grinding ceramics at a relatively high processing speed, it could not be applied to the processing conditions when finishing lapping processing of ceramic materials. .

  As a technique that can improve the efficiency of the lapping treatment of the ceramic material, Japanese Unexamined Patent Application Publication No. 2003-145416 (Patent Document 2) discloses a technique using a tribochemical reaction. Specifically, it is a polishing material composed of a ceramic sintered body, and includes an element that causes the ceramic to be polished to react at one or more kinds of grain boundaries, grains, and pores of the sintered body. A technique for polishing a ceramic material in water using a polishing material that has been disclosed is disclosed. Thereby, since wear of a ceramic material can be promoted in water, the efficiency of the lapping process can be improved.

Further, as a technology that can improve the efficiency of the lapping treatment of ceramic materials, the Fine Ceramics Molding / Processing and Joining Technology Editorial Committee, “Fine Ceramics Molding / Processing and Joining Technology”, pages 91-96 (Non-Patent Document 1) ) Discloses a technique using a mechanochemical reaction. Specifically, the workpiece is polished using a surface plate in which soft particles such as chromium oxide, iron oxide, or cerium oxide are fixed with a resin bond. In this method, a high pressure is generated at the contact point local area between the soft particles and the workpiece, and a solid phase reaction occurs. And the product by a solid-phase reaction is removed by frictional force, and grinding | polishing of a workpiece | work advances.
JP 7-132448 A JP 2003-145416 A Fine Ceramics Forming / Processing and Joining Technology Editorial Committee, “Fine Ceramics Forming / Processing and Joining Technology”, pages 91-96

  However, in the technique of Patent Document 2, the polishing material is made of a ceramic sintered body. For this reason, in order to manufacture an abrasive material, it is necessary to mix materials to be polished ceramics and perform pressure molding and sintering in a rare gas atmosphere. Need to pass. In addition, since the polishing material is made of a ceramic sintered body, the size and shape of the polishing material are also limited. As a result, since it is difficult to mass-produce the polishing material, it is difficult to improve the lapping efficiency.

  Further, since the technique of Non-Patent Document 1 utilizes a solid-phase reaction caused by frictional heat between soft particles and a workpiece, applying the technique of Non-Patent Document 1 to wet processing reduces the frictional heat and improves the lapping processing efficiency. There was a problem of lowering. This problem is also described in Non-Patent Document 1. Further, there is a problem that the surface plate is clogged with the soft particles scraped off by polishing, and the lapping processing efficiency is lowered. Furthermore, since the surface plate made of soft particles is easily deformed during polishing, there is a problem that the polishing accuracy is lowered.

  Accordingly, an object of the present invention is to provide a lapping method and a processing apparatus that can improve lapping efficiency.

  The lapping method of the present invention is a lapping method in which the surface of a workpiece made of ceramics is lapped with a polishing material, and the polishing material contains abrasive grains that are harder than the workpiece. A liquid containing particles that cause a tribochemical reaction on the workpiece (hereinafter also referred to as the above-mentioned particles) is supplied between the workpiece and the polishing material to perform lapping.

  A lapping apparatus of the present invention is a lapping apparatus that lappings a surface of a workpiece made of ceramics with an abrasive material. The lapping apparatus includes a polishing material containing abrasive grains that are harder than the workpiece, and a workpiece. A supply unit for supplying a liquid containing particles that cause a tribochemical reaction between the workpiece and the polishing material, a drainage unit for discharging the liquid containing the workpiece from the polishing material, A housing having one tank and a second tank is provided. The liquid discharged from the drainage section is supplied to the first tank, the liquid overflowing from the first tank flows into the second tank, and the liquid in the second tank is supplied from the supply section.

  The inventor of the present application, as a result of intensive investigations on effective means for improving the efficiency and reducing the cost of the lapping process, results in a liquid containing particles that cause a tribochemical reaction on the workpiece from the workpiece and the workpiece. It has been found that it is effective to supply a polishing material containing abrasive grains having high hardness. That is, according to the lapping method and the processing apparatus of the present invention, a tribochemical reaction occurs on the friction surface of the workpiece, and a reaction product of the workpiece is generated. The abrasive material removes this reaction product and, at the same time, mechanically removes the workpiece, creating a new workpiece surface. Then, the tribochemical reaction occurs again on the surface of the new workpiece, and a reaction product of the workpiece is generated. In the present invention, such an action occurs repeatedly. As a result, the surface of the workpiece can be removed chemically and mechanically, so that the lapping processing efficiency can be improved.

  Here, the tribochemical reaction is a phenomenon in which when a friction is applied to a workpiece, a chemical reaction proceeds on the friction surface due to the frictional energy to generate a reaction product. According to the tribochemical reaction, the chemical reaction can be caused even at a temperature and an atmosphere where the chemical reaction on the surface does not proceed. Since the reaction product of the workpiece is usually softer than the original workpiece, it is easier to remove than the workpiece itself.

  Further, according to the lapping method and processing apparatus of the present invention, since the polishing material does not need to be made of a ceramic sintered body, it is not necessary to go through a complicated manufacturing process to manufacture the polishing material. There are no restrictions on the size and shape of the. The liquid can be easily obtained by adding particles that cause a tribochemical reaction to the workpiece. Therefore, the wrapping processing efficiency can be improved. Moreover, deterioration of the polishing material can be suppressed.

  In addition, according to the lapping method and processing apparatus of the present invention, since abrasive grains that are harder than the workpiece are selected as the polishing material, deformation of the polishing material during polishing can be suppressed, and polishing accuracy can be improved. Can be improved. Further, since the polishing material scraped off by the polishing is removed by the liquid, the polishing material is not easily clogged, and the lapping processing efficiency is improved.

  In addition, according to the lapping apparatus of the present invention, the particle size of foreign matter (polishing powder, dropped abrasive grains, etc.) contained in the liquid supplied to the first tank causes a tribochemical reaction in the workpiece. Since the particle size is larger than the particle size, the sedimentation rate of the foreign matter is faster than the particle sedimentation rate. For this reason, the foreign matter stays at the bottom of the first tank and does not easily flow into the second tank, but the particles are uniformly dispersed in the first tank and flow into the second tank at substantially the same concentration as the first tank. As a result, the liquid from which only the foreign matter is removed can be supplied again, and the liquid can be recycled and used.

  In the lapping method and processing apparatus of the present invention, the workpiece preferably contains silicon nitride or sialon.

  Since silicon nitride and sialon are materials that are prone to tribochemical reactions, the lapping efficiency of the lapping method and processing apparatus of the present invention is particularly high.

  In the lapping method and processing apparatus of the present invention, the liquid is preferably an emulsion-type water-soluble cutting oil or a solution-type water-soluble cutting oil.

  Thereby, the liquid serves as a lapping liquid and also serves as a dispersion solvent for the particles. Moreover, clogging of the polishing material can be prevented. Furthermore, by using an emulsion-type water-soluble cutting oil or a solution-type water-soluble cutting oil, the particles can be uniformly dispersed in the liquid.

  In the lapping method and processing apparatus of the present invention, preferably, the liquid is made of water or an aqueous solution, and the pH of the liquid is 9 or more and 12 or less.

  Thereby, the liquid serves as a lapping liquid and also serves as a dispersion solvent for the particles. In order to uniformly disperse particles in water or an aqueous solution, it is desirable to charge the surface potential positively or negatively. In a neutral region of pH 5 or more and less than pH 9, the surface potential of the particles is near 0, and the particles tend to aggregate with each other. Although the particles are easily dispersed in the acidic region below pH 5, there is a problem that the processing apparatus and the polishing material are corroded and there is a concern about the safety of handling the liquid. In the alkaline region of pH 9 or more and pH 12 or less, the dispersion of the particles is good, and there is no problem of corrosion of the processing apparatus or the polishing material, and the safety of handling the liquid is not so much a problem. In the alkaline region where the pH is greater than 12, there is a problem that the processing apparatus and the abrasive material corrode and there is a concern about the safety of the liquid handling.

  In the lapping method and processing apparatus of the present invention, preferably, the hardness of the particles is equal to or lower than the hardness of the workpiece.

  Thereby, while the workpiece causes a tribochemical reaction by the particles, it is possible to prevent the particles from causing unnecessary processing scratches and defects.

  In the lapping method and processing apparatus of the present invention, preferably, the particles are made of an oxide of at least one element selected from the group consisting of silicon, iron, chromium, and titanium.

  These oxides are suitable as the particles because they have an effect of promoting the tribochemical reaction of ceramics.

  In the lapping method and processing apparatus of the present invention, the abrasive grains are made of at least one material selected from the group consisting of diamond, CBN, and boron carbide, and the grain size of the abrasive grains is smaller than No. 400. It is especially effective in cases.

  The above materials are suitable as abrasive grains because of their excellent hardness. Further, when the abrasive grains are processed under the condition that the grain size is finer than No. 400, preferably finer than No. 800, the removal amount of the reaction product of the workpiece by the tribochemical reaction is mechanical. Therefore, a large synergistic effect between chemical removal and mechanical removal can be obtained.

  Preferably, in the lapping method of the present invention, the workpiece is disposed between two surface plates each having an abrasive material attached to at least one, and the two surface plates are moved relative to each other to wrap the workpiece. To do.

Thereby, planar lapping can be performed on the workpiece.
In the lapping method and processing apparatus of the present invention, the liquid is preferably at a temperature higher than room temperature and not higher than 80 ° C., more preferably not higher than 60 ° C.

  By making the temperature of the liquid higher than room temperature, the tribochemical reaction is promoted, and the lapping processing efficiency can be further improved. Moreover, the safety | security of work and the ease of management are securable by making the temperature of a liquid into 80 degrees C or less, More preferably, 60 degrees C or less.

  Preferably, the lapping apparatus of the present invention further includes a control device for controlling the temperature of the liquid supplied from the supply unit.

  Thereby, since the temperature of the liquid can be controlled to a temperature suitable for the lapping process, the lapping process efficiency can be further improved.

  According to the lapping method and the processing apparatus of the present invention, the lapping efficiency can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, the configuration of the lapping apparatus according to the present embodiment will be described with reference to FIGS. FIG. 1 is a plan view showing a main configuration of a lapping apparatus according to an embodiment of the present invention, and FIG. 2 is a side view showing a main configuration of the lapping apparatus according to an embodiment of the present invention. With reference to FIG. 1 and FIG. 2, the lapping apparatus 1 in this Embodiment is a lapping apparatus which carries out the plane lapping process of the surface of the process sample 10 which consists of ceramics, Two surface plates 2 and 3, A grindstone 6 as an abrasive material, a supply pipe 4 as a supply section, a drain port 7 and a drain pipe 8 as drainage sections are mainly provided.

  The two surface plates 2 and 3 are arranged so that a flat surface extends in the horizontal direction so as to sandwich each of the three processed samples 10. Of the two surface plates, the lower surface plate 2 has a circular planar shape, and an annular grindstone 6 is fixed to the upper surface of the surface plate 2. The surface plate 2 and the grindstone 6 can rotate together as a unit by a motor (not shown) connected to the rotary shaft 2a. Of the two surface plates, the upper surface plate (attachment) 3 has a circular planar shape and can be rotated by a motor (not shown) connected to the rotation shaft 3a. Further, the surface plate 3 applies a downward load (in the direction of the surface plate 2) to the processed sample 10 to fix the processed sample 10 between the surface plates 2 and 3.

  On the surface plate 2, one end of the supply pipe 4 is arranged in addition to the surface plate 3. The supply pipe 4 extends into the tank 9 (FIG. 3) via a pump (not shown). The structure of the tank 9 will be described later. The processing liquid 5 as a liquid is continuously supplied onto the grindstone 6 by the supply pipe 4. Thereby, the machining liquid 5 is supplied between the machining sample 10 and the grindstone 6. Further, a drain port 7 is opened in the grindstone 6 and the surface plate 2. The drain port 7 is connected to a drain pipe 8, and the drain pipe 8 extends into the tank 9. The machining fluid 5 supplied onto the grindstone 6 is discharged through the drain port 7 and the drain pipe 8.

  The processed sample 10 is made of ceramics, for example, silicon nitride ceramics or sialon ceramics.

  The grindstone 6 includes abrasive grains that are harder than the processed sample 10. Specifically, abrasive grains made of diamond, CBN, boron carbide or the like are included. The grain size of the abrasive grains is smaller than 400, preferably smaller than 800. This is because the processing amount of the reaction product of the workpiece by the tribochemical reaction becomes larger relative to the removal amount of the workpiece to be mechanically removed as the finer grain is processed. This is because a great synergistic effect between the mechanical removal and the mechanical removal can be obtained. Further, the grindstone 6 is fixed to the surface plate 2 by using a binding material such as a resin bond, a bidified bond, a metal bond, or an electrodeposition bond.

  FIG. 3 is a cross-sectional view showing the configuration of the tank of the lapping apparatus according to one embodiment of the present invention. With reference to FIGS. 1-3, the lapping apparatus 1 in this Embodiment is further provided with the tank 9 as a housing | casing. The tank 9 has three staying tanks 9a to 9c, and each of the staying tanks 9a to 9c is filled with the processing liquid 5. The liquid level of the processing liquid 5 is the highest in the retention tank 9a (first tank), the second highest in the retention tank 9b, and the lowest in the retention tank 9c (second tank). Thereby, the processing liquid 5 overflowing from the upper part of the retention tank 9a flows into the retention tank 9b, and the processing liquid 5 overflowing from the upper part of the retention tank 9b flows into the retention tank 9c. Further, the other end of the drain pipe 8 is inserted into the staying tank 9a, whereby the working liquid 5 discharged from the drain pipe 8 is supplied to the staying tank 9a. Further, the other end of the supply pipe 4 is inserted into the retention tank 9 c via the pump 14, whereby the working fluid 5 in the retention tank 9 c is supplied from the supply pipe 4 onto the grindstone 6 by the power of the pump 14. . That is, the processing liquid 5 is used after being circulated through the tank 9 or the like.

  A thermometer 13 is provided in the staying tank 9c. A heater 11 a is attached to the outer periphery of the tank 9, and a heater 11 b is attached to the outer periphery of the supply pipe 4. Each of the thermometer 13 and the heaters 11 a and 11 b is electrically connected to the temperature control device 12. The temperature control device 12 heats the heaters 11 a and 11 b based on the temperature measured by the thermometer 13, thereby controlling the temperature of the machining fluid 5. As a result, the machining liquid 5 having an appropriate temperature can be supplied onto the grindstone 6. The temperature of the working fluid 5 is preferably higher than room temperature and 80 ° C. or lower, and more preferably 60 ° C. or lower. By making the temperature of the working fluid 5 higher than room temperature, the tribochemical reaction is promoted, and the lapping processing efficiency can be further improved. Moreover, the safety | security of work and the ease of management are securable by making the temperature of the processing liquid 5 into 80 degrees C or less, More preferably, 60 degrees C or less.

  Further, a water level meter 17 for measuring the water level of the staying tank 9a is provided in the staying tank 9a, and a water supply source for supplying a solvent (for example, water) into the staying tank 9a on the staying tank 9a. 15 is provided. Each of the water level gauge 17 and the water supply source 15 is electrically connected to the water level control device 16. When the water level control device 16 detects that the water level of the staying tank 9a is low, it supplies water from the water supply source 15 to the staying tank 9a. As a result, the water levels of the retention tanks 9a to 9c can be kept constant.

  In the present embodiment, a processed sample is processed by the following method using the lapping apparatus 1 described above.

  First, the machining liquid 5 containing particles that cause a tribochemical reaction in the machining sample 10 is supplied onto the grindstone 6. The hardness of the particles in the processing liquid 5 is equal to or lower than the hardness of the processing sample 10, and the particles in the processing liquid 5 are made of, for example, silicon oxide, iron oxide, chromium oxide, or titanium oxide. Thus, the tribochemical reaction of the processed sample can be promoted, and the workpiece is mechanically removed by the particles. The solvent of the working fluid 5 is, for example, an emulsion (emulsion) type water-soluble cutting oil, a solution (solid solution) type water-soluble cutting oil, water, or an aqueous solution. Is 9 or more and 12 or less. Thereby, the processing liquid 5 serves as a lapping liquid and also serves as a dispersion solvent for the particles. Moreover, clogging of the grindstone 6 can be prevented. Furthermore, the particles can be uniformly dispersed in the machining liquid 5. The “emulsion type” is a liquid in which the water-soluble cutting oil component can be dispersed in a colloidal form, and the “solution type” means that the water-soluble cutting oil component is dissolved and present. It means a liquid that can be made. For adjusting the pH of the working fluid 5, inorganic bases such as alkali metal salts, alkaline earth metal salts, and ammonium salts, and organic bases such as ethylenediamine and ethanolamine can be used.

  The addition amount of the particles is preferably 0.2% by mass or more and 15% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less. A tribochemical reaction easily occurs in the processed sample 10 by setting the addition amount of the particles to 0.2% by mass. By making the addition amount of the particles 15% by mass or less, it is possible to prevent the particles from interfering with mechanical removal of the processed sample 10 by the grindstone 6, and to suppress a decrease in processing speed. it can.

  The average particle size of the particles is preferably 3 μm or less, and more preferably 1 μm or less. By setting the average particle size of the particles to 3 μm or less, the frequency of contact with the processed sample 10 can be increased, and the reaction efficiency of the tribochemical reaction per unit volume of the particles can be increased. Further, the particles are less likely to precipitate in the solvent, and the dispersed state in the solvent can be maintained. Thereby, the production | generation efficiency of the processed product in the surface of the process sample 10 can be improved, and a processing speed can fully be improved. The particle size of the particles is preferably equal to or less than that of the grindstone 6. By making the particle size of the particles equal to or less than the particle size of the grindstone 6, it is possible to inhibit the particles from interfering with the mechanical removal of the processed sample 10 by the grindstone 6, and to suppress a decrease in the processing speed. Can do.

  Each of the rotating shafts 2a and 3a is rotated in a state where the machining liquid 5 is supplied onto the grindstone 6. Further, the processing liquid 5 flows between the processing sample 10 and the grindstone 6 by the rotation of the surface plate 2. As a result, slip occurs between the surface plates 2 and 3 and each of the three processed samples 10, and the processed sample 10 is lapped, for example, into a spherical shape. In addition, a tribochemical reaction occurs on the surface of the processed sample 10.

  Alternatively, the processing sample may be uniformly lapped by moving the position of the surface plate 3 in the radial direction of the surface plate 3 while the surface plate 2 is rotated.

  The processing liquid 5 that has flowed out between the processed sample 10 and the grindstone 6 contains foreign substances such as abrasive powder and dropped abrasive grains. The processing liquid 5 containing foreign matter is supplied to the bottom of the retention tank 9 a of the tank 9 through the drain port 7 and the drain pipe 8. By supplying the working liquid 5 to the staying tank 9a, the working liquid 5 in the staying tank 9a overflows from the upper part of the partition wall that separates the staying tank 9a and the staying tank 9b, and flows into the staying tank 9b. At this time, since the particle size of the foreign matter contained in the machining liquid 5 supplied to the retention tank 9a is larger than the particle size of the particles, the sedimentation rate of the foreign matter contained in the machining fluid 5 is compared with the sedimentation rate of the particles. And fast. For this reason, the foreign matter contained in the processing liquid 5 stays at the bottom of the staying tank 9a and hardly flows into the staying tank 9b, but the concentration of the particles contained in the working liquid 5 flowing from the staying tank 9a into the staying tank 9b is almost the same. Absent. Thereby, the foreign material contained in the machining liquid 5 is removed. Similarly, the foreign substance contained in the processing liquid 5 is further removed by providing the retention tank 9c. Then, the machining liquid 5 from which only the foreign matters have been removed is heated to a desired temperature and supplied again via the supply pipe 4.

  In the present embodiment, the case where the number of staying tanks is three (three stages) is shown, but the number of staying tanks is arbitrary, and two (two stages) or more (eight stages) or less. Preferably there is. By setting the number to 2 or more, foreign substances having a relatively large particle size can be precipitated, and by setting the number to 8 or less, it is possible to prevent the particles themselves from being settled and the concentration of the particles from being lowered.

  According to the lapping method and the processing apparatus 1 of the present embodiment, a tribochemical reaction occurs on the friction surface of the processed sample 10 and a reaction product of the processed sample 10 is generated. The grindstone 6 removes the reaction product and mechanically removes the surface of the processed sample 10 to create a new surface of the processed sample 10. Then, a tribochemical reaction occurs again on the surface of the new processed sample 10, and a reaction product of the processed sample 10 is generated. In the present embodiment, such an action repeatedly occurs. As a result, the surface of the processed sample 10 can be removed chemically and mechanically, so that the lapping processing efficiency can be improved.

  Moreover, according to the lapping method and the processing apparatus 1 of the present embodiment, since the grindstone 6 does not need to be made of a ceramic sintered body, it is not necessary to go through a complicated production process to produce the grindstone. There are no restrictions on the size and shape of the wheel. The processing liquid 5 can be easily obtained by adding particles that cause a tribochemical reaction to the processing sample 10 to the liquid. Therefore, the wrapping processing efficiency can be improved. Moreover, deterioration of a grindstone can be suppressed.

  In addition, according to the lapping processing apparatus 1 of the present embodiment, the particle size of the foreign matter contained in the processing liquid 5 supplied to the staying tank 9a is such that the processing sample 10 causes a tribochemical reaction. Therefore, the sedimentation rate of the foreign matter is faster than the sedimentation rate of the particles. For this reason, the foreign matter stays at the bottom of the staying tank 9a and hardly flows into the staying tanks 9b and 9c. However, the particles are uniformly dispersed in the staying tank 9a and have substantially the same concentration as the staying tank 9c. Flow into. As a result, the machining liquid 5 from which only the foreign matter is removed can be supplied again, and the machining liquid 5 can be recycled and used. In particular, when the particles are removed using a conventional filter, the particles are trapped in the filter and the concentration of the particles in the processing liquid 5 decreases, or the filter is frequently clogged by the particles. Problem arises.

  Note that the lapping apparatus of the present invention is not limited to the case where the workpiece is disposed on the two surface plates extending in the horizontal direction as described above, and the object to be sandwiched between the two surface plates extending in the vertical direction. It may be a structure in which a workpiece is arranged.

  In this example, the influence of the grindstone particle size and the machining fluid on the lapping processing speed was examined. Specifically, a lapping process sample made of nitride ceramics was lapped using the lapping apparatus shown in FIGS. A cylindrical sample having a diameter of 15 mm and a height of 10 mm was used as a processed sample, and three processed samples were fixed to the attachment. Diamond was used as the grindstone, and lapping processing was performed by changing the particle size in the range of 170-800. In Comparative Example A1 and Inventive Example A2, diamond of No. 170 is used, and in Comparative Example B1 and Inventive Example B2, diamond of No. 400 is used, Comparative Example C1, Comparative Example C2, and Inventive Example In C3 to C9, diamond having a particle size of 800 was used. In Comparative Example D1, a processing sample was lapped with a surface plate (casting surface plate) without using a grindstone. A resin bond was used as a bonding material between the grindstone and the lower surface plate. Moreover, the following were used as a processing liquid.

  Comparative Example A1, Comparative Example B1, and Comparative Example C1: A white kerosene-based oily working fluid that is a conventional working fluid was used.

  Comparative Example C2: An emulsion type water-soluble cutting oil was used as it was without mixing the particles.

  Invention Example A2, Invention Example B2, Invention Example C3, and Comparative Example D1: A colloidal silica aqueous solution (manufactured by Fujimi Incorporated, to which emulsion type water-soluble cutting oil and 2% by mass of silica fine particles are added. A mixed processing liquid (hereinafter referred to as an emulsion mixed processing liquid) mixed with COMPOLAD 50) was used.

  Invention Example C4 to Invention Example C7: Emulsion-type water-soluble cutting oil with 2% by mass of silicon oxide (Cai Kasei, Nanotek), iron oxide (Toda Kogyo, 100ED), chromium oxide (Nihon Kagaku Kogyo, A working fluid in which chromex S-1) or titanium oxide (Ci Kasei, Nanotek) was dispersed was used.

  Invention Example C8: A mixed working fluid (hereinafter referred to as a solution mixed working fluid) in which a solution-type water-soluble cutting oil and a colloidal silica aqueous solution to which 2% by mass of silica fine particles were added was mixed.

  Invention Example C9: An aqueous colloidal silica solution to which silica fine particles corresponding to 2% by mass were added was used.

  Table 1 shows the processing speed ratio of lapping processing for each sample with respect to a comparative example having the same grindstone particle size.

  Referring to Table 1, the processing speed of the example of the present invention is greatly improved as compared with the processing speed of the comparative example, particularly when a fine grindstone of No. 400 or more is used. On the other hand, in Comparative Example D1, the processing speed is low despite using the emulsion mixed processing liquid. Therefore, the improvement of the processing speed of the example of the present invention is considered to be due to the synergistic effect of the hardness of the grindstone and the processing liquid.

  In addition, the present invention example C3 and the present invention example C9 are compared, and the present invention example C3 using the emulsion mixed processing liquid is improved in the present invention example C9 using the colloidal silica aqueous solution alone. The improvement of the processing speed is larger. On the other hand, compared with Comparative Example C2 and Invention Example C3, the processing speed of Comparative Example C2 using the emulsion-type water-soluble cutting oil alone is not so improved. The improvement is thought to be due to the synergistic effect of the emulsion-type water-soluble cutting oil and colloidal silica.

  Further, comparing Comparative Example C1 with Invention Example C4 to Invention Example C7, the processing speeds of Invention Example C4 to Invention Example C7 are all greatly improved to about 2.9 times to 3.1 times. ing. From this, it can be seen that the processing speed can be improved by adding predetermined oxide particles to the emulsion type aqueous solution instead of using the emulsion mixed processing liquid.

  Further, comparing the comparative example C1 and the inventive example C8, the processing speed of the inventive example C8 is greatly improved to 3.22 times. From this, it can be seen that the processing speed is improved by using the solution mixed processing fluid instead of using the emulsion mixed processing fluid.

  In this example, a working fluid different from the working fluid used in Example 1 was used, and the influence of the grindstone particle size and the working fluid on the lapping processing speed was examined. Specifically, using the same lapping method and processing apparatus as in Example 1, a processing sample made of nitride ceramics was lapped. As a grindstone, diamond of No. 170 particle size is used in Comparative Example E1 and Invention Example E2, and diamond of No. 400 particle size is used in Comparative Example F1 and Invention Example F2, and Comparative Example G1 and Invention Example G2 are used. In ~ G6, diamonds with a particle size of 800 were used. In Comparative Example H1, a processing sample was lapped with a surface plate (casting surface plate) without using a grindstone. The followings were used as the working fluid of this example.

  Comparative Example E1, Comparative Example F1, and Comparative Example G1: A white kerosene-based oily working fluid that is a conventional working fluid was used (same as Comparative Example A1, Comparative Example B1, and Comparative Example C1 of Example 1). .

  Invention Example E2, Invention Example F2, Invention Example G2, and Comparative Example H1: A colloidal silica aqueous solution to which silica fine particles corresponding to 2 mass% were added was prepared, and diluted with water to adjust the pH of the colloidal silica aqueous solution to pH 11. Adjusted and used.

  Invention Example G3 to Invention Example G6: A working fluid in which 2% by mass of silicon oxide, iron oxide, chromium oxide, or titanium oxide was dispersed in a KOH aqueous solution having a concentration of 0.001 mol / l was used.

  Table 2 shows the processing speed ratio of lapping processing for each sample with respect to a comparative example having the same grindstone particle size.

  Referring to Table 2, the processing speed of the example of the present invention is greatly improved as compared with the processing speed of the comparative example, particularly when a fine grindstone of No. 400 or more is used. On the other hand, in Comparative Example H1, the processing speed is low although the colloidal silica aqueous solution is used. Therefore, it is considered that the improvement in the processing speed in the example of the present invention is due to the synergistic effect of the hardness of the grindstone and the processing liquid.

  Further, comparing the comparative example G1 with the inventive example G3 to the inventive example G6, the processing speeds of the inventive example G3 to the inventive example G6 are greatly improved to about 1.8 to 2 times. . From this, it can be seen that the processing speed is improved even when predetermined oxide particles are added to the aqueous solution instead of using the colloidal silica aqueous solution.

  In addition, when performing the lapping process of the inventive examples G2 to G6, the pH of the processing liquid is changed in the range of 2 to 13, and in the processing liquid of particles made of silicon oxide, iron oxide, chromium oxide, or titanium oxide. The dispersion state of was evaluated. Specifically, the above particles were added to an aqueous KOH solution, stirred for 10 minutes with a beaker, and observed for 5 hours. As a result, at pH 5 to pH 9, particles were aggregated and settled and difficult to redisperse. However, at pH 2 to pH5 and pH9 to pH13, the particles were kept in a dispersed state or redispersed even if precipitated. It was possible.

  In this example, the influence of the temperature of the working fluid on the processing speed of the lapping processing was examined. Specifically, a processing sample made of nitride ceramics was lapped using the same method as in Example 1. As the grindstone, diamond having a grain size of 800 was used, and as a bonding material between the grindstone and the lower surface plate, resin bond was used. Further, as the processing liquid, an emulsion-type water-soluble cutting oil and a colloidal silica aqueous solution (processing liquid of the present invention example C3) to which 2% by mass of silica fine particles were added were used. About the temperature of the process liquid, it changed in the range of 10 to 80 degreeC, and measured the processing speed in each temperature. FIG. 4 shows the relationship between the processing liquid temperature and the processing speed ratio of lapping processing. The processing speed ratio in FIG. 4 is a value when the processing speed is 1 when the temperature of the processing liquid is 20 ° C. (room temperature).

  Referring to FIG. 4, the processing speed is improved as the temperature of the processing liquid increases. From this result, it can be seen that the machining efficiency is further improved by raising the temperature of the working fluid above room temperature.

  The embodiments and examples disclosed above are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

  The present invention is suitable for planar lapping such as silicon nitride ceramics and sialon ceramics.

It is a top view which shows the main structures of the lapping apparatus in one embodiment of this invention. It is a side view which shows the main structures of the lapping apparatus in one embodiment of this invention. It is sectional drawing which shows the structure of the tank of the lapping apparatus in one embodiment of this invention. It is a figure which shows the relationship between the process liquid temperature in Example 3 of this invention, and a process speed ratio.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Lapping apparatus, 2, 3 Surface plate, 2a, 3a Rotating shaft, 4 Supply pipe, 5 Process liquid, 6 Grinding stone, 7 Drain port, 8 Drain pipe, 9 Tank, 9a-9c Retention tank, 10 Process sample, 11a , 11b Heater, 12 Temperature control device, 13 Thermometer, 14 Pump, 15 Water supply source, 16 Water level control device, 17 Water level meter.

Claims (11)

A lapping method for lapping a surface of a workpiece made of ceramics with an abrasive material,
The abrasive material includes abrasive grains that are harder than the workpiece,
A lapping method, comprising: supplying a liquid containing particles that cause a tribochemical reaction to the workpiece between the workpiece and the polishing material to perform lapping.   The lapping method according to claim 1, wherein the workpiece includes silicon nitride or sialon.   The lapping method according to claim 1 or 2, wherein the liquid is an emulsion-type water-soluble cutting oil or a solution-type water-soluble cutting oil.   The lapping method according to claim 1 or 2, wherein the liquid is made of water or an aqueous solution, and the pH of the liquid is 9 or more and 12 or less.   The lapping method according to any one of claims 1 to 4, wherein the hardness of the particles is equal to or less than the hardness of the workpiece.   The lapping method according to any one of claims 1 to 5, wherein the particles are made of an oxide of at least one element selected from the group consisting of silicon, iron, chromium, and titanium.   The abrasive grain is made of at least one material selected from the group consisting of diamond, CBN, and boron carbide, and the grain size of the abrasive grain is smaller than No. 400. A wrapping method according to crab.   The workpiece is disposed between two surface plates each having at least one of the abrasive materials attached thereto, and the workpiece is lapped by moving the two surface plates relatively. The lapping method according to any one of claims 1 to 7.     The lapping method according to claim 1, wherein the liquid has a temperature higher than room temperature and not higher than 80 ° C. A lapping apparatus for lapping a surface of a workpiece made of ceramics with an abrasive material,
The polishing material containing abrasive grains having a hardness higher than that of the workpiece;
A supply unit for supplying a liquid containing particles that cause a tribochemical reaction to the workpiece between the workpiece and the polishing material;
A drainage section for discharging the liquid containing the workpiece from the polishing material;
A housing having a first tank and a second tank;
The liquid discharged from the drainage unit is supplied to the first tank, the liquid overflowing from the first tank flows into the second tank, and the liquid in the second tank is supplied to the supply unit A lapping apparatus characterized by being supplied from:   The lapping apparatus according to claim 10, further comprising a control device for controlling a temperature of the liquid supplied from the supply unit.

Images