JPS5877410A - Electric discharge machining unit - Google Patents

Abstract

PURPOSE:To prevent a fire from happening attributable to hydrocarbon, by supplying an electric discharge gap with an EDM fluid of liquid hydrocarbon, while designing to feed water into an EDM tank. CONSTITUTION:A pump 35 is driven by a motor 36, and liquid hydrocarbon including kerosene, etc., is fed into a space formed up by a workpiece 3, an EDM electrode 4 and a diaphragm 9 via an inflow port 11. On the other hand, water is fed into an EDM tank 1 by means of a pump 33. The overflowed fluid from an outflow port 12 goes up inside a cover 14 whereby water is also filled up inside the cover and when the water level reaches 1a, water is discharged out of the tank via a discharge port 1c; the water is separated from the EDM fluid and repeats regenerating and returning to the tank afterward.

Description

[Detailed Description of the Invention] In electrical discharge machining in which machining is performed in a machining fluid filled in a machining tank, liquid hydrocarbon compounds such as kerosene have been generally used as the machining fluid. When using Kt1, it is important to perform good electrical discharge machining in all machining areas from rough machining to finishing machining Kt1. Ru. However, kerosene is easily ignited and always carries the risk of fire outbreak, and although electric discharge machining equipment equipped with various fire extinguishing devices has been provided, it is difficult to avoid fire accidents and In this regard, if water (distilled water) is used as the machining fluid, the risk of fire will be eliminated, but since the electrical resistance value of water is smaller than that of crocin, applying a voltage pulse with a large pulse width or peak current to the machining gap will Arc discharge is likely to occur, and electrolytic action increases, making it impossible to perform good electrical discharge machining.If water is used as a machining fluid, it is relatively difficult to perform machining in the machining range from rough machining to semi-finish machining. If this is difficult, it is desirable to use a liquid hydrocarbon compound such as kerosene as the processing fluid.

The present invention takes advantage of the above points and is proposed to use a hydrocarbon compound as a machining fluid and to prevent the occurrence of fire. In the machining gap formed by the machining electrode and the machining workpiece, a partition wall is provided surrounding the lateral periphery of a machining electrode that is provided on the workpiece and is arranged opposite to the workpiece, and A machining system that is equipped with a machining fluid supply device that supplies a machining fluid made of a liquid hydrocarbon compound and a water supply device that supplies water into a machining tank, and in which machining is performed using a hydrocarbon compound such as kerosene as a machining fluid. The feature is that electrical discharge machining is performed while the part is immersed in water.

Hereinafter, the present invention will be specifically explained based on the drawings.

FIG. 1 is a front sectional view showing an apparatus according to an embodiment of the present invention, and FIG. 2 is a view taken along the line A--A in FIG.

In Figure 1, l is the processing tank, 1m is the overflow wall in the processing tank 1, 1b is the drain hole, and lc is the overflow drain hole◇
Reference numeral 2 is a nine processing table provided at the inner bottom of the processing tank 1 to form an x-y plane. Reference numeral 63 is a workpiece fixedly placed on the processing table 2, and 4 is a workpiece facing the upper surface of the workpiece 3. It is a processing electrode arranged in a manner that it is held by an electrode holder 5 and that the electrode holder 5
The 0-stage ▲7, which is attached to the stage 57 via the electrode mounting jig 6, is machined by a servo device (not shown) in two axial directions intersecting the X-Y thousand-plane plane according to the machining state). The vertical reciprocation in the Z-axis direction is carried out for the purpose of maintaining the appropriate degree of machining debris κ in the machining fluid at the machining amount IIK by eliminating the tar in the machining debris generated during one machining period 11. Further, the workpiece 3 and the machining electrode 4 are connected to a machining power source 8. 9m is a spacing member provided to surround a portion of the side surface of the processing electrode 4 that is away from the top surface of the workpiece 3, and 9b is a spacing member provided to surround the separation member 9a and provided on the top surface of the workpiece 3. A wall member provided with a distance of 1 m between the separating member 9a and the wall member 9b.
G is formed. Note that the term ``separation member'' here refers to a member that separates the wall member '9b from the side surface of the processing electrode 4, and the term ``partition wall'' refers to a member that separates the processing part from the water that fills the surrounding area. 0 Separation member 9 Hatake, wall member 9 meaning a wall that separates
Both b are made of synthetic resin, heat-resistant rubber, or t9 wall member 9b
is composed of a porous material similar to a sponge,
Both members 9as9b are integrally formed with screws or adhesive.
Moreover, both members 9a and 9b are not necessarily manufactured separately, and may be integrally molded from the beginning. The partition wall 9 and the processing electrode 4 do not necessarily need to be fixed together; for example, a synthetic resin or hard rubber molded into a shape that surrounds the side surface of the processing electrode 4 may be used as the separation member 9.1, and the partition wall 9. is placed on the upper surface of the workpiece 3, and while the processing electrode 4 is in sliding contact with the separation member 9a, or between the two, 0.5 to 1. It is possible to provide a gap of about Off so that the processing electrode 4 can move in the Z-axis direction without coming into contact with the separation member 9. In addition, when the partition wall 9 and the processing electrode 4 are configured integrally,
In order to enable the partition wall 9 to follow the movement of the processing electrode 4 or to prevent the partition wall 9 from interfering with the movement of the processing electrode 4, at least the wall member 9b is made of a flexible material having elasticity similar to that of soft rubber. In this case, the partition wall 9 is brought into close contact with the side recess of the processing electrode 4 using a tightening AIO. In addition, the flexible wall member 9
When using b, a band-shaped flexible material is placed around the separating member 9go. Just attach it and secure the ends with adhesive or pins. The separating member 9al' is provided with an inflow hole 11 and an outflow hole 12 for machining fluid, and the machining fluid inflow hole 11 is connected to a machining fluid supply device via a machining fluid supply pipe 13.
The number of inflow holes 11 and outflow holes 12 are appropriately distributed depending on the size and shape of the processing electrode 40. 9. Wall member 9
b is made of a porous material 9], the processing electrode 4 and the separation member 9
If a gap is provided between a, it is not necessarily necessary for the outflow hole.

Furthermore, 114 is an inverted funnel-shaped machining fluid collection cover that is fixed to the stem 7 and arranged to cover the upper area of the workpiece, and is made of fire-resistant metal or metal coated with synthetic resin. Consists of layers of round wood. A gas discharge hole 15 is provided at the upper end of the machining liquid collection cover 14, and the discharge hole 15 is connected to a solenoid valve 16.
It is connected to a gas processing device 18 via a gas exhaust pipe 17 having a gas discharge pipe 17. Reference numeral 19 denotes a gas exhaust valve provided in the pipe 17, and a drive motor for the pump 19. Furthermore, machining fluid discharge holes 21 are provided at appropriate locations on the side surface of the collection cover 14, and the discharge holes 21 are connected to the water separation treatment device U via a machining fluid discharge pipe having a solenoid valve 22. The part is a machining fluid discharge pump installed in the pipe n, and the name is the drive motor of the pump part. Inside the collecting cover 14, there is a detector for detecting the water level and the machining fluid level. It will be done.

141.14b is a level switch for liquid level detection, 14C
.

14'514e is a detector for detecting water level. Detector 1
4c114d and 14e are provided facing each other at the same level within the collection cover. In this embodiment, they are located facing the sea bream surface inside the cover and the stem, and the medium interposed between the opposing detectors. A signal that changes depending on the type of water (water or machining fluid) K is detected.

For example, the resistivity of the medium interposed between the two electrodes was detected by using the opposing detector as a current-carrying electrode), or the opposing detector was configured with a light-emitting element such as a light-emitting diode and a light-receiving element, and the light-receiving device changed depending on the type of the intervening medium. [detecting the amount] or, alternatively, the opposing detector is configured with an ultrasonic oscillator and a sonic receiver to detect the received energy that varies depending on the species 111 of the intervening medium). In addition to using a detector that detects signal changes due to the intervening substance species 111 as described above, a level switch that utilizes the difference in specific gravity between water and processing fluid may also be used. Further, 14f is an air vent hole, and 14g is a valve 0γ for opening and closing the hole 14f.
is the collection cover 14 in response to the detection signal from the detection.
A control device that controls the discharge of gas and processing fluid in the
The armpit control device 4 controls the electromagnetic valve 16, motor application, electromagnetic valve n, and motor base. In addition, field is water-over-regeneration equipment, 4 is water storage container, (capital) is processing fluid-over-regeneration equipment, 3
1-wire machining liquid storage container, 32 is a water supply pipe connected to the machining tank 1, 33 is a nine supply pump installed in the water supply pipe 32, U is a pump NO drive motor, is a machining fluid supply pump interposed in the machining fluid supply pipe 13, 37.3B is a drive motor for the pump 35, and 37.3B are both flow rate control valves.
Drive the machining fluid (liquid hydrocarbon compound such as kerosene)
The water is supplied from the inlet hole 11 to the space (machining part) formed by the workpiece 3, the machining electrode 4, and the gap 11G, and the pump 33 is driven by the motor 34 to supply water to the machining tank l.
supply within. At this time, the valve 14g of the collection cover is left open. Until the machining tank 1 is filled with water, the machining fluid is continued to be supplied as necessary to prevent water from entering the machining section, and the machining fluid overflowing from the outflow hole 12 rises above the water surface. As the water level rises, the air inside the collection cover 14 flows into the holes 14.
water is discharged from f, and the collection cover 14 is also filled with water.

The water level further rises and the collection cover becomes immersed in water. When the water level reaches the upper end of the overflow wall 1a, the machining fluid floating on the water surface goes over the wall 1a together with the water and flows out of the machining tank from the discharge hole IC. leaks to. The water and processing fluid that flowed out are collected, separated and recycled. When the inside of the collection cover 14 is filled with water, the valve 14g is closed and the control device I is activated to start monitoring by each detector. Thereafter, the machining fluid overflowing from the machining area floats in the water and is collected and contained within the collection cover 14, so that the flammable machining fluid does not float above the water surface of the machining tank. Moreover, even if some machining liquid deviates from a part of the collection cover and floats on the water surface of the machining tank, the floating machining liquid will be discharged from the overflow wall la along with the water. Once the machining tank l has been heated with water, the amount of water supplied is adjusted by the flow rate regulating valve blades, and the amount of machining liquid supplied to the machining section is also adjusted as appropriate by the flow rate regulating valve 37. In this state, normal electric discharge machining is performed by applying a voltage pulse between the workpiece 3 and the machining electrode 4 from the machining section W8.

A liquid hydrocarbon compound is fed under pressure to the machining part, and gas is generated along with tar and machining debris in the machining gap due to electrical discharge machining. When using kerosene as the processing fluid,
Gaseous normal hexane, cyclohexane, hydrogen, propane, trace amounts of carbon monoxide, and carbon dioxide are generated, and since some water is mixed into the processing gap, hydrogen and oxygen are generated by decomposition of water. The nine gases generated flow out into the water from the outflow hole 12, float to the surface, and are collected and contained within the collection cover 14.
Some of the tar and processing waste is also contained within the collection cover while adhering to the gas bubbles. Normal hexane and cyclohexane are cooled in water and most of them are liquefied and stored. Also,
Machining fluid in an amount greater than that required for machining is supplied to the machining part under pressure, and the surplus machining fluid also flows out into the water from the outflow hole 12 and floats to the surface, where it is stored in the collection cover 14. .

A part of the generated tar is dissolved in this surplus machining fluid and is discharged and removed from the machining section, and furthermore, tar and machining waste are discharged and removed from the machining section into water by the flow of the surplus machining fluid that flows out. In this way, tar and machining debris generated in the machining gap can be removed from the machining part by the cleaning action of the surplus machining fluid, and the bopping effect due to the cleaning action of the surplus machining fluid and the vertical reciprocating movement of the machining electrode 4. The concentration of machining debris in the machining gap is adjusted and controlled. Therefore, the amount of machining fluid supplied to the machining portion is controlled to change so as to maintain the machining debris concentration in the machining gap appropriately, and machining is always performed in a good discharge state. First, since the wall member 9b of the partition wall 9 is separated from the discharge generation site by the separation member 9aK, the presence of the partition wall 9 does not have a sudden effect on machining, and the partition wall 9 is not damaged by pulsed discharge. . Furthermore,
It is preferable that the separating member 9a and the wall member 9b constituting the partition wall 9 be made of rubber magnets, or that the magnets are arranged inside the members, so that the machining waste generated in the machining fluid is transferred to the wall surface of the partition wall 9. It can be removed by adsorption. The machining fluid inflow hole 11 and outflow hole 12 may be provided on the side surface of the wall member 9b, and if a gap is provided between the machining electrode 4 and the separation member 9a, the gap acts as the outflow hole. Needless to say.

On the other hand, in the collection cover 14, various substances are accommodated in a stacked state in the order of gas, liquid hydrocarbon compound, and water from the top, and the accommodation level of each substance is monitored by a detector.

When the liquid level of the machining fluid (liquid hydrocarbon compound) decreases due to the accumulation of gas in the upper part of the collection cover 14 and reaches the position 14b, the skeleton switch 14b detects this and operates. In response to this detected operation signal, the solenoid valve 16 is opened by the control device 27, the motor is energized, and the operating circuit of the solenoid valve 16 and the rotation drive circuit of the motor are self-maintained. , pump 19
is driven, gas is fed to the gas processing device 18, and the liquid level of the machining liquid is near the upper end of the collection cover.
When it rises to position a, cough switch 14a operates,
This detection operation signal cancels the self-holding circuit, closes the solenoid valve 16, and also stops energizing the motor to stop the pump 19. This operation is repeated in response to changes in the liquid level to discharge the gas. Such a means for discharging wheat gas is used when it is necessary to forcefully feed the gas to the gas processing device, and if the natural flow of gas is sufficient for discharging the gas, there is no need to provide a level switch, solenoid valve, pump, etc.

When the amount of machining fluid stored in the collection cover 14 increases and the interface (water level) between the machining fluid and water drops to a position below the detector 14d, the detector 14d disposed opposite
When the substance present in r14 changes from water to machining fluid, the detection signal by the detector 14d changes. When the control device n discriminates this detection signal and detects that the water level has fallen below the position of the detector 14d, it activates the solenoid valve 2.
2 is opened, the motor 4 is energized to drive the pump section, and the machining fluid in the collection cover is sucked through the discharge hole 21 and sent to the water separation treatment device 24. Here, it is undesirable to repeatedly start and stop the pump section (it makes the operation complicated),
Thereafter, since it is desirable that the machining fluid be constantly sucked and discharged during machining, the amount of machining fluid discharged is adjusted by changing and controlling the rotational speed of the motor 26. That is, at the stage when it is detected that the machining fluid has reached the level of the detector 14d, the motor is operated at a relatively low rotational speed, and the amount collected in the collecting capane is larger than the amount discharged. K to increase the number. At this time, the operating circuit of the solenoid valve part and the low-speed drive circuit of the motor are automatically maintained. Eventually, the amount of machining fluid in the collection cover increases and the water level further decreases.
When it is detected that the machining fluid has reached the level of the detector 14e, the control device 27 increases the rotational speed of the motor 4 and increases the amount of machining fluid discharged by the pump section.

At this time, the motor's high-speed drive circuit is self-maintained at 0.
As the amount of discharge increases, the machining fluid inside the collecting cover decreases, and the water level rises to the position of the detector 14d.
When the detection signal changes to a signal that detects water, the water detection signal releases the self-holding of the high-speed drive circuit of the motor 26, and the motor 26 starts operating at a low rotation speed again.

Thereafter, by repeating these operations, the water level within the collection cover 14 will be maintained between the detectors 14d and 146. In addition, the amount of machining fluid collected in the collection cover is extremely reduced, and the amount of discharge becomes excessive even when the motor 26 rotates at a low speed, and the water level rises, causing the position of the detector 14C near the machining fluid discharge hole 21 to drop. When the water reaches this point, the water detection signal from the detector 14C releases the self-holding of the operating circuit of the solenoid valve B and the low-speed drive circuit of the motor, and the solenoid valve 22 is closed and the operation of the pump section is stopped. After that, when the amount of machining fluid stored in the collecting cover increases and the water level decreases, the machining fluid will be discharged again by the above-mentioned operation.Also, the change control of the machining fluid discharge amount is controlled by the pump drive. In addition to changing and adjusting the rotation speed of the motor, a flow control valve may be provided in the discharge pipe, and the opening degree of the valve may be changed and controlled in accordance with changes in the water level.

The machining liquid discharged from inside the collection cover in this way is
The mixed water is separated from the machining fluid in the water separation treatment equipment, and the separated water and machining fluid are sent to the water-over-regeneration equipment and the machining fluid-over-regeneration equipment, respectively, where they are regenerated. After that, it is stored in the water storage container 29 and the machining fluid storage container 31.

In addition, since the inner surface of the collection cover 14 and the area around the waste 7 are contaminated by adhesion of generated tar, etc., ultrasonic transducers are installed at appropriate locations inside the collection cover and in the processing tank to prevent contamination. Prevention and cleaning should be carried out. In this case, 25 to 15
Ultrasonic waves of 0KHz, 2o~sQw frequency are used, and the cleaning effect is enhanced by washing away with excess machining fluid.Furthermore, the cleaning effect can be improved by using two or more frequencies in combination. can be increased.

3 and 4 show the wall member 9b of the partition wall 9 in the present invention.
This shows an example in which the device is made of a porous material such as sponge, and the same reference numerals as in FIGS. 1 and 2 indicate the same parts. In this embodiment, a partition wall 9 is formed by a separation member 9a made of a metal surface coated with rubber, synthetic resin, or the like, and a wall member 9b made of a porous material fixed to the inner surface of the member 9a. is configured, and the separating member 9a
The partition wall 9 is placed on the workpiece 3 with a minute gap 9C of about 0.5 to 1.0 mm interposed between the electrode 4 and the workpiece 3. In addition, a machining fluid flow path is formed from a machining fluid inlet hole 11 opening on the side surface of the machining electrode 40, passing through the electrode and opening into the machining gap), and a machining fluid discharge hole 12 is provided on the side surface of the separating member 9a. ing. A plurality of outflow holes 12 are provided as necessary. In the embodiment shown in FIG. 3, the machining fluid is supplied from the inflow hole 11 through the inside of the electrode to the machining gap as shown by the arrow, and is supplied to the partition wall 9 together with the machining products.
The wall member 9 is made of sponge or the like.
0 flowing out into the water from the outflow hole 12 through b and other processing*a generated gases are discharged and floated into the water from the gap 9C between the partition 119 and the processing electrode 4, and are collected by the collection cover 14, Tar and processing waste adhere to the porous wall member 9b and are filtered. Therefore, the processing fluid collected from the collection cover 14 has less dirt and can be easily processed by the processing 11 filtration and regeneration device.) , it is possible to always supply clean machining liquid to the machining gap to perform efficient machining, and the machining speed can be approximately doubled. Tar contamination can be prevented and reduced. However, in this embodiment, the porous wall member 9b is heavily contaminated, and the filtering effect of the armpit member 9bK is rapidly reduced. The 411th!1st embodiment is a rounded 4 that corresponds to 11 in such a way,
The machining fluid inlet hole 11 is also provided on the upper surface of the separating member 9, and by flowing the clean machining fluid into the porous member 9b, tar can be dissolved and removed. ebopt overlife can be suppressed. Further, the separating member 9a is made of a rubber magnet or the like to have a magnetizing effect,
The porous wall member 9b may be made of a magnetic material, or magnet particles may be scattered within the porous wall member, such as a slot/ji, so that processing waste is magnetically attracted to the porous wall member. The filtering effect of the elastic wall member 9b can be improved.

It should be noted that the processing liquid made of liquid hydrocarbon compound in the present invention does not need to be entirely hydrocarbon oil such as kerosene or trans oil. (Usually, even when bundled, the weight ratio is IIs
The above-mentioned surfactants can also be drawn by dispersing and dissolving them in water (usually so-called pure water). Nonionic surfactants are preferable as they can maintain high resistance of the processing liquid, such as polyether-modified surfactants. It is desirable to use a modified silicone oil such as silicone oil, i.e., a water-soluble silicone oil with the addition of less than about a few degrees of oil.As described above, according to the present invention, a liquid hydrocarbon compound such as kerosene is used as a processing fluid. The machining part to be subjected to electrical discharge machining is immersed in water and machining is carried out in nine states, and
Combustible gases generated during processing and machining liquid flowing out from the machining part are collected and contained within the collection cover, which has at least the lower peripheral edge immersed in water in the machining tank, so there is no risk of fire. Electric discharge machining can be performed safely and efficiently in all machining areas from rough machining to finishing machining.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an apparatus according to an embodiment of the present invention, FIG. 2 is a view taken from the direction of arrow A in FIG. 1, and FIGS. 3 and 4 are apparatuses according to other embodiments of the present invention. FIG. 2 is a partially enlarged front sectional view of FIG. l...Processing tank, 1m--Overflow wall, 1b...Drain hole, 1cm/Overflow liquid drain hole, 2...Processing table, 3...Workpiece, 4... Processing electrode, 6... Electrode holder, 6...
...Electrode mounting jig? - Stem, 8 Processing power supply, 9 Partition wall, 9a Separation member, gb- one member, 1G Fastener, 11 Processing fluid inflow hole, 12.
... Machining fluid outflow hole, 13... Machining fluid supply pipe, 14...
・Processing liquid collection cover, 14a to 14e...detector 14
r...Air vent hole, 14g...Valve, 15...Gas exhaust hole, 16...Solenoid valve, 17...Gas exhaust pipe, 1
8... Gas treatment device 19... Pump, processing... Pump drive motor, 21... Machining liquid discharge hole, 22...
Solenoid valve, n... Processing liquid discharge pipe, S... Water separation treatment device, 6... Pump, name... Pump drive motor, 2
7...Control device, 4...Water p over-refill device, 4...
Water storage container, (capital)...Processing liquid filtration and regeneration device, 31.
... Processing liquid storage container, 32... Water supply pipe, 33...
Pump, U...Pump drive motor, 35...Pump, 36...Pump drive motor, 37...Flow rate control valve, 38...Flow rate control valve Figure 2, Part 4

Claims (1)

[Scope of Claims] (1) A machining electrode and a workpiece are disposed facing each other in a machining tank, and a machining liquid is interposed in the machining gap formed between the two, and a voltage pulse is applied to the keypad in relation to both. In an electrical discharge machining device that performs electrical discharge machining by applying a voltage, a machining electric current is provided on a workpiece arranged on a worktable at the bottom of a machining tank and is placed opposite to the workpiece. A partition wall provided surrounding the circumference of the O side surface, a machining fluid supply device that supplies a machining fluid made of a liquid hydrocarbon compound between the machining steps, and a water supply device that supplies water into the machining tank. (2) A patented electrical discharge machining device characterized in that the partition wall is made of a porous material (3) The above-mentioned electrical discharge machining device characterized in that the partition wall has a magnetic adsorption effect Electrical discharge machining apparatus 0 according to claim 1 (4) A machining electrode and a workpiece are disposed facing each other in a machining tank, and a machining fluid is interposed in a machining gap formed between the two, and In an electrical discharge machining device that performs electrical discharge machining by applying a voltage pulse between the two, a machine is provided on a workpiece that is placed and fixed on a processing table at the bottom of a processing tank, and is opposed to the workpiece. a partition wall provided to surround the side surface of the machining electrode arranged in the machining gap; a machining fluid supply device for supplying a machining fluid made of a liquid hydrocarbon compound to the machining gap; and a water supply supplying water to the machining tank. The apparatus further includes an inverted funnel-shaped machining liquid collecting par that supports the machining electrode or is fixed to the stem and is disposed in the machining tank to cover the upper region of the workpiece. At the same time, a machining liquid discharge device connected to the side opening of the collection cover via a pipe, a detection device for detecting the water level in the collection force par, and a detection signal from the detection device to detect the machining liquid. An electrical discharge and machining device characterized by comprising a control device for controlling a liquid discharge device. (6) A patented electrical discharge machining device characterized in that the machining fluid collection cover has an ultrasonic cleaning device.