JPH0242613B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a machining fluid treatment device for electrical machining equipment such as electrical discharge machining that uses an electrical discharge machining fluid whose main component is water. In the field of drilling and die-sinking using rod-shaped or full-shaped electrodes in the field of electric discharge machining, hydrocarbon oil-based fluids such as kerosene (white kerosene) and transformer oil are usually used as machining fluids. On the other hand, in the field of so-called wire cut electrical discharge machining using wire electrodes, ordinary water, especially pure water, has been commonly used as the machining fluid. In the former case, kerosene is sometimes used because it is convenient for preventing rust in the machine, but it is generally used in the processing condition range of finishing processing where the processing speed is slow but the machined surface roughness is small and dimensional accuracy is high. The machining performance of each type is generally better than others over the entire machining condition range, from rough machining where the machined surface is rough but the machining speed is high, and is approximately proportional to the set machining conditions. It is relatively cheap and easy to obtain, has a relatively long life, and does not cause any particular pollution problems during processing or after-treatment such as disposal, but it is relatively easy to dispose of. It is thought that this is due to the following reasons. However, the biggest drawback of hydrocarbon oil-based machining fluids such as kerosene and transformer oil is that the fluids are flammable, and electrical machining such as electrical discharge machining is carried out in the machining fluids. Alternatively, a pair of electrodes (one is a machining electrode and the other is a workpiece) are faced to each other with a minute gap in between, and current is applied to the gap to generate intermittent electrical discharge, electrical discharge, etc. On the other hand, this type of electrical processing equipment performs automatic processing without an operator being present at the machine all the time during its operation. For this reason, the processing fluid used is kerosene with various additives added to raise the ignition temperature, and in recent years, automatic fire extinguishing devices for fire detection have been installed in each machine. Items that are attached to electrical discharge machining equipment still pose a risk of ignition and fire.
For this reason, although it is a machine for automatic processing as described above, it is difficult to operate unattended or overnight. The latter, processing liquid water, poses no danger of fire or the like, and even if various additives such as rust preventive agents are required, they are extremely cheap and easy to dispose of, and unlike hydrocarbon oils, they are not harmful to human skin. It has various advantages over hydrocarbon oil-based machining fluids, such as those that do not cause problems with machining fluids, etc., and in terms of machining performance, for example, the duration of voltage pulses is approximately several tens of microseconds.
It is fully comparable to hydrocarbon oil-based machining fluids in the so-called finish machining condition range where the machined surface roughness is less than about 10 μRmax, and is suitable for medium to rough machining with machined surface roughness of more than the above. When the machining conditions are close to 1, or when the machining area of the machining electrode becomes large, the machining speed may drop dramatically, machining becomes difficult, or the electrode wear increases and the electrode decreases. There is a drawback that consumable machining cannot be performed, so the machining conditions for the above-mentioned machining liquid water are limited to the so-called finishing machining condition range.
Furthermore, it is only used in wire cut electric discharge machining (usually numerical control method), which corresponds to machining modes where the machining area is not large. However, as long as the so-called pure water of 5×10 ³ Ωcm or more is used as the machining fluid (of course, it also includes those to which around a few percent or less of rust preventive agents etc. are added), the machining voltage pulse (or discharge current pulse) ) width (τ _po or τ _D ) is around 30 to 20 μRmax or above, i.e., when the processing conditions are higher than medium processing conditions,
For example, extremely special machining conditions such as when the no-load voltage of the voltage pulse (τ _po ) is made particularly large, or when the discharge current amplitude (Ip) of the discharge pulse (τ _D ) is made particularly large; Conventional conventional voltage pulses (τ _po ) or discharge pulses (τ _D ), and if necessary, each condition of the pause time (τ _pff ) between voltage pulses (τ _po ), or modifications to these that are relatively easily possible. At present, even if the method is elaborated, it cannot be put to practical use because of the sudden decrease in processing speed and increase in electrode wear as described above. Therefore, the present inventors have already mixed water as the main component with a surfactant of about 10% or less, or around a few percent, or, at the same time, mixed a hydrocarbon oil-based so-called conventional machining fluid component of around a few percent. Furthermore, we are developing an electrical discharge machining fluid to which a microscopic amount of less than 1% by volume (apparent) of fine conductive particles such as metal powder of around several μm diameter or less is added. If an electric discharge machining fluid containing a small amount of a surface active agent or hydrocarbon oil is used, the machining speed will decrease and the degree of electrode wear will be reduced, and there will be no risk of fire, so for example, numerically controlled overnight unattended machines can be used. Machining by driving becomes possible. However, such surfactants have the disadvantage that they are generally expensive. For this reason, for example, Japanese Patent Application No. 56-176128 and Japanese Patent Application No.
In prior inventions such as No. 56-181567, a novel electrical discharge machining method was proposed in which the machining fluid containing the above-mentioned surfactant was consumed with almost no waste.
That is, for example, "a machining electrode and a workpiece electrode are opposed to each other with a minute interval between them, and a voltage pulse is applied intermittently while there is a rest period in the opposed micromachining gap where machining fluid is supplied. In the electric machining method, the part of the workpiece electrode facing the machining electrode is removed by an electric discharge generated by applying the same, and the machining gap is maintained and controlled as the machining progresses. In this method, a substantially non-flammable water-based machining fluid containing water as the main component is used as the machining fluid, and a total type electrode for drilling or engraving having a machining area of around several cm ² or more is used as the machining electrode. The machining fluid is continuously applied to the machining gap while the machining electrode and the workpiece electrode are placed in air so that at least the machining gap is formed and maintained in the air outside the stored machining fluid. When machining is performed by the electric discharge that is injected selectively or intermittently, machining gap inclusions and products such as electric discharge machining debris, sparks, machining fluid and its decomposition products are removed from the outer periphery of the machining gap. An electric machining method characterized by controlling and restricting the supply of the machining fluid into the machining gap so that the machining progresses while maintaining the state in which the machining fluid is ejected and scattered into the air by the electric discharge. In this type of control, the control to limit the supply of machining fluid into the machining gap ensures that almost all of the machining fluid supplied to the machining gap is used by vaporizing, vaporizing, decomposing, burning, etc. The ideal state is that the process is completed, but the processing area, processing shape, processing electrode shape, how to provide the processing fluid supply nozzle, how to form or provide the processing fluid supply path and opening on the electrode or the workpiece, Depending on the machining shape, machining conditions, or machining state depending on the progress of machining, the above machining liquid may be sprayed and supplied to the machining gap at a supply amount, for example, several times the amount that is consumed in the machining gap as described above. However, it is inevitable that such machining fluid may be supplied as a result, and in such a case, as described in the above-mentioned prior invention, more than a portion of the excessively supplied machining fluid is removed. The solid waste is recovered in a mixed state with processing waste and processing liquid slag that can be disposed of (for example, processing waste that does not contain active ingredients such as surfactants, water containing combustion slag of active ingredients, etc.). The method is to perform separation and other treatments before recirculating and supplying the raw materials, but these treatments are quite difficult. In other words, water other than the usually expensive surfactant (pure water), hydrocarbon oils such as spindle oil added in small amounts as necessary, and others added as necessary such as rust preventives. Since these additives are relatively inexpensive, it is not necessarily necessary to recover them. However, if you try to recover the above-mentioned surfactants while they are dissolved in water, you will not be able to separate and remove the various impurities generated during electrical discharge machining. Therefore, the specific resistance of the machining fluid could not be improved or recovered, and the regeneration treatment of the machining fluid was difficult. That is, in the treatment of the above-mentioned processing fluid, it is necessary to separate the organic matter such as surfactant and hydrocarbon oil into the organic matter such as water and other inorganic matter, and then deionize the latter. It was difficult to regenerate the processing fluid and recover and reuse the surfactant except by discarding the latter and using fresh pure water. The present invention has the advantage that there is no fear of the occurrence of fire, etc., unmanned overnight operation is possible, and it can be realized economically, or it further contains a small amount of hydrocarbon oil or fine conductive powder. An object of the present invention is to provide a machining fluid processing device in an electrical discharge machining machine that uses an electrical discharge machining fluid whose main component is water. The present invention aims to recover and reuse expensive surfactants after use, and as a surfactant,
A surfactant recovery device that uses an aqueous solution whose solubility significantly decreases (that is, has a cloud point) as the temperature of the aqueous solution increases, and that heats the processed solution to separate it from water as a solid component. The surface active agent recovery device includes a regeneration treatment tank that stores the processed liquid, a heating device that heats the processed liquid in the regeneration treatment tank to a temperature higher than the clouding point, and a surface active agent that is precipitated by heating. A stirring device that stirs the adhered material that promotes the separation of the surfactant by adhering the surfactant to the processed liquid in the regeneration treatment tank, and a regeneration of the supernatant liquid in which the surfactant is deposited. Equipped with a device for discharging the supernatant to the outside of the treatment tank, and a water supply device that flows water (pure water) into the regeneration treatment tank after discharging the supernatant liquid to reduce the temperature and redissolve the surfactant in the water. It is characterized by With such a configuration, electric discharge machining using a water-based machining fluid as described in the invention of the prior application such as the above-mentioned Japanese Patent Application No. 56-176128 can be economically practical as far as the machining fluid is concerned. In addition, the water-based machining fluid can be used in conventional electrical discharge machining methods other than the special electrical discharge machining method described in the prior invention. However, it is considered to be useful because its processing performance is equivalent to or higher than that of water (pure water), and there is less electrode wear. The present invention will be explained below with reference to the drawings. The drawing shows one embodiment of the present invention, and 1 is an electrical discharge machining tank in which an electrode 2 and a workpiece 3 are set, and the electrical discharge machining fluid is supplied in a limited amount to the machining gap between the electrode 2 and the workpiece 3 in a necessary amount. The used electrical discharge machining fluid 4 containing machining waste, decomposition products, etc., which is sprayed and supplied to the destination, is collected as described below.
At least the surfactant contained therein can be recovered and reused. In the present invention, as the electrical discharge machining fluid 4, an aqueous solution containing water as a main component and having a cloud point by mixing at least a surfactant is used. The machined liquid after being used in the electrical discharge machining tank 1 is led to the sedimentation tank 5, and the machined waste 1
0 Other product solids are precipitated. The settling tank 5
Two limit switches LS ₁ and LS ₂ for detecting liquid level are provided with an interval in the vertical direction, and a stirring device 7 is also provided. Reference numeral 8 denotes a regeneration tank. The regeneration tank 8 has a volume that is approximately a fraction of that of the sedimentation tank 5. When the limit switch LS ₁ is activated, the pump 9 and piping 9a cause the sedimentation tank 5 to be drained.
The processed liquid inside is introduced into the regeneration treatment tank 8, and when the limit switch LS ₂ or LS ₃ is activated, the introduction is stopped. Inside the regeneration treatment tank 8, there are a heating device 11 that heats the processed liquid from which most of the solids have been removed by precipitation above the clouding point, an agitation device 12, a temperature sensor 13, and a limit switch for detecting the liquid level.
LS ₃ and LS ₄ are installed, and fine powder such as iron powder 14 is deposited to attach the surfactant during heating. 15, when oil such as kerosene oil is mixed into the machining fluid, it does not contain a surfactant and is extracted from the machining fluid slag (mostly water and the supernatant liquid pumped from the recycling tank 8) to be disposed of. This oil separation tank is provided to separate and recover partially pumped iron powder (including some processing scraps), and the regeneration treatment tank 8 and the oil separation tank 15 are connected to a discharge pipe with a pump 16. 17 and
It is connected by a return pipe 19 having a pump 18 and a return pipe 19 to which the iron powder (surfactant is partially attached if kept at a temperature). The oil separation tank 15 separates oil from water (drained liquid) based on the difference in specific gravity between water and oil, and is divided into an oil separation side and a discharge side by an intermediate partition plate 20. A filter 21 is installed to remove iron powder and processing waste, and a concentration sensor 22 for ions generated by processing is installed on the drain outlet side of the filter 21. After the concentration sensor 22 detects the concentration, the drain The water is discharged through a pipe 23.
The pump 18 is operated appropriately to return the deposited iron powder to the regeneration treatment tank 8 to prevent consumption and loss of the iron powder in the treatment tank 8. Reference numeral 24 denotes an iron powder for separating the iron powder that is simultaneously pumped up from the pumped processing liquid by sedimentation when a solution in which a surfactant is dissolved by injecting cold pure water is pumped up from the processing tank 8 and reused as a processing liquid. The separation tank 24 and the regeneration treatment tank 8 are a separation tank, and the separation tank 24 and the regeneration treatment tank 8 are a reuse processing fluid suction pipe 2 having a pump 25.
6 and an iron powder return pipe 28 having a pump 27. 29 is a filter provided as necessary to remove iron powder from the machining fluid pumped up from the processing tank 8; 30 is a filter that guides the machining fluid from which the iron powder has been removed to the machining fluid tank 31 for reuse. It is a return pipe. In the processing liquid tank 31, oil such as kerosene oil, surfactant, etc. 32 are mixed in order to add or replenish the necessary amount, and a pump 33 is used to
The electrode 2 is connected to the electrode 2 via a valve 34 and piping 35, 36.
Alternatively, it is supplied from one or both of the processing tanks 1 to the processing gap between the workpiece 3 or to fill the processing tank 1. 37 is an ion exchange resin for removing ions from the tap water 38; 39 is a pure water tank for storing pure water after ion removal; the pure water in the pure water tank 39 is pumped by a pump 40 to a pipe having a valve 41; 42, it can be combined with the processing liquid and supplied to the processing parts such as the electrode 2, and can also be introduced as cold pure water into the regeneration treatment tank 8 via a pipe 44 having a valve 43. I'm starting to be able to do it. Next, the operation of this device will be explained. The processed liquid in the processing tank 1 is supplied to the settling tank 5,
When the liquid level reaches the limit switch LS ₁ , the pump 9 is turned on and the processed liquid flows into the regeneration treatment tank 8. When the liquid level in the treatment tank 8 reaches the limit switch LS ₃ , the pump 9 is turned off and then , preferably rapidly heated by a heating device 11, and stirred the processed liquid together with iron powder of 3μφ pre-filled with about 20% by volume of the introduced processed liquid, for example, by a stirring device 12, for example, 0.5 m//.
The iron powder 14 is forcibly stirred at a speed of sec, that is, so that the iron powder 14 floats and moves throughout the processing tank 8. When the processed liquid is heated above the cloud point (for example, 55 ° C.), the surfactant in the processed liquid is adsorbed on the surface of the iron powder, and the amount of iron powder 14 is sufficient for the surface active agent. Almost all of the surfactant dissolved in the processed liquid is adsorbed onto the surface of the iron powder 14, and settles to the bottom of the regeneration tank 8 when the stirring is stopped. On the other hand, ions generated by electrical discharge machining are left behind in the supernatant liquid, and most of the decomposition products from each tank that are floatable in water remain in the supernatant liquid, and oil is mixed in. If so, the oil will remain in the liquid or float to the surface. Therefore, after agitation is stopped, a certain amount of sedimentation time is allowed, or the sedimentation is forcibly performed, for example, by magnetic means, and the supernatant liquid is pumped into oil by the pump 16 until the lower limit switch LS ₄ is activated. By introducing the liquid into the separation tank 15 and allowing it to stand still, most of the suspended matter in the ions and decomposition products in the processed liquid can be pumped up and removed together with the water with reduced purity. Further, oil can be recovered in an oil separation tank 15 if necessary. The processed liquid from which oil and solids have been removed by the filter 21 is water with reduced purity, so it may be supplied to the resin tank 37 and reused, but since this may damage the resin 37, it is usually is discharged via the drain pipe 23. After discharging the supernatant liquid, open the valve 43 and drive the pump 40 to drive the pure water (preferably cold water) in the pure water tank 39, so if necessary, install a cooling device between the tank 39 and the pure water. ) is allowed to flow into the regeneration treatment tank 8 through the piping 44 until the limit switch LS ₃ is activated, and the iron powder 14 to which the surfactant is attached is suspended, and the iron powder is The adsorbed surfactant is dissolved in water and regenerated as a processing fluid. The iron powder is separated from the recycled machining fluid by stopping stirring and settling, and the supernatant regenerated machining fluid is passed through the iron powder separation tank 24 and the filter 29 to sufficiently remove the iron powder, and the machining fluid is returned through the return pipe 30. and return it to the machining liquid tank 31, and add oil such as kerosene oil or
Add or replenish surfactant and others 32, mix, and pump 33 to valve 34 and piping 35, 3.
6 to the processing section such as the electrode 2. In addition, in the specific example in the above-mentioned example,
The volume up to the limit switch LS ₃ above the regeneration treatment tank 8 was set to 10, the processing amount per cycle was set to 6, the processing amount per minute was set to 200 c.c./min, and the cycle time per cycle was set to 30 minutes. The recovery rate of the surfactant in this case was 95%. In addition, for example, in electrical discharge machining as described in the invention of the prior application such as the aforementioned Japanese Patent Application No. 56-181567, the machining fluid flow rate changes depending on the machining conditions (electrical conditions) and the degree of difficulty of the machining shape. The relationship between the flow rate f _R and the optimum minimum flow rate f(v)min is as follows. f _R = f (v) min + F Here, f (v) min changes in relation to machining conditions such as voltage pulse τ _po and current pulse Ip, and F is a flow rate that is not involved in machining, that is, machining shape and machining state. In order to supply machining fluid to each part of the machining gap as desired, it is necessary to supply more than the necessary amount of machining fluid, but as a result, the flow rate of the machining fluid that is excessive . The flow rate F that is not involved in this machining is unused machining fluid, so the total supply amount of pure water (machining fluid) F _T that needs to be supplied to the machining parts such as the electrode 2 is F _T = F + f (v) It becomes min×α. However, α is a coefficient that changes depending on the processing conditions. By controlling this total pure water supply amount F _T , it becomes a recycled processing fluid. Such pure water may be supplied not only to the regeneration treatment tank 8 but also to the processing liquid tank 31, or may be supplied via a valve 41 to join the pipe 36. It's okay. In the illustrated embodiment, the processed liquid is treated in the treatment tank 8 to cause the surfactant to adhere to and settle on the iron powder 14, and the supernatant liquid is pumped out to the oil-water separation tank 15 by the pump 16, and then to the pure water tank. If the amount of pure water supplied from 39 to the processing tank 8 by the pump 40 corresponds exactly to the unused flow rate of the processing fluid, the surface of the liquid returned to the liquid tank 31 via the piping 30 will be reduced. The concentration of the activator will match that of the initial unused machining fluid, but the flow rate α×f(v)min consumed during machining will vary considerably depending on the momentary machining conditions of the machining gap. Therefore, the amount of pure water supplied from the pure water tank 39 to the processing tank 8 is larger than the amount of pure water corresponding to the above flow rate.
For example, the processed liquid treated in the processing tank 8, that is, about 60% of the liquid pumped into the oil separation tank 15, should be adjusted to the concentration of the surfactant and other substances in the processing liquid tank 31 or at a stage before it. is desirable.
Of course, if necessary, the flow rate α×f(v)min may be detected by continuous detection of the processing state, and the amount of pure water supplied to the processing tank 8 by the pump 40 may be automatically controlled each time. The surfactant may be a polyethylene glycol type nonionic surfactant, a lauryl alcohol or nonylphenol type surfactant added with ethylene oxide, or a surfactant based on lauryl alcohol or nonylphenol, or a surfactant based on the above-mentioned patent application filed in 1983.
-176128, various silicone oil-based surfactants or alkylphenol-based ones are used, and the mixing amount of these is about 0.1 to 15% by weight, especially about 0.1 to 5%. preferable. In addition, in order to prevent an increase in electrode wear, or to stabilize machining performance such as machining speed, the amount of hydrocarbon oil, such as spindle oil or kerosene oil, should be reduced to about 10% or less, preferably 4 to 4%. It is preferable to add about a few percent of 5% or less, and if necessary, to stabilize the processing conditions and improve the processing speed, about 0.01 to 0.5% of conductive powder such as fine metal powder is mixed. The above-mentioned hydrocarbon oil is uniformly dispersed in the form of minute oil droplets in water, which is the main component, by adding the above-mentioned surfactant.
In addition, the iron powder that is attached to the treatment tank 8 and is added for magnetic field separation for high-speed separation has a size of about 0.1μ to 20μ, and the mixed amount is about 0.1 to 10% by weight. It is desirable that Note that when magnetic field separation is not used, sand, other ceramic powder, non-magnetic metal powder, or the like that does not dissolve in water may be used in place of the iron powder. In addition to separating by applying a magnetic field, it is also possible to use dielectric powder such as synthetic resin powder instead of iron powder to perform electrostatic or dielectric separation by applying a DC or AC electric field, or to perform electrostatic or dielectric separation by applying a DC or AC electric field. In the case of a water-based electrical discharge machining fluid, in which fine powders of graphite, iron, copper, nickel, zinc, etc. are added to the fluid as necessary for electrical discharge machining, machining waste may be used to supplement the iron powder 14. The fine powder may also be used as adsorbent powder in the processing tank 8. In any case, if the adsorbed materials such as iron powder in the treatment tank 8 decrease, the intended treatment in the treatment tank 8 cannot be performed, so the oil separation tank 15 and the separation tank 24 are used to collect and process them. The structure is such that the water is returned to tank 8.
Further, instead of powder, various steel materials may be used as objects to be adsorbed by inserting them in multiple cylindrical shapes around the stirring blades and between the inner circumferential wall of the processing tank 8. In addition, to explain the separation effect due to the above-mentioned magnetic field and electric field using experimental results, discharge was performed using a machining fluid made by adding 1% of a nonionic silicone oil-based ^surfactant and 1% of spindle oil to water with a specific resistance of 10 5 Ωcm. After processing,
12% ethylene oxide in nonyphenol
Mix the molar addition and add 5μφ iron powder.
After mixing 15% and heating to 65℃ while stirring,
The activator adheres to the iron powder and processing waste, separates it from the water spindle oil and other water-dissolved substances, and allows it to settle by natural settling for about 3 hours.The supernatant liquid is pumped out and the precipitate is cooled. When pure water was added and dissolved, approximately 96% of the surfactant was recovered. Furthermore, when a magnetic field of 1100 G (Gauss) was applied at 50 Hz after the above-mentioned stirring, 99.5% of processing waste and surfactant were recovered by precipitation separation and then water dissolution in 35 minutes. When a DC magnetic field was applied, 98% recovery was achieved. Further, in the above embodiment, the supernatant liquid in the regeneration treatment tank 8 was discharged after solids such as iron powder and oil and water were separated, but it is also possible to pass the supernatant liquid through an ion exchange resin and reuse it. You may also do so. Reusing the supernatant fluid saves water and eliminates pollution problems caused by discharge of electrical discharge machining fluid. Table 1 shows the experimental results of electrical discharge machining using an electrical discharge machining fluid using polyether-modified silicone oil as a surface active agent. In the experiment, approximately 30 mm was used as a processing electrode.
Using a φ copper electrode, S55C iron material is the workpiece,
Voltage pulse duration (τ _po ) approximately 60 μS, pause time (τ _pff ) approximately 20 μS, and discharge current amplitude (Ip) approximately 45 A.
When processing was carried out using various processing fluids, the results shown in Table 1 below were obtained.

[Table] In the above table, A is when pure water with a specific resistance of approximately 0.5 x 10 ⁴ Ωcm is used as the machining fluid, and B is when a solution consisting of 80% polyethylene glycol and the balance of water from A above is used as the machining fluid. In this case, C is a machining fluid that can be purchased as an electrical discharge machining fluid at a gas station, etc., and if a hydrocarbon oil consisting essentially of kerosene is used as the machining fluid, although the ignition point has been raised with additives, D, E , F, G are the experimental results of the present invention, and are sold by Shin-Etsu Chemical Co., Ltd. under the product name KF-352, with a viscosity of approximately 1600CS (25℃), a specific gravity of approximately 1.03 (25℃),
Polyether-modified silicone oil with a refractive index of about 1.446 (25°C) is dissolved in the water of A above, D is about 0.2%, E is about 0.5%, F is about 1.0%, and G is about 2.0% to make a processing liquid. In this case, the numbers without parentheses are A,
As in the case of machining fluids B and C, these are the results when electrical discharge machining is performed in the conventional conventional machining mode, whereas the numerical values in parentheses are those obtained when applied to the novel electrical discharge machining method described in the prior invention mentioned above. This is the case. Above, the present invention has been explained about the so-called electric discharge machining fluid for electrical machining and the electric discharge machining method using the machining _fluid . ，
One or more kinds of electrolytes such _as NaNO ₂ , KNO ₃ , KNO 2 , Na ₂ CO ₃ , NaOH, etc. can be added thereto to be used as a machining fluid for electrolytic discharge machining or electrical discharge electrolytic machining. As described above, in the present invention, since the electrical discharge machining fluid mainly consists of water containing a surface active agent and having a cloud point, it is possible, for example, to perform electrical discharge machining in numerically controlled overnight unattended operation. It goes without saying that it becomes possible to do this without wasting the expensive surfactant added to the main ingredient water, such as by discarding it.
Since the surface active agent can be recovered and used until it is decomposed or wasted due to the action of electric discharge machining, there is an advantage that electric discharge machining can be carried out more economically than when conventional kerosene is used. Further, in the present invention, since the processing liquid is regenerated through a series of operations of heating the processed liquid in the regeneration treatment tank, discharging the supernatant liquid, and adding pure water, the surfactant is separated. Therefore, the device can be realized economically without requiring a filter or the like.

[Brief explanation of the drawing]

The drawing is a system diagram showing one embodiment of the present invention. 8... Regeneration treatment tank, 11... Heating device, 12...
... Stirring device, 15... Oil separation tank, 39... Pure water tank.

Claims (1)

[Scope of Claims] 1. In an electrical processing device that uses an aqueous solution mixed with a surfactant as a machining fluid, the solubility of the surfactant decreases significantly as the temperature of the aqueous solution increases, and The surfactant recovery device is equipped with a surface active agent recovery device that heats the processed liquid to separate it from water as a solid content, and the surface active agent recovery device includes a regeneration treatment tank that stores the processed liquid, and The adhering material promotes the separation of the surfactant by adhering the surfactant, the agitation device stirs the processed liquid in the regeneration treatment tank, and the supernatant liquid in which the surfactant is deposited is regenerated. It is equipped with a supernatant liquid discharge device that discharges the supernatant liquid to the outside of the treatment tank, and a water supply device that causes water to flow into the regeneration treatment tank after the supernatant liquid is discharged, thereby lowering the temperature and redissolving the surfactant in the water. A machining fluid treatment device for electrical machining, which is characterized by: 2. The machining fluid treatment device for electrical machining according to claim 1, wherein the machining fluid further contains hydrocarbon oil, and the supernatant fluid discharge device includes an oil recovery device.