JP2007021660A - Method of mirror-polishing complicated shape body, and mirror-polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of mirror-polishing a complicated shape body, in which fluid polishing is implemented in a manner being out of contact with a polishing object, without generating stress over the entire area of the object immersed in polishing solution even if the polishing object has a complicated shape with bumps and dips, to thereby finish the polishing object with a mirror surface, and to provide a mirror-polishing device. <P>SOLUTION: According to the mirror-polishing method, magnetic field generating sources 7 for generating magnetic fields are arranged on a peripheral surface and an external bottom surface of a flow bath 2, and the magnetic polishing solution 1 is charged in the flow bath, followed by hanging a specimen 3 (polishing object) from a support portion 6 to be immersed in the solution. The magnetic polishing solution 1 is mixed with nonmagnetic abrasive grains and α-cellulose as a thickening agent. Then the specimen 3 is rotated by a driving motor 5 linked to the support portion 6, and the flow bath 2 is suitably oscillated by an oscillation stand 8 linked thereto, to thereby agitate the polishing solution in the bath. In this manner the specimen 3 is immersed in the magnetic polishing solution 1 over the overall area except for a mounted surface, and the magnetic field is exerted on the overall surface, followed by pressing the abrasive grains by magnetic clusters generated in the polishing solution, to thereby carry out polishing by relative movement of the abrasive grains. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mirror polishing method and a mirror polishing apparatus for complex shaped bodies having complicated uneven shapes such as precision machine parts and molds, and more specifically, a polishing object that is a complicated shaped body can be moved. Further, the present invention relates to an improvement in performing fluid polishing in the presence of a magnetic polishing liquid in the vicinity thereof.

  As a technique for finishing the surface to be polished into a mirror surface, in general, lapping or lapping is performed in which an abrasive in which free abrasive grains are dispersed is rubbed between the object to be polished and a lapping surface. Polishing is performed by using a finer abrasive grain and performing a rubbing operation with a polishing object using a soft tool called a polishing pad.

  Non-contact polishing technology includes float polishing, which is performed by rotating the tin plate and the object to be polished simultaneously in a polishing solution in which a fine polishing agent is turbid, and polishing with the fluid pressure of the polishing solution interposed between them. This is a technique that slightly raises the object and proceeds with the polishing agent in the polishing liquid.

In addition, magnetic polishing techniques that perform polishing by applying a magnetic field are well known. For example, there are inventions disclosed in Patent Documents 1 and 2. Patent Document 1 proposes a technique that improves the performance of the polishing liquid by adjusting dispersed particles in the magnetic polishing liquid and can be applied to precise polishing and finishing. In Patent Document 2, the behavior of polishing is improved by making the relative movement properly between the particle brush made of magnetic abrasive grains and the object to be polished, and by coating the magnetic abrasive grains with a nonmagnetic layer. Technologies that can be applied to smooth polishing and finishing have been proposed. Such a method using magnetic polishing has a merit that polishing can be performed without stress even on a polishing object with low strength because it can perform so-called non-contact polishing, and is preferred for precision finishing applications.
JP 2002-170791 A JP 2002-283216 A

  However, the conventional mirror polishing technique has the following problems. In the case of magnetic polishing technology, magnetic abrasive grains (particle brushes), that is, grinding tools, are activated by a magnetic field, so that the polishing of the object to be polished proceeds well on the facing part where the magnetic pole of the magnetic field source faces, and the outer periphery that does not face the magnetic pole The part has a characteristic that polishing does not proceed relatively. For this reason, it is difficult to finish the entire surface of the object to be polished uniformly, and there is a problem that unevenness is partially generated.

  In particular, when the object to be polished is a complex shape (complex shape body) having irregularities such as grooves, it is possible to mount the irregularities such as grooves on the support part in a posture that does not face the magnetic poles for the convenience of workpiece mounting. For this reason, there is a problem that complicated uneven portions such as the bottom of a groove in the outer peripheral portion that does not face the magnetic pole cannot be properly polished.

  The object of the present invention is to solve the above-mentioned problems. The purpose of the present invention is to perform fluid polishing that is non-contact with the object to be polished, and the entire surface immersed in the polishing liquid even if the object to be polished is a complex shape having irregularities such as grooves It is an object of the present invention to provide a mirror polishing method and a mirror polishing apparatus for a complex-shaped body that can be polished without stress and finished into a mirror surface.

  In order to achieve the above-described object, the mirror polishing method according to the present invention is a method for supporting a polishing object having a complicated shape in a movable manner, and performing fluid polishing in the presence of a magnetic polishing liquid. A magnetic field generating source for generating a magnetic field is provided on the outer periphery and bottom bottom of the fluid tank, the fluid tank is filled with magnetic polishing liquid, the object to be polished is attached to the support, and is suspended and positioned in the fluid tank. Then, at least the entire surface except the mounting surface is immersed in the magnetic polishing liquid. Then, nonmagnetic abrasive grains are mixed in the magnetic polishing liquid, and the polishing object is rotated by activating the rotating means linked to the support portion, and the magnetic polishing liquid is temporally moved by the magnetic field generation source. A steady or fluctuating magnetic field is applied, and the magnetic polishing liquid is stirred by a stirring means to perform fluid polishing in a non-contact state.

  Further, the mirror polishing apparatus according to the present invention includes a fluid tank filled with a magnetic polishing liquid, a magnetic field generation source that generates a magnetic field assembled on the outer periphery and bottom of the fluid tank, and a support unit that supports the object to be polished in a suspended state. And rotating means for rotating the support portion in conjunction with the support section, and stirring means for stirring the magnetic polishing liquid in the fluidized tank. The polishing target is positioned in the fluidized tank, and at least the entire surface except the mounting surface with the support portion is immersed in a magnetic polishing liquid, and nonmagnetic abrasive grains are mixed in the magnetic polishing liquid and rotated. The configuration is such that the polishing object is rotated by starting the means, a magnetic field generation source applies a magnetic field that is constantly or fluctuating in time to the magnetic polishing liquid, and the magnetic polishing liquid is agitated by starting the stirring means. To do.

In addition, the magnetic polishing liquid used in each invention was obtained by dispersing 10 to 95 wt% of ferromagnetic particles having a particle diameter of 1 to 80 μm in a dispersion medium such as water or kerosene having a kinematic viscosity of about 0.01 to 100 mm ² / s. A composite fluid in which 5 to 90 wt% of a fluid in which spherical magnetite particles having a particle diameter of 10 to 50 nm are uniformly dispersed in a dispersion medium such as water or kerosene having electrical insulation properties is mixed with the fluid is used. It is preferable to mix nonmagnetic abrasive grains of ˜100 μm and further mix 5 to 90 wt% of a fibrous substance such as α-cellulose or a resin such as polyvinyl alcohol as a thickener.

  Accordingly, in the present invention, the fluid tank has a magnetic field generation source on the outer periphery and bottom, and therefore, a magnetic field acts between the object to be polished located in the fluid tank and a magnetic cluster is generated in the magnetic polishing liquid. . Specifically, in the compositions shown in claims 2 and 4, a large number of ferromagnetic particles (for example, iron particles) and magnetite particles are aggregated by a magnetic attractive force to form a magnetic cluster. Since the magnetic clusters follow the magnetic flux, a large number of needles are arranged in opposition to the object to be polished, whereby the abrasive grains present in the magnetic polishing liquid are suppressed on the surface of the object to be polished. In addition, since there are abrasive grains entangled in the magnetic cluster, they are also restrained on the surface to be polished.

  In this state, the polishing object is rotated by the rotating means, so that the low grains move while contacting the surface of the polishing object by relative movement. For this reason, an abrasive grain grinds the convex part of the surface of grinding | polishing object, and a smoother surface is obtained.

  Further, since the magnetic polishing liquid is agitated by the stirring means, the magnetic polishing liquid is also exchanged in the recess to be polished, and the abrasive grains move around in the magnetic polishing liquid, so that the polishing action is performed and the polishing proceeds.

  Furthermore, there are magnetic clusters that jump off the magnetic field of the magnetic field generation source (permanent magnet). These disperse in the magnetic polishing liquid and eventually disappear, but since the shape is maintained for a while, the magnetic polishing liquid flows around each part such as the side of the object to be polished, The wraparound magnetic cluster hits the part and acts as a grinding, or moves the abrasive grains present in the vicinity at the part, and as a result, polishing proceeds even on the side that does not face the rotation axis. Of course, the floating magnetic cluster also moves around the concave portion to be polished and acts as a grinding, and polishing proceeds.

  In addition, since the magnetic polishing liquid contains a thickener such as α-cellulose, the added thickener acts to retain the magnetic cluster, and as a result, a large number of abrasive grains come into contact with the surface to be polished. Can be promoted and polishing can be performed with high efficiency.

  In this case, the polishing target located in the fluidized tank is immersed in the magnetic polishing liquid over the entire surface except for the mounting surface with the support, and the magnetic field generation source faces each surface. The magnetic field acts, and therefore, the entire surface except the mounting surface to be polished can be polished.

  In the mirror polishing of the complex shaped body according to the present invention, the entire surface of the polishing object located in the fluidized tank is immersed in the magnetic polishing liquid except for the mounting surface with the support, and the magnetic field generation source faces each surface. As a result, a magnetic field acts on the entire surface, and therefore the entire surface excluding the mounting surface to be polished can be polished by the magnetic cluster.

  This is non-contact fluid polishing with respect to the object to be polished. Therefore, even a polishing object with low strength is polished without stress, and the magnetic polishing liquid is stirred by the stirring means, so that the polishing action can be promoted. Therefore, even if the object to be polished is a complex shape having irregularities such as grooves, the entire surface immersed in the polishing liquid can be polished without stress and finished to a mirror surface.

  FIG. 1 shows a preferred embodiment of the present invention. In this embodiment, the mirror polishing apparatus has a flow tank 2 filled with the magnetic polishing liquid 1, and rotates while positioning the polishing target (sample 3) in the flow tank 2, while applying a magnetic field to the flow tank 2. Appropriate vibrations are made to act, and fluid polishing is performed by magnetic clusters generated in the magnetic polishing liquid 1.

The magnetic polishing liquid 1 is a mixture of non-magnetic abrasive grains. Specifically, the magnetic polishing liquid 1 is a strong particle having a particle diameter of 1 to 80 μm in a dispersion medium such as water or kerosene having a kinematic viscosity of about 0.01 to 100 mm ² / s. 5 to 90 wt% of a fluid in which spherical magnetite particles having a particle diameter of 10 to 50 nm are uniformly dispersed in a dispersion medium such as water or kerosene having electrical insulating properties is mixed with a fluid in which magnetic particles are dispersed in an amount of 10 to 95 wt%. The composite fluid is mixed with non-magnetic abrasive grains having a particle diameter of 0.01 to 100 μm, and further mixed with 5 to 90 wt% of a fibrous substance such as α-cellulose or a resin such as polyvinyl alcohol as a thickener. .

  A rotating shaft 4 faces the fluid tank 2 from above, and a sample 3 is attached to and supported by the tip of the rotating shaft 4 and rotated by a drive motor 5 connected to the other end of the shaft. The drive motor 5 may be a rotary drive mechanism such as a drilling machine, a lathe, an NC lathe, or a milling machine. The sample 3 is attached to the support 6 connected to the tip of the rotary shaft 4 and can be attached and detached. It has become.

  The fluid tank 2 has a magnetic field generation source 7 such as a permanent magnet attached to the outside thereof, and a vibration of an appropriate operation is performed by a vibration table 8 linked thereto. A plurality of magnetic field generation sources 7 are arranged in the entire outside of the fluid tank 2 so that the magnetic field can be applied uniformly to the inside of the fluid tank 2. The magnetic field generation source 7 is not limited to a permanent magnet, and for example, an electromagnet can be preferably applied. The point is that any magnetic field can be applied to the magnetic polishing liquid 1.

  In polishing the sample 3, first, the positional relationship of the sample 3 with respect to the fluidized tank 2 is initially set so that the sample 3 is immersed in the magnetic polishing liquid 1. Then, the drive motor 5 and the vibration table 8 are activated to rotate the sample 3 and the fluid tank 2 is oscillated, and a magnetic field is applied to the magnetic polishing liquid 1 by the magnetic field generation source 7.

  The vibration table 8 has a drive source (not shown), and is configured to move (vibrate) in the plane opposite to the rotation shaft 4, and a plurality of vibration modes are set for the movement. That is, the vibration operation by the vibration table 8 is, for example, a simple rotation operation centered on a fixed point, a rotation operation for drawing a figure 8, or a vibration operation reciprocating in a fixed direction on the surface opposite to the rotation shaft 4. There are a plurality of vibration modes, and these are appropriately selected or combined during the polishing operation. Note that the vibration table 8 may be configured to perform a motion operation including longitudinal vibration in the axial direction of the rotary shaft 4.

  According to such a configuration, as shown in FIG. 2, magnetic flux is generated for the sample 3 in the fluidized tank 2, and a magnetic cluster 9 is generated in the magnetic polishing liquid 1. That is, since the magnetic field generation source 7 is attached to the outside of the fluidized tank 2, a magnetic field acts to generate a magnetic flux between the magnetic field generation source 7 and the sample 3, and ferromagnetic particles (for example, iron particles) and magnetite particles are generated. Many are aggregated by the magnetic attractive force to form a magnetic cluster 9. Since the magnetic clusters 9 are along the magnetic flux, a large number of needles are arranged in opposition to the sample 3.

  At this time, in the magnetic polishing liquid 1, the α-cellulose 10 added as a thickener occupies a position in a woven state between the magnetic clusters 9, and nonmagnetic abrasive grains 11 are further added. Some are entangled in the cluster 9, but many of them are present on the surface of the sample 3 because the liquid is in a stirring state. Therefore, the abrasive grains 11 present in the magnetic polishing liquid 1 are pressed against the surface of the sample 3 by the magnetic clusters 9 arranged in a needle shape and the α cellulose 10 in the woven state. In addition, since there are abrasive grains 11 entangled in the magnetic clusters 9 and α-cellulose 10, they are also suppressed to the surface of the sample 3.

  Since the rotating shaft 4 rotates in this state, that is, the sample 3 rotates, the low particle 11 moves while contacting the surface of the sample 3 by relative movement. For this reason, the abrasive grain 11 grinds the convex part of the surface of the sample 3, and a smoother surface is obtained. That is, mirror polishing can be performed.

  When the magnetic field is stationary, the magnetic clusters 9 are aligned along the magnetic flux, and the aligned state is maintained by the magnetic force, so that the abrasive grains 11 can be properly applied to the surface (polishing surface) of the sample 3 for polishing. Further, when the magnetic field is fluctuating, the magnetic cluster 9 is shaken, and at this time, the abrasive grains 11 hit the polishing surface appropriately and polishing can be performed. Thus, even in a non-contact state with respect to the sample 3, it can be polished by the pressing action of the magnetic cluster 9 and the α cellulose 10, and fluid polishing can be performed.

  In this case, the sample 3 positioned in the fluidized tank 2 is immersed in the magnetic polishing liquid 1 in the entire surface except for the mounting surface with the support portion 6, and the magnetic field generation source 7 faces each surface. A magnetic field acts on the entire region, and therefore, the entire surface except the mounting surface of the sample 3 can be polished.

  Further, since the magnetic polishing liquid 1 is agitated by moving the fluidizing tank 2, the magnetic polishing liquid 1 is also replaced in the concave portion of the sample 3, and the abrasive grains 11 move around in the magnetic polishing liquid 1, so that the polishing action is performed. Will proceed.

  By the way, the magnetic cluster 9 may be out of the magnetic field of the magnetic field generation source 7. These disperse in the magnetic polishing liquid 1 and eventually disappear. However, since the shape is maintained for a while, the magnetic polishing liquid 1 flows into each part such as the concave portion of the sample 3 due to the flow motion. Thus, the magnetic cluster 9 that has entered the region hits the part and acts as a grinding, or moves the abrasive grains 11 present in the vicinity at the part. As a result, the entire surface of the sample 3 is polished, and the polishing progresses even at the bottom of the concave portion having a complicated shape.

  In addition, since the magnetic polishing liquid 1 contains α-cellulose 10 as a thickener, the added thickener acts to hold the magnetic cluster 9, and as a result, a large number of abrasive grains 11 are formed on the surface of the sample 3. The contact situation can be promoted and polishing can be performed with high efficiency.

  Therefore, according to the mirror polishing according to the present invention, the magnetic cluster 9 generated in the magnetic polishing liquid 1 can perform non-contact fluid polishing on the sample 3 (the object to be polished). Since the stirring is performed by the stirring means, the polishing action can be promoted. The entire surface of the sample 3 except for the mounting surface with the support portion 6 is immersed in the magnetic polishing liquid 1, and the magnetic field generation source 7 faces each surface, so that a magnetic field acts on the entire surface, and therefore Even if the object to be polished is a complex shape having irregularities such as grooves, the entire surface can be mirror-finished without unevenness. And since it is non-contact fluid grinding | polishing, it can grind | polish without stress even if it is a grinding | polishing object with weak intensity | strength.

  As an object to be polished, there are a part having an annular groove as shown in FIG. 3 and a cam part having a cam groove on the outer peripheral side surface of a cylinder as shown in FIG. By using the polishing apparatus of the present embodiment, it is possible to polish a component having such a complicated shape and perform mirror finish. Of course, the shape and type of the object to be polished are not limited to those illustrated.

  The sample was polished using the mirror polishing apparatus shown in FIG. That is, in order to demonstrate the effect of the present invention, a predetermined sample was polished under different polishing conditions, and the surface roughness Ra (arithmetic average roughness) was evaluated for the sample. As the magnetic polishing liquid, the composition shown in Table 1 was used, and samples having the shape and dimensions shown in FIGS. 3A and 3B were used for the evaluation test.

  In other words, the magnetic polishing liquid contains, in its composition, alumina having a particle diameter of 0.05 μm as non-magnetic abrasive grains and α-cellulose as a thickener. In the evaluation test, as shown in FIGS. 3 (a) and 3 (b), the sample has a disk shape with an outer diameter of 12 mm and a thickness of 5 mm and a concentric annular groove. Polishing was performed, and as a result, a surface roughness Ra as shown in the table was obtained.

  The sample is made of brass, and is schematically shown in FIG. 1. However, when the sample 3 is positioned in the fluidized tank 2, the relationship with the inner surface of the tank is set to be about 1 mm. The rotation speed of the rotating shaft 4 (sample 3) was 800 rpm, the polishing time was 1 hour, and the vibration table 8 was rotated in the opposite direction to the rotating shaft 4, and the rotating speed was 30 rpm.

  As a result, the surface roughness Ra was 11 nm at the annular groove portion (concave portion), 10 nm at the center surface (convex portion), and 8 nm at the outer peripheral side portion. In sample 3, it was confirmed that the surface finishing can be performed to the same extent on the entire surface including the outer peripheral side portion.

  That is, according to the mirror polishing according to the present invention, the mirror polishing can be performed with a sufficient surface roughness. This is the entire surface except the bottom surface fixed to the support portion 6, that is, the entire surface immersed in the magnetic polishing liquid. As a matter of course, the depth of the concave portion of the complicated shape can be polished properly, and the usefulness of the present invention has been confirmed.

1 is a configuration diagram showing a preferred embodiment of a mirror polishing apparatus according to the present invention. It is explanatory drawing which shows the fluid grinding | polishing by a magnetic cluster. It is the perspective view (a) and sectional drawing (b) which show the geometric dimension of the complex shape body used as the sample of the grinding | polishing test. It is a perspective view which shows the other examples of a complicated shape body.

Explanation of symbols

1 Magnetic polishing liquid 2 Fluid tank 3 Sample (polishing object)
DESCRIPTION OF SYMBOLS 4 Rotating shaft 5 Drive motor 6 Support part 7 Magnetic field generation source 8 Shaking table 9 Magnetic cluster 10 Alpha cellulose 11 Abrasive grain

Claims (4)

There is a method of mirror polishing of a complex shape body that supports a polishing object that is a complex shape body so as to be movable, and performs fluid polishing in the vicinity of a magnetic polishing liquid,
A magnetic field generation source for generating a magnetic field is provided on the outer periphery and bottom of the fluid tank
The fluid tank is filled with the magnetic polishing liquid,
The object to be polished is attached to a support part, is placed in the fluidized tank in a suspended state, and at least the entire surface excluding the attachment surface is immersed in the magnetic polishing liquid,
Nonmagnetic abrasive grains are mixed in the magnetic polishing liquid,
The polishing object is rotated by activating a rotating means linked to the support part, and a magnetic field generating source applies a magnetic field that is temporally steady or fluctuating to the magnetic polishing liquid. A mirror polishing method for a complex-shaped body, characterized in that fluid polishing is performed in a non-contact state by stirring with a stirring means. The magnetic polishing liquid is
With respect to a fluid in which 10 to 95 wt% of ferromagnetic particles having a particle size of 1 to 80 μm are dispersed in a dispersion medium such as water or kerosene having a kinematic viscosity of about 0.01 to 100 mm ² / s, the particle size is 10 to 50 nm. A non-magnetic abrasive particle having a particle diameter of 0.01 to 100 μm is mixed with a composite fluid in which 5 to 90 wt% of a fluid in which spherical magnetite particles are uniformly dispersed in a dispersion medium such as water or kerosene having electrical insulation properties is mixed. The method for mirror polishing a complex-shaped body according to claim 1, further comprising a fibrous material such as α-cellulose or a resin such as polyvinyl alcohol as a thickener mixed in an amount of 5 to 90 wt%. . A fluid tank that fills the magnetic polishing liquid, a magnetic field generation source that generates a magnetic field assembled on the outer periphery and bottom of the fluid tank, a support part that supports the polishing object in a suspended state, and a support part that is linked to the support part. Rotating means for rotating, and stirring means for stirring the magnetic polishing liquid in the fluidized tank,
The polishing object is positioned in the fluidized tank, and set so that at least the entire surface excluding the attachment surface with the support portion is immersed in the magnetic polishing liquid,
The magnetic polishing liquid is mixed with non-magnetic abrasive grains, and the polishing object is rotated by starting the rotating means. A mirror polishing apparatus for a complex shaped body, wherein the magnetic polishing liquid is agitated by applying a variable magnetic field and activating the stirring means. The magnetic polishing liquid is
With respect to a fluid in which 10 to 95 wt% of ferromagnetic particles having a particle size of 1 to 80 μm are dispersed in a dispersion medium such as water or kerosene having a kinematic viscosity of about 0.01 to 100 mm ² / s, the particle size is 10 to 50 nm. A non-magnetic abrasive particle having a particle diameter of 0.01 to 100 μm is mixed with a composite fluid in which 5 to 90 wt% of a fluid in which spherical magnetite particles are uniformly dispersed in a dispersion medium such as water or kerosene having electrical insulation properties is mixed. 4. The mirror polishing apparatus for complex shaped bodies according to claim 3, further comprising a fibrous substance such as α-cellulose or a resin such as polyvinyl alcohol as a thickener mixed with 5 to 90 wt%. .

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