JP5282894B2 - Barrel polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a barrel polishing method which shortens a polishing time and polishes the surface of a workpiece to a super-smooth surface state. <P>SOLUTION: The barrel polishing method comprises: a roughly polishing step S1 of providing, as a barrel polishing apparatus, a fluidized barrel polishing apparatus including a polishing tank 1 constructed so that the interior thereof can be washed, introducing spherical media having a smooth surface, abrasive grains which are ground with the progress of polishing, a compound, and water into the polishing tank 1, and polishing a workpiece; a washing step S2 of, after the roughly polishing step S1, supplying water into the polishing tank 1 to remove, by washing, the abrasive grains, the compound, and powder produced by abrasion of the workpiece and media remaining within the polishing tank 1, discharging the abrasive grains, the compound, and powder produced by abrasion of the workpiece and media to the outside of the polishing tank 1, and allowing the washed workpiece and media to stay within the polishing tank 1; and a smoothly polishing step S5 of, after the washing step S2, introducing fresh compound and water into the polishing tank 1 and polishing the workpiece. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a barrel polishing method for ultra-smooth polishing a workpiece made of a metal material using a fluidized barrel polishing apparatus.

In the barrel polishing apparatus, a workpiece (hereinafter referred to as “work”) and an abrasive (hereinafter referred to as “media”) are put into a polishing tank (= container) to create a polishing action (= polishing power) that rubs against each other. There are four models with different polishing mechanisms, and 1) centrifugal barrel polishing apparatus, 2) fluid barrel polishing apparatus, 3) vibration barrel polishing apparatus, and 4) rotating barrel polishing apparatus, in this order, the polishing force applied to the workpiece is large.

The relationship between the polishing force and the surface roughness of the polished workpiece in each of the barrel polishing apparatuses described above is that the surface roughness of the workpiece does not become rough under the processing conditions where the polishing power is large, and the surface roughness is reduced. However, it is necessary to reduce the polishing force, and there is a conflicting relationship that the polishing time becomes long.

Further, the polishing time by each barrel polishing device described above varies depending on the type of workpiece, the purpose of processing, the media to be used, etc., but in normal polishing processing such as deburring, R-end processing of the edge portion, or surface smoothing processing. 1) within 1 hour with centrifugal barrel polisher, 2) within 1.5 hours with fluid barrel polisher, 3) within 2 hours with vibratory barrel polisher, 4) several hours with rotating barrel polisher Polishing is taking place.

Conventionally, processing time required for ultra-smooth polishing processing in which the surface roughness of a workpiece is regarded as important and the surface roughness is polished to an arithmetic average roughness: Ra 0.05 μm or less (≈10-point average roughness: Rz 0.3 μm or less). May vary depending on the type of workpiece, but may require 4 to 5 times the normal polishing. However, in recent years, there has been a growing demand for ultra-smooth polishing using a barrel polishing apparatus in which the surface roughness of the smooth polishing is Ra 0.05 μm or less (≈Rz 0.3 μm or less). The “ultra-smooth polishing process” refers to a process of polishing the surface roughness of the workpiece to Ra 0.02 μm or less (≈Rz 0.15 μm or less).

Patent Document 1 is disclosed in the prior art in which smooth polishing is performed using a barrel polishing apparatus according to the present invention. In Patent Document 1, smooth polishing of a workpiece made of high carbon bearing steel is polished for 4 hours by using a non-spherical polishing stone and alumina for abrasives with a vibrating barrel polishing apparatus, and after washing with water only for 2 hours. An example is shown in which the surface roughness (= 10-point average roughness) Rz 0.37 μm is obtained by polishing. The polishing time according to the prior art is shortened to a total of 6 hours as described above, compared to the conventional 22 hours.

Japanese Patent No. 3791837

In the above-described prior art, the polishing process time of the smooth polishing process was shortened to 6 hours, and the work was improved. However, as described above, in recent years, there is a demand for further reducing the polishing process time. In general barrel polishing using abrasive media and ceramic media fired with a binder such as clay or porcelain, for example, when processing cylindrical workpieces, media, compound and water are usually used In the above processing conditions, it is the limit to smooth polishing to a surface roughness of Ra 0.02 μm (≈Rz 0.15 μm), and as described above, it corresponds to the demand for ultra-smooth polishing using a barrel polishing apparatus. I couldn't.

An object of the present invention is to realize a barrel polishing method capable of further shortening the conventional polishing time and facilitating the ultra-smooth polishing.

In order to achieve the above object, according to the first aspect of the present invention, in the barrel polishing apparatus, the barrel polishing apparatus includes a polishing tank that is provided with a rotating plate that rotates horizontally at the bottom and is configured to be washable inside. Using a fluid barrel polishing device that forms at least a work, media, and water into the polishing tank and is swirled and fluidized by rotation of the rotating disk to form a mixed mass and polish the work. A rough polishing step in which abrasive grains A, a compound, and water, which are pulverized as the media progresses, are put into the polishing tank and the workpiece is polished, and water is supplied into the polishing tank after the rough polishing process. The used abrasive grains A, compound, water, and the abrasive powder of the work, media, and abrasive grains A are washed out and discharged to the outside of the polishing tank, and the cleaned work and media remain in the polishing tank. Washing Degree and, using the technical means and a smoothing polishing step of polishing a workpiece by newly introducing compound and water in the polishing vessel after the cleaning process.

According to the first aspect of the present invention, the work or media put in the polishing tank is caused to flow by the rotating device whose polishing mechanism rotates horizontally at the bottom of the polishing tank. Adopts a fluidized barrel polishing apparatus whose polishing action (= polishing power) is the second largest after the centrifugal barrel polishing apparatus, and the abrasive grains used in the rough polishing process include alumina and silicon carbide that are usually used in barrel polishing. Adopting abrasive grains A that are softer than abrasive grains and that are pulverized as the polishing progresses, the surface roughness of the workpiece can be reduced without requiring polishing time. In the cleaning process, a fluidized barrel polishing apparatus is used as the polishing apparatus. Therefore, if cleaning water is supplied to a mass formed by rotating a rotating disk and flowing a work and a medium in the polishing tank, the cleaning water is supplied to the mass. The used abrasive grains A, compound, water, and workpieces, media, and abrasive grains A that have passed through the inside of the polishing tank are removed from the polishing tank through the sliding contact gap between the polishing tank and the rotating disk. Easily washed and discharged. The cleaned workpiece and media are suitable as a pretreatment for smooth polishing because the obstructive factors for improving the surface roughness in the next smooth polishing step can be eliminated as described above and can remain in the polishing tank. is there. In the smooth polishing process, the surface of the spherical media with a hard and smooth surface rubs against each other while pressing the polishing surface of the workpiece, so that polishing marks are removed from the surface of the workpiece polished in the previous rough polishing step. In addition, “super smooth polishing” for polishing to a smoother surface can be realized in a short time. The workpiece that has undergone the smooth polishing step of the final polishing is inverted in the polishing tank of the fluid barrel polishing apparatus, and discharged to the outside of the polishing tank together with the used media, compound, and water. After the washing process of spraying a rust preventive, the work and media wear powder, compound and water are washed away, and then the work and media are removed by a sorter to recover the work, which is the final product.

According to a second aspect of the present invention, in the barrel polishing method according to the first aspect, the abrasive grain A is a technical means comprising at least one of powders of silica, permis, shirasu, pearlite, white clay, and limestone. Use.

As in the invention according to claim 2, the powder of silica, permis, shirasu, pearlite, white clay, limestone is softer and more polished than alumina or silicon carbide that is usually used as abrasive grains for barrel polishing. Since it becomes easy to grind | pulverize with progress of this, since the grinding | polishing trace of the surface of a workpiece | work is fine and surface roughness becomes small, it can be used suitably as the abrasive grain A for rough | crude grinding | polishing processes which is a pre-process of a smooth grinding | polishing process.

In invention of Claim 3, the said abrasive grain A used for the barrel polishing method of Claim 1 or Claim 2 uses the technical means whose average particle diameter is 15 micrometers-3 micrometers.

The rough polishing step is a step of performing a ground treatment for smooth polishing, and if the particle size of the abrasive grains A used in the rough polishing step is too large, the polishing mark becomes large, and if it is too small, the polishing power decreases. Since the processing time is shortened, it is preferable to use abrasive grains having an average particle diameter of 15 μm or less and 3 μm or more as in the invention of claim 3.

According to a fourth aspect of the present invention, in the barrel polishing method according to any one of the first to third aspects, the medium is a baked or sintered medium having a particle diameter of 2 to 6 mm. Is used.

Since the medium according to any one of claims 1 to 3 is used for smooth polishing as in the invention according to claim 4, the material is a hard fired or sintered medium. Since a polishing mark should not be formed during the polishing, it can be suitably used for smooth polishing by making the shape spherical and making it a hard fired or sintered medium having a particle size of 2 to 6 mm. If the particle size is less than 2 mm, the polishing force becomes small and the polishing time becomes long. If the particle size exceeds 6 mm, polishing marks are likely to be formed on the surface of the workpiece, and it becomes difficult to make the surface roughness extremely small. .

According to a fifth aspect of the present invention, in the barrel polishing method according to any one of the first to fourth aspects, the abrasive used in the rough polishing step between the cleaning step and the smooth polishing step. A second rough polishing step in which the abrasive B, which is softer than the particles A and has a smaller particle size, and which is pulverized as the polishing proceeds, a compound, and water are newly introduced into the polishing tank to polish the workpiece. Then, after the second rough polishing step is completed, cleaning water is newly supplied into the polishing tank, and used polishing abrasive grains B, compound, water, and workpieces, media, and abrasive grains B remaining in the polishing tank. And a second cleaning step of cleaning and discharging the wear powder out of the polishing tank and leaving the cleaned work and media in the polishing tank.

As in the invention according to claim 5, between the cleaning step and the smooth polishing step, the abrasive is softer and smaller in particle size than the abrasive grain A used in the rough polishing step and pulverized as the polishing proceeds. A second rough polishing step in which grains B, compound, and water are newly added into the polishing tank to polish the workpiece, and abrasive grains remaining in the polishing tank by supplying water to the polishing tank after the second rough polishing process. A second cleaning step can be performed in which the abrasive powder of B, compound, work and media is washed and discharged out of the polishing tank and the cleaned work and media remain in the polishing tank. In the second rough polishing step, since the abrasive grains B that are pulverized with the progress of polishing and are softer than the abrasive grains A used in the rough polishing step are used, the surface of the workpiece is further roughened than the rough polishing step. Can be a smooth surface. In the second cleaning step, the same effects as in the cleaning step described above, the abrasive grains B used in polishing in the second rough polishing step, which becomes an impediment for improving the surface roughness in the next smooth polishing step, compound, Water, workpieces, media, and abrasive powder B can be easily washed out of the polishing tank through the sliding contact gap between the polishing tank and the rotating disk, and the cleaned work and media remain in the polishing tank. Therefore, the next smooth polishing step for further improving the surface roughness can be performed.

According to a sixth aspect of the present invention, in the barrel polishing method according to any one of the first to fifth aspects, the amount of water added to the polishing tank in the rough polishing step or the second rough polishing step is The technical means is 6 to 30% with respect to the workpiece and the medium, and the amount of water added to the polishing tank in the smooth polishing step is 60% to 100% with respect to the workpiece and the medium.

As in the invention described in claim 6, the amount of water added to the polishing tank in the rough polishing step or the second rough polishing step is preferably 6 to 30% with respect to the workpiece and the medium. If the amount of water is less than 6%, the viscosity of the mass increases during polishing, the temperature in the polishing tank rises, the constituent members of the polishing tank expand, and the sliding contact between the rotating disk and the fixed tank occurs. There is a possibility that troubles such as the clogging of the gap and the rotation of the rotating disk stop occur. Moreover, since the mixing ratio with respect to the water of the abrasive grain A used for a rough | crude grinding | polishing process or the abrasive grain B used for a 2nd rough | crude grinding | polishing process will fall when the quantity of water exceeds 30%, the said abrasive grain A Alternatively, the polishing action (= polishing power) given to the workpiece of the abrasive grains B tends to decrease. The amount of water in the smooth polishing step is preferably 60% to 100%, which is larger than that in the rough polishing step, in order to have a buffering action that suppresses the polishing force by the media to such an extent that the surface roughness of the workpiece can be improved. . Here, the “amount of water relative to the workpiece and the medium” is the volume of water relative to the apparent volume when the workpiece and the medium are put into the polishing tank.

According to a seventh aspect of the present invention, in the barrel polishing method according to the fifth or sixth aspect, the technical means wherein the abrasive grain B is made of at least one of cerium, chromium, and iron oxides. Use.

As in the invention described in claim 7, oxides of cerium, chromium, and iron are compared with powders of silica, permis, shirasu, pearlite, white clay, limestone, etc. used for the abrasive grains A in the rough polishing step. Since it is softer, the surface of the workpiece can be polished with less polishing marks, and can be suitably used as the abrasive grain B for further smoothing the surface roughness of the workpiece after the rough polishing step.

According to an eighth aspect of the present invention, in the fluid barrel polishing method according to any one of the fifth to seventh aspects, the technical means is that the average particle diameter of the abrasive grains B is 5 μm to 1 μm. Use.

In the smooth polishing step of the fluid barrel polishing method according to any one of claims 5 to 7, the second rough polishing step is for polishing to an ultra-smooth surface in which the surface roughness of the workpiece is further reduced. It is a step for performing a ground treatment, and the average particle size of the abrasive grains B used in the second rough polishing step needs to be smaller than the particle size of the abrasive particles A used in the rough polishing step of claim 5. If the average particle size is 5 μm or less, and if the average particle size is too small, the polishing power decreases. Therefore, it is preferable to use abrasive grains having an average particle size of 1 μm or more.

According to a ninth aspect of the present invention, in the barrel polishing method according to any one of the first to eighth aspects, the fluid barrel polishing apparatus has a shaft that is fixed or rotatable at an upper rotation center of the rotating disk. Technical means comprising a supported cylindrical inner cylinder are used.

After the flow direction of the workpiece, media, and abrasive grains put into the polishing tank by the rotation of the rotating disk in the conventional fluid barrel polishing apparatus rises from the bottom rotating disk along the side wall of the fixed tank, and reaches the top Then, the direction is changed in the direction of the center of rotation of the rotating disk, descends and swirls to form a mass. With respect to the shape of the mass, the upper part of the center of rotation of the rotating disk is concave to form a hollow area. In the hollow area of the mass, the pressing force with which the flowing work, media, and abrasive grains rub against each other is released, and the polishing power is reduced. In the fluid barrel polishing apparatus according to the ninth aspect of the present invention, the cylindrical inner cylinder provided at the upper center of the rotation center of the rotating disk can block the cavity of the mass and prevent the polishing force from being lowered. Efficiency can be improved.

According to a tenth aspect of the present invention, in the barrel polishing method according to any one of the first to ninth aspects, the workpiece is a cylindrical workpiece made of a metal material, and the surface of the workpiece is A technical means having been polished to a surface roughness of Ra 0.02 μm or less is used.

As in the invention described in claim 10, the barrel polishing method of the present invention can obtain a workpiece subjected to ultra-smooth polishing in which the surface roughness of a cylindrical workpiece made of a metal material is Ra 0.02 μm or less. If it is possible to further reduce the surface roughness, or if it is necessary to change the polishing conditions due to different workpiece materials, physical properties, etc., as necessary between the cleaning step and the smooth polishing step A cylindrical workpiece made of a metal material that has been subjected to ultra-smooth polishing by providing the second rough polishing step and the second cleaning step can be obtained.

It is explanatory drawing which shows the structure of the fluid barrel grinding | polishing apparatus used for this invention. It is explanatory drawing which shows the structure of the fluid barrel grinding | polishing apparatus used for this invention. It is explanatory drawing which shows the process of the fluid barrel grinding | polishing method. It is explanatory drawing which shows the example of a change of the process of the fluid barrel grinding | polishing method. It is explanatory drawing which shows the relationship of the surface roughness which can be provided to the workpiece | work by the difference in media shape, and its grinding | polishing time.

The fluid barrel polishing method of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram showing the configuration of a fluid barrel polishing apparatus used in the present invention, in which a polishing tank 1 for polishing a workpiece is formed in a cylindrical shape, and a lower end opening of the fixed tank 2 is shown. It has a platen-like rotating disk 4 that rotates horizontally by forming a sliding contact gap 3 around the periphery. A passage 6 is formed between the turntable 4 and the bottom plate 5 of the fixed tank 2 so that a sliding contact gap 3 communicates with a hole 8 formed in the center of rotation of the turntable 4. The attached drain pipe 7 is connected.

FIG. 2 shows an example of the above-described fluid barrel polishing apparatus in which the inner cylinder 9 that is supported in a fixed or rotatable manner is provided on the rotation center of the rotating disk 4 of the fluid barrel polishing apparatus shown in FIG. As a polishing apparatus that further improves the polishing efficiency, a fluid barrel polishing apparatus according to the invention filed by the present inventors in PCT / JP2005 / 002233 is provided.

FIG. 3 is a process explanatory diagram of a fluid barrel polishing method comprising a rough polishing process, a cleaning process, and a smooth polishing process, and the polishing process is composed of two processes. The polishing process will be described in detail below. .

In the rough polishing step S1, a workpiece, a medium, abrasive grains A that are pulverized as the polishing proceeds, and a compound and water as a polishing aid are put into the polishing tank 1 of the fluid barrel polishing apparatus. When the turntable 4 is rotated, the work, media, abrasive grains A, compound, and water charged in the polishing tank 1 rise from the bottom turntable 4 along the side wall of the fixed tank 2 and reach the top. Thereafter, the direction is changed in the direction of the center of rotation of the rotating disk 4 and descends and flows in the polishing tank 1 to form a mass M and the workpiece is polished.

The relationship between the reachable surface roughness that can be imparted to the workpiece and the polishing time in the media selection is determined by the shape of the media as shown in FIG. The media used in the present invention is hard and has a smooth surface, or a sintered or sintered media. The shape of the media must be spherical, for example, alumina balls. As apparent from FIG. 5, when the media shape is triangular, cylindrical, non-spherical, etc., the polishing power is larger than that of the spherical shape, so the polishing time is shortened in the initial stage of the polishing process. Although the surface roughness can be reduced, the reachable surface roughness obtained at the end of the polishing process is larger than the spherical shape. The media particle size is preferably 2 to 6 mm. This is because if the particle diameter is less than 2 mm, the polishing force becomes small and the polishing time becomes long, and if it exceeds 6 mm, the polishing force becomes large and it becomes difficult to reduce the surface roughness.

The abrasive grain A used in the rough polishing step S1 is softer than alumina or silicon carbide normally used as the abrasive grain for barrel polishing, and silica, permis, shirasu, pearlite, which are pulverized as the polishing progresses. Select from powder of white clay or limestone. These abrasive grains A have an appropriate hardness (Mohs hardness 6-4) and have a polishing power proportional to the hardness at the initial stage of polishing, but are pulverized in the polishing tank as the polishing progresses. Since the polishing power is reduced, the surface roughness can be reduced as the polishing time elapses. Since the abrasive grain A has an appropriate polishing force as described above, it is possible to accurately perform the base treatment for polishing the surface of the workpiece in an ultra-smooth manner. Here, the average particle diameter of the abrasive grains A is preferably 15 μm to 3 μm.

As the compound used in the rough polishing step S1, a compound containing silica powder and an inorganic salt and containing a surfactant as a main component is used.

Further, the amount of water added in the rough polishing step S1 is preferably 6 to 30% with respect to the volume (100%) of the workpiece and the medium.

In wet fluid barrel polishing in which water is added for polishing, it is common to polish by adding water so that the volume is usually 70 to 100% by volume with respect to the volume (100%) of the workpiece and media. In addition, when polishing is performed by adding abrasive grains as in the present invention, if the polishing is performed by adding a large amount of water as described above, the mixing ratio of the abrasive grains input for polishing to water decreases. Therefore, the action (= polishing power) that the abrasive grains are interposed between the workpiece and the media and pressed and rubbed against each other is reduced. Further, since the concentration of the compound added at the same time is lowered and the effect as a polishing aid is also lowered, it is necessary to increase the amount of addition in order to obtain the effect. Therefore, in the present invention, it is necessary to reduce the amount of water in order to use the abrasive grains, and 6 to 30% is preferable with respect to the volume (100%) of the workpiece and the medium. However, if the amount of water is less than 6%, the viscosity of the mass increases during polishing, the temperature in the polishing tank rises, the constituent members of the polishing tank 1 expand, and the turntable 4 and fixed tank 2 expand. And the sliding contact gap 3 is closed and the rotation of the turntable 4 is stopped. On the other hand, if the amount of water exceeds 30%, the action of the abrasive grains added as described above rubbing against the workpiece is reduced, and sufficient polishing power cannot be obtained.

As described above, in the rough polishing step S1 of the present invention, the amount of water to be added using the abrasive grains A that are softer than alumina and silicon carbide that are usually used in barrel polishing and pulverized as the polishing progresses. By reducing the number, the polishing time can be shortened, and the surface roughness of the workpiece can be reduced.

In the next cleaning step S2, the work, media, abrasive grains A, compound, and water charged in the polishing tank 1 are swirled and flowed by the rotation of the rotating disk 4 to form a mass M, and the rough polishing step S1. The cleaning water is continuously supplied to the mass M in the polishing tank 1 after finishing the cleaning to clean the mass M. Polished used abrasive grains A, compound, water, and abrasive powder of the workpiece, media, and abrasive grains A in the mass M flow from the drain pipe 7 through the sliding contact gap 3, the hole 8, and the passage 6 together with the cleaning water. The work and media that have been discharged out of the system of the barrel polishing apparatus and cleaned remain in the polishing tank 1.

Since the polishing apparatus used in the present invention is the fluidized barrel polishing apparatus having the above-described configuration, in the cleaning step S2, only the workpiece and the medium cleaned as described above are left in the polishing tank 1, and the abrasive grains A used for polishing are used. The cleaning and discharging of the compound, water, and the wear powder of the workpiece, the medium, and the abrasive grains A can be easily washed out in a short time. As a result, in the subsequent smooth polishing step S5, the work and media from which the obstruction factors for improving the surface roughness of the work are eliminated can be left in the polishing tank 1, and preparation for entering the next smooth polishing step S5 is performed. Is completed.

In the subsequent smooth polishing step S5, the compound and water are newly added into the polishing tank 1 where the cleaned work and media remain, and the work, media, compound and water are swirled and flowed by the rotation of the rotating disk 4. The surface of the workpiece roughly polished in the rough polishing step S1 is polished ultra-smoothly. The medium is a hard, spherical shape that has been used and cleaned in the rough polishing step S1, and is polished by a pressing force (= polishing force) on which the medium acts on the workpiece by the swirling flow of the workpiece, the medium, the compound, and the water. Is done. In addition, the amount of water input in the smooth polishing step S5 is such that the surface roughness of the workpiece is reduced and improved by the polishing force acting on the workpiece with the media intervening water, and the polishing time is not required to be mischievous. The amount needs to have a buffering action that suppresses the polishing force to a certain extent, and needs to be larger than the rough polishing step S1. For example, it is preferably 60% to 100% with respect to the volume (100%) of the workpiece and the medium.

The compound used in the smooth polishing step S5 can be appropriately selected according to the workpiece, polishing conditions, and the like. Although the compound used in the rough polishing step S1 can be used, it is preferable to use a compound for glossy finishing with high lubricity.

FIG. 4 is a process explanatory diagram showing a modified example in which the process of the present invention includes a rough polishing process, a cleaning process, a second rough polishing process, a second cleaning process, and a smooth polishing process, and the polishing process includes three processes. The changes will be described below.

As a modification of the present invention, the rough polishing step S1 and the cleaning step S2 can be repeated before the smooth polishing step S5. Here, as shown in FIG. 4, the second rough polishing step is referred to as a second rough polishing step S3, and the subsequent cleaning step is referred to as a second cleaning step S4. In the second rough polishing step S3, abrasive grains B that are pulverized as the polishing proceeds and are softer than the abrasive grains A used in the rough polishing step S1 are used. For example, when using silica powder having an average particle diameter of 7 μm for the abrasive grains A used in the coarse polishing step S1, cerium oxide having an average particle diameter of 2 μm or less for the abrasive grains B used in the second rough polishing process S2 is used. Can be used. Thereby, since the surface roughness of the workpiece can be a smooth surface having a smaller surface roughness than the rough polishing step S1, the surface roughness can be further reduced in the subsequent smooth polishing step S5. . For example, when a very smooth surface such as Ra 0.01 μm (≈Rz 0.06 μm) is required, it can be suitably used. The second cleaning step S4 is a cleaning step of the second rough polishing step S3, and is a step provided for the same effect as the cleaning step S2 of the rough polishing step S1.

  As an example carried out in order to make the present invention concrete, Example 1 in which the polishing step consists of two steps, Example 2 in which the polishing step, which is a modification thereof, consists of three steps, and a comparative example will be described below. Table 1 below shows the media, abrasive grains, compound specifications, and the amount of water used in Examples 1 and 2 of the present invention.

In Example 1, a cylindrical member made of stainless steel (SUS420J2) and having a diameter of 3 mm and a length of 80 mm was used. The surface roughness of the workpiece before polishing was Ra 0.053 μm (≈Rz 0.38 μm). As a fluid barrel polishing device, a fluid barrel polishing device (manufactured by Shinto Blator, model: EVFX-1) shown in FIG. 2 having a polishing tank capacity of 40 L was used. This fluid barrel polishing apparatus is provided with a cylindrical inner cylinder rotatably supported on the rotation center of the rotating disk of the fluid barrel polishing apparatus used in Example 2 to be described later, so that the polishing force is increased. It is configured.

The media used in the rough polishing step S1 are spherical alumina sintered media (Shinto Blator: V-4) having a particle diameter of 4 mm, abrasive grains A are silica powder having an average particle diameter of 7 μm, and the compound is silica powder. , A powder compound containing inorganic salt and surfactant (manufactured by Shinto Brater Co., Ltd .: GPP) was used, and the weight ratio of the workpiece to the media was 1: 5, for a total of 15 L. The polishing tank 1 was charged with 30 g of abrasive grains A, 200 g of compound, and 1.5 L of water, and polished for 90 minutes. Here, the ratio of water to the volume (100%) of the work and the medium is 13% by volume.

In the next cleaning step S2, cleaning water is supplied while the workpiece, media, abrasive grain A, compound, and water in the polishing tank 1 are swirled and flowed to remove the abrasive grain A, compound, water, and polishing debris from the polishing tank 1. Then, the cleaned work and media remained. At this stage, the surface roughness of the workpiece was Ra 0.022 μm (≈Rz 0.15 μm), and the time required for the cleaning step S2 was about 4 minutes.

In the subsequent smooth polishing step S5, 40 mL of gloss polishing liquid compound (GLB) and 10 L of water are added to the workpiece and media that have been cleaned and left in the polishing tank 1 for 15 minutes. Polishing was performed. Here, the ratio of water to the workpiece and the media is about 67%. The surface roughness of the workpiece after this step was Ra 0.014 μm (≈Rz 0.089 μm), and could be polished to an ultra-smooth surface.

As described above, the fluid barrel developed so that the polishing force shown in FIG. 2 is increased in the polishing apparatus even if the polishing process in which the second rough polishing process S3 and the second cleaning process S4 are not performed is a two-step polishing method. Since the polishing power can be increased by using the polishing apparatus, the surface of the workpiece can be polished to an ultra-smooth surface in a short time of 2 hours or less including the cleaning process time.

In Example 2, a cylindrical member having a diameter of 1.6 mm and a length of 14 mm made of high carbon chromium steel (SUJ2) was used as the workpiece. The surface roughness of the workpiece before polishing was Ra 0.10 μm (≈Rz 0.60 μm). As the fluid barrel polishing apparatus of the polishing apparatus, a fluid barrel polishing apparatus (manufactured by Shinto Blator: EVF-04) shown in FIG. 1 having a polishing tank capacity of 40 L was used.

The media used in the rough polishing step S1 were spherical alumina sintered media (Shinto Blator: V-4) having a particle diameter of 4 mm, abrasive grains A were silica powder having an average particle diameter of 7 μm, and the compound was silica powder. , A powder compound containing inorganic salt and surfactant (manufactured by Shinto Brater Co., Ltd .: GPP) was used, and the weight ratio of the workpiece to the media was 1: 5, for a total of 15 L. In the polishing tank 1, 30 g of abrasive grains, 200 g of compound, and 1.5 L of water were added, and polishing was performed for 90 minutes. The addition ratio of water is 13% by volume with respect to the volume of the workpiece and the medium (100%).

In the next cleaning step S2, cleaning water is supplied while the workpiece, media, abrasive grain A, compound, and water in the polishing tank 1 are swirled and flowed to remove the abrasive grain A, compound, water, and polishing debris from the polishing tank 1. Then, the cleaned work and media remained. At this stage, the surface roughness of the workpiece was Ra 0.015 μm (≈Rz 0.11 μm), and the time required for the cleaning step S2 was about 4 minutes.

In the subsequent second rough polishing step S3, 30 g of cerium oxide having an average particle size of 2 μm as abrasive grains B, 40 mL of compound, and 1.5 L of water are added to the work and media remaining in the polishing tank 1. Polishing for 30 minutes was performed. As the compound used in the second rough polishing step S3, a gloss polishing liquid compound (manufactured by Shinto Blator: GLB) was used. The addition ratio of water is 13% by volume with respect to the volume of the workpiece and the medium (100%).

In the next second cleaning step S4, cleaning was performed in the same manner as in the cleaning step S2, and the cleaned work and media remained. The surface roughness of the workpiece at this stage was Ra 0.012 μm (≈Rz 0.072 μm), and a smoother surface was obtained than when the cleaning step S2 was completed. The time required for the second cleaning step S4 was about 4 minutes.

In the subsequent smooth polishing step S5, 40 mL of the same gloss polishing liquid compound as used in the second rough polishing step S3 (manufactured by Shinto Blator: GLB) and 10 L of water were added, and polishing was performed for 30 minutes. . The addition ratio of water is 67% by volume with respect to the volume of the workpiece and the medium (100%). Further, the surface roughness of the workpiece after the smooth polishing step S5 was Ra 0.009 μm (≈Rz 0.06 μm).

In the present invention, the polishing step is made into three steps, and the surface roughness of the workpiece can be polished ultra-smoothly with Ra of 0.01 μm or less in a short time of 3 hours or less including the cleaning step time.

As a comparative example, the medium used in Example 1 was changed to an irregular medium having an average particle diameter of 6 mm, and in the rough polishing step S1, the compound was changed to a gloss polishing liquid compound (manufactured by Shinto Blator: GLB). In the smooth polishing step S5, polishing was performed under the same conditions except for the media. As a result, the surface roughness of the workpiece after the rough polishing step S1 is Ra 0.028 μm (≈Rz 0.185 μm), and the surface roughness of the workpiece after the smooth polishing step S5 is Ra 0.022 μm (≈Rz 0.132 μm). This surface could not be polished to an ultra-smooth surface. Thereby, it was confirmed that the shape of the media used in the present invention is not an indeterminate shape, but a spherical media having a smooth surface.

[Effect of Best Embodiment]
(1) According to the fluid barrel polishing method of the present invention, in the rough polishing step S1, it is softer than alumina, silicon carbide, etc., which are usually used as abrasive grains for barrel polishing, and is pulverized as the polishing proceeds. Since polishing is performed using powder having an appropriate hardness (= molecular structure) as abrasive grains, it has a polishing power proportional to the hardness at the initial stage of polishing, but is pulverized in a polishing tank as the polishing proceeds. Accordingly, the polishing force can be reduced and the surface roughness can be reduced, so that it is possible to accurately perform the base treatment for ultra-smooth polishing the surface of the work without requiring a polishing time. In the next cleaning step S2, abrasive grains A, compounds, water, and workpieces, media, and abrasive grains A that remain in the polishing tank after the rough polishing and become obstacles to improve the surface roughness in smooth polishing. Can be easily cleaned and discharged out of the polishing tank, and at the same time, the cleaned work and media can remain in the polishing tank. can do. In the subsequent smooth polishing step S5, the polishing is performed only by the pressing force (= polishing force) applied to the workpiece by the hard, spherical media surface used in the rough polishing step S1, and thus the polishing force is small. Thus, a smoother surface than the surface of the workpiece polished in the rough polishing step S1 can be obtained. Thereby, the surface of a workpiece | work can be grind | polished to an ultra-smooth surface in a short time.

(2) The powder of silica, permis, shirasu, pearlite, white clay, limestone used for the abrasive grain A in the rough polishing step S1 is compared to alumina, silicon carbide, etc., which are usually used as the abrasive grains for barrel polishing. Since it is soft and has an appropriate hardness (= molecular structure) that is pulverized with the progress of polishing, it can be suitably used as the abrasive grain A used in the rough polishing step S1. Moreover, since the average particle diameter of the abrasive grains A is set to 15 μm to 3 μm, rough polishing can be performed without roughening the surface roughness as a ground treatment for polishing the surface of the workpiece to an ultra-smooth surface.

(3) The media used in the present invention employs a ball media made of a hard fired or sintered material having a spherical shape and a particle diameter of 2 to 6 mm, and the media and workpiece are swirled and flowed in a polishing apparatus. By adopting a fluid barrel polishing apparatus that applies a pressing force (= polishing force) to the polishing surface of the workpiece to polish the surface of the workpiece, the polished media and workpiece can be easily cleaned, and the rough polishing step S1 is started. Since it can be used for polishing without replacement through each polishing step up to the smooth polishing step S5, the surface roughness of the workpiece can be reduced, and the work efficiency is also good.

(4) Further, as a modification of the present invention, between the cleaning step S2 and the smooth polishing step S5, the abrasive grains A are softer and smaller in particle size than the coarse polishing step S1, and pulverized as the polishing proceeds. The abrasive grain B, compound and water to be added are newly introduced into the polishing tank, and after the second rough polishing process S3 for polishing the workpiece, water is supplied into the polishing tank 1 after the second rough polishing process S3. Abrasive grains B, compound, water used for polishing in the second rough polishing step S3, which has the same effect as the cleaning step S2, and becomes an impediment for improving the surface roughness in the next smooth polishing step S5, and A second cleaning step S4 in which the wear powder of the workpiece, media, and abrasive grains B is easily washed and discharged out of the polishing vessel through the sliding contact gap between the polishing vessel and the rotating disk, and the washed workpiece and media remain in the polishing vessel; , So that you can carry out Material changes over click, or those that can handle when there is surface roughness is further reduced demand.

(5) The amount (volume%) of water added to the work and medium (volume = 100%) in the polishing tank 1 in each polishing process is 6 in the rough polishing process S1 or the second rough polishing process S3. If it is less than%, the viscosity of the mass increases during polishing, the temperature in the polishing tank rises, the constituent members of the polishing tank 1 expand, and the sliding contact gap 3 between the rotating disk 4 and the fixed tank 2 increases. May be obstructed and the rotation of the turntable 4 may stop. If the amount of water added exceeds 30%, the mixing ratio of the media and abrasive grains to the water will decrease, and the polishing action (= polishing power) given to the workpiece by the media or abrasive grains will decrease. Therefore, the addition amount is set to 6 to 30% to solve the above-mentioned problems and perform accurate rough polishing. Further, in the smooth polishing step S5, by setting it to 60% or more, water is interposed between the medium and the workpiece, and the pressing force (= polishing force) acting on the workpiece is suppressed, thereby reducing the surface roughness of the workpiece. By making it 100% or less, the pressing force (= abrasive force) on which the medium acts on the workpiece is appropriately maintained, and at the same time, the decrease in the concentration of the compound is suppressed to prevent unnecessary addition. It is what I did.

(6) The oxides of cerium, chromium, and iron used in the abrasive grain B in the second coarse polishing step S3 are silica, permis, shirasu, pearlite, white clay, limestone used in the abrasive grain A in the coarse polishing step S1, Therefore, the surface of the workpiece can be polished with less marks, and the surface roughness of the workpiece after the rough polishing step S1 can be further smoothed. Moreover, since the average particle diameter of the abrasive grains B is set to 5 μm to 1 μm, it is possible to perform a ground treatment for polishing the surface of the work to an ultra-smooth surface.

(7) If a fluid barrel polishing apparatus having a cylindrical inner cylinder 9 that is fixedly or rotatably supported at the upper rotation center of a rotating disk 4 of a conventional fluid barrel polishing apparatus is used, media and abrasive grains can be used as workpieces. The pressing force (= polishing power) applied to the workpiece can be increased, so it can be used when workpieces with different materials, physical properties, etc. require large polishing power, or when polishing efficiency needs to be improved. Easy.

(8) As apparent from the above description, the fluid barrel polishing method of the present invention can easily perform ultra-smooth polishing with a surface roughness of a cylindrical workpiece made of a metal material of Ra 0.02 μm or less. is there.

DESCRIPTION OF SYMBOLS 1 Polishing tank 2 Fixed tank 3 Sliding contact gap 4 Turntable 5 Bottom plate 6 Passage 7 Drain pipe 8 Hole 9 Inner cylinder M

Claims (10)

A barrel polishing apparatus is provided with a polishing tank that is provided with a rotating table that rotates horizontally at the bottom and is configured to be washable inside. At least a work, a medium, and water are put into the polishing tank, and the rotating table rotates. Using a fluid barrel polishing apparatus that forms a mixed mass by swirling and polishing, and polishing a workpiece, the spherical media having a smooth surface, the abrasive grains A that are pulverized as the polishing progresses, the compound, and water A rough polishing step for polishing a workpiece by putting it into a polishing tank, and a polishing used abrasive grain A, a compound, water, and a workpiece and a medium which are supplied to the polishing tank and remain in the polishing tank after the rough polishing step. A cleaning step of cleaning and discharging the abrasive powder of the abrasive grains A to the outside of the polishing tank and leaving the cleaned work and media in the polishing tank; a new compound and water in the polishing tank after the cleaning process; Barrel polishing method characterized by comprising a smoothing polishing step of polishing a workpiece by introducing. 2. The barrel polishing method according to claim 1, wherein the abrasive grain A is made of at least one of powders of silica, permis, shirasu, pearlite, clay, and limestone. 3. The barrel polishing method according to claim 1, wherein the abrasive grains A have an average particle diameter of 15 μm to 3 μm. The barrel polishing method according to any one of claims 1 to 3, wherein the medium is a fired or sintered medium having a particle diameter of 2 to 6 mm. Between the washing step and the smooth polishing step, abrasive grains B that are softer and have a smaller particle diameter than the abrasive grains A used in the rough polishing step and are pulverized as the polishing proceeds, a compound, and water , A second rough polishing step in which the workpiece is polished by newly charging the polishing bath, and after the second rough polishing step, water is supplied into the polishing bath and the abrasive grains B remaining in the polishing bath are left. And a compound, and a second cleaning step of cleaning and discharging the wear powder of the work and media out of the polishing tank and leaving the cleaned work and media in the polishing tank. The barrel polishing method according to any one of claims 1 to 4. The amount of water added to the polishing tank in the rough polishing step or the second rough polishing step is 6 to 30% with respect to the workpiece and the medium, and the amount of water added to the polishing tank in the smooth polishing step. The barrel polishing method according to any one of claims 1 to 5, wherein the ratio is 60% to 100% with respect to the workpiece and the medium. The barrel polishing method according to claim 5 or 6, wherein the abrasive grain B is made of at least one of cerium, chromium, and iron oxides. 8. The barrel polishing method according to claim 5, wherein the abrasive grains B have an average particle diameter of 5 μm to 1 μm. 9. The fluidized barrel polishing apparatus includes a cylindrical inner cylinder that is rotatably or pivotally supported at an upper center of a rotation center of the rotating disk. A barrel polishing method according to claim 1. 10. The work according to claim 1, wherein the work is a cylindrical work made of a metal material, and the surface of the work is polished to have a surface roughness of Ra 0.02 [mu] m or less. Barrel polishing method as described in one.

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