JPH0134731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric discharge machining apparatus, and more particularly to an electric discharge machining apparatus that performs electric discharge machining on a workpiece in a machining fluid containing organic compounds mixed with water at a proportion that does not burn them.

Generally, in electric discharge machining equipment that uses machining fluid, the concentration of the machining fluid being circulated changes as machining is performed.
This has caused a decline in machining performance or machining accuracy. Therefore, in this type of equipment, a processing fluid concentration measuring device is attached to the processing fluid circulation device, and the measurement results of this concentration measuring device are displayed on an appropriate display device, indicating whether replenishment is required or not, and the type of replenishing fluid. , it was previously proposed to form it as shown as an indication of quantity.

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. There was a device consisting of an activated carbon filtration tank 16 and a machining fluid circulation device 20 that circulates the machining fluid 10 by disposing an ion exchange tank 18 for improving the specific resistance value of the machining fluid 10 in the middle thereof. . In the machining liquid 10 in the machining tank 12,
The electrode 22 and the workpiece 24 are positioned facing each other. The machining fluid circulation device 20 includes a drain fluid tank 26 to which machining fluid 10 containing sludge is fed 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. Drainage tank 2
The processing liquid 10 in 6 is sent by a pressure pump 30 to a filter 14 made of paper, cloth, etc., and then divided and a part of it is sent to a supply liquid tank 28. The remainder that is diverted and sent to the supply liquid tank 28 is sent to the electromagnetic valve 32
The liquid is sent to the activated carbon filtration tank 16 and the ion exchange tank 18 in sequence via the
sent to. 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 the 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. Further, numerals 40 and 42 in the figure are valves that respectively adjust the flow rate of the machining fluid 10. Further, between the activated carbon filtration tank 16 and the ion exchange tank 18, a filtration determination device 44 for visual determination and a concentration measuring device 46 for the processing liquid 10 are provided. A display device 48 attached to the control box 38 displays whether replenishment is required or not, as well as the type and amount of replenisher, based on the measurement results of the concentration measuring device 46.

Next, we will explain the operation of this conventional device.
Machining fluid 10 containing sludge as a result of electrical discharge machining is sent to drain tank 12 . In this drain tank 12, 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 fluid 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. Furthermore, since the machining liquid 10 from the activated carbon filtration tank 16 passes through the filtration determination device 44, it is not only possible to visually determine the lifespan of the activated carbon, but also passes through the concentration measurement device 46, and the measurement results are is displayed on the display device 48, so that water, organic compounds, etc. can be easily replenished. In addition,
When the concentration measuring device 46 is operated at appropriate time intervals, it contributes to power saving and the like.

However, such a machining fluid circulation device 20
In this case, although the concentration measurement and display of the processing fluid 10 are automated, replenishment must be done manually each time using the indicated amount of replenisher of the indicated type, which requires a human being for replenishment. However, the productivity was extremely low.

The present invention was created in view of the problems with the previous proposal, and its purpose is to automatically replenish the replenisher fluid in conjunction with the measurement of the concentration of the machining fluid, improve productivity, and constantly improve productivity. It is an object of the present invention to provide an electrical discharge machining device that can perform electrical discharge machining using machining fluid in the best condition.

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. A machining fluid circulation device is provided with an ion exchange tank disposed midway therein, and a concentration measuring device for measuring the organic compound concentration of the machining fluid after passing through the activated carbon filtration; and a machining fluid replenishment device that controls the concentration of the machining fluid to be constant.

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 explanations will be omitted.

In the present invention, a replenishing device 50 for the machining fluid 10 is provided in the conventional device. This replenishing device 50 includes a concentrated liquid tank 52 that stores the concentrated processing liquid 10, a pressure pump 54 that sends the processed liquid 10 in the concentrated liquid tank 52 to the supply liquid tank 28, a water supply pipe 56, and a valve. 58 is configured to be activated by a signal indicating the measurement result from the concentration measuring device 46.

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 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 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.

Furthermore, since the machining fluid 10 from the activated carbon filtration tank 16 passes through the filtration determination device 44, not only can the activated carbon be visually determined, but it also passes through the concentration measuring device 46, so the machining fluid 10 passes through the filtration determination device 44. The concentration of organic compounds in 10 can be determined. As a result of this determination, for example, if the concentration is low, the concentrated liquid tank 5
2 pressure pump 54 is operated to supply the concentrated processing liquid 1.
The replenishing device 50 is operated to send water to the supply liquid tank 28, and when the concentration is high, the valve 58 is opened and the replenishment device 50 is operated to send water to the supply liquid tank 28.

In the present invention, the machining fluid 1 is provided in the machining fluid circulation device 20.
0 concentration measuring device 46 and a replenishing device 50 that automatically supplies water or concentrated machining fluid 10 into the machining fluid 10 based on the measurement result of the concentration measuring device 46, replenishment is automatic. In addition to improving productivity, the machining fluid can be
concentration can be maintained at an ideal constant value, and the performance and accuracy of electric discharge machining can be improved.

Note that the concentration measuring device 46 is provided downstream of the activated carbon filtration tank 16. 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.

Further, a liquid level meter (not shown because it is well known) is provided in the concentrated liquid tank 52, and a lamp 60 is provided in the control box 38 to indicate when the processing liquid 10 in the concentrated liquid tank 52 is below a certain level. By operating the switch 62 provided in the control box 38, the pressure pump 54 pumps the machining liquid 1 in the concentrated liquid tank 52.
A dissolving device 64 for dissolving water and organic compounds, which is configured to draw up 0 and inject it into the concentrated liquid tank 52 again.
When attached, it is convenient because not only can the water and organic compound be completely dissolved, but also the dissolution can be done automatically. In addition, 66 in Fig. 2 is a timer to allow the melting work to be performed only for a certain period of time.
68 is a valve that opens when the processing liquid 10 in the concentrated liquid tank 52 is sent to the supply liquid tank 28;
This is a valve that opens when performing melting work.

As described above, according to the present invention, an activated carbon filtration tank and a concentration measuring device are provided in the machining fluid circulation device, and the replenishing device is automatically operated based on the measurement results of the concentration measuring device. The concentration of organic compounds in the processing fluid can be automatically kept constant at all times, and even if the concentration of organic compounds changes due to water evaporation, etc., this can be automatically corrected. can be kept constant. This allows electrical discharge machining to be performed in the optimum condition at all times.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a conventional device, and FIG. 2 is a system diagram of the device of the present invention. 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. 50 is a replenishing device, 52 is a concentrated liquid tank, and 64 is a dissolving device.

Claims (1)

[Scope of 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 exchange for improving specific resistance. A machining fluid circulation device is provided with a tank in the middle, and a concentration measuring device for measuring the organic compound concentration of the machining fluid after passing through the activated carbon filtration tank; An electric discharge machining apparatus characterized by comprising a machining fluid replenishment device that controls the concentration of an organic compound to be constant. 2. The electric discharge machining apparatus according to claim 1, wherein the replenishing device is configured to replenish the machining fluid with an appropriate amount of water or a concentrated liquid of an organic compound in a concentrated liquid tank. 3. The electric discharge machining apparatus according to claim 2, wherein the concentrated liquid tank is equipped with a water and organic compound dissolving device and a liquid level meter.