JP2006239803A - Electrochemical machining electrode tool tool and manufacturing method for it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical machining electrode tool and a manufacturing method for it, attaining very high adhesion of an insulating material and an electrode tool base material, whereby even in a long-time use, electrolyte will not permeate into an interface between the insulating material and the electrode tool base material to maintain high accuracy over a long period of time, and also dispensing with an insulating material filling tool for insulating resin mold to facilitate manufacture. <P>SOLUTION: This electrochemical machining electrode tool includes: a conductive pattern formed by a projecting part 5 to 50 μm high, in which the electrode tool base material is exposed; and an insulating thin film formed of deposited polymer resin or deposited resin 5 to 50 μm provided on the surface of the electrode tool base material outside of the conductive pattern. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an electrode tool for electrolytic machining used for electrolytic machining and a manufacturing method thereof, and more specifically, the accuracy of electrolytic machining of a dynamic pressure groove in a fluid bearing can be performed with high accuracy over a long period of time. The present invention relates to an electrode tool for electrolytic processing with a high level and a method for manufacturing the electrode tool with a small number of manufacturing steps.

As a typical structure of a fluid dynamic pressure bearing used in a hard disk drive or the like, for example, a rotary shaft with a flange, and a radial dynamic pressure groove is formed on an inner peripheral surface to which the rotary shaft is fitted, and one end surface of the flange A hollow cylindrical sleeve in which a thrust dynamic pressure groove is formed on the end surface facing the inner surface, and a disk-shaped sleeve that forms a thrust dynamic pressure groove on the inner end surface facing the other end surface of the flange and closes one opening of the sleeve. Examples include a thrust plate and a lubricating oil filled in a minute gap between the outer peripheral surface of the rotating shaft, the inner peripheral surface of the sleeve, and the inner end surface of the thrust plate. Conventional electrolytic machining for simultaneously machining a radial dynamic pressure groove and a thrust dynamic pressure groove on a sleeve of such a fluid dynamic pressure bearing is performed by a method as shown in FIG. 1, for example. That is, the outer periphery of the other end of the sleeve 1 having an inner diameter whose one end is expanded is held by an air chuck (not shown), and the electrode tool 2 for electrolytic processing is inserted into the inner diameter of the sleeve 1 from the expanded inner diameter. . The electrode tool 2 has a small diameter portion 2c and a large diameter portion 2d and moves up and down integrally with a stopper 3 made of urethane resin. A conductive pattern 2a corresponding to the radial dynamic pressure groove and a conductive pattern 2b corresponding to the thrust dynamic pressure groove are formed on the outer peripheral surface of the small diameter portion 2c and the step between the small diameter portion 2c and the large diameter portion 2d, respectively. Yes. By pressing the end face of the stopper 3 tightly against the end face of the sleeve 1, the electrode tool 2 is axially positioned with respect to the sleeve 1, and the gap between the outer face of the electrode tool 2, the inner face of the stopper 3, and the inner face of the sleeve 1. As a result, the flow path 5 of the electrolytic solution 4 is formed. The electrolytic solution 4 is supplied from the upper part of the stopper 3 and is discharged from the lower end surface of the sleeve 1 through the flow path 5. When a DC pulse current is allowed to flow between the inner surface of the sleeve 1 and the surfaces of the conductive patterns 2a and 2b of the electrode tool 2 through the electrolytic solution 4 while supplying the electrolytic solution 4, the conductivity of the inner surface of the sleeve 1 is increased. Only a limited surface facing the surface of the pattern is dissolved electrochemically, and a radial dynamic pressure groove 1a and a thrust dynamic pressure groove 1b are formed on the inner surface of the sleeve 1, respectively. The general minimum groove width of these dynamic pressure grooves is 40 to 50 μm.

In addition, as shown in FIG. 2, the electrolytic machining for forming the thrust dynamic pressure groove 10a in the thrust plate 10 of the fluid dynamic pressure bearing also presses the stopper 12 against the thrust plate 10 to conduct electricity corresponding to the thrust dynamic pressure groove 10a. After positioning the electrode tool 11 having the pattern 11a, it can be performed in the same manner. In any case, it is necessary to completely insulate the surface other than the conductive pattern with a non-conductive resin or the like. If the insulation is lost locally, stray current is generated from it, and if the insulation film is thin and the insulation is not sufficient as a whole, a transmission current is generated in a wide range, and other than the desired region The accuracy of the dynamic pressure groove that is melted to the surface and is electrolytically processed deteriorates.

As shown in the schematic diagram of FIG. 3, the conventional electrode tool for dynamic pressure groove machining used for the above-described electrolytic machining is manufactured by the following method.
1) First, deep engraving processing is performed on the electrode base material 30 by a micro end mill having a blade diameter of 0.1 to 1.0 mm, leaving a conductive pattern surface 31 and a width of about 40 to 200 μm and a height of 0.1 mm. The convex part 32 of about 1 to 0.5 mm is formed (pattern engraving process).
2) The electrode base material 30 is placed in the insulating material filling jig 33, filled with the insulating material 34 (thermosetting epoxy resin), and then evacuated to remove bubbles in the filled insulating material 34 and heat. Harden.
3) The disposable filling jig 33 is removed, and the excess insulating material 34 is also roughly removed.
4) Finishing is performed by finish grinding so that the conductive pattern surface 31 and the other electrode substrate surface 35 are flush with each other.

The above manufacturing method has many steps and the filling jig is also disposable, which has been a factor in raising the manufacturing cost of the electrode tool. In addition, since the electrode tool according to the above manufacturing method does not have sufficient adhesion between the electrode base material and the insulating material, the interface between the electrode base material and the insulating material is eroded and weakened by the electrolytic solution, and the insulating material becomes the electrode base. It peeled from the material and could not maintain high accuracy over a long period of time. In addition, in order to ensure a sufficient adhesion area between the electrode base material and the insulating material, the depth of the groove between the convex portions embedded with the insulating material cannot be made too small, 0.1 to 0.5 mm. It was necessary to make it about a depth. Furthermore, in pattern engraving to form convex portions, it is common to use a micro end mill with a blade diameter of about 0.1 to 1.0 mm, but the groove width between the convex portions and the contour shape of the conductive pattern The diameter of the inner circular arc portion had to be set larger than the blade diameter of the micro end mill. However, with the miniaturization of hydrodynamic bearings, the conductive pattern of electrode tools for machining dynamic pressure grooves tends to become finer, and the width of the convex part, the groove width between the convex parts, and the diameter of the inner arc part of the contour have been increased. There is a need to make it smaller. However, in the conventional manufacturing method, since the groove width between the convex portions and the diameter of the inner arc portion of the contour are limited by the blade diameter dimension of the micro end mill, it is difficult to realize a fine conductive pattern. Furthermore, in pattern engraving using a micro end mill with a very small blade diameter, breakage of the end mill is likely to occur due to cutting resistance, so that the processing conditions cannot be raised and the processing time is increased. In addition, since the miniaturized convex portion has a very thin standing wall shape, the convex portion is likely to be deformed or collapsed due to a load during pattern engraving, and an accurate conductive pattern may not be formed on the electrode substrate. . Moreover, in order to ensure the rigidity of the tool necessary for processing, a general micro end mill has a cutting blade portion with a diameter and an axial length equal to the blade diameter value, and a portion without a cutting blade (shank portion) is a blade. Since it is thicker than the diameter, it cannot be cut deeper than the blade diameter value. Therefore, in the conventional manufacturing method, when the blade diameter of the micro end mill is reduced, the cutting depth that can be cut is also reduced, the height of the convex portion is inevitably reduced, and the adhesion area between the electrode substrate and the insulating material is reduced. There is also a problem that the adhesion of the insulating material is further weakened.

Therefore, as a conventional technique, in the dynamic pressure groove processing apparatus for forming a dynamic pressure groove having a shape corresponding to the exposed pattern of the conductive portion of the electrode tool on the workpiece surface, the resin fine particles are attached to the surface of the electrode base material, There is known one using an electrode tool for electrolytic processing in which a region other than the predetermined pattern is covered with an insulating resin layer formed by baking. Furthermore, the electrode substrate surface is described in which a hole of a dynamic pressure groove pattern to be processed is formed in advance and an electrode tool for electrolytic processing having a structure in which a resin sheet is fixed is used. By using a resin layer adhered and baked as a non-conductive material, or by using a resin sheet patterned in advance to the required shape, compared to conventional resist film formation and resin embedding, It is described that the adhesion can be greatly improved, and a polyimide resin having a high insulating property can be suitably used as the material of the resin fine particles (Patent Document 1).

However, in the electrode tool for electrolytic processing used for electrolytic processing of a fine surface shape, the insulating coating in the region other than the processing pattern becomes fine, so the adhesion force of the insulating resin, which is a non-conductive material used for this, to the substrate However, there is a problem that this insulating film is peeled off due to the influence of the electrolyte flowing during the electrolytic processing. Conventionally, many non-conductive material resins used for such insulating coatings are cured by ultraviolet rays or heat, and their adhesion to a conductive substrate used for electrode tools is generally low. Furthermore, since the electrolytic processing of such a fine surface shape is performed by setting the processing gap between the electrode tool and the workpiece to be narrow, the insulating film formed on the wall surface of the gap is not allowed to flow in the electrolyte solution. The force in the shearing direction received from is also large. When such peeling of the insulating film occurs, it becomes impossible to transfer an accurate machining pattern to the workpiece, and the peeling piece of the insulating film clogs the machining gap between the electrode tool and the workpiece. Problems also arise. This clogging of the peeled piece partially obstructs the flow of the electrolyte, and causes a defect in the processed shape of the part, resulting in a yield of a final product using the workpiece as a member, that is, a hydrodynamic bearing or the like. Will be affected. In addition, in the worst case, the clogging of the peeled piece may cause an electrical short circuit in some way, causing damage to both the electrode tool and the workpiece, which may necessitate replacement of these.

In order to solve these problems, a workpiece on which a recess is to be formed on the surface and an electrode in which a conductive portion having a predetermined pattern is formed on the surface of the conductive substrate are immersed in an electrolytic solution facing each other. At the same time, the workpiece and the electrode are connected to the positive electrode and the negative electrode of the machining power source, respectively, and an electric current is passed to form a recess having a shape corresponding to the conductive portion pattern of the electrode on the workpiece surface. An electrode tool for electrolytic processing is described in which an electrodeposition coating film is formed as an insulating film in a region other than the conductive part pattern on the surface of the electrode, and is used for electrodeposition coating. As the resin (electrodeposition paint), an epoxy resin, a urethane resin, or a polyimide resin is preferably employed in consideration of the withstand voltage in electrolytic processing and the corrosion resistance against the electrolytic solution. In addition, according to the electrode for electrolytic processing of the present invention, the adhesion between the substrate and the insulating coating can be obtained by using a coating by electrodeposition coating as the insulating coating covering the region other than the conductive portion on the surface of the electrode (electrode tool). It is described that these adhesion surfaces can maintain the machining pattern on the surface of the electrode tool for a long period of time because the electrolytic solution hardly penetrates and the occurrence of damage such as peeling is suppressed. Patent Document 2).
Preferably, after that, a film made of another non-conductive material resin is formed on the upper surface of the electrodeposition coating film. The non-conductive material resin used in this case is not particularly limited, but it is desirable that the resin is selected in consideration of adhesion (familiarity) with the previously formed electrodeposition coating film, Then, the substrate having a non-conductive material film formed on the surface is removed by removing the non-conductive material film and the electrodeposition coating film on the conductive portion of the surface by polishing or the like to expose the processing pattern on the substrate surface. In addition, it is described that an electrode tool in which the surface of the conductive portion and the insulating coating is flush can be obtained (Patent Document 2).
However, in electrodeposition coating, the coating thickness depends on the concentration distribution and current density of the electrodeposition coating in the electrodeposition tank, so it is difficult to manage the coating thickness, and it is uniform in corners and fine conductive patterns. It is difficult to form a coating film with a sufficient thickness. Therefore, the insulating coating of the electrode tool is locally thinned, and sufficient insulation performance may not be obtained. Furthermore, in order to reduce the burden on the environment, a large-scale wastewater treatment facility after electrodeposition coating is required, and it is difficult to introduce it into a factory.

After forming a recess in a portion of the electrode tool facing the workpiece that does not correspond to the dynamic pressure groove and coating a non-conductive material on the entire portion facing the workpiece, the surface of the electrode exposed portion is There is further a typical prior art regarding an electrode tool for electrolytic processing formed by processing so as to be exposed and flush with the surface of a non-conductive material (see Patent Document 3). In the electrolytic processing method of the dynamic pressure groove using the electrode tool for electrolytic processing, the surface of the electrode exposed portion is made flush with the surface of the non-conductive material, so that the electrolytic processing is performed. Even if the processing gap is narrowed to improve, the electrolytic product generated by processing and the electrolytic solution that has risen in temperature are not retained, so that the electrolysis conditions can be maintained as desired, and the electrolytic product with respect to the non-conductive material can be maintained. The clogging of the non-conductive material caused by the collision is eliminated and the flow rate of the electrolyte is prevented from being lowered. By preventing the flow rate from being lowered in this way, the current density is prevented from being lowered and the workpiece is processed. Not only is the surface roughness of the processed surface of the object improved, but the electrolytic processing speed is also increased. Further, the concave portion is formed by an etching method or a cutting method, and a non-conductive material such as an epoxy resin is coated on the entire surface facing the workpiece by printing or the like. It is described that the exposed electrode exposed portion and the surface of the nonconductive material coated on the recess are flush with each other. However, in the manufacturing method of coating an epoxy resin or the like by printing or the like, as described above, the adhesion between the electrode substrate and the epoxy resin is not sufficient, so the interface between the electrode substrate and the non-conductive material is an electrolyte solution. As a result, the non-conductive material is peeled off from the electrode base material and cannot maintain high accuracy over a long period of time.

JP 2002-79425 A JP 2003-340648 A Japanese Patent 3339792

The inventor has very high adhesion between the insulating material and the electrode base material, and the electrolyte does not penetrate into the interface between the insulating material and the electrode base material even when used for a long time. An electrode tool for electrolytic processing that can be maintained and that does not require an insulating material filling jig for an insulating resin mold and the like, and a manufacturing method thereof are provided.

In order to achieve the above object, the present inventor has intensively researched and found that when a vapor-deposited resin or a vapor-deposited resin is used, the adhesion to the electrode substrate is very high, and the electrode is used over a long period of time. We found that an insulating thin film that does not allow electrolyte to penetrate into the interface with the base material can be formed. As a result, it is possible to produce an electrode tool for electrolytic processing that can maintain high accuracy over a long period of time and an efficient electrode tool for electrolytic processing. Invented the method.
That is, the present invention relates to a conductive pattern formed by the upper surface of the convex part from which the electrode base material is exposed, and an insulating thin film made of vapor deposition polymerization resin or vapor deposition resin provided uniformly on the surface of the electrode base material other than the conductive pattern. It is an electrode tool for electrolytic processing characterized by comprising.
Moreover, this invention can make the surface of an electrically conductive pattern, and the surface of the insulating thin film by vapor deposition polymerization resin or vapor deposition resin provided uniformly on the surface of electrode base materials other than an electroconductive pattern.
Moreover, this invention can make the height of a convex part 5-50 micrometers.
Moreover, this invention can make the thickness of the insulating thin film provided uniformly 5-50 micrometers.
Furthermore, the present invention provides an insulating thin film comprising a vapor-deposited polyimide resin, a vapor-deposited tetrafluoroethylene / perfluorovinyl ether copolymer, and a vapor-deposited tetrafluoroethylene / hexafluoropropylene copolymer. It can be set as one kind selected.
In the present invention, the electrode base material of the electrode tool for electrolytic processing can be one selected from copper, brass, phosphor bronze, iron-copper alloy, or austenitic stainless steel.

The present invention removes a part of the surface of the electrode base material by a chemical removal method or a mechanical removal method to provide a convex portion, and covers the entire surface of the electrode base material provided with the convex portion. Thus, an insulating thin film having a thickness of 5 to 50 μm is uniformly formed by vapor deposition or vapor deposition polymerization, and the surface covered with the insulating thin film is ground or etched to expose the electrode substrate on the upper surface of the convex portion. It is also the manufacturing method of the electrode tool for electrolytic processing characterized by making it form a conductive pattern.
Moreover, the finishing height of the convex part after grinding or etching the surface covered with the insulating thin film can be 5-50 micrometers.
In addition, the chemical removal method for removing a part of the surface of the electrode substrate to provide a convex portion is etching, and the mechanical removal method is one selected from laser processing, precision blast processing, or cutting processing. There can be.
Furthermore, when grinding or etching the surface covered with the insulating thin film according to the present invention, the surface of the conductive pattern and the surface of the insulating thin film made of vapor deposition polymerization resin or vapor deposition resin provided on the surface of the other electrode substrate Can be finished to be flush with each other.

According to the electrode tool for electrolytic processing of the present invention, even if it is a fine conductive pattern, a work piece in which a dynamic pressure groove pattern corresponding to the conductive pattern is accurately processed with high reproducibility with a single tool ( It was found that more than 300,000 workpieces) can be made.
In addition, according to the method of manufacturing an electrode tool for electrolytic processing of the present invention, a disposable resin-filling jig is not required and the number of manufacturing processes is reduced, so that the manufacturing time can be greatly shortened and the cost of the electrode tool is reduced. Not only that, it is possible to respond quickly to changes in the design of conductive patterns for new products and improved products. Moreover, since the insulating thin film by vapor deposition or vapor deposition polymerization has strong adhesive force with an electrode base material, the height of a convex part will be enough about 5-50 micrometers, and if removal methods, such as etching, laser processing, and precision blasting, are used, The conductive pattern can be miniaturized without being limited by the blade end size of the micro end mill. In addition, even when pattern engraving is performed with a micro end mill, a shallow cutting depth of about 50 μm or less is sufficient, so cutting resistance is reduced, plastic deformation of the convex portion and breakage of the micro end mill are suppressed, and cutting is easy. Become.

The insulating resin used in the present invention is a material having high chemical resistance to an electrolytic solution typified by NaNO ₃ (sodium nitrate), high volume resistivity, good adhesion to the electrode substrate, and vapor deposition. Any material can be used as long as it can be used. Typically, a vapor-deposited polyimide resin, a vapor-deposited tetrafluoroethylene / perfluorovinyl ether copolymer, a vapor-deposited tetrafluoroethylene- One type selected from a hexafluoropropylene copolymer, and particularly a polyimide resin that is vapor-deposited and polymerized is preferably used.
The polyimide resin that can be used in the present invention can include tetracarboxylic acid anhydrides, polyisocyanate compounds, and carboxylic acid halides as shown in FIG. Tetracarboxylic acid anhydride can be preferably used. Moreover, as an amine compound which is another raw material, an amine compound as shown in FIG. 5 can be exemplified.

As a typical example of the vapor deposition polymerization of a polyimide resin, as shown in the schematic diagram of FIG. 6, a carboxylic acid anhydride monomer 61 and a diamine monomer 62 in a gas phase state are respectively connected to an inlet 66 and a reactor 65, respectively. A polyamic acid thin film is formed on the surface of the electrode base material 60 through the introduction port 67 and separately guided into a vacuum reactor 65 having a temperature of about 200 ° C. where the electrode base material 60 is allowed to stand. 63 is produced in a uniform and desired thickness. Unreacted monomer 64 is exhausted from the exhaust port 68 to the outside of the reaction apparatus. Since the thickness of the thin film 63 is determined by the polymerization reaction time, the film thickness can be easily managed. Next, the electrode base material 60 is taken out from the reaction device 65, and the thin film 63 is further heated to about 300 ° C. to accelerate the dehydration reaction and convert the polyamic acid into polyimide. The polyimide thin film thus obtained has excellent insulating properties, adheres very strongly to the electrode substrate 60, and forms a polymer in a thin film with a nanostructure. Therefore, the polyimide thin film itself has strong strength. And it is confirmed that there is no pinhole.

In the conventional non-deposition polymerization film formation method in which a polyamic acid solution is applied to an electrode substrate and converted to polyimide by heating, an insulating film having a uniform thickness is not formed, as shown in FIG. The insulating film 76 is formed thin at the corners 74 of the protrusions 70 and thick at the corners 75 between the protrusions 70. Further, even in the conventional film formation method by electrodeposition coating, the amount of the electrodeposition component deposited as a film on the electrode substrate surface depends on the concentration distribution of the solution (aqueous electrodeposition coating material) and the current density. The same problem occurs. In addition, as shown in FIG. 7b, in the case of a fine conductive pattern in which the distance between the convex portions is narrowed to about several tens of μm, electrodeposition coating is applied to the surface 78 other than the convex side surface 77 and the convex portion 70. There may be a problem that the film 79 is not normally formed. In this way, when the film thickness is locally thin or not formed normally, defective insulation occurs in the subsequent finishing process, or stray current is generated during electrolytic processing due to insufficient insulation locally. The surface other than the desired region is dissolved, and the processing accuracy of the dynamic pressure groove is deteriorated. On the other hand, as shown in FIG. 7c, the insulating thin film 71 produced by the vapor deposition polymerization of the present invention has a desired thickness both in the corner 74 and the corner 75, and in the miniaturized conductive pattern. Therefore, the electrode base material 60 is sufficiently insulated, and an electrode tool capable of machining a dynamic pressure groove with high accuracy can be reliably realized.

FIG. 8 shows a typical resin used for the vapor-deposited polymerization resin or the insulating thin film made of the vapor-deposited resin of the present invention. The vapor deposition polymerization resin is polyimide, and examples of the vapor deposition resin include a PFA resin (tetrafluoroethylene / perfluoropropyl vinyl ether) or an FEP resin (tetrafluoroethylene / hexafluoropropylene copolymer). .

Representative electrode tools of the present invention include a sleeve electrode tool having the shape shown in FIG. 9a and a thrust plate electrode tool having the shape shown in FIG. 9b. The manufacturing method of these electrode tools is shown in the schematic diagram of FIG. A part of the surface of the electrode substrate 60 is removed on a predetermined surface of the electrode substrate 60 such as blanked copper, brass, phosphor bronze, austenitic stainless steel or the like by using a chemical removal method or a mechanical removal method. Thus, the protrusion 70 having a predetermined height is provided, and the insulating thin film 71 having a predetermined thickness is uniformly formed on the entire surface of the electrode substrate 60 on which the conductive pattern is formed, using a vapor deposition polymerization resin or a vapor deposition resin. The thickness of the insulating thin film 71 is desirably 5 to 50 μm. If the thickness of the insulating thin film 71 is less than 5 μm, sufficient insulation is not achieved as a whole, a transmission current is generated, and the processing accuracy of electrolytic processing is deteriorated, and when the thickness of the insulating thin film 71 exceeds 50 μm. This is because it is difficult to produce a thin film by vapor deposition polymerization or vapor deposition, and the production time of the insulating thin film 71 becomes long, which is not cost-effective. The height of the convex portion 70 does not need to be increased as compared with the thickness of the insulating thin film 71, and it is desirable that the electrode surface be flat or substantially flat after finishing by grinding or etching. Is preferably provided in consideration of the finishing allowance so that the thickness becomes 5 to 50 μm. As a method for removing a part of the surface of the electrode substrate 60, there are the following methods.
B) Removal processing by cutting using a micro end mill b) Removal processing by laser processing machine c) Removal processing by etching processing d) Removal processing by precision blast processing The insulating thin film 71 can withstand a continuous use temperature of 200 ° C. It is preferable that the material exhibits a high volume resistivity that is not attacked and does not generate a transmission current during processing. Any resin material can be used to achieve this, but polyimide resin, PFA resin, and FEP resin are suitable as familiar materials. Table 1 shows the characteristic values.

Next, a part of the insulating thin film 71 covering the surface on which the convex portion 70 is provided is removed by finish grinding, and the electrode base material is exposed on the upper surface of the convex portion 70 to form a conductive pattern. The surface 72 of the conductive pattern from which the electrode base material is exposed may be higher than the surface 73 of the insulating thin film 71 covering the portion other than the conductive pattern, as shown in FIG. 10, or as shown in FIG. It is good as well. In the case of flushing, a smooth finished surface can be obtained by slightly grinding and finishing the surface 73 of the insulating thin film 71 together with the upper surface of the convex portion 70. Alternatively, the height of the convex portion 70 and the thickness of the insulating coating 71 may be made equal, and only the insulating thin film 71 covering the upper surface of the convex portion 70 may be ground or etched to finish it flush.

FIG. 12 shows each step of the electrolytic machining electrode tool manufacturing process for the present invention and the conventional example. In the prior art, 9 steps are required, but in the present invention, it can be manufactured in only 5 steps. Furthermore, the electrode base material of the electrode tool for electrolytic processing used in the present invention includes a copper-based alloy or an iron-based alloy, and the copper-based alloy is copper, brass, phosphor bronze, and the iron-based alloy is iron-copper-based. An alloy or austenitic stainless steel (SUS303, 304, etc.) can be used.

Another feature of the present invention is that a uniform insulating thin film can be formed on a three-dimensional electrode substrate as shown in FIG. 9a, and then a predetermined portion of the insulating thin film is obtained by grinding or etching. The conductive pattern can be easily formed simply by removing the film.

Furthermore, in the present invention, as shown in FIG. 11, the surface 72 of the conductive pattern and the surface 73 of the insulating thin film made of 5-50 μm vapor-deposition polymerization resin or vapor deposition resin provided on the surface of the electrode substrate other than the conductive pattern are provided. Finish polishing can be performed until it is flush.

The present invention has the following advantages.
B) Since the whole is covered with a thin insulating thin film, an insulating resin filling step is not required, so that rough processing for removing the insulating resin can be omitted, and a filling jig is not required.
B) Since the electrode tool can be easily manufactured, the delivery time and cost are greatly improved.
C) By forming an insulating thin film uniformly on the surface of the electrode substrate by vapor deposition or vapor deposition polymerization, the generation of bubbles and pinholes during the thermal curing of the insulating resin is eliminated, and consequently the generation of stray current during electrolytic processing is suppressed. This leads to an improvement in the quality of the dynamic pressure groove processed by the electrode tool.
D) Since the adhesion of the insulating thin film is improved, the insulating thin film hardly peels off even if the height of the convex portion is low, and the life of the electrode tool can be extended.
E) Since the height of the convex portion of the electrode tool is 50 μm or less, a fine conductive pattern can be processed using various processing methods.

The electrode tool for electrolytic processing according to the present invention is not limited to the shape shown in FIGS. 9a and 9b, and a conductive pattern formed by exposing the electrode substrate on the upper surface of the convex portion, and other electrodes. Any shape may be used as long as it is composed of an insulating thin film made of a vapor deposition polymerization resin or a vapor deposition resin having a thickness of 5 to 50 μm covering the surface of the base material. Also, not only for sleeves and thrust plates, but also for electrode tools for electrolytic machining that process dynamic pressure grooves in any flow member such as the outer peripheral surface of the rotating shaft and the end surface of the flange portion of the rotating shaft It is.

(Example 1 of making an electrode tool for electrolytic processing)
As a first example, a thrust plate electrode tool 55 having the shape shown in FIG. 9B was produced by the procedure shown in FIG. Copper was used as the electrode substrate 60. Using a micro end mill having a blade diameter of 0.04 to 0.5 mm, a convex portion 70 having a height of 30 μm and a minimum width of 30 μm is centered on one end face 56 of the electrode base material 60 which is blank-processed and formed into a hollow cylinder. A plurality of herringbone-like conductive patterns were formed along the outer periphery of the hole. The electrode base material 60 on which the conductive pattern is formed is allowed to stand in a vacuum reaction device 65 shown in FIG. A combination of tetracarboxylic acid anhydride and aromatic diamine is selected as the monomer, the temperature in the vacuum reactor 65 is set to 200 ° C., and each volatilized monomer is supplied into the vacuum reactor 65 from the inlets 67 and 66, respectively. . The monomer is polymerized in the gas phase to form the polyamic acid polymer 63 and uniformly adheres to the surface of the electrode substrate 60. Unreacted monomer 64 is exhausted from exhaust port 68. The reaction is continued until the desired thickness of the polyamic acid polymer 63 is deposited. After the polyamic acid polymer 63 having a desired thickness is formed on the surface of the electrode base material, the electrode base material 60 is taken out from the vacuum reactor 65 and heated to about 300 ° C. to dehydrate the polyamic acid polymer 63, and polyimide To convert to As shown schematically in FIG. 10, an insulating thin film 71 made of polyimide was uniformly formed with a film thickness of 7 μm. FIG. 13 is an enlarged cross-sectional photograph showing the state of generation of the insulating thin film 71 generated on the surface of the electrode substrate 60. It was found that the insulating thin film 71 made of polyimide was also formed with a uniform thickness at the corners and corners of the protrusions. Next, the upper surface of the convex portion covered with the insulating thin film 71 is ground by a surface grinder to remove 20 μm, the electrode base 60 is exposed to form a conductive pattern, and finally the convex portion having a height of 17 μm is formed. A thrust plate electrode tool 55 made of an insulating thin film having a thickness of 7 μm was obtained. FIG. 14 is a top view photograph of the electrode tool 55 for thrust plate. FIG. 15 is an enlarged photograph of a part of the same upper surface observed with a scanning electron microscope. In the photograph taken with a scanning electron microscope, the surface of the insulating thin film is shown in black, and only the metal surface is shown in white. From FIG. 15, it can be confirmed that the conductive pattern is clearly formed and the insulating film is formed uniformly without any pinholes.

(Example 2 of creating an electrode tool for electrolytic machining)
As a second example, a sleeve electrode tool 50 having the shape shown in FIG. 9A was produced. Copper was used as the electrode substrate 60. In order to facilitate manufacture, after the blank portion is formed as the small diameter portion 51 and the large diameter portion 52 of the electrode tool 50 in FIG. 9a as separate members, and a predetermined convex portion is formed on each blank using a micro end mill. Adopted a method of combining and integrating each other. Other than that, it is substantially the same as the procedure shown in FIG. A cylindrical blank is processed as a member for a small diameter portion, and a plurality of convex portions 53 having a height of 50 μm and a minimum width of 50 μm are provided on the outer peripheral surface 51a using a micro end mill having a blade diameter of 0.2 to 0.7 mm, and a sleeve Herringbone-like conductive patterns corresponding to the radial dynamic pressure grooves were formed. Similarly, a cylindrical blank having a center hole on one side end face is processed as a member for a large diameter portion, and using a micro end mill having a blade diameter of 0.04 to 0.5 mm, the end face 52b has a height of 30 μm and a minimum width. A plurality of 30 μm convex portions 54 were provided along the outer periphery of the center hole to form a herringbone-like conductive pattern corresponding to the thrust dynamic pressure groove of the sleeve. Next, the small diameter member was press-fitted and integrated into the center hole of the large diameter member to form an electrode substrate 60 for a sleeve. The electrode base material 60 on which the conductive pattern is formed is allowed to stand in a vacuum reaction device 63 shown in FIG. A combination of tetracarboxylic acid anhydride and aromatic diamine is selected as the monomer, the temperature in the vacuum reactor 63 is set to 200 ° C., each monomer is volatilized, and supplied to the vacuum reactor 65 from the inlets 67 and 66, respectively. To do. The monomer is polymerized in the gas phase to form the polyamic acid polymer 63 and uniformly adheres to the surface of the electrode substrate 60. Unreacted monomer 64 is exhausted from exhaust port 68. The reaction is continued until the desired thickness of the polyamic acid polymer 63 is deposited. After the polyamic acid polymer 63 having a desired thickness is formed on the surface of the electrode base material 60, the electrode base material 60 is taken out from the vacuum reactor 65 and heated to about 300 ° C. to dehydrate the polyamic acid polymer 63, Convert to polyimide. As shown schematically in FIG. 10, an insulating thin film 71 made of polyimide was uniformly formed with a thickness of 10 μm. Grinding with a cylindrical grinder is performed to remove the upper surface of the convex portion 53 of the small diameter portion 51 covered with the insulating coating 71 by 10 μm and the upper surface of the convex portion 54 of the large diameter portion 52 to expose the electrode substrate 60. Thus, a conductive pattern was formed, and a sleeve electrode tool 50 shown in FIG. 9A was obtained. The small diameter portion 51 was finished to satisfy the coaxiality requirement with the large diameter portion 52. FIG. 16 is a side view photograph of the sleeve electrode tool 50.

(Creation example 3 of electrode tool for electrolytic machining)
As a third example, a sleeve electrode tool 50 having the shape shown in FIG. 9A was produced in substantially the same manner as the procedure shown in FIG.
As the electrode substrate 60, brass which is a copper-based alloy was used. Similarly to Example 2, an electrode substrate 60 obtained by integrally combining a small diameter member and a large diameter member each formed with a plurality of convex portions 53 and convex portions 52 each having a height of 20 μm is shown in FIG. Let stand in the reactor 63. A combination of tetracarboxylic acid anhydride and aromatic diamine is selected as the monomer, the temperature in the vacuum reactor 63 is set to 200 ° C., each monomer is volatilized, and supplied to the vacuum reactor 65 from the inlets 67 and 66, respectively. To do. The monomer is polymerized in the gas phase to form the polyamic acid polymer 63 and uniformly adheres to the surface of the electrode substrate 60. Unreacted monomer 64 is exhausted from exhaust port 68. The reaction is continued until the desired thickness of the polyamic acid polymer 63 is deposited. After the polyamic acid polymer 63 having a desired thickness is formed on the surface of the electrode base material 60, the electrode base material 60 is taken out from the vacuum reactor 65 and heated to about 300 ° C. to dehydrate the polyamic acid polymer 63, Convert to polyimide. As schematically shown in FIG. 11, an insulating thin film 71 made of polyimide was uniformly formed with a film thickness of 20 μm. Only the insulating thin film 71 covering the upper surface of the convex part is removed by etching to expose the electrode substrate 60, and the surface 73 of the insulating thin film 71 covering the surface other than the convex part and the surface 72 of the conductive pattern are flush with each other. A conductive pattern was formed as follows.

The electrode tool for electrolytic processing of the present invention can maintain high accuracy over a long period of time, in which the electrolytic solution does not penetrate into the interface between the insulating material and the electrode base material even when used for a long time. It eliminates the need for a filling process and eliminates the need for a filling jig, making it an easy-to-manufacture electrode tool for electrolytic processing, which is revolutionary in that it can contribute to the rapid development of more accurate and compact fluid bearings. And there is a high industrial applicability.

Illustration of electrolytic processing method (sleeve processing) Illustration of electrolytic machining method (thrust plate machining) Conventional manufacturing method of electrode for electrolytic processing Example of polyimide raw material (polycarboxylic acid) Example of polyimide raw material (polyamine) Example of vacuum reactor Insulation film formation state explanatory diagram Illustration of resin as a typical example of the present invention Electrode machining electrode tool for machining dynamic pressure grooves Method for manufacturing a general electrode tool for electrolytic machining according to the present invention Method of manufacturing a flush electrode tool according to the present invention Comparison of conventional manufacturing process of electrode tool and manufacturing process according to the present invention Cross-sectional enlarged photograph of the electrode tool for electrolytic processing obtained in Example 1 Upper surface photograph of electrode tool for electrolytic processing obtained in Example 1 The photograph which observed the upper surface of the electrode tool for electrolytic processing obtained by Example 1 with the scanning electron microscope Side view photograph of electrode tool for electrolytic processing for sleeve obtained by Example

Explanation of symbols

1 sleeve 2 machining electrode 2a conductive pattern (radial)
2b conductive pattern (thrust)
2c Small-diameter portion 2d Large-diameter portion 3 Stopper 30 Electrode material 31 in conventional manufacturing technology explanatory diagram Conductive pattern surface 32 in conventional manufacturing technology explanatory diagram Protruding portion 33 in conventional manufacturing technology explanatory diagram Insulating material in conventional manufacturing technology explanatory diagram Filling jig 34 Insulating material 35 in conventional manufacturing technology explanatory diagram Electrode base material surface 4 Electrolyte 5 Flow path 50 Sleeve electrode tool 51 Sleeve electrode tool small diameter portion 51a Sleeve electrode tool small diameter The outer peripheral surface of the sleeve 52 The large-diameter portion of the electrode tool for sleeve 52a The outer peripheral surface of the large-diameter portion of the electrode tool for sleeve 53 The convex portion of the small-diameter portion of the electrode tool for sleeve 54 The convex portion of the large-diameter end face of the electrode tool for sleeve End face of thrust plate 56 thrust play

6 reactor details 60 electrode substrate 61 carboxylic anhydride monomer 62 diamine monomer 63 polyamic acid coating 64 unreacted monomer 65 reactor 66 carboxylic anhydride monomer inlet 67 diamine monomer inlet 68 exhaust port 7 electrode tool details 70 convex 71 Insulating coating 72 Conductive pattern surface 73 Insulating coating surface 74 Corners 75 of convex portions Corners 76 between convex portions Thick insulating films 77 Protruding side surfaces 78 Surfaces other than convex portions 79 Electrodeposition coating film 10 Description of conventional manufacturing technology Hydrodynamic bearing thrust plate 10a in the drawing, conventional hydrodynamic groove 11 in the conventional manufacturing technology explanatory diagram, electrode tool 11a in the conventional manufacturing technology explanatory diagram, electrode tool conductive pattern 12 in the conventional manufacturing technology explanatory diagram, conventional manufacturing technology explanatory diagram, Hydrodynamic bearing stopper

Claims (10)

A conductive pattern formed by the upper surface of the convex portion where the electrode base material is exposed, and a vapor-deposited polymerized resin or an insulating thin film made of a vapor-deposited resin provided uniformly on the surface of the electrode base material other than the conductive pattern, Electrode tool for electrolytic machining.
  2. The electrolysis according to claim 1, wherein the surface of the conductive pattern and the surface of the insulating thin film made of vapor deposition polymerization resin or vapor deposition resin provided uniformly on the surface of the electrode substrate other than the conductive pattern are flush with each other. Electrode tool for machining. The height of a convex part is 5-50 micrometers, The electrode tool for electrolytic processing of Claim 1 or Claim 2 characterized by the above-mentioned. The electrode tool for electrolytic processing according to claim 1, wherein the thickness of the uniformly provided insulating thin film is 5 to 50 μm.   The insulating thin film is one type selected from a vapor-deposited polyimide resin, a vapor-deposited tetrafluoroethylene / perfluorovinyl ether copolymer, and a vapor-deposited tetrafluoroethylene / hexafluoropropylene copolymer. The electrode tool for electrolytic processing according to claim 1, wherein the electrode tool is used for electrolytic processing. 6. The electrode base material of the electrode tool for electrolytic machining is one selected from copper, brass, phosphor bronze, iron-copper alloy, or austenitic stainless steel. Electrode machining electrode tool described in 1. A part of the surface of the electrode substrate is removed by a chemical removal method or a mechanical removal method to provide a convex portion, and an insulating resin is deposited so as to cover the entire surface of the electrode substrate on which the convex portion is provided. Alternatively, by vapor deposition polymerization, an insulating thin film having a thickness of 5 to 50 μm is uniformly formed, and the surface covered with the insulating thin film is ground or etched to expose the electrode base material on the upper surface of the convex portion. The manufacturing method of the electrode tool for electrolytic processing characterized by forming. The method for manufacturing an electrode tool for electrolytic processing according to claim 7, wherein a finish height of the convex portion is 5 to 50 μm.   9. The electrode tool for electrolytic processing according to claim 7 or 8, wherein the chemical removal method is etching, and the mechanical removal method is one selected from cutting, laser processing, and precision blasting. Manufacturing method. When grinding or etching the surface covered with the insulating thin film, the surface of the conductive pattern and the surface of the insulating thin film made of vapor-deposited polymer resin or vapor-deposited resin provided on the surface of the other electrode substrate are flush with each other. The method for manufacturing an electrode tool for electrolytic processing according to claim 7, wherein the electrode tool is electrolytically processed.