JPH0134730B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electric discharge machining apparatus, particularly an electric discharge machining apparatus that performs electric discharge machining on a workpiece in a machining liquid containing an organic compound mixed with water at a proportion that does not burn it.

In general, electric discharge machining equipment that uses machining fluid has been used to maintain the specific resistance value of the machining fluid above a certain value, so ion exchange resins have been used to improve the resistivity value. However, it is known that ion exchange resins tend to adsorb sludge generated by electrical discharge machining, which significantly shortens their lifespan. Therefore, in order to remove sludge of 2μ or more,
Previously, we proposed using an activated carbon filtration tank with a filter made of paper, cloth, etc., to remove sludge of 2μ or less.

This apparatus, as shown in FIG. 1, includes a machining tank 12 in which electrical discharge machining is performed in a machining fluid 10 made of a solution of water and an organic compound, and a filter 14 that removes sludge from the machining fluid 10 in the machining tank 12. , an activated carbon filtration tank 16, and an ion exchange tank 18 for improving the specific resistance value of the machining fluid 10, which is disposed in the middle thereof, and a machining fluid circulation device 20 that circulates the machining fluid 10. In the machining fluid 10 of the machining tank 12, an electrode 22 and a workpiece 24 are placed facing each other. The machining fluid circulation device 20 includes a drain fluid tank 26 to which machining fluid 10 containing sludge is delivered after electrical discharge machining is performed in the machining tank 12, and a supply fluid tank 28 to supply the machining fluid 10 to the machining tank 12. have. The machining liquid 10 in the drain tank 26 is sent to a filter 14 made of paper, cloth, etc. by a pressure pump 30, and then divided and a portion is sent to the supply liquid tank 28. Divided supply liquid tank 2
The remainder sent to the activated carbon filtration tank 16 and the ion exchange tank 18 are passed through the electromagnetic valve 32 in the middle.
After being sent to the supply liquid tank 28, it is similarly sent to the supply liquid tank 28. The machining fluid 10 in the supply fluid tank 28 is sent to the machining tank 12 by a pressure pump 34, and a part of the machining fluid 10 is diverted and passed through a resistivity measuring device 36 to measure its resistivity value. In the figure, reference numeral 38 denotes a control box that opens and closes the electromagnetic valve 32 and adjusts the flow rate of the machining fluid 10 sent to the ion exchange tank 18 according to the resistivity value measured by the resistivity measuring device 36. Also, in the figure 40,
42 are valves that respectively adjust the flow rate of the machining fluid 10. Furthermore, between the activated carbon filtration tank 16 and the ion exchange tank 18, a filtration judgment device 44 for visual judgment is provided.
is provided.

Next, we will explain the operation of this conventional device.
The machining fluid 10 containing sludge as a result of electrical discharge machining is sent to the drain tank 26 . In this drain tank 26, the heavy sludge is precipitated, and the machining liquid 10 containing light sludge is sent to the filter 14 by the pressure pump 30.
The processing liquid 10 containing 1 μm of sludge is filtered. This filtered machining fluid 10 is supplied to the supply fluid tank 2
8, and is further circulated to the processing tank 12 by the pressure pump 34, passing through a valve 40 for adjusting the flow rate. Further, a part of the machining fluid 10 sent from the supply fluid tank 28 to the machining tank 12 is diverted, and a resistivity value is measured by a resistivity measuring device 36, and this value is set as a value preset in the control box 38. In the following cases, open the electromagnetic valve 32 and let a part of the processing fluid 10 sent from the filter 14 to the supply fluid tank 28 pass through the activated carbon filtration tank 16 and the ion exchange tank 18 in order to remove 2 to 1 μm of sludge. At the same time, the specific resistance value is increased to maintain the specific resistance value of the entire machining fluid 10 in the supply fluid tank 28 at the set value, and the machining fluid 10 is fed into the machining tank 12. Furthermore, since the machining fluid 10 from the activated carbon filtration tank 16 passes through the filtration determination device 44, the lifespan of the activated carbon can be visually determined.

However, in this type of machining fluid circulation device 20, consumption of the machining fluid 10 due to use,
In other words, the concentration of the processing liquid 10 containing organic compounds is to be measured manually, which not only has poor workability but also makes it difficult for the measurement results to
It was troublesome to have to calculate the amount of water or organic compound to be replenished each time.

The present invention has been made in view of these problems, and its purpose is to provide an electric discharge machining device that allows machining fluid concentration to be easily measured and machining to be performed in the best possible condition at all times. It is in.

In order to achieve the above object, the present invention provides a machining tank for performing electric discharge machining in a machining fluid consisting of a solution of water and an organic compound, a filter for removing sludge from the machining fluid, an activated carbon filter tank, and a specific resistance value. The present invention is characterized by comprising a machining fluid circulation device having an ion exchange tank disposed midway therein, and a device for measuring the concentration of organic compounds in the machining fluid after passing through an activated carbon filtration tank, in the machining fluid circulation device.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

The present invention is shown in FIG. 2, and the same members as in FIG. 1 are given the same reference numerals, and their explanation will be omitted.

The processing liquid 10 that has passed through the activated carbon filtration tank 16 is sent to the ion exchange tank 18 via the filtration determination device 44, but in the present invention, a filtration determination device is provided between the activated carbon filtration tank 16 and the ion exchange tank 18. Apart from 44,
A concentration measuring device 46 for the processing fluid 10 is provided.

Next, the operation of the apparatus according to the present invention will be described. As a result of electrical discharge machining, the machining fluid 10 containing sludge is sent to the drain tank 26. In this drainage tank 26, the heavy sludge is precipitated, and the machining liquid 10 containing light sludge is sent to the filter 14 by the pressure pump 30.
The processing liquid 10 containing 1 μm of sludge is filtered. This filtered machining fluid 10 is supplied to the supply fluid tank 2
8, and is further circulated by the pressure pump 34 to the processing tank 12 through a flow rate adjustment valve 40. Further, a part of the machining fluid 10 sent from the supply fluid tank 28 to the machining tank 12 is diverted, and a resistivity value is measured by a resistivity measuring device 36, and this value is set as a value preset in the control box 38. In the following cases, open the electromagnetic valve 32 and let a part of the processing fluid 10 sent from the filter 14 to the supply fluid tank 28 pass through the activated carbon filtration tank 16 and the ion exchange tank 18 in order to remove 2 to 1 μm of sludge. At the same time, the specific resistance value is increased to maintain the specific resistance value of the entire machining fluid 10 in the supply fluid tank 28 at the set value, and the machining fluid 10 is fed into the machining tank 12. Here, in the present invention, since the activated carbon filtration tank 16 is provided in the machining fluid circulation device 20, it is possible to adsorb and remove sludge and impurities of 2 to 1 μm or less, which were conventionally considered impossible to remove. For this reason, the processing liquid 10 obtained from the activated carbon filtration tank 16
Since trace amounts of organic matter such as pigment components, sludge, and impurities are removed to a high degree, sludge and the like are not adsorbed to the ion exchange resin in the ion exchange tank 18, extending the life of the ion exchange resin and maintaining its performance. I can figure it out.

In addition, specifically, the activated carbon filtration tank 16 of the present invention
The life of the ion exchange resin is 1.3 to 1.4
Data has been obtained that the effect is increased by about twice as much. In other words, when using the ion exchange resin 51 and controlling the passage of the machining fluid 10 to the activated carbon filtration tank 16 and the ion exchange tank 14 with a specific resistance of 10×10 ⁴ Ωm measured by the specific resistance measuring device 34, the initial resistivity of the machining fluid 10 is 11×10 ⁴ Ωm. Hot processing fluid 10
The processing amount (corresponding to the processing period) of the workpiece until the specific resistance of the workpiece becomes 8×10 ⁴ Ωm or less was 7 kg without the activated carbon filtration tank 42, but with the activated carbon filtration layer 42 In some cases, it grew to about 10kg.

As described above, by providing the activated carbon filter tank 16, the amount of sludge etc. that adheres to the ion exchange resin can be greatly reduced, and the effect that the original ability of the ion exchange resin can be fully exhibited is obtained. It will be done.

In the present invention, the processing fluid 10 from the activated carbon filtration tank 16 not only passes through the filtration determiner 44 but also passes through the concentration measuring device 46 . Therefore, not only can the lifespan of the activated carbon be visually determined by the filtration determining device 44, but also the concentration of organic compounds in the processing fluid 10 can be determined. Therefore, when the concentration of organic matter in the processing liquid 10 is low, concentrated processing liquid can be replenished, and when it is high, water can be replenished.

As described above, according to the present invention, since the device 46 for measuring the concentration of the machining fluid 10 after removing sludge or the like is provided in the machining fluid circulation device 20, the machining fluid can be constantly replenished by replenishing concentrated machining fluid or water. The liquid 10 can be maintained in the best condition, and the accuracy of electrical discharge machining can be improved.

Furthermore, the concentration measuring device 46 is connected to the activated carbon filtration tank 16.
It is located after. Therefore, very fine sludge of 2 to 1 μm or less is also removed from the processing fluid 10 flowing into the concentration measuring device 46. Therefore,
It is possible to accurately measure the concentration of organic processing compounds in the processing fluid.

In other words, the organic compound mixed in the processing liquid 10 is usually sugar, but in this concentration measurement,
Floating sludge etc. have an adverse effect. Furthermore, in the optical method used to measure the concentration of sugars, the influence of pigment components is also large. However, in the present invention, most of the impurities that adversely affect these measurements are removed in the activated carbon filtration tank 16.
Very accurate concentration measurements of organic compounds can be made.

Next, an embodiment of the concentration measuring device 46 and the display device 48 that displays the measurement results of the device 46 will be described with reference to FIGS. 2 and 3.

The concentration measuring device 46 is composed of a transparent pipe 50 through which the machining liquid 10 after sludge removal passes, a light source 52 provided on one side of the pipe 50, and a plurality of light receiving sections 54 provided on the other side. A timer 56 is used to energize the light source 52 at regular intervals. On the other hand, the display device 48 is attached to the control box 38, and includes a lamp 58 corresponding to the plurality of light receiving sections 54 provided in the concentration measuring device 46, and a transparent display plate 60 provided on the front side of the lamp 58. is formed from.

The operation of these devices is such that the light from the light source 52 that is periodically energized by the timer 56 passes through the processing liquid 10 in the transparent pipe 50 and reaches the light receiving section 54, but at this time, due to the refraction of the light, there are multiple Light receiving section 54
The concentration of the organic compound in the processing liquid 10 is measured by displaying which of the light receiving parts 54 the light has reached using the lamp 58 and the transparent display plate 60.

The translucent display plate 60 displays the concentration of organic compounds in the processing fluid as a measurement result, but the measurement results may indicate whether the concentration of organic compounds is inappropriate and whether replenishment is required. Furthermore, whether the replenisher is water or a concentrated processing fluid containing concentrated organic compounds and the amount of replenishment may be displayed at the same time.

In this way, by interlocking the display device 48 with the concentration measuring device 46, it is easy to use and it is easy to detect defective machining fluids.
There have been no accidents due to use of 0. Furthermore, if the display device 48 is formed to display the type of replenishment and the amount of replenishment,
Work efficiency is significantly improved. Furthermore, if the timer 56 is used to periodically measure the concentration,
Not only does it contribute to power savings, but it also has high work efficiency.

Note that the concentration measuring device 46 can also be formed to measure strain, specific gravity, torque, etc. without using light as described above.

Furthermore, it goes without saying that the present invention can be applied to a machining fluid circulation device for a wire-cut electrical discharge machine.

As described above, according to the present invention, since the activated carbon filtration tank, the organic compound concentration measuring device, and its display device are provided in the machining fluid circulation device, the organic compound concentration in the machining fluid can be accurately grasped, and the The liquid can always be kept in the best condition, improving the accuracy of electrical discharge machining.

[Brief explanation of drawings]

FIG. 1 is a system diagram of the conventional device, FIG. 2 is a system diagram of the device of the present invention, and FIG. 3 is a schematic diagram showing the relationship between the concentration measuring device and the display device. In each figure, the same members are given the same symbols, 10 is the machining fluid, 12 is the machining tank, 14 is the filter, 16 is the activated carbon filtration tank, 18 is the ion exchange tank, 20 is the machining fluid circulation device, and 46 is the concentration measurement. The device 48 is a display device.

Claims (1)

[Claims] 1. A machining bath for performing electric discharge machining in a machining fluid consisting of a solution of water and an organic compound, a filter for removing sludge from the machining fluid, an activated carbon filtration tank, and an ion exchanger for improving specific resistance. A machining fluid circulation device with a tank disposed in the middle thereof, a concentration measuring device in the machining fluid circulation device for measuring the concentration of organic compounds in the machining fluid after passing through the activated carbon filtration tank, and a measurement result of the concentration measuring device. An electrical discharge machining device comprising: a display device that displays the following. 2. An electric discharge machining apparatus according to claim 1, characterized in that the display device is formed to display whether or not the machining fluid needs to be replenished. 3. The electric discharge machining apparatus according to claim 2, wherein the display device is formed to display the distinction between replenishers and the amount of replenishment.