JP2006281424A - Abrasive, polishing tool, polishing device, manufacturing method for abrasive, manufacturing method for polishing tool, and polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abrasive, a polishing tool, and a polishing device, which are excellent in polishing capability, as well as the manufacturing method for the abrasive, manufacturing method for the polishing tool, and polishing method using electroviscous fluid (ER fluid) characterized by stabilized electroviscous effects and excellent preservation stability. <P>SOLUTION: Because the abrasive is composed of electric rheorogiegel (ERG) 12 and abrasive grains 12A, it is possible to change the hardness of ERG in accordance with the surface roughness of work (object for processing), and to carry out polishing efficiently. Furthermore, because abrasive grains do not disperse or settle out in ERG, electric rheorogiegel property is not reduced, so that the property of the abrasive is maintained for a long period of time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an abrasive, a polishing tool, a polishing apparatus, an abrasive manufacturing method, an abrasive tool manufacturing method, and an abrasive method.

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 tool 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 tool of Patent Document 1, it is necessary to prepare in advance an abrasive 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 material, a polishing tool, a polishing apparatus, a polishing material manufacturing method, and a polishing tool manufacturing method that are excellent in freedom and polishing ability not affected by the shape of an object to be polished using an ER fluid. And providing a polishing method.

The abrasive of the present invention is characterized by containing an electrorheological gel (hereinafter also referred to as “ERG”) and abrasive grains.
Here, ERG is a gel substance in which the ER fluid has lost its fluidity. Further, “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 used. Can be obtained.

According to the present invention, since the abrasive contains ERG and abrasive grains, the function as an abrasive utilizing the characteristics of ERG can be exhibited. In other words, when ERG is pressed against the workpiece surface with a constant force, the ERG itself deforms into a shape that follows the workpiece surface shape, so there is no need to manufacture the abrasive material according to the workpiece surface shape in advance. The degree of freedom is very high.
Also, since the hardness of the ERG can be changed according to the surface roughness of the workpiece (workpiece), when the surface roughness of the workpiece is large, the ERG is hardened by applying a high voltage to the ERG. When the surface roughness of an object becomes small, polishing can be efficiently performed by lowering the voltage applied to ERG and softening it.
Furthermore, since the abrasive grains do not diffuse or 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, as a method of applying a voltage to the ERG, two methods of a double-sided electrode and a single-sided electrode can be considered. The double-sided electrode is a method in which voltage is applied from both sides across the ERG, and the work itself is one electrode for the ERG. On the other hand, the one-side electrode is a method of applying a voltage by arranging positive and negative electrodes on one side of the ERG.
For example, when the symmetry of polishing is conductive, such as a mold used for injection molding of a plastic lens or the like, both side electrodes and one side electrodes can be used. On the other hand, when polishing a non-conductive material such as a plastic lens, a voltage can be applied to the ERG by using one side electrode.
That is, this abrasive can be used to polish the lens surface directly or to polish a lens molding die.

In the abrasive of the present invention, the abrasive grains are preferably held on the surface layer portion of the 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.

In the present invention, it is preferable that the liquid component in the ERG is an electrically insulating medium, and dispersed phase particles are dispersed in the electrically insulating medium.
According to the present invention, since the liquid component in the ERG is an electrically insulating medium, the ER effect is suitably expressed without current flowing when a voltage is applied. Further, since the dispersed phase particles are dispersed in the electrically insulating medium, the ER effect can be stably obtained for a long time without the dispersed phase particles being settled.

In the present invention, ERG preferably has a structure in which an electrically insulating medium and dispersed phase particles are dispersed in a crosslinked polysiloxane.
According to the present invention, since the basic skeleton of ERG is a polysiloxane crosslinked body, a large amount of an electrically insulating medium can be held in the skeleton, which is suitable for the production of ERG.

In the present invention, the polysiloxane crosslinked product is preferably a hydrosilylation reaction product of a hydrogen silicone and an unsaturated group-containing compound.
According to the present invention, since the polysiloxane crosslinked product is a hydrosilylation reaction product of a hydrogen silicone and an unsaturated group-containing compound, the production is easy.

The polishing tool of the present invention is characterized in that the above-mentioned abrasive is fixed to a tool body.
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 side, etc. It means the state fixed to.
According to the present invention, since the abrasive is fixed to the tool body, the above-described effects can be suitably achieved when the abrasive is used as an abrasive tool without peeling from the tool body.

The polishing apparatus of the present invention includes the above-described polishing tool.
According to the present invention, since the polishing apparatus includes the above-described polishing tool, the above-described effects can be suitably achieved as the polishing apparatus.

In the manufacturing method of the abrasive in the present invention, after the electrorheological fluid is gelled in contact with the surface to be polished of the workpiece, the contact surface of the electrorheological fluid after gelation with the workpiece is processed. And the abrasive grains are dispersed on the contact surface.
According to the production method of the present invention, after producing ERG, the abrasive can be obtained by a simple method of dispersing abrasive grains on the surface of the ERG. Furthermore, since the surface of the ERG has a shape corresponding to the planned polishing surface of the workpiece (workpiece), polishing can be performed extremely efficiently. For example, when a plastic lens molding die is polished, the surface of the abrasive must be convex or concave, and the abrasive must be replaced according to each case. According to this, since an abrasive material automatically matched to the surface shape of the mold can be obtained, it is extremely convenient.

The present invention relates to a method for producing an abrasive material comprising an electrorheological fluid containing abrasive grains as an abrasive material, wherein the electrorheological fluid is subjected to gelation in contact with a planned polishing surface of a workpiece. The contact surface of the gelled electrorheological fluid with the workpiece is dissociated from the workpiece.
According to the production method of the present invention, since the abrasive grains are already contained in the electrorheological fluid, the electrorheological fluid can be directly used as an abrasive just by gelling it into ERG.

The present invention relates to a method for manufacturing a polishing tool having an abrasive at the tip, wherein the abrasive is gelled in a state where an electrorheological fluid is in contact with a planned polishing surface of a workpiece, and after the gelation The contact surface of the electrorheological fluid with the workpiece is dissociated from the workpiece, and abrasive grains are dispersed on the contact surface.
According to the present invention, since gelation is performed in a state where the electrorheological fluid is in contact with the surface to be polished of the workpiece, a polishing tool can be manufactured along the surface shape of the workpiece, and the polishing efficiency is improved. To do.

The present invention is a method for manufacturing a polishing tool provided with an abrasive at the tip, wherein the abrasive is gelated in a state where an electrorheological fluid containing abrasive grains is in contact with a surface to be polished of a workpiece. The contact surface of the gelled electrorheological fluid with the workpiece is dissociated from the workpiece.
According to the present invention, since the abrasive grains are already contained in the electrorheological fluid, the electrorheological fluid can be made into an abrasive only by gelling it into ERG, and the abrasive is provided at the tip. Therefore, it is simple as a method for manufacturing an abrasive tool. Furthermore, since gelation is performed in a state where the electrorheological fluid is in contact with the surface to be polished of the workpiece, a polishing tool can be manufactured along the surface shape of the workpiece, and the polishing efficiency is improved.

The polishing method of the present invention is characterized by polishing using a polishing material containing ERG and abrasive grains while controlling the voltage applied to the ERG.
According to the present invention, polishing is performed while controlling the voltage applied to the ERG, whereby the hardness of the ERG can be controlled, and polishing according to the surface roughness of the workpiece (workpiece) becomes possible.

Hereinafter, embodiments of the present invention will be described in detail.
(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 affinity ER composite particles are described in, for example, Japanese Patent Application No. 11-202351, Japanese Patent Application No. 8-274920, Japanese Patent Application No. 7-231828, and the like. Has been.

  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.)
Examples of the alkyl group represented by R ₁ include a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, a dodecyl group, and the like, and an aralkyl group includes, for example, a benzyl group, a phenethyl group, and the like. 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, A 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 linear or branched alkyl group having a valence of 3 or more, and includes, for example, a methynyl group, an ethynyl group, a propynyl group, a butynyl group, an octynyl group, and a dodecynyl group. 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, methyleneoxyethynyl, methyleneoxypropynyl, ethyleneoxypropynyl, methyleneoxyethyleneoxymethynyl, ethyleneoxyethyleneoxyethynyl, propyleneoxyethyleneoxypropynyl , 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. Further, 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) Abrasive manufacturing method [Configuration of abrasive manufacturing apparatus]
FIG. 1 is a sectional view of an abrasive manufacturing apparatus 1 for manufacturing an abrasive according to this embodiment, and FIG. 2 is an exploded perspective view thereof.

The abrasive manufacturing apparatus 1 is formed at the center of the ERG fixing member 12, the workpiece holding side wall member 11, the ERG fixing member 12 that is a conductive member that can be inserted into and removed from the workpiece holding side wall member 11, and is rotatable. ER fluid injection portion 13, workpiece holding base member 14 that supports workpiece 10, clearance portion 15 formed between ERG fixing member 12 and workpiece 10, and a clearance adjustment member that adjusts the clearance of clearance portion 15 16, a discharge port 17 formed on the side surface of the work holding side wall member 11, a voltage application unit 18 provided in the work holding side wall member 11 and the ERG fixing member 12, and an apparatus base 19. .
Here, in the present embodiment, the abrasive manufacturing apparatus 1 itself has no heating device. When heating for gelation, for example, the ER fluid held in the clearance 15 can be easily gelled by placing it on a heating substrate (hot plate) at a predetermined temperature.

As will be described later, the abrasive material manufacturing apparatus 1 is a polishing tool manufacturing apparatus and also a main body of the polishing apparatus.
Moreover, the workpiece | work 10 which exists in the inside of the workpiece | work holding | maintenance side wall member 11 is a grinding | polishing target object, for example, is a metal mold | die used for injection molding, such as a plastic lens. The workpiece 10 only needs to be conductive, and the shape of the surface is not particularly problematic. The workpiece holding side wall member 11 is a cylindrical structure (sleeve) for holding the workpiece 10.

  Although details will be described later, the ERG fixing member 12 is a conductive structure that also serves as a main body of the polishing tool after adsorbing and holding ERG. (When this ERG fixing member 12 becomes a polishing tool, it rotates at a high speed in the workpiece holding side wall member 11.) Further, an ER fluid that is a flow path for pouring ER fluid into the center of the ERG fixing member 12 An injection part 13 is formed.

  The workpiece holding base member 14 is a member that supports the workpiece 10 from below. The workpiece holding base member 14 preferably has an uneven portion that fits with the workpiece 10 so that the workpiece 10 does not rotate during polishing.

The clearance portion 15 is a space for pouring ER fluid into a gel and is formed by the above-described workpiece holding side wall member 11, ERG fixing member 12, and workpiece (workpiece) 20.
The clearance adjustment member 16 is a donut-shaped spacer disposed between the upper surface of the workpiece holding side wall member 11 and the flange portion of the ERG fixing member 12, and the thickness of the clearance portion 15 is changed by changing the thickness thereof. That is, the thickness of the ERG to be manufactured can be changed.

The discharge port 17 is a flow path formed in the side wall of the work holding side wall member 11 and is used when discharging excess ER fluid to the outside.
The voltage application unit 18 is arranged in a voltage application unit positive electrode 18A arranged in a screw hole formed through the side wall surface of the workpiece holding side wall member 11 and a screw hole formed in the ER fluid injection unit 13. And a voltage application unit negative electrode 18B. The voltage application unit positive electrode 18 </ b> A has an electric wire arranged in the center hole, and the tip electrode is pressed against the workpiece 10. The voltage application unit negative electrode 18B is configured to energize the rotating ERG fixing member 12 with a brush. These are used when the polishing apparatus is operated, and details will be described later.
The workpiece holding side wall member 11 and the workpiece holding base member 14 are fixed to the apparatus base 19 with bolts 191. For the workpiece holding side wall member 11, the workpiece holding base member 14, and the apparatus base 19, an electrically insulating material made of synthetic resin such as bakelite or ceramic is used.

[Manufacture of abrasives and polishing tools]
Below, the manufacturing method of the abrasive | polishing material using the above-mentioned abrasive | polishing material manufacturing apparatus 1 is demonstrated using FIG. 1, FIG. The manufacturing method of ERG is as described in the embodiment (1), but when manufacturing an abrasive with ERG, it is performed as follows.

The ER fluid before gelation (formulation is shown in Table 1) is poured from the ER fluid injection part 13 of the abrasive manufacturing apparatus 1 into the clearance part 15. Excess ER fluid is discharged from the outlet 17.
Thereafter, the ER fluid in the clearance portion 15 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 ERG fixing member 12 is extracted from the workpiece holding side wall member 11 while the ERG is adsorbed and held by the ERG fixing member 12.
Then, abrasive grains are dispersed on the surface of the ERG adsorbed and held by the ERG fixing member 12.
As shown in FIG. 3, the ERG fixing member 12 includes a polishing material 12 </ b> A made of ERG and abrasive grains at the tip, and constitutes a polishing tool 100. As will be described later, the polishing tool 100 becomes a main body portion of the polishing apparatus after being inserted into the workpiece holding side wall member 11 of the abrasive manufacturing apparatus 1.

(3) Polishing apparatus and operation thereof FIG. 4 schematically shows a polishing apparatus 200 including the abrasive manufacturing apparatus 1.
The polishing apparatus 200 includes an abrasive material manufacturing apparatus 1, a torque sensor 2, a high voltage power supply unit 3, a motor 4, a power transmission unit 5, and a control unit 6.
The aforementioned polishing tool 100 is rotatably inserted into the workpiece holding side wall member 11 of the abrasive manufacturing apparatus 1.

The torque sensor 2 measures the torque when the abrasive 12 </ b> A (the polishing tool 100) rotates and transmits it to a PC (Personal Computer) as the control means 6. The state of polishing can be confirmed by this change in torque. The PC 6 is connected to the torque sensor 2 and the high-voltage power supply unit 3 via the A / D conversion board 61 and the resistor 62.
The high-voltage power supply unit 3 applies a high DC voltage to the ERG via the voltage application unit positive electrode 18A and the voltage application unit negative electrode 18B, and exhibits the ER effect. The voltage application unit positive electrode 18 </ b> A is electrically connected to the workpiece 10 through a hole formed in the workpiece holding side wall member 11. The voltage application unit negative electrode 18B is connected to the tip of the ER fluid injection unit 13 formed in the ERG fixing member 12.

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).
The motor 4 rotates the polishing tool 100 through a power transmission means (belt) 5 at a predetermined rotational speed. Then, the surface of the workpiece 10 is polished by the abrasive 12A.

According to the present embodiment as described above, it is possible to obtain the abrasive 12A, the polishing tool 100, and the polishing apparatus 200 including these, making use of the characteristics of ERG.
That is, since the ER fluid before gelation follows the workpiece surface and gels while maintaining the shape, it is possible to manufacture the abrasive 12A and the polishing tool 100 having an optimum polishing shape for each workpiece. it can.
Further, when the abrasive 12A is pressed against the surface of the workpiece 10, since the ERG is a gel having appropriate elasticity, the ERG itself is deformed into a shape following the surface shape of the workpiece. It is not necessary to manufacture in advance according to the surface shape of the workpiece, and the degree of freedom in manufacturing the abrasive becomes very high.

Further, since the polishing tool 100 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.
Furthermore, since the dispersed phase particles are dispersed in the ERG, the dispersed phase particles do not settle and the ER effect can be stably obtained for a long period of time.

Moreover, in the manufacturing method of the abrasive | polishing material in this embodiment, after manufacturing ERG, an abrasive | polishing material can be obtained by the simple method of sprinkling an abrasive grain on the surface of the ERG.
Furthermore, since the surface of the ERG has a shape corresponding to the planned polishing surface of the workpiece 10, polishing can be performed extremely efficiently. For example, when polishing a mold for molding a plastic lens, it is necessary to make the surface of the polishing material convex or concave, and the polishing material must be replaced according to each case. According to the method, since an abrasive material automatically adapted to the surface shape of the mold can be obtained, it is very convenient.

  The polishing method of this embodiment is characterized in that polishing is performed using a polishing material containing ERG and abrasive grains while controlling the voltage applied to the ERG. Therefore, the hardness of the ERG can be controlled by controlling the voltage applied to the ERG, and appropriate polishing according to the surface roughness of the workpiece 10 becomes possible.

  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.

  For example, in the above-described embodiment, ERG is produced by gelling the ER fluid in the clearance part 15, but after producing ERG outside the apparatus in advance, abrasive particles may be dispersed to form an abrasive. .

  In this embodiment, since the workpiece 10 to be polished is a conductive mold, both side electrodes can be used. On the other hand, for example, when a non-conductive material such as plastic is directly polished, a one-side electrode 500 as schematically shown in FIG. 5 may be used. The one-side electrode 500 is configured by alternately arranging positive electrodes 500 </ b> A and negative electrodes 500 </ b> B, and a voltage can be applied to the ERG 700 in contact with the nonconductive workpiece 600 from the opposite side.

Hereinafter, the present invention will be described in more detail with reference to polishing examples, but the present invention is not limited to the contents of these examples.
[Examples 1 to 4]
(Abrasive properties and polishing conditions)
In each example, specific conditions other than those described in the above-described embodiment are as follows.
ERG thickness: 0.5mm (ERG is a disk shape)
Rotation speed: 50rpm
Work: SUS420

In addition, the abrasive grains used in each example are as follows Example 1: GC # 600
Example 2: GC # 1200
Example 3: GC # 2000
Example 4: Diamond slurry # 4000

  In each example, at a voltage of 2 KV / mm, each workpiece (SUS420) was polished until the arithmetic average roughness (centerline average roughness) Ra reached a steady state, and then Ra reached a steady state at 1 KV / mm. Polishing was performed until Ra reached a steady state with no electric field.

(Result)
6 to 9 show changes in the arithmetic average roughness (centerline average roughness) of each workpiece surface in Examples 1 to 4 described above. In either case, it was confirmed that the surface of the workpiece could be satisfactorily polished and that the accuracy of the polished surface could be adjusted by changing the voltage.
In FIGS. 6 to 9, the figure (A) shows the transition of Ra at the center of the workpiece, and the figure (B) shows the transition of Ra on the outer periphery of the workpiece. The polishing efficiency at the center of the workpiece was as good as that at the periphery of the workpiece, although the polishing rate was slower than that at the periphery of the workpiece.

FIG. 10 shows a mechanism (estimation) for exhibiting the ER effect. When there is no electric field (FIG. 10A), the electrode 7 is supported by the ER particles 81 constituting the ERG 8, but when an electric field is applied (FIG. 10B), the ER particles 81 enter the back and the gel part. 82 is considered to adhere to the electrode 7.
Next, as shown in FIG. 11, when the abrasive grains 83 are present on the surface of the gel portion 82, many ER particles 81 having a high slip characteristic are present on the surface when there is no electric field. Since it is not fixed and slips easily in the gap between the electrode 7 and the ERG 8, the polishing efficiency is poor. However, it is considered that when a high voltage is applied, the ER particles 81 enter the gel, and at the same time, the gel portion 82 works to push up the abrasive grains 83 and presses the abrasive grains 83 against the electrode 7. Further, since the viscosity and adhesive force of the gel part 82 are greatly increased and the abrasive grains 83 are strongly fixed, it is estimated that the higher the voltage, the greater the polishing force on the electrode 7 (corresponding to the workpiece 10 of the present application). Is done.

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

Sectional drawing of the abrasives manufacturing apparatus which concerns on embodiment of this invention. The disassembled perspective view of the abrasives manufacturing apparatus in the said embodiment. The perspective view of the grinding | polishing tool in the said embodiment. The schematic diagram of the grinding | polishing apparatus in the said embodiment. The schematic diagram of the one-side electrode in other embodiment. The figure which shows transition of Ra in the Example of this invention (GC # 600) The figure which shows transition of Ra in the Example of this invention (GC # 1200). The figure which shows transition of Ra in the Example of this invention (GC # 2000) The figure which shows transition of Ra in the Example of this invention (diamond slurry # 4000). The figure which estimated the mechanism of ERG effect expression in the Example of this invention. The figure which estimated the mechanism of the effect expression of the abrasives in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Abrasive material manufacturing apparatus, 10 ... Work, 11 ... Work holding side wall member, 12 ... ERG adhering member, 12A ... Abrasive material, 13 ... ER fluid injection part, 14 ... Work holding base member, 15 ... Clearance part, 16 DESCRIPTION OF SYMBOLS ... Clearance adjustment member, 17 ... Discharge port, 18 ... Voltage application part, 19 ... Device base, 81 ... ER particle, 82 ... Gel part, 83 ... Abrasive grain, 100 ... Polishing tool, 200 ... Polishing apparatus

Claims (12)

  An abrasive comprising electrorheological gel (hereinafter also referred to as “ERG”) and abrasive grains. In the abrasive according to claim 1,
An abrasive, wherein the abrasive grains are held on a surface layer portion of the ERG. In the abrasive according to claim 1 or 2,
A polishing material, wherein the liquid component in the ERG is an electrically insulating medium, and dispersed phase particles are dispersed in the electrically insulating medium. In the abrasive according to any one of claims 1 to 3,
An abrasive characterized in that the ERG has a structure in which an electrically insulating medium and dispersed phase particles are dispersed in a crosslinked siloxane. In the abrasive according to claim 4,
An abrasive characterized in that the polysiloxane crosslinked product is a hydrosilylation reaction product of hydrogen silicone and an unsaturated group-containing compound.   A polishing tool, wherein the abrasive according to any one of claims 1 to 5 is fixed to a tool body.   A polishing apparatus comprising the polishing tool according to claim 6. A method for producing an abrasive material that gels an electrorheological fluid into an abrasive material,
Gelling in a state where the electrorheological fluid is in contact with the surface to be polished of the workpiece,
The contact surface of the electrorheological fluid after gelation with the workpiece is dissociated from the workpiece,
A method for producing an abrasive, characterized in that abrasive grains are dispersed on the contact surface. A method for producing an abrasive material comprising gelling an electrorheological fluid containing abrasive grains into an abrasive material,
Gelling in a state where the electrorheological fluid is in contact with the surface to be polished of the workpiece,
A method for producing an abrasive, wherein the contact surface of the gelled electrorheological fluid with the workpiece is dissociated from the workpiece. A method for manufacturing a polishing tool provided with an abrasive at the tip,
The abrasive is
Gelling with the electrorheological fluid in contact with the planned polishing surface of the workpiece,
The contact surface of the electrorheological fluid after gelation with the workpiece is dissociated from the workpiece,
A method for producing a polishing tool, characterized in that abrasive grains are dispersed on the contact surface. A method for manufacturing a polishing tool provided with an abrasive at the tip,
The abrasive is
Gelation is performed with the electrorheological fluid containing abrasive grains in contact with the planned polishing surface of the workpiece,
A method for producing a polishing tool, wherein the contact surface of the electrorheological fluid after gelation with the workpiece is dissociated from the workpiece.   A polishing method comprising polishing using a polishing material containing ERG and abrasive grains while controlling a voltage applied to the ERG.

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