JP2002346838A - Method and apparatus for maintaining purity of processing pure water in wire electric discharge machining, method and apparatus for wire electric discharge machining, method and apparatus for maintaining pure water, and method and electrode for electrolysis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for elongating a life of resin by promoting ability of ion exchange resin in wire electric discharge machining which carries out electric discharge machining using a wire electrode in pure water, a technology for maintaining purity of pure water by which the life of the resin is similarly elongated, and a method and an electrode for electrolysis which can be effectively utilized in each of the technologies described above. SOLUTION: In order to maintain purity of pure water in wire electric discharge machining in pure water, ion exchange resin 14 is used in combination with deionization utilizing electrolysis. Three-phase electrodes are used in the electrolysis. The electrolysis is carried out by alternating such a state in turn that a DC voltage is applied to one electrode and two other electrodes are ground. The electrodes for electrolysis have three electrodes formed by a pair of flat plate parts adjoining each other making an angle of 120 deg., and each electrode is assembled in such a configuration that each of a pair of the flat plate parts faces one of a pair of the flat plate parts of other electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for maintaining the purity of pure water for machining water in wire electric discharge machining, a method and an apparatus for wire electric discharge machining, a method and apparatus for maintaining pure water,
And an electrolysis method and an electrode used for the electrolysis.
In the wire electric discharge machining technique, a wire electrode usually placed in a dielectric fluid has one pole (for example, a negative pole), and the workpiece has another pole (for example, a positive pole). The present invention can be generally applied to various types of electric discharge machining in which a workpiece is machined by electric discharge using a wire electrode disposed in pure water. Further, the present invention can be used for various technologies that require maintaining the purity of pure water. Further, the present invention can be used for various electrolysis techniques.

[0002]

2. Description of the Related Art Conventionally, it is known to perform various types of machining using electric discharge. For example, in a wire electric discharge machining technique, a workpiece is processed by electric discharge between wire electrodes arranged in a liquid. If it is a wire discharge,
Fine processing according to the fineness of the wire can be achieved.

[0003] The liquid in which the discharge electrode is arranged is called a machining liquid. Oils are sometimes used as the machining fluid.However, if oils are used, there are problems such as fires and other disasters, and there are problems such as thermal deterioration and cracking of the workpiece. In order to solve the problem, pure water has been used as a working fluid. According to such water processing, the processing speed is generally higher than that of oil processing. When pure water is used as the working fluid, it is usually called electrode water. (For the electric discharge machining technology using deionized water as a machining fluid, see, for example, JP-A-11-320259).

Accordingly, such pure water is used as a working fluid (electrode water).
In the electric discharge machining described above, the electric discharge between the electrodes arranged in the machining fluid processes the workpiece arranged in the machining fluid. In wire electric discharge machining, a portion to be machined of a workpiece is machined with a precision corresponding to the fineness of the wire electrode by electric discharge between the wire electrodes in a machining fluid.

[0005] In the wire electric discharge machining technology in pure water,
If other conditions such as the fineness of the wire electrode are constant, the processing speed and other processing conditions are determined by the temperature and purity of the pure water. Therefore, it is set so that optimum processing can be realized by maintaining the conditions of the pure water such as the temperature and purity of the pure water constant.

[0006] The material of the wire used as the wire electrode is typically brass (brass), but brass coated with zinc or tungsten for fine processing is sometimes used. With the electric discharge machining, the wire is consumed, and its components inevitably enter the pure water as ions. In addition, from the workpiece (usually a metal), its components enter the pure water as ions. For this reason, since the purity of pure water used as a working fluid decreases with time, the purity of pure water is maintained so that its electrical conductivity does not exceed the allowable range in processing. Need to be kept. Usually, pure water used as a machining fluid in a wire electric discharge machine has an electric conductivity (μS / cm (2
5 ° C.)) of 8.0 to 30.0 μS / cm (specific resistance of 12
The range of 5,000 to 33,333 Ω · cm (25 ° C.) is considered to be appropriate and preferable. In actual processing, a particularly narrow allowable range is set within this range in order to achieve necessary processing. The electric conductivity is controlled so as not to be higher than the range. (The electric conductivity range of general tap water is about 200.0 to 300.0 μS / cm (25 ° C.).

A conventional technique for maintaining pure water in wire electric discharge machining will be described with reference to FIG.
Pure water used as a machining fluid in wire electric discharge machining is pure water deionized by ion exchange. For example, general tap water, groundwater, rainwater, etc. are used as raw water,
Cations and anions are exchanged in the ion exchange resin cylinder of the pure water supply device to obtain deionized water, which is used as a machining fluid for electric discharge machining. In FIG. 12, pure water as a processing liquid is disposed in a processing tank 101, and a wire electrode and a workpiece are disposed in the pure water to perform a predetermined processing. Processing fluid (pure water)
Is reduced by discharge heat, spontaneous evaporation, etc., but when raw water is replenished as make-up water, processing is stopped and waited until the specified electric conductivity is reached.

In the prior art shown in FIG. 12, maintenance of the purity of pure water as a working fluid is achieved by the following circulation system. Once the pure water in the processing tank 101 is
02 and then through a filter element and then in a fresh water tank 104
5 (usually forming an ion-exchange resin tube), deionized and cleaned, and returns to the processing tank 101. With such a circulation system, the pure water maintains an appropriate electric conductivity range.

[0009] More specifically, pure water as a working fluid generally contains 8.0 to 30.0 μS / cm (25 ° C.) described above.
A specific purity within the range is selected and used as a designated liquid. When specified, processing is performed while maintaining the specified value while ion exchange is performed by the sensor operation.

As a practical example, 20 μS / cm (25 ° C.)
(50,000 Ω · cm (25 ° C.)), the ion exchange operation of the ion exchange resin is performed so as not to exceed 20 μS / cm during and after processing. In this case, the harder the process, the faster the ion-exchange resin deteriorates. The specified value is 3
The deterioration life of the ion-exchange resin is shorter in the case of 10 μS / cm than in the case of 0 μS / cm, that is, in the case where high purity and high purity are required to be maintained. Constant within the resin).

When the purity of pure water is increased, the processing speed tends to be slightly reduced, but the generation of rust is suppressed. However, when high purity is required, ion dissociation is high, and the resin capacity of the ion exchange resin operates at the limit capacity, and the deterioration is accelerated.

[0012] In the conventional wire electric discharge machine, the average processing time until the ion exchange resin used as described above is deteriorated is about 180 hours. Therefore, every time the processing time elapses, the ion exchange resin needs to be replaced, so that the cost burden is large. Further, if the ion exchange resin has a short deterioration life, a problem may occur in processing. For example, when a long processing is required, such as when the workpiece is large, if the need to replace the resin comes out during the processing, the processing conditions will change before and after the replacement, which is completely different from the previous conditions. It may take a lot of trouble to make the same, or after all, the desired processing may not be achieved. In fact, some workpieces require 90 hours, or even 200 hours. If the ion exchange resin is inevitably replaced during the processing of such a workpiece, the processing is stopped. Once it returns to the initial start position, after replacing the ion exchange resin, it follows the same predetermined processing path again, returns to the previous processing stop position, and starts processing the workpiece again. It is difficult to restart the processing from the position, and an error is inevitably generated, causing a step or a gap. Generally, three steps of roughing, medium processing, and finishing are performed. In finishing, precision processing on the order of microns is possible. It is extremely problematic that the ion exchange resin needs to be replaced during the finishing. It is. In addition, as described above, the conditions always change after the exchange of the ion exchange resin, and it is difficult to continuously process under the same conditions, and there is a possibility that a problem may occur in precision.

More importantly, there is a problem that the ion exchange resin used in the wire electric discharge machine cannot be regenerated and is entirely industrial waste. The ion exchange resin used in wire electric discharge machines has a strong dissociation of metal ions at the time of electric discharge, and has a high speed of polluting the exchange layer (surface layer, inner hole layer) of the ion exchange resin. , Playback will not work. That is, the ion exchange resin is made of a granular resin, which is composed of a diffusion skin layer forming a surface layer and a resin layer inside the diffusion skin layer. When the ion concentration is low due to the necessity of maintaining high-purity water as in wire electric discharge machining, the diffusion of the ion exchange resin in the diffusion skin is rate-limiting,
In addition, at the pore exchange portion in the particle, the metal causes clogging in the pore, and a state where regeneration is impossible. Therefore, the entire amount will be industrial waste. For this reason, it is strongly desired to extend the life of the ion exchange resin and reduce the amount of industrial waste.

[0014] The above-mentioned problem is always a problem when the purity of pure water is to be maintained using an ion exchange resin.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above prior art. The object of the present invention is, first, in a wire electric discharge machining technique for processing a workpiece by electric discharge with a wire electrode arranged in pure water, an ion exchange resin for maintaining the purity of pure water. An object of the present invention is to provide a wire electric discharge machining technique which promotes an ion exchange capacity to extend a deterioration life thereof, thereby solving a machining problem associated with an early resin exchange, making it advantageous in cost, and reducing waste. Secondly, it is a pure water purity maintaining technology that can be used for the above-mentioned technology, and in the case where pure water purity maintenance is required, solves the problem associated with early resin replacement in the same manner as described above, and makes it cost-effective. It is to provide a technology capable of reducing waste. Thirdly, it is an object of the present invention to provide an electrolysis method and an electrode used for the electrolysis that can be effectively used for the above-mentioned technologies.

[0016]

In order to realize the above-mentioned object, the present invention employs the following technical means. A method for maintaining the purity of pure water for machining water in wire electric discharge machining according to the present invention includes purifying the pure water in wire electric discharge machining in which a workpiece is machined by electric discharge using a wire electrode arranged in pure water. The method for maintaining purity is characterized in that the purity of the pure water is maintained by an ion exchange resin, and the purity is maintained by deionization using electrolysis. The present invention can be embodied in a form using electrolysis that performs at least decation (demetalization ion). (The same applies to each invention relating to the following wire electric discharge machining).

The apparatus for maintaining the purity of pure water for machining water in wire electric discharge machining according to the present invention is the above pure water in wire electric discharge machining for machining a workpiece by electric discharge using a wire electrode disposed in pure water. An apparatus for maintaining the purity of water, comprising: an ion exchange system that maintains the purity of the pure water by using an ion exchange resin; and an electrolysis system that performs deionization using electrolysis. is there.

[0018] A wire electric discharge machining method according to the present invention is a wire electric discharge machining method for machining a workpiece by electric discharge using a wire electrode arranged in pure water, wherein the ion exchange resin is used to remove the pure water. It is characterized in that the wire electric discharge machining is performed while maintaining the purity and also using the purity maintenance by deionization using electrolysis.

A wire electric discharge machine according to the present invention is a wire electric discharge machine for machining a workpiece by electric discharge using a wire electrode placed in pure water, wherein the wire electrode and the workpiece are processed. A wire electric discharge machine main body having a machining tank in which the pure water to be placed is disposed and performing electric discharge machining therein, an ion exchange system for maintaining the purity of the pure water, and And an electrolysis system for performing deionization using electrolysis for maintaining the temperature.

The method for maintaining the purity of pure water according to the present invention is a method for maintaining the purity of pure water by deionizing pure water to maintain the purity of the pure water. It is characterized in that the purity of pure water is maintained and the purity of the water is maintained by deionization using electrolysis. In carrying out the present invention, an electrode for electrolysis according to the present invention, which will be described later, that is, an electrode in which one electrode is formed by a pair of plate-shaped portions adjacent to each other at an angle of 120 ° is used as a first electrode , A second electrode, and an electrode for electrolysis having three electrodes as the third electrode can be used.

The pure water purity maintaining device according to the present invention is a pure water purity maintaining device for maintaining the purity of pure water by deionizing from pure water, wherein the ion exchange resin is used. An ion exchange system for maintaining the purity of pure water and an electrolysis system for performing deionization using electrolysis are provided. In practicing the present invention, an electrode for electrolysis according to the present invention described later, that is, 120
An electrode in which one electrode is formed by a pair of flat plate portions adjacent to each other at an angle of ° is referred to as a first electrode, a second electrode, and a third electrode.
An electrode for electrolysis having three electrodes can be used.

The electrolysis method according to the present invention is an electrolysis method for performing deionization by electrolysis, wherein a three-phase electrode is used as a polarity driving electrode, and a one-phase electrode is used as a constant grounding electrode. One of the three-phase electrodes for driving is applied with direct current, the other two of the three-phase electrodes are grounded and electrolysis is performed, and the electrodes to which direct current is applied are alternately changed. Then, electrolysis is performed in the above state. The present invention can be used for the above-described respective wire electric discharge machining techniques and the pure water purity maintaining technique. In the present invention, the electrodes to which the direct current is applied may be sequentially changed at equal time intervals. As the interval, 1 minute to 3 minutes can be adopted. For example, such an equal time interval control can be performed by a relay. In addition, the one-phase electrode serving as the always-grounding electrode may be configured to form an electrode cover that covers all or a part of the three-phase electrode for driving the polarity in a non-contact manner.

The electrode for electrolysis according to the present invention is an electrode used for electrolysis, wherein one electrode is formed by a pair of flat plate portions adjacent to each other at an angle of 120 °, and
And three electrodes as a second electrode, a second electrode, and a third electrode, and the first electrode, the second electrode, and the third electrode are each a pair of plate-like portions that form each electrode. Are combined in a structure facing one of the pair of plate-like portions forming another electrode. In the present invention, the first electrode, the second electrode, and the third electrode may further include an electrode serving as an electrode cover that covers all or a part of the electrodes in a non-contact manner.

[0024] In the electrolysis method according to the present invention, the electrode in which one electrode is formed by a pair of plate-shaped portions adjacent to each other at an angle of 120 ° is formed by the first electrode, the second electrode, and the second electrode. In addition to having three electrodes as the three electrodes, the first electrode and the second electrode
The third electrode and the third electrode use an electrode having a structure in which each of a pair of flat portions forming each electrode is combined with one of the pair of flat portions forming another electrode in a structure facing each other. One of the first electrode, the second electrode, and the third electrode is applied with a direct current, and the other two electrodes are electrolyzed in a state of being a ground electrode, and the direct current is applied. The electrodes are sequentially changed, and electrolysis is performed in the above state. In the present invention, the apparatus further includes an electrode serving as an electrode cover that covers all or a part of the first electrode, the second electrode, and the third electrode in a non-contact manner, and the electrode forming the electrode cover is always grounded. It can be configured as a pole.

According to each of the wire electric discharge machining techniques according to the present invention, by using deionization using electrolysis together,
The advantages of reducing the consumption of the ion exchange resin, extending the life of the ion exchange resin, solving the processing problems associated with early resin exchange, reducing costs and reducing waste. Is brought.

According to the purity maintaining technology of each pure water according to the present invention, the deionization using the electrolysis is also used in combination, whereby the consumption of the ion exchange resin can be suppressed, and the life of the ion exchange resin can be extended. Thus, various problems associated with the early resin exchange can be solved, resulting in an advantageous effect that cost can be reduced and waste can be reduced.

According to the electrolysis method and the technology for electrodes used in the electrolysis according to the present invention, the electrolysis method and the electrolysis method which can be effectively used for the above-mentioned respective wire electric discharge machining techniques and the techniques for maintaining the purity of pure water. Electrodes can be provided.

[0028]

Next, a preferred embodiment of the present invention will be described. However, needless to say, the present invention is not limited by the following embodiments and the specifically described embodiments.

FIG. 1 is a block diagram of a preferred embodiment embodying the present invention. In the example of FIG. 1, a processing system using electrolysis technology is attached to a wire electric discharge machine,
As a whole, a wire electric discharge machine is constituted.

The processing system is designated by the reference numeral 1. The processing system 1 includes a processing tank 2 and a controller 3 located below the processing tank 2, and these are installed on an installation table 4. The treatment tank 2 is used for electrolyzing the water to be treated and deionizing the water to purify the water to be treated, and is provided with an electrode for electrolysis described later herein. The controller 3 controls processing conditions such as electrolysis conditions.

The water to be treated is introduced into the treatment tank 2 by the injection system 5 and is led out by the pouring system 6. Injection system 5,
Although the hose is used as the pouring system 6 in this embodiment, it may be a pipe or other appropriate inflow / outflow system. The water to be treated enters the processing tank 2 from the injection system 5 through the injection port 7 of the processing tank 2. In addition, it exits from the spout 8 of the processing tank 2 and enters the pouring system 6. The outlet 8 is located slightly below the inlet 7. Reference numeral 9 denotes a mouth for overblowing. Usually, the water level is maintained at the height of the spout 8. However, in some cases, it is assumed that the water level rises to around the inlet 7 (the filtering screen 19 described later with reference to FIG. Assuming that the water level rises due to clogging, automatic operation at night, etc.), the overblow port 9 is provided at the same position as the injection port 7 to prevent the water level from becoming too high even in the above case. It is.

The main body 10 of the wire electric discharge machine includes a machining tank 11.
The processing tank 11 is filled with pure water as a processing liquid, and the wire electrode and the workpiece are arranged in the pure water to perform a predetermined processing. This pure water is purified in the water tank 12 installed in the wire electric discharge machine main body 10, and its electric conductivity is maintained. The pure water in the processing tank 11 is filtered through a filter 13 and is deionized and purified in an ion exchange resin 14 (here, an ion exchange resin cylinder) in a water tank 12.
It returns to the processing tank 11. As the circulating system, a system similar to the system shown in FIG. 2 and described above can be employed. For example, a configuration in which pure water is once sent to the filter 13 through the pollution tank can be adopted.

In the present embodiment, the processing system 1 is provided in parallel with the above-described wire electric discharge machine main body 10 to assist the purification of pure water in the water tank 12 and reduce the load on the ion exchange resin 14. I do. That is, the water tank 12 and the processing tank 2 of the processing system 1 are connected to the injection system 5,
The deionization in the ion exchange resin 14 and the deionization due to electrolysis in the treatment system 1 can proceed simultaneously at the same time. In some cases, it is possible to perform the treatment separately instead of proceeding simultaneously, but it is preferable to proceed simultaneously during wire electric discharge machining.

The pure water purification system of the present embodiment can be applied to any wire electric discharge machine. Wire EDM technology can be applied to various types of machining, typically cutting, cutting, round machining, corner machining, slit machining, etc. It is possible to process even large workpieces. The present invention can be preferably used for any wire electric discharge machining. Particularly effective when the purity of pure water is high and the load on the ion exchange resin is large, or when the workpiece is large, such as when the ion exchange resin may need to be replaced during processing, etc. It can be said.

Generally, the wires consumed by the discharge are guided by a guide mechanism or the like, and are fed out one after another. The material of the wire is typically brass (brass), but brass coated with zinc, and tungsten may also be used for fine processing. In the practice of the present invention, any of them should be used without problems Can be. If the problem of the mechanical strength can be overcome, the gap between the electrodes can be reduced as the thickness becomes smaller, which is advantageous for fine processing. In the present embodiment, a case where a brass wire is used is shown as a typical case. Conventionally, there has been a case where zinc and the like in the wire have been melted and the electrical conductivity has been concerned.

Next, the configuration of the processing tank 2 in the processing system 1 according to this embodiment will be described in detail. FIG. 2 shows an outline view of the processing tank 2. The processing tank 2 of the present embodiment has a handle 15 such as a trunk for travel, and is easy to carry. This is because the wire electric discharge machine main body 10 itself is quite large and is often fixedly installed in a processing factory, so that the processing tank 2 can be carried and installed. Therefore, by appropriately providing a control mechanism, the processing tank 2 can be relatively easily attached to any kind of electric discharge machine at any place. Therefore, it can be said that the present invention can be easily implemented by using such a processing tank 2.

In FIG. 2, the inlet 7, the spout 8, and the overblow 9 are provided on the side surface of the processing tank 2. A drain port (waste water port) 16 located further below the spout 8 is for cleaning the tank.

The processing tank 2 is arranged at a position higher than the water tank 12 as shown in FIG. As a result, the water after the treatment in the treatment tank 2 is poured into the water tank 12 from the spout 8 by gravity. In FIGS. 1 and 2, reference symbol P is a pump for injecting into the processing tank 2,
It is arranged in the pure water of the water tank 12. In the water tank 12, it is preferable that the injection pump P and the hose forming the pouring system 6 be located as far apart as possible. It is preferable to make a small hole in the upper part of the hose that forms the pouring system 6, because the natural fall is smooth. The processing tank 2 is preferably located near the water tank 12 as a planar position. Specifically, the system installation place where the installation base 4 is placed (see FIG. 1)
It is preferable to place the processing tank 2 near the water tank 12, and place the installation table 4 having substantially the same height as the water tank 12 here.

Next, the internal structure of the processing tank 2, particularly the installation of the electrodes, will be described with reference to FIG. FIG. 3 shows the inside of the processing tank 2 viewed from above. As shown in FIG. 3, the processing tank 2 is partitioned by a filtration partition net 19 into an injection-side tank 17 into which ion-exchanged pure water is injected, and an injection-side injection-side tank 18. In this example, the filtering net 1
9 was formed of SUS. A mat for filtration (a plastic mat for buffer called a plastic mat can be used) is provided in the pouring side tank 18, through which the water to be treated is discharged.

An electrode main body and a cathode filter are arranged in the injection-side tank 17, where deionization is performed by electrolysis. In the present embodiment, since the electrode body and the cathode filter are detachably assembled, this assembly is referred to as an electrode assembly and denoted by reference numeral 20.

The electrode assembly 20 used in this embodiment will be described below. As shown in FIG.
The electrode assembly 20 disposed in the water to be treated (pure water which is a processing liquid) includes a polarity driving electrode 22 forming an electrode body and a cathode filter which is a constantly grounding electrode 23.
The polarity driving poles 22 are three-phase electrodes 22A, 22B, 22
C. The pole 23 for constant grounding forms a cover on which the pole 22 for polarity driving is completely covered. That is, here, the always-ground electrode 23 forms an electrode cover that covers all (or a part of) the three-phase electrodes 22A, 22B, and 22C for polarity driving in a non-contact manner. Further, as shown in FIG. 3, the constant grounding pole 23 has a filter shape with a large number of holes opened, that is, it forms a cathode filter.

In this electrode assembly 20, as shown in FIG. 5, a normally grounding electrode 23 forming a cathode filter has a support (housing) for electrically insulatingly supporting the polarity driving electrode 22; Screws 24 stop at four places. This can be easily released and removed. Reference numeral 25 denotes a cathode connection cord for always connecting the grounding electrode 23 to the ground side. Reference numeral 26 denotes an electrode cord that bundles the cathode connection cord 25 and the connection cord for the polarity driving pole 22 and connects them to the controller 3 (see FIG. 1). The cord is generally made of copper,
The connection between the cord and the electrode was filled with an insulating silicon resin or the like, and strictly sealed with water.

The polarity driving pole 22 in the present embodiment.
6 is shown in a perspective view in FIG. As shown in FIG. 6, the polarity driving pole 22 is composed of a first electrode 22A and a second electrode 22A.
, And a third electrode 22C. The electrodes 22A, 22B, 22C are assembled electrically insulated from each other. Reference numeral 27 denotes an assembling bolt and spacer fixing nut, which is made of insulating plastics. It is practical to assemble it by attaching it to an insulating support (housing). The spacer fixing nut 27 serves as a spacer for keeping the electrodes at equal intervals.

Each of the electrodes 22A, 22A in this embodiment
2B and 22C are shown in FIG. 6 and as shown in FIG.
A pair of flat plate portions 22A adjacent to each other at an angle of 120 °
One electrode is formed by 1,2A2. In FIG. 6 and FIG. 7, the plate-like portions are indicated by reference numerals only for the electrode 22A to avoid complicating the drawings.
The same applies to C. These electrodes 22A, 22B, 22C
Are combined in a structure in which each of a pair of flat portions forming each electrode faces one of the pair of flat portions forming another electrode. In other words, three 120 ° angle portions are combined to 360 ° to form the whole. As described above, since the electrodes are maintained at equal intervals by the spacer fixing nut 27, the distance between the opposing surfaces of the flat portions is kept constant. Reference numeral 28 denotes a threaded (male thread) rod for energizing from a power source, and each electrode 22A, 22B, 22
It is fixed to the bent portion C (the bent side forming an angle of 120 °). Here, the threaded rod 28 is connected to each of the electrodes 22A and 22A.
B and 22C were formed of the same material and fixed by welding. The tip of the threaded rod 28 enters the support (housing) and is electrically connected. In addition, waterproof treatment is performed. Although the threaded rod 28 is provided at the bent portion in the illustrated example, it may be provided on the outer side of each pole (a portion indicated by reference numeral 29 in FIG. 7) when the degree of freedom in place is limited due to the vicinity of the center. .

In this embodiment, the electrodes 22A, 22B and 22C for polarity driving are made of titanium. The opposite surface was plated with platinum. The cathode filter, which is always the grounding electrode 23, was made of stainless steel. The permanent grounding electrode 23 has a U-shaped cover in the drawing, but may be a semicircular or other lid type as long as it can fulfill the same cover function. The U-shaped shape of this example is excellent in terms of ease of attachment and detachment and cleaning. Constant grounding pole 23
Also acts as a guard against electric shock. As will be described later, the polarity driving poles 22A, 22B, and 22C each have a polarity that is sequentially changed (for example, the polarity is rotationally driven using a relay circuit in an applied power supply unit). There is no adhered substance, and the cations (such as calcium) in the water always adhere to the inner surface of the grounding electrode 23 (on the side of the polarity driving electrode). However, the constantly grounding electrode 23 is easy to remove and clean. It is advantageous because it is easy.

The polarity driving poles 22A, 22B, 22C
Will be described below. Each electrode 22A of this example,
Titanium (Ti) was selected as the material of 22B and 22C, and the opposite surfaces, which would be opposite electrodes as described above, were plated with platinum. Although the thickness is arbitrary, it is preferably about 1 mm in consideration of workability. Length and width are
It is optional and may be determined by the applied voltage. It may be plate-like or net-like, but this should be determined by the amount of flowing water and the electrical conductivity of pure water. FIG. 8 shows the electrode material 221 at the stage when the size of the electrode and whether it is plate-shaped or net-shaped are determined by design (shown as a plate-shaped member in the figure).

At the center of the electrode material 221 (see FIG. 8), 1
It is bent at an angle of 20 ° to obtain the structure shown in FIG. The shape of the bend is indicated by reference numeral 222.

The above-mentioned threaded rod 28 is fixed as a connecting rod required for energization. Three such electrode materials are prepared.

The three structures shown in FIG. 10 are combined as described above, that is, the electrodes 22A, 22B, and 22C are combined with each other so that each of a pair of plate-like portions forming each electrode forms another electrode.
The structure shown in FIG. 7 is obtained by combining the two flat plate portions so as to face each other. The symbol S♯ indicates that the intervals are equalized by the spacer.

Next, with reference to FIGS. 7 and 11, a description will be given of the sequential change of each polarity of the polarity driving poles 22A, 22B and 22C. As shown in FIG.
3 (D) is a fixed GRD (zero V). Electrode 22
A, 22B, and 22C are configured such that one of them becomes an anode and the other two become a cathode (zero V), and these are alternately changed. That is, when the electrode 22A is an anode, the electrode 22A
B and 22C are cathodes. This is the state for the first minute in FIG. Next, the electrode 22B is used as an anode,
A and 22C are cathodes. This is the state for the next minute in FIG. Next, the electrode 22C is used as an anode,
A and 22B are cathodes. This is the state for the next one minute in FIG. This is sequentially repeated (see FIG. 11). The polarity change of the electrodes is performed every minute in the example of FIG. 11 and a three-minute cycle, but the interval is arbitrary. It is common and preferred to alternate at intervals of 10 minutes or less (eg, 1 to 3 minutes).

As a result, the electrodes 22A, 22B, 22C
These become the cathode 2 with respect to the anode 1, and the reduction potential of the cathode characteristics required for improving the water quality becomes superior. Therefore, anode electrical deterioration can be prevented. In addition, each electrode 22A, 22B, 22C
When viewed individually, the state of being an anode and the state of being a cathode alternate, so that no deposition of metal deposits occurs here. This is because the cations precipitated in the state of the cathode are removed in the state of the anode. For this reason, the deposits are always concentrated and adhere to the grounding electrode 23 (cathode cover). Thus, the polarity driving poles 22A, 22A
The anode deterioration is prevented on the 2B and 22C, and the ground deposits (Ca, Si, Mg, etc.) do not adhere and can be used without cleaning at all. Therefore, the polarity driving pole is permanent without maintenance. Operation becomes possible. The maintenance only needs to be performed on the grounding electrode 23 (cathode cover) at all times, and as described above, the detachment and cleaning are easy.

Next, the effect when wire electric discharge machining is performed by using the above-described electrolysis treatment system 1 together will be described with reference to data. First, processing system 1
Whether the ions in the pure water were actually captured by
That is, whether or not the processing system 1 actually contributes to maintaining the purity of pure water is clarified by analyzing the electrode deposits on the processing system 1. Furthermore, the life of the ion exchange resin when wire electric discharge machining is performed (replacement time required)
The data will be used to explain how the process is performed and whether or not the life of the ion exchange resin is actually extended and waste is reduced.

An electrode test of the processing system 1 was performed as follows, and the state of electrode deposits in the processing system 1 was examined. Pure water having an electric conductivity in the range of 10 to 30 μS / cm is charged as a machining fluid into the machining tank 11 of the wire electric discharge machine body 10, and the wire electrode (made of brass) and the workpiece are put in the pure water. And processed. Simultaneous water tank 1
In 2, deionization was performed by the ion exchange resin 14, and in the treatment system 1, deionization was performed by electrolysis.

In particular, the polarity driving pole 22 of the processing system 1
The gaps (intervals) between the electrodes A, 22B, and 22C are:
It was fixed at 5 mm. The current was kept constant at a constant current of 0.8 A to obtain a deposition current. Voltage is variable, 0.8A
To maintain the voltage. The distance between the polarity driving electrode and the always-grounded electrode 23 (cathode cover) (the distance between the polarity driving electrode and the always-grounded electrode at the closest point. In FIG. 4, the polarity-driving electrode 22A, The distance between the upper end of 22B and the constant grounding pole 23) was 8 mm.

When the test was conducted under the above conditions, deposits were found on the grounding electrode 23 (cathode cover). Power consumption was between 48W and 28.6W. When the electric conductivity of pure water as a working fluid is 10 μS / cm, 20 μS
/ Cm, 30 μS / cm,
Precipitation was observed. As a result, the working fluid is 10 to 30
It is understood that deionization by electrolysis contributes to the case where pure water having any electric conductivity in the range of μS / cm is used.

The results of the analysis of the precipitates are shown in Table 1 below. The substances shown are precipitated substances from fresh water ion-exchanged with the ion-exchange resin. The ion exchange capacity indicates the amount of the substance that could not be exchanged (supersaturated substance). The amount of zinc is particularly large, which is Zn in the raw material (brass, Zn + Cu) of the processed wire, and the tendency of ion dissociation is Zn> Cu, so it is considered that zinc was large. The measurement (analysis) results are shown on a dry basis.

[0057]

[Table 1]

As is clear from the above analysis results, the ions in the pure water, which is the processing fluid, are actually captured by the processing system 1, from which the processing system 1 actually contributes to maintaining the purity of the pure water. You can see that it is. Therefore,
It can clearly be seen that the treatment system 1 reduces the burden on the ion exchange resin.

Next, an actual machine test was performed to determine how long the ion exchange resin can be actually prolonged and how long the processing time can be extended by using this system.

The actual machine used for the test was a U53K machine manufactured by Makino Milling Machine Co., Ltd. The test was performed by requesting Electric Discharge Chamber Co., Ltd. As the ion exchange resin cylinder, two pure water vessels (5 liters × 2) were used. When wire electric discharge machining is performed using ion exchange resin according to the conventional technology,
The total processing time (life of the ion exchange resin) was as follows. (1) General life (in the case of using pure water of 30 μS / cm to 20 μS / cm): Within 180 to 160 hours (processing time). That is, when using pure water of 30 μS / cm, the maximum was within 180 hours, and when using pure water of 20 μS / cm, the maximum was within 160 hours. (2) Precise machining life (15 μS / cm to 10 μS / cm
In the case of using pure water): within 120 to 90 hours (processing time). That is, when using 15 μS / cm of pure water, the maximum was within 120 hours, and when using 10 μS / cm pure water, the maximum was within 90 hours. The test was performed at a pure water electrical transmission rate specified by the manufacturer of the wire electric discharge machine.
The results are as above, in any case at most 1
The total processing time was within 80 hours.

Next, when the wire electric discharge machining is continuously performed using the above-described processing system according to the present invention,
The results of examining the total processing time (life of the ion exchange resin) are shown. Processing is performed using pure water of 30 μS / cm. The material of the workpiece is an actual order processing for actual machine use, so it is possible to receive orders for stainless steel, iron-based materials (iron for molds, etc.), super steels, aluminum, etc. It was miscellaneous. The first: From October 7, 2000 to December 2, 2000 ... 75
2 hours processing time Second time: December 2, 2000-March 7, 2013 ...
784 hours of processing time Third time: March 7, 2001 to May 19, 2001 890
Further processing time is continuing

As is evident from the above test results, a dramatic increase in the life of 780 hours or more, more preferably 890 hours or more, was achieved from the conventional ion exchange resin life of 180 hours. By extending the life of the ion exchange resin, it is possible to greatly reduce the cost required for replacing the ion exchange resin. Further, since the life of the ion exchange resin is extended, waste can be reduced, which is extremely advantageous. In the past, the exchange time was short, and it was necessary to select the workpiece and processing conditions in accordance with it, and there was no margin for freedom, but the flexibility of the ion exchange resin has been extended, so the freedom is much greater. became. Problems due to variations in processing conditions and processing results accompanying the exchange of the ion exchange resin are reduced, and processing reliability is increased.

[0063]

As described in detail above, according to the present invention,
First, in a wire electric discharge machining technique for machining a workpiece by electric discharge from a wire electrode placed in pure water, the ion exchange capacity of an ion exchange resin for maintaining the purity of pure water is promoted to deteriorate the ion exchange resin. It has been possible to provide a wire electric discharge machining technique that can prolong the service life, solve the machining problems associated with early resin replacement, make it cost-effective, and reduce waste. Secondly, it is a pure water purity maintaining technology that can be used for the above-mentioned technology, and in the case where pure water purity maintenance is required, solves the problem associated with early resin replacement in the same manner as described above, and makes it cost-effective. The technology that can reduce waste can be provided. Thirdly, an electrolysis method and an electrode used for electrolysis that can be effectively used in each of the above technologies can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a wire electric discharge machine according to the present invention.

FIG. 2 is a perspective view showing an example of a processing tank in a processing system using electrolysis.

FIG. 3 is a diagram showing a configuration example of electrode grounding in a processing tank in a processing system by electrolysis.

FIG. 4 is a view showing an example of an arrangement of an electrode assembly that can be used in the embodiment of the present invention, and showing a change in the polarity of an electrode.

FIG. 5 is a configuration diagram showing an example of an electrode assembly that can be used for implementing the present invention.

FIG. 6 is a perspective view showing an example of a polarity driving electrode that can be used for carrying out the present invention.

FIG. 7 is a cross-sectional view showing an example of a polarity driving electrode that can be used for implementing the present invention.

FIG. 8 is a diagram for explaining the formation of an example of a polarity driving electrode that can be used for carrying out the present invention (1).

FIG. 9 is a diagram for explaining formation of an example of a polarity drive electrode that can be used for carrying out the present invention (2).

FIG. 10 is a diagram for explaining the formation of an example of a polarity driving electrode that can be used for carrying out the present invention (3).

FIG. 11 is a diagram illustrating an example of a change in polarity of electrodes of a polarity driving electrode.

FIG. 12 is a diagram for explaining a conventional technique.

[Explanation of symbols]

1 ... processing system (by electrolysis), 2 ... processing tank, 3 ... controller, 4 ... installation table,
5 injection system, 6 injection system, 7 injection port, 8
····························································································································· Electrode assembly ,
22 ... Pole for polarity drive, 22A ... (forms a pole for polarity drive) Electrodes A, 22B ... (forms a pole for polarity drive)
Electrodes B, 22C (which form a polarity driving electrode) Electrode C,
23 ... Always ground electrode.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3C059 AA01 AB05 EA02 EA08 EB08 4D025 AA06 AB02 DA06 DA10 4D061 DA05 DB13 DC20 EA02 EB01 EB05 EB14 EB20 EB30 EB33 EB39 GC16

Claims (13)

[Claims] 1. A method for maintaining the purity of pure water in wire electric discharge machining in which a workpiece is machined by electric discharge using a wire electrode disposed in pure water, the method comprising the steps of: A method for maintaining purity of pure water for machining water in wire electric discharge machining, wherein purity maintenance is performed and purity maintenance by deionization using electrolysis is used in combination. 2. An apparatus for maintaining the purity of pure water in wire electric discharge machining for machining a workpiece by electric discharge using a wire electrode disposed in pure water, wherein the pure water is maintained by an ion exchange resin. An apparatus for maintaining the purity of pure water for machining water in wire electric discharge machining, comprising: an ion exchange system that maintains purity; and an electrolysis system that performs deionization using electrolysis. 3. A wire electric discharge machining method for machining an object to be processed by electric discharge using a wire electrode arranged in pure water, the method comprising maintaining the purity of the pure water with an ion exchange resin, A wire electric discharge machining method, wherein the wire electric discharge machining is carried out together with the maintenance of purity by deionization using decomposition. 4. A wire electric discharge machining apparatus for machining a workpiece by electric discharge using a wire electrode disposed in pure water, wherein the pure water in which the wire electrode and the workpiece are to be disposed is removed. A wire electric discharge machine body having a machining tank for performing electric discharge machining therein, an ion exchange system for maintaining the purity of the pure water, and an electrolysis for maintaining the purity of the pure water And an electrolysis system for performing deionization using a wire. 5. A method for maintaining the purity of pure water, wherein the purity of the pure water is maintained by deionizing the pure water by performing deionization from the pure water. A method for maintaining the purity of pure water, which comprises maintaining purity by deionization using decomposition. 6. An apparatus for maintaining the purity of pure water by deionizing pure water to maintain the purity of the pure water, wherein the ion exchange system maintains the purity of the pure water using an ion exchange resin. And an electrolysis system for performing deionization using electrolysis. 7. An electrolysis method for performing deionization by electrolysis, comprising: a three-phase electrode as a polarity driving electrode;
One of the three-phase electrodes for driving the polarity is applied with direct current, and the other two of the three-phase electrodes are electrolyzed in a state of being a ground electrode; and An electrolysis method characterized in that electrolysis is performed in this state by sequentially changing electrodes to which a direct current is applied. 8. The electrolysis method according to claim 7, wherein the sequential change of the electrodes to which the direct current is applied is performed at equal time intervals. 9. The one-phase electrode as the always grounding electrode,
The electrolysis method according to claim 7 or 8, wherein an electrode cover is formed to cover all or a part of the three-phase electrodes for polarity driving in a non-contact manner. 10. An electrode used for electrolysis, wherein a pair of flat plate portions adjacent at an angle of 120 ° form one electrode.
The first electrode, the second electrode, and the third electrode have three electrodes as the first electrode, the second electrode, and the third electrode, on which the electrodes are formed. Wherein each of the pair of flat portions forming a pair is combined with each other in a structure facing one of the pair of flat portions forming another electrode. 11. The first electrode, the second electrode, and the third electrode.
11. The electrode according to claim 10, further comprising an electrode forming an electrode cover that covers all or a part of these electrodes in a non-contact manner. 12. An electrode in which one electrode is formed by a pair of plate-shaped portions adjacent to each other at an angle of 120 ° is a first electrode,
The first electrode, the second electrode, and the third electrode have three electrodes as a second electrode and a third electrode,
An electrode having a structure in which each of a pair of plate-like portions forming each electrode is combined with each other in a structure facing one of the pair of plate-like portions forming another electrode, wherein the first electrode and the second electrode are used. One of the electrode and the third electrode
One electrode is applied with direct current, and the other two electrodes are subjected to electrolysis in a state of being a ground electrode, and the electrodes to which direct current is applied are alternately changed to perform electrolysis in the above state. Electrolysis method. 13. The first electrode, the second electrode, and the third electrode.
13. The electrolysis method according to claim 12, further comprising an electrode forming an electrode cover that covers all or a part of the electrode in a non-contact manner, wherein the electrode forming the electrode cover is always a grounding electrode.