JP2009012180A - Polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing device excellent in flexibility and polishing capability regardless of a shape of a polishing object. <P>SOLUTION: The polishing device is equipped with: a workpiece holding member 11 holding a workpiece 10; a polishing tool 300 having a polishing agent 12A containing an electric rheology gel (ERG) and abrasive grains to polish the workpiece 10 by keeping the polishing agent 12A in contact with the workpiece 10; a tool holding member 310 holding the polishing tool 300; a rotary drive means 450 to rotate the polishing tool 300 or the workpiece 10 around the axis substantially orthogonal to the polishing surface; and a voltage applying means 123 to apply the voltage to the ERG. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing apparatus for polishing a workpiece having a predetermined-shaped polishing surface.

Conventionally, compositions called electrorheological fluids (hereinafter also referred to as ER fluids) are known. This composition is, for example, a fluid obtained by dispersing dispersed phase particles in an electrically insulating medium. When an external electric field is applied to the fluid, its viscosity increases remarkably, and in some cases solidifies. It is a fluid composition having a so-called electrorheological effect (hereinafter also referred to as ER effect).
Since this ER fluid has the ER effect as described above, it is used in the field of power transmission or braking of devices such as clutches, dampers, shock absorbers, and vibration elements by electric control.

On the other hand, there is an attempt to apply to the polishing of an optical element using the specific property of such an ER fluid. For example, in the polishing apparatus described in Patent Document 1, a gap is provided on the back side of a polishing polisher for polishing an optical element, and ER fluid is filled therein. Then, by controlling the voltage applied to the ER fluid, the polishing polisher is hard at the initial stage of polishing and softly changed at the end of polishing. As a result, the surface accuracy of the surface of the optical element that is the workpiece is to be improved.
Further, as in Patent Document 2, there is also known an apparatus that performs polishing by moving an optical element relative to an ER fluid while rotating an optical element in an ER fluid in which abrasive grains are dispersed. According to this polishing apparatus, by changing the applied voltage and changing the viscosity of the ER fluid, it is possible to polish the entire surface of the aspherical optical element with an optimum polishing pressure.

JP 2002-307280 A Japanese Patent Laid-Open No. 08-229793

However, in the polishing apparatus of Patent Document 1, it is necessary to prepare in advance a polishing material corresponding to the shape of the object to be polished, called a polishing polisher. In addition, since a metal plate exists between the polishing polisher and the ER fluid, the unique properties of the ER fluid are not fully utilized.
On the other hand, in the polishing apparatus of Patent Document 2, since the abrasive grains dispersed in the ER fluid are the main subject of polishing, the pressure for pressing the abrasive grains against the optical element depends on the flow of the ER fluid and is applied to the aspherical optical element. It is difficult to increase the polishing power.
Furthermore, although the ER fluid using the above dispersed phase particles has many excellent ER effects as described above, when left standing for a long period of time, the dispersed phase particles settle in the dispersion medium, In addition, once settled, there is a problem that it is agglomerated and re-dispersion becomes difficult.

  Accordingly, an object of the present invention is to provide a polishing apparatus that uses an ER fluid and has an excellent degree of freedom and polishing ability independent of the shape of the object to be polished.

  A polishing apparatus of the present invention is a polishing apparatus that polishes a workpiece having a predetermined-shaped polishing surface, and includes a workpiece holding member that holds the workpiece, an electrorheological gel (hereinafter also referred to as “ERG”), and abrasive grains. A polishing tool configured to polish the workpiece by bringing the polishing material into contact with the workpiece, a tool holding member that holds the polishing tool, and the polishing tool or the workpiece. Rotating driving means for rotating about an axis substantially orthogonal to the polishing surface, and voltage applying means for applying a voltage to the ERG are provided.

Here, ERG is a gel substance in which the ER fluid has lost its fluidity. “Including ERG and abrasive grains” means, for example, a structure in which abrasive grains are dispersed in ERG. If gelling is performed by dispersing abrasive grains in ER fluid, Such a structure is obtained.
According to the polishing apparatus of the present invention, since the polishing material contains ERG and abrasive grains, the function as a polishing apparatus utilizing the characteristics of ERG can be exhibited. That is, when the ERG is pressed against the workpiece surface with a constant force, the ERG itself is deformed into a shape that follows the workpiece surface shape, and therefore it is not always necessary to manufacture the abrasive in accordance with the workpiece surface shape in advance.

Further, since the polishing apparatus includes a rotation driving unit that rotates and drives the polishing tool or the workpiece, and a unit that applies a voltage to the ERG constituting the polishing material, the elasticity (hardness) of the ERG during the polishing. Can be changed to change the polishing characteristics. That is, since the hardness of the ERG can be changed according to the surface roughness of the workpiece, for example, when the surface roughness of the workpiece is large, the ERG is hardened by applying a high voltage to the ERG. When the roughness is reduced, polishing can be performed efficiently by lowering the voltage applied to the ERG to make it softer. In the polishing, either the polishing tool or the workpiece may be rotated.
Furthermore, since the abrasive grains do not diffuse and settle in the ERG, the performance as an abrasive can be maintained over a long period of time without deteriorating the electrorheological characteristics.

In addition, it is preferable that this abrasive grain is hold | maintained in the surface layer part of ERG.
According to the present invention, since the abrasive grains are held in the surface layer portion of the ERG, when the abrasive comes into contact with the workpiece, the ER effect is directly reflected in the abrasive grains. It can be carried out.

Moreover, it is preferable that the abrasive is fixed to the tool body of the polishing tool.
Here, the abrasive is fixed to the tool body when the abrasive is adhering to the tool body due to its own adsorption force or by creating a groove on the tool body side. It means the state fixed to the main body.
According to the present invention, since the abrasive is fixed to the tool body, the above-described effects can be suitably achieved without the abrasive being peeled off from the tool body when used as an abrasive tool.

In the present invention, a first sleeve that holds the workpiece holding member rotatably about a substantially vertical axis with the polishing surface facing upward, and an upper portion of the first sleeve, the abrasive And a second sleeve that holds the tool holding member so that the tool holding member cannot rotate and is slidable in the rotation axis direction of the work holding member, and the rotation driving means rotates the work holding member. Is preferred.
According to the present invention, since the tool holding member is provided with the second sleeve that holds the tool holding member so that it cannot rotate and is slidable in the direction of the rotation axis of the workpiece holding member, the polishing tool always has a constant pressure when polishing the workpiece. You will be in contact with the workpiece under your own weight. Therefore, the contact pressure fluctuation during polishing is reduced, and the polishing operation can be performed stably.

In the present invention, a third sleeve that holds the tool holding member rotatably about a substantially vertical axis in a posture in which the abrasive is faced upward, and is located on the top of the third sleeve, the polishing surface And a fourth sleeve that holds the work holding member in a non-rotatable and slidable direction in the direction of the rotation axis of the tool holding member, and the rotation driving means rotates the tool holding member. Is preferred.
According to the present invention, since the work holding member is provided with the fourth sleeve that holds the work holding member so that it cannot rotate and is slidable in the direction of the rotation axis of the tool holding member, the work is always kept at a constant pressure ( It will come into contact with the polishing tool under its own weight. Therefore, the contact pressure fluctuation during polishing is reduced, and the polishing operation can be performed stably.

In the present invention, the polishing tool is composed of a conductive tool main body and the abrasive provided at the tip of the tool main body, and the voltage applying means is inserted into the center of the tool holding member, and one end is A first electrode that is in contact with the tool body, the other end of which is in contact with the power supply member, a second electrode that is disposed at the center of the work holding member, has one end in contact with the work, and the other end in contact with the power supply member. It is preferable that the work is electrically conductive.
According to the present invention, since the tool body and the workpiece are conductive, it is possible to apply a voltage by arranging electrodes on both sides of the ERG by the first electrode and the second electrode constituting the voltage applying means. Therefore, for example, it is suitable for polishing a lens molding die.

In the present invention, the polishing tool includes an electrically insulating tool main body and the abrasive provided at the tip of the tool main body, and the voltage application means is disposed in the vicinity of the abrasive of the tool main body. The first electrode and the second electrode having different polarities are preferably included.
According to the present invention, a voltage can be applied to one side of the ERG to control the hardness of the ERG, which is suitable when the workpiece is an electrically insulating material such as a plastic lens.

In the present invention, a ball bearing or an aerostatic bearing is provided between the workpiece holding member and the first sleeve, or between the tool holding member and the third sleeve. Is preferred.
According to the present invention, the ball bearing bearing or the aerostatic bearing is provided between the work holding member and the first sleeve or between the tool holding member and the third sleeve. The holding member or the tool holding member can be smoothly rotated.

In the present invention, it is preferable that a displacement driving means for displacing one of the workpiece holding member and the tool holding member in an axial direction substantially orthogonal to the polishing surface is provided.
According to the present invention, since the displacement driving means for displacing one of the workpiece holding member and the tool holding member in the axial direction substantially orthogonal to the polishing surface is provided, the contact pressure between the polishing surface of the workpiece and the polishing tool is provided. Can be controlled freely, and the polishing efficiency can be increased. That is, as described above, one of the workpiece holding member and the tool holding member is displaced by the displacement driving means instead of pushing down the polishing tool or the workpiece by gravity, so that, for example, the rotation axis of the polishing surface is kept horizontal. Thus, a polishing apparatus can be manufactured and installed, and the degree of freedom as a polishing apparatus is very large.

[First Embodiment]
The first embodiment of the present invention will be described in detail below.
(1) Structure and manufacturing method of ERG ERG in the present embodiment is ERG in which an electrically insulating medium and dispersed phase particles are dispersed. Specifically, ERG in which an electrically insulating medium and dispersed phase particles are dispersed in a polysiloxane crosslinked body is used. The crosslinked polysiloxane is preferably a hydrosilylation reaction product of hydrogen silicone and the unsaturated group-containing compound.

Examples of the electrically insulating medium used in this embodiment include silicone oil, diphenyl chloride, and transformer oil. Silicone oil has excellent electrical characteristics such as dielectric breakdown voltage and volume resistivity, and is physically and chemically. Since it is stable, it can exhibit stable electrical characteristics over a long period of time, and since it has high flame retardancy, it can be preferably used. The viscosity of the electrically insulating medium used in the present invention is not limited, preferably, from 1 to 100,000 mm ² / s at 25 ° C., particularly preferably 5~1000mm ² / s. When the viscosity is less than 1 mm ² / s, the storage stability of ERG is lowered, which is not preferable. On the other hand, if it exceeds 100,000 mm ² / s, bubbles are involved during stirring, the bubbles are difficult to escape, and this may cause trouble in handling, which is not preferable.

As the silicone oil, for example, one or more of dimethyl silicone oil, fluorine-modified silicone oil, and phenyl-modified silicone oil are preferably used. Examples of the fluorine-modified silicone oil include polysiloxane having a trifluoropropyl group (CF ₃ C ₂ H ₄ —), polysiloxane having a nonafluorohexyl group (C ₄ F ₉ C ₂ H ₄ —), and cyclic poly Examples include siloxane compounds. Among these, it is preferable to use a dimethyl silicone oil that is chemically and electrically inert and cheaper than the modified silicone as the dispersed phase in the ER fluid.

  The dispersed phase particles used in this embodiment constitute an ER fluid dispersed in an electrically insulating medium, and the surface of particles such as silica gel, cellulose, starch, soybean casein, polystyrene ion exchange resin, etc. There are solid particles and carbon particles that adsorb and retain water. Further, as the dispersed phase particles, composite particles for ER fluid (hereinafter abbreviated as “ER composite particles”) composed of a core made of an organic polymer compound and a surface layer made of electrically semiconductive inorganic particles, or ER. An ER fluid composite particle (hereinafter abbreviated as “affinity ER composite particle”) in which the surface of the composite particle is subjected to an affinity surface treatment to enhance the affinity with the electrically insulating medium is also used. Since stable ER effect and good storage stability are maintained, ER composite particles or affinity ER composite particles are preferably used as the dispersed phase particles.

  Details and manufacturing methods of the ER composite particles or the affinity ER composite particles are described in, for example, JP-A-2001-26793, JP-A-10-121084, and JP-A-9-79404. .

  The dispersed phase particles can be uniformly stirred and mixed in an electrically insulating medium to form an ER fluid. Although the content rate of a dispersed phase particle is not specifically limited, It is preferable to set it as the range of 1 to 75 weight% of ER fluid, especially the range of 10 to 60 weight%. If the content is less than 1% by weight, a sufficient ER effect cannot be obtained, and if it exceeds 75% by weight, the initial viscosity in the state where no voltage is applied becomes excessive and becomes unsuitable for use.

    In the present embodiment, the electrically insulating medium and the dispersed phase particles are dispersed in a gel skeleton. The gel skeleton is not limited, but an electrically insulating one is preferable. Specifically, a crosslinked polysiloxane is preferable because it can retain a large amount of an electrically insulating medium in the skeleton, and in particular, a hydrosilylation reaction product of a hydrogen silicone and an unsaturated group-containing compound is easy to manufacture. It is preferable for the reason. Here, the hydrogen silicone is, for example, a dialkyl polysiloxane having a hydrogen atom bonded to a silicon atom of a siloxane chain, and examples thereof include a compound represented by the following formula (B).

(In the formula, R ₁ independently represents a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. N ₁ represents an integer of 0 to 500.)
Alkyl groups represented by R _1, for example, a methyl group, an ethyl group, a propyl group, butyl group, octyl group, include dodecyl group, the aralkyl group includes such as benzyl group, phenethyl group, The aryl group includes, for example, a phenyl group, toluyl group, naphthyl group and the like. The substituted alkyl group represented by R ₁ includes, for example, a halogenated alkyl group such as a trifluoropropyl group and a chloropropyl group, and a cyanoalkyl group such as a 2-cyanoethyl group. Preferably, R ₁ is a methyl group and n ₁ is an integer of 10 to 200. Specific examples of the hydrogen silicone include those represented by the following formula (B-1), formula (B-2) and formula (B-3).

  Examples of the unsaturated group-containing compound include those represented by the following formula (D).

(In the formula, R ₂ independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and R ₃ represents a carbon number. 1 to 18 alkylene group, an aryl alkylene group having 7 to 21 carbon atoms, a hetero atom-containing alkylene group having 1 to 6 hetero atoms and 1 to 12 carbon atoms, or a direct bond, and n ₂ is an integer of 3 or more. And Z is a linking group having the same valence as n _2, and is a carbon atom, a silicon atom, a monosubstituted trivalent silicon atom, an aliphatic group having 1 to 30 carbon atoms, or a heteroatom having 1 to 6 atoms. A C1-C30 hetero atom containing organic group or a C2-C50 linear, branched or cyclic alkylsiloxane group is shown.)
Examples of the alkyl group represented by R ₂ include a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, a dodecyl group, and the like, and examples of the aryl group include a phenyl group, a toluyl group, and a naphthyl group. Group etc. are included. Examples of the alkylene group represented by R ₃ include a methylene group, an ethylene group, a propylene group, a butylene group, an octylene group, a dodecylene group, and the like, and examples of the aryl alkylene group include a phenylmethylene group, a phenylethylene group, Phenylethylidene group and the like are included. The term “heteroatom-containing alkylene group” as used for R ₃ is a group containing oxygen, sulfur or nitrogen atoms as heteroatoms, and the heteroatoms are considered to be carbon atoms in their entirety. A group that can be regarded as a group. Such groups include methyleneoxymethylene groups, methyleneoxyethylene groups, methyleneoxypropylene groups, ethyleneoxypropylene groups, methyleneoxyethyleneoxymethylene groups, ethyleneoxyethyleneoxyethylene groups, propyleneoxyethyleneoxypropylene groups, those Those in which oxygen atoms are replaced with sulfur or nitrogen atoms and those in which some of those oxygen atoms are replaced with sulfur and / or nitrogen atoms are included. The aliphatic group represented by Z includes a trivalent or higher linear or branched alkyl group, and includes, for example, a methynyl group, an ethynyl group, a propynyl group, a butynyl group, an octynyl group, a dodecynyl group, and the like. It is. The term “heteroatom-containing organic group” as used for Z means an aliphatic or aromatic functional group containing oxygen, sulfur or nitrogen atoms as heteroatoms. Such functional groups include methyleneoxymethynyl group, methyleneoxyethynyl group, methyleneoxypropynyl group, ethyleneoxypropynyl group, methyleneoxyethyleneoxymethynyl group, ethyleneoxyethyleneoxyethynyl group, propyleneoxyethyleneoxypropynyl group , Phenylenebis (methyloxyethynyl) groups, those having their oxygen atoms replaced with sulfur or nitrogen atoms, and those having some of their oxygen atoms replaced with sulfur and / or nitrogen atoms. The monosubstituted trivalent silicon atom of Z includes, for example, the chemical formula ≡Si-alkyl group, and specific examples thereof include ≡Si—CH ₃ . Preferably, R ₂ is a hydrogen atom or a methyl group, and R ₂ is —CH ₂ OCH ₂ —, —CH ₂ OCH ₂ CH ₂ —, or —CH ₂ OCH ₂ CH ₂ OCH ₂ —. Specific examples of the unsaturated group-containing compound include the following formula (D-1), formula (D-2), formula (D-3), formula (D-4), formula (D-5), formula (D -6) and those represented by formula (D-7).

  Since hydrosilylation has a large temperature dependence of reaction rate, it can be mixed at room temperature or lower and heated to promote the reaction. This is a great advantage of the hydrosilylation reaction. When the reactants are mixed with an appropriate viscosity, molded, and then heated, a polymer having a desired shape can be obtained at once. The heating temperature in this case is about 50 to 150 ° C., preferably about 60 to 120 ° C.

  A catalyst is preferably used for this hydrosilylation reaction. Known catalysts that can be used in the hydrosilylation reaction include compounds such as platinum, ruthenium, rhodium, palladium, osmium, and iridium. In particular, platinum compounds are useful. Examples of platinum compounds include chloroplatinic acid, platinum alone, alumina, silica, carbon black and the like supported on solid platinum, platinum-vinylsiloxane complex, platinum-phosphine. Complexes, platinum-phosphite complexes, platinum alcoholate catalysts and the like can be used. In the case of a platinum catalyst, about 0.0001% by weight can be added as platinum. When the electrically insulating medium and the dispersed phase particles are preliminarily mixed with the hydrogen silicone and the unsaturated group-containing compound prior to the hydrosilylation reaction, it is preferable that ERG is obtained directly. It is also possible to impregnate into ERG.

The crosslinking density of the ERG composition in the present embodiment is determined to some extent by the molecular weight of the compound represented by the above formula (B). The polyfunctional compound represented by the compound (B) and the above formula (D) is as follows: The following equation (1) is followed.
Formula: 0.5 ≦ [(number of moles of compound (D) × valence of compound (D)) / (number of moles of compound (B) × 2)] ≦ 1.5 (1)
In this case, an ERG composition having a preferable crosslinking density is obtained particularly when the lower limit of the formula (1) is 0.8 and the upper limit is 1.2.

  Further, the hydrogen silicone and the unsaturated group-containing compound are present in a total amount of 0.5 to 70% by weight, preferably 1 to 30% by weight of ERG.

  Since the ERG of this embodiment is an electrically insulating medium and dispersed phase particles dispersed in a gel skeleton, the dispersed phase particles do not settle. In addition, since the dispersed phase particles can move inside the gel skeleton when a voltage is applied, it is considered that the ER effect is expressed by arranging in the electric field direction.

Hereinafter, specific examples of ERG production will be shown. First, dispersed phase particles were prepared by a manufacturing method as shown below.
Antimony-doped tin oxide (manufactured by Ishihara Sangyo Co., Ltd., SN-100P, electric conductivity: 1.0 × 10 ⁰ Ω ^-1 / cm) 30 g titanium hydroxide (manufactured by Ishihara Sangyo Co., Ltd., general name: hydrous titanium, C-II, Electrical conductivity: 9.1 × 10 ⁻⁶ Ω ⁻¹ / cm) 10 g butyl acrylate 300 g 1,3-butylene glycol dimethacrylate 100 g polymerization initiator (azobisisovaleronitrile) 2 g Disperse in 1800 ml of water containing 25 g of calcium phosphate as a dispersion stabilizer, and perform suspension polymerization with stirring at 60 ° C. for 1 hour. The resulting product is acid-treated, washed with water, dehydrated and dried. Particles were obtained. 2 g of iron phthalocyanine (P-26 manufactured by Sanyo Dye Co., Ltd.) was added to 200 g of the particles and subjected to a composite treatment for 75 hours using a ball mill, and this was then used with a jet airflow processor (manufactured by Nara Machinery Co., Ltd., hybridizer). A jet stream treatment was performed at a peripheral speed of 75 m / sec for 210 seconds to obtain ER composite particles of dispersed phase particles.

The dispersed phase particles are uniformly dispersed in dimethyl silicone oil as an electrically insulating medium, and a compound represented by formula (B-1), a compound represented by formula (D-1) and a platinum catalyst are added and mixed. ERG was obtained by heating at 90 ° C. for 6 hours. The dimethyl silicone oil used here is L-45 (100) (manufactured by Toray Dow Corning Silicone Co., Ltd.), viscosity at room temperature (25 ° C.) is 100 mm ² / s, specific gravity is 0.97 / 25 ° C., refractive index. 1.402 / 25 ° C. The platinum catalyst is a zero-valent platinum catalyst dissolved in 10 mm ² / s dimethyl silicone at a platinum concentration of 0.3% by weight. Table 1 shows the formulation of ERG in this example.

The characteristics of the ERG thus obtained were examined.
(1-1) Measurement of shear stress and current value The ERG obtained above is put into a double cylinder type rotational viscometer, a DC voltage of 2.0 kv / mm is applied between the inner and outer cylinders, and the inner cylinder electrode is rotated. A force was applied to measure the shear stress (Pa) at 25 ° C. and a shear rate of 100 sec ⁻¹ . The results are shown in Table 2.

(1-2) Evaluation of sedimentation property of ERG Next, the sedimentation property at normal temperature was evaluated using the following measurement method for the ERG. The ERG was introduced into a test tube having an inner diameter of 6 mm so as to have a depth of 100 mm, and allowed to stand for 6 months at room temperature (25 ° C.), and the thickness of the supernatant layer of the test tube due to particle sedimentation of the ER composite particles. Was measured. The larger the sedimentation, the larger this value. The results are shown in Table 3.

  From the results in Table 2, it can be seen that the ERG in this example is in a range where the shear stress at the time of voltage application is improved and can be practically used. From the results shown in Table 3, no sedimentation of the ER composite particles was observed even when the ERG of this example was allowed to stand for 6 months. Therefore, it can be seen that the storage stability after standing at room temperature is remarkably excellent and can withstand long-term use.

(2) Manufacture of polishing tool First, the manufacturing method of the polishing tool used with the polisher mentioned below is explained.
FIG. 1 is a sectional view of the polishing tool material manufacturing apparatus 1 and FIG. 2 is an exploded perspective view thereof.
The polishing tool material manufacturing apparatus 1 includes an apparatus base 19, a workpiece holding member 11 that is provided at the center of the upper surface of the apparatus base 19, and holds the workpiece 10, and is provided on the outer periphery of the upper surface of the apparatus base 19 to polish the workpiece 10. A tool body holding member 13 that holds the tool body 12 with a predetermined gap with respect to the surface 10A, and a gap formed between the polishing surface 10A of the workpiece 10 and the tool body 12 to fill the ER fluid. A fluid filling space 14, an ER fluid supply means 15, and a heating means 16 are provided.

The workpiece 10 is an object to be polished, and is, for example, a conductive mold used for injection molding of a plastic lens or the like. The shape of the surface of the workpiece 10 is not particularly problematic.
The workpiece holding member 11 includes a cylindrical side wall member 111 that holds the workpiece 10 from the side surface and a base member 112 that supports the workpiece 10 from the bottom surface. The side wall member 111 and the base member 112 are fixed with bolts, and are integrated as the work holding member 11. Further, the workpiece 10 is fitted and fixed to the workpiece holding member 11.
The tool body 12 is made of a conductive metal, and a groove (not shown) is formed at the tip so that the ERG can be fixed.

The tool main body holding member 13 includes an outer cylinder 131 disposed outside the work holding member 11 and a tool main body support member 132 attached to one end of the outer cylinder 131 and having the tool main body 12 attached thereto. . An inner cylinder 121 that fixes the tool body 12 is disposed inside the outer cylinder 131. The outer cylinder 131 is fixed to the apparatus base 19 and integrally holds the work holding member 11 and the tool main body 12.
A spacer 18 is inserted between the outer cylinder 131 and the tool body support member 132 as thickness adjusting means for adjusting the gap dimension of the ER fluid filling space 14.

The ER fluid filling space 14 is formed in a gap between the polishing surface 10 </ b> A of the workpiece 10 and the tool body 12, and ER fluid supply means 15 for supplying ER fluid is connected to the ER fluid filling space 14.
The ER fluid supply means 15 is formed in the tool body 12, one end is opened in the ER fluid filling space 14, and the other end is formed in the outer surface of the tool body 12 and the side wall member 111. And a discharge passage 152 having one end opened to the ER fluid filling space 14 and the other end opened to the outer surface of the side wall member 111.
The discharge path 152 communicates with a hole 131A formed in the center of the side wall of the outer cylinder 131, and mainly functions as a path for discharging the excess ER fluid flowing into the ER fluid filling space 14 from the supply path 151 to the outside. To do.

  After filling with the ER fluid, a band heater (heating means) 16 is wound around the side surface of the outer cylinder 131, and the ER fluid filled in the ER fluid filling space 14 can be heated to be gelled (transformed into ERG). ing.

Below, the manufacturing method of the polishing tool raw material using the above-mentioned polishing tool raw material manufacturing apparatus 1 is demonstrated.
Although the manufacturing method of ERG is as having described in the said embodiment (1), when manufacturing the polishing tool provided with ERG, it carries out as follows.

The ER fluid before the gelation (formulation is shown in Table 1) flows from the supply path 151 of the ER fluid supply means 15 into the ER fluid filling space 14. Excess ER fluid is discharged from the discharge path 152.
Thereafter, the ER fluid in the ER fluid filling space 14 is heated at 90 ° C. for 6 hours by the band heater 16 wound around the outer cylinder 131 to complete the gelation, thereby obtaining ERG. The lower surface of the ERG has a shape corresponding to the shape (concave surface, convex surface, etc.) of the upper surface of the workpiece 10.
FIG. 3 shows the tool main body 12 separated from the outer cylinder 131, the tool main body holding member 13 and the inner cylinder 121, and then the ERG 122 facing upward. The ERG 122 is fixed to the tip of the tool body 12 to constitute the polishing tool material 200.
Here, as shown in FIG. 4, if abrasive grains 122 </ b> A are dispersed on the surface of the ERG 122 fixed to the tip of the tool body 12 to make the abrasive 12 </ b> A, the abrasive tool material 200 becomes the abrasive tool 300.
Here, as the abrasive grains, silica powder such as GC # 600, GC # 1200, GC # 2000, diamond slurry # 4000, or the like is preferably used.
When the abrasive grains 122A are already included in the ER fluid, the above-described polishing tool material 200 becomes the polishing tool 300 as it is simply by the ER fluid becoming the ERG 122 by the above-described gelation reaction. In this case, the polishing tool material manufacturing apparatus 1 also serves as the polishing tool manufacturing apparatus 100.

(3) Polishing apparatus and its operation FIG. 5 shows a cross-sectional view of the polishing apparatus 400 according to this embodiment.
The polishing apparatus 400 includes a workpiece holding member 11 that holds the workpiece 10, a polishing tool 300 that polishes the workpiece 10 by bringing the abrasive 12A into contact with the workpiece 10, a tool holding member 310 that holds the polishing tool 300, and the workpiece 10. Is configured to include a rotation driving means 450 that rotates and rotates a shaft about an axis substantially orthogonal to the polishing surface 10A, and a voltage application means 123 that applies a voltage to the polishing material 12A (ERG).
That is, the polishing apparatus 400 removes the tool body 12, the inner cylinder 121, the work 10, and the work holding member 11 from the polishing tool material manufacturing apparatus 1 or the polishing tool manufacturing apparatus 100 of FIG. Is.

  The work holding member 11 for fixing the work 10 is held around by a work holding rotating member 113, which are integrated. The work holding and rotating member 113 is rotatably held by the first sleeve 140 via the aerostatic bearing 113A.

Further, on the upper portion of the first sleeve 140, a second tool holding member 310 that holds the polishing tool 300 with the polishing material 12 </ b> A facing downward is held so as to be non-rotatable and slidable in the direction of the rotation axis of the workpiece 10. The sleeve 340 is fixed with bolts.
That is, the tool holding member 310 is suppressed in rotation by the rotation suppressing member 340A located at the upper part of the second sleeve 340, but is slidable in the vertical direction, so that it is integrated with the polishing tool 300, It will contact | abut to the workpiece | work 10 with the dead weight.

  The rotation driving means 450 includes a motor 450A, a pulley 451, a belt 452, and a pulley 453, and the workpiece holding rotating member 113, the workpiece holding member 11, and the workpiece 10 are integrated with the polishing surface 10A at a predetermined rotational speed. And rotate around a substantially orthogonal axis. And the surface of the workpiece | work 10 is grind | polished with the fixed grinding | polishing tool 300 (abrasive material 12A). Here, a predetermined torque may be set, and the voltage may be automatically raised or lowered according to the torque, or the voltage may be changed manually. When the voltage is increased, the ERG becomes harder, and when the voltage is lowered, the ERG becomes softer (original hardness).

  In FIG. 5, the motor 450 </ b> A is rotated together with the workpiece holding and rotating member 113 and the workpiece holding member 11 in the workpiece 10 positioned below the polishing apparatus 400, but the polishing tool 300 and the inner cylinder 121, the workpiece 10 and The workpiece holding member 11 may be upside down. That is, the polishing tool 300 may be rotated at the lower part and the workpiece 10 fixed at the upper part may be polished.

  The voltage applying means 123 for applying a voltage to the abrasive 12A (ERG) is inserted into the center of the tool holding member 310, one end is in contact with the polishing tool 300, and the other end is a power supply member (not shown). The first electrode 123A that is in contact with the second electrode 123B that is disposed at the center of the workpiece holding and rotating member 113, has one end in contact with the workpiece 10 and the other end in contact with the power supply member. The first electrode 123A and the second electrode 123B have different polarities, and are set such that, for example, the first electrode is a positive electrode and the second electrode is a negative electrode.

    According to the first embodiment as described above, the polishing apparatus 400 includes the polishing material 12A including the ERG 122 and the abrasive grains 122A in the polishing tool 300 that forms the core of the polishing apparatus 400. Therefore, the polishing using the characteristics of ERG is performed. The function can be demonstrated. That is, when the polishing tool 300 (abrasive 12A) is pressed against the surface of the workpiece 10, the ERG 122 at the tip is a gel having appropriate elasticity, so that the ERG 122 itself is deformed into a shape that follows the surface shape of the workpiece. Therefore, it is not always necessary to manufacture the tip portion (abrasive material 12A) of the polishing tool 300 according to the surface shape of the workpiece in advance.

  Further, in the polishing tool (material) manufacturing apparatuses 1 and 100, the ER fluid before gelation has a shape that follows the surface of the workpiece 10 and gels while maintaining the shape. A polishing tool 300 having an optimal polishing shape can be provided. That is, conventionally, when polishing a mold for molding plastic lenses, etc., it is necessary to make the surface of the abrasive convex or concave, and the abrasive had to be changed according to each case, According to the present embodiment, since the surface of the ERG 122 has a shape that follows the polishing surface 10A of the workpiece 10, an abrasive 12A that automatically matches the surface shape of the mold or the like is obtained. .

In addition, since the polishing tool 300 includes the abrasive 12A in which the abrasive grains are held on the surface layer portion of the ERG, the ER effect is directly reflected on the movement of the abrasive grains when contacting the workpiece 10. Polishing can be performed efficiently.
That is, since the hardness of the ERG can be changed according to the surface roughness of the workpiece 10, when the surface roughness of the workpiece is large, the ERG is hardened by applying a high voltage to the ERG. When the degree decreases, polishing can be efficiently performed by lowering the voltage applied to the ERG to soften it.

  Further, since the polishing apparatus 400 includes the second sleeve 340 that holds the tool holding member 310 so as to be slidable in the direction of the rotation axis of the workpiece holding member 11, the polishing tool 300 is always used for polishing the workpiece 10. The workpiece 10 is contacted with a constant pressure (self-weight). Therefore, the contact pressure fluctuation during polishing is reduced, and the polishing operation can be performed stably.

  In the polishing apparatus 400, since the dispersed phase particles are dispersed in the ERG 122 of the polishing tool 300, the dispersed phase particles do not settle and the ER effect can be stably obtained for a long period of time.

[Second Embodiment]
Also in the second embodiment, the manufacturing method and properties of ERG are the same as those in the first embodiment.
In the first embodiment, the polishing tool is manufactured and then incorporated into the polishing apparatus. However, in the second embodiment, the polishing tool (material) manufacturing apparatus and the polishing apparatus are integrated. In addition, the same code | symbol is attached | subjected to the member with the same function as 1st Embodiment, and description is abbreviate | omitted.

FIG. 6 shows a cross-sectional view of the polishing apparatus 500.
The polishing apparatus 500 includes a workpiece holding member 511 that holds the workpiece 10 from the bottom surface, a polishing tool 520 that polishes the workpiece 10, a tool holding member 530 that rotatably holds a tool body of the polishing tool 520, and a polishing tool 520. Rotation driving means 450 for rotating the tool body about an axis substantially orthogonal to the polishing surface (not shown), and in a gap formed between the polishing surface of the workpiece 10 and the tool body of the polishing tool 520 An ER fluid filling space 14 for filling the ER fluid into the ER fluid, an ER fluid supply means 15 for supplying the ER fluid to the ER fluid filling space 14, and heating the ER fluid filled in the ER fluid filling space 14 to ERG Heating means 16 and voltage applying means 123 (123A, 123B) for applying a voltage to the ERG.
Here, the tool holding member 530 in the second embodiment has the functions of the outer cylinder 131 (FIG. 1) and the tool holding member 310 (FIG. 5) of the tool main body holding member 13 in the first embodiment.
Further, the tool body portion of the polishing tool 520 is made of metal like the workpiece 10 and is conductive. Further, the work holding member 511 and the tool holding member 530 are made of a non-conductive substance such as bakelite.

In the first embodiment, the polishing tool 300 is manufactured by the dedicated polishing tool (material) manufacturing apparatuses 1 and 100. However, in the second embodiment, the polishing apparatus 500 also serves as the polishing tool (material) manufacturing apparatus. .
Specifically, the polishing tool 520 is manufactured as follows.
First. The ER fluid before gelation (formulation is shown in Table 1) is poured into the ER fluid filling space 14.
Thereafter, the ER fluid inside the ER fluid filling space 14 is heated at 90 ° C. for 6 hours to complete the gelation, and ERG is obtained. The lower surface of the ERG has a shape corresponding to the shape (concave surface, convex surface, etc.) of the upper surface of the workpiece 10.

Next, the tool main body is extracted from the tool holding member 530 while the ERG is held by the tool main body (before becoming the polishing tool 520). Then, abrasive particles are dispersed on the surface of the ERG held by the tool body to obtain a polishing tool 520.
The polishing tool 520 becomes a main body portion of the polishing apparatus 500 after being inserted into the tool holding member 530 of the polishing apparatus 500.

  The rotation driving means 450 of the polishing apparatus 500 transmits the power from the motor 450A to the polishing tool 520 via the belt 452, and rotates the polishing tool 520 at a predetermined rotation speed. Then, the surface of the workpiece 10 is polished by the polishing tool 520.

According to the polishing apparatus 500 of the second embodiment as described above, the same effect as that of the first embodiment can be obtained.
Further, since the polishing apparatus 500 also serves as a polishing tool (material) manufacturing apparatus, the manufacturing and polishing operations of the polishing apparatus 500 are simple and advantageous from the standpoint of apparatus manufacturing cost.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention. In addition, the specific structure, shape, and the like when carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

  In this embodiment, since the workpiece 10 to be polished is a conductive mold, so-called both-side electrodes can be used. On the other hand, for example, positive and negative electrodes having different polarities can be arranged in the vicinity of the abrasive of the nonconductive tool body, and a voltage can be applied to the ERG by a so-called one-side electrode method. For example, when a non-conductive material such as plastic is directly polished, a one-sided electrode 800 as schematically shown in FIG. 7 may be used. The one-side electrode 800 is configured by alternately arranging positive electrodes 800A and negative electrodes 800B, and a voltage can be applied from the opposite side to the ERG 900 that is in contact with the non-conductive workpiece 10 '. Since the hardness of the ERG can be controlled by applying a voltage to one side of the ERG 900, it is suitable when the workpiece 10 'is an electrically insulating material such as a plastic lens.

  Further, as shown in the polishing apparatus 600 of FIG. 8, unlike the polishing apparatus 500 of the second embodiment, the driving force of the motor 450A may be directly transmitted to the polishing tool 520 through the coupling 450B. In the coupling 450B, the rotating shaft of the motor 450A and the polishing tool 520 are fixed by a bolt 450B1 and a key 450B2. The motor 450A is fixed by a frame 19A of the apparatus base 19 on which the polishing apparatus 600 is placed. Here, the work holding member 511 and the tool holding member 530 have an integral structure.

Further, as shown in the polishing apparatus 700 of FIG. 9, the vertical movement of the polishing tool 520 is constrained by the coupling 450C, and a piezoelectric element (PZT) 540 is disposed below the work holding member 511, and its displacement Thus, the pressing force of the polishing tool 520 on the workpiece 10 may be controlled. According to the polishing apparatus 700, more precise polishing is possible by controlling the pressing force at the time of polishing in addition to the ERG hardness control by voltage. In the coupling 450C, the rotating shaft of the motor 450A and the polishing tool 520 are fixed by a bolt 450C1 and a key 450C2.
In addition to the motor driving method as described above, a method of rotating a polishing tool or a workpiece manually by providing a manual handle or the like may be adopted as the rotation driving means.

  The polishing apparatus of the present invention can be suitably used for polishing a mold used for injection molding of a plastic lens or the like.

1 is a cross-sectional view of a polishing tool material manufacturing apparatus according to a first embodiment of the present invention. The disassembled perspective view of the polishing tool raw material manufacturing apparatus in the said embodiment. The perspective view of the grinding | polishing tool raw material in the said embodiment. The perspective view of the grinding | polishing tool in the said embodiment. Sectional drawing of the grinding | polishing apparatus in the said embodiment. Sectional drawing of the grinding | polishing apparatus which concerns on 2nd Embodiment of this invention. The schematic diagram of the one-side electrode in other embodiment of this invention. Sectional drawing of the grinding | polishing apparatus in other embodiment of this invention. Sectional drawing of the grinding | polishing apparatus in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Polishing tool raw material manufacturing apparatus, 10 ... Work, 11,511 ... Work holding member, 12 ... Tool main body, 12A ... Polishing material, 13 ... Tool main body holding member, 14 ... Fluid filling space, 15 ... Fluid supply means, 16 DESCRIPTION OF SYMBOLS ... Band heater (heating means), 18 ... Spacer (thickness adjusting means), 100 ... Polishing tool manufacturing apparatus, 123 ... Voltage application means, 140 ... First sleeve, 200 ... Polishing tool material, 300, 520 ... Polishing tool, 310, 530 ... Tool holding member, 340 ... Second sleeve, 400, 500, 600, 700 ... Polishing apparatus

Claims (6)

A polishing apparatus for polishing a workpiece having a predetermined shaped polishing surface,
A workpiece holding member for holding the workpiece;
A polishing tool comprising an abrasive comprising an electrorheological gel (hereinafter also referred to as “ERG”) and abrasive grains, and polishing the workpiece by bringing the abrasive into contact with the workpiece;
A tool holding member for holding the polishing tool;
Rotation driving means for rotating the polishing tool or the workpiece around an axis substantially orthogonal to the polishing surface;
A polishing apparatus comprising voltage applying means for applying a voltage to the ERG. The polishing apparatus according to claim 1,
A first sleeve that holds the workpiece holding member rotatably about a substantially vertical axis in a posture with the polishing surface facing upward;
A second sleeve that is positioned above the first sleeve and holds the tool holding member in a posture in which the abrasive is faced down so that the tool holding member cannot rotate and is slidable in the rotation axis direction of the workpiece holding member;
The polishing apparatus, wherein the rotation driving means rotates the work holding member. The polishing apparatus according to claim 1,
A third sleeve for holding the tool holding member rotatably about a substantially vertical axis in a posture with the abrasive facing upward;
A fourth sleeve that is positioned above the third sleeve and holds the work holding member in a posture in which the polishing surface is faced down so that the work holding member cannot rotate and is slidable in the rotation axis direction of the tool holding member;
The polishing apparatus, wherein the rotation driving means rotates the tool holding member. In the polishing apparatus according to claim 2 or 3,
The polishing tool is composed of a conductive tool body and the abrasive provided at the tip of the tool body,
The voltage applying means is inserted in the center of the tool holding member, one end is in contact with the tool body, and the other end is in contact with the power supply member, and one end is arranged in the center of the work holding member. A second electrode in contact with the workpiece and having the other end in contact with the power supply member,
A polishing apparatus, wherein the workpiece is conductive. In the polishing apparatus according to any one of claims 2 to 4,
A ball bearing or an aerostatic bearing is provided between the workpiece holding member and the first sleeve, or between the tool holding member and the third sleeve. Polishing equipment. The polishing apparatus according to claim 1, wherein
A polishing apparatus comprising displacement drive means for displacing one of the workpiece holding member and the tool holding member in an axial direction substantially orthogonal to the polishing surface.

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