JPH0248376B2 - WAIYAKATSUTOHODENKAKOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire-cut electric discharge machining apparatus, and in particular, a machining fluid supply circuit for generating a discharge between a wire and a workpiece and supplying machining fluid to a machining area for cutting the workpiece. , relates to improvements in wire-cut electrical discharge machining equipment.

Conventionally, a machining fluid supply circuit system as shown in FIG. 1 has been used to supply machining fluid to the discharge gap between the wire and the workpiece in the machining area to remove machining powder and cool the wire. In Figure 1, 10
12 is a workpiece, 12 is a wire electrode, and 14 is an upper nozzle for spouting machining liquid 18 to a machining area 16, which has a guide 20 for guiding the wire electrode 12 inside. 22 and 24 are a lower nozzle and a lower guide located below the workpiece 10, respectively. 26, 28 are an upper hydraulic pressure gauge and a lower hydraulic pressure gauge indicating the ejection pressure of the upper or lower working fluid 18; 30;
Reference numerals 32 denote an upper valve and a lower valve for adjusting the liquid amount in the upper or lower part. 34 is a machining fluid pipe constituting a machining fluid supply circuit, and 36 is a pump that supplies the machining fluid 18 in the machining fluid tank 38.
is pressurized and delivered to processing area 16 through line 34, valves 30 and 32, and nozzles 14 and 22. Although not shown, the upper side of the nozzle 14 and the lower side of the nozzle 22 have very small holes necessary for the wire to pass through.

As described above, the machining fluid 18 is supplied to the machining zone 16 by the pump 36, and the flow rate in the machining zone 16 is adjusted to a certain appropriate amount by the valves 30, 32.

The conventional apparatus is constructed as described above, but in order to improve machining performance, especially machining speed, it is necessary to increase the flow rate of machining liquid 18 in machining zone 16 to facilitate discharge of machining powder. Therefore, it is desirable to use a high-head, high-flow pump as the pump 36.

FIG. 2 shows an example of the pressure flow characteristics of such a pump. During normal processing, nozzle 14 or 2
In order to reduce the distance between 2 and the surface of the workpiece 10 and increase the flow velocity to the processing area 16, processing is performed while spouting the processing fluid 18 at the high pressure section at point 40 with the pump characteristics shown in Fig. 2, for example. It's summery. However, as shown in Fig. 3, when the thickness of the workpiece 10 decreases during processing, the gap between the nozzle 14 and the surface of the workpiece 10 increases, and the flow resistance of the machining fluid circuit as seen from the pump decreases. Then, we move on to the characteristic of point 42 in FIG. This results in a large increase in the flow rate from Q ₁₂ to Q ₁₃ , and the flow rate increases between the nozzle 14 and the workpiece 1.
The scattering 44 of the machining fluid 18 from the gap 0 increases,
There was a drawback that liquid splashing 44 to the outside became a problem. In addition, in order to prevent this scattering 44, at the beginning of processing, the flow rate and hydraulic pressure are reduced in advance by the valve 30 or 32 to a point where scattering does not become a problem even if the gap between the nozzles 14, 22 and the workpiece 10 widens. It was necessary to lower the hydraulic pressure and reduce machining performance.

In addition, as another method to prevent scattering, the nozzle 1
There is also a method of immersing the entire workpiece 10 and the workpiece 10 in the machining liquid 18, but this method requires the installation of a machining liquid reservoir, which increases the size of the equipment, makes it expensive, and has poor operability. There were some drawbacks such as:

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to increase the flow rate by reducing the flow resistance between the nozzle and the workpiece and increase the liquid flow rate by providing a flow rate control device in the machining fluid supply circuit. It is an object of the present invention to provide a wire-cut electric discharge machining device that suppresses the scattering of machining liquid, prevents the occurrence of rust due to external scattering of machining fluid, and allows sanitary work.

In order to achieve the above purpose, a wire electrode is provided facing the workpiece and generates electrical discharge in the machining area between the workpiece and the machining fluid pipe, which is pumped up from the machining fluid tank using a pump. A machining fluid supply circuit that supplies machining fluid to a machining area through a nozzle, and a valve that is disposed in the machining fluid conduit and adjusts the amount of machining fluid to a set amount. The present invention is characterized in that a flow rate control device is provided in the circuit to prevent the machining fluid from flowing beyond a preset flow rate.

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

The present invention is illustrated in FIG.
Components that are the same as those in the drawings are given the same reference numerals and their explanations will be omitted.

In FIG. 4, 46 is a pressure-compensated flow control valve (hereinafter referred to as a constant flow valve) provided in the machining fluid pipe 34, and the flow rate set by this constant flow valve 46 is as shown in FIG. Flow rate during normal processing
The flow rate is set to Q _{20 at point 48, which is slightly larger than Q 12} , ie, point ₄₀ . This constant flow valve 4
6 prevents the machining fluid from flowing into the machining fluid pipe line 34 at a flow rate exceeding a preset flow rate. When this constant flow valve 46 is provided, the pressure flow characteristics at the output portion of the constant flow valve 46 side of the pump 36 are as shown in FIG. The one-dot chain line in the figure shows the characteristics when the constant flow valve 46 is not provided. That is, in the processed part where the normal plate thickness does not change, the characteristic point 40 in Fig. 5
If processing is performed at a pressure and flow rate of
The flow rate does not increase above _Q20 .

This occurs when the thickness of the workpiece 10 decreases and the gap between the nozzle 14 and the workpiece 10 becomes larger as shown in FIG. Even if the flow resistance between the workpieces 10 decreases, the flow rate is automatically kept below _Q20 by the constant flow valve 46, so the flow rate will be _Q13 as in the state without the constant flow valve in Fig. 2. It does not increase significantly. Therefore, nozzle 14,2
Splashing of liquid between the workpiece 2 and the workpiece 10 can be suppressed to a small amount. Furthermore, even when there is no workpiece 10, the amount of machining fluid 18 does not increase beyond _Q20 , so that the amount of splattering and supply of machining fluid 18 can be kept low.

In the above embodiment, there is a constant flow valve 4 in the machining fluid supply circuit.
However, by installing a solenoid valve and a flow rate or pressure sensor in the circuit, and operating the solenoid valve by sensing an increase in flow rate or a change in pressure, the pipe resistance of the machining fluid supply circuit can be reduced. It is also possible to suppress the increase in flow rate by increasing the flow rate. Further, the same effect can be obtained by changing the motor rotation speed of the supply pump 36 based on the signal from the flow rate sensor to suppress an increase in the flow rate.

As explained above, the present invention includes a flow rate control device that prevents the machining fluid from flowing beyond a preset flow rate in the machining fluid supply circuit that supplies the machining fluid to the machining area. It is possible to suppress an increase in the flow rate ejected from the nozzle due to a decrease in the flow resistance of the machining liquid supply circuit system due to a decrease in the thickness of the workpiece, etc., and as a result, it is possible to prevent the occurrence of liquid scattering between the nozzle and the workpiece. This prevents rust from forming and is also hygienic.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the configuration of a conventional machining fluid supply circuit for wire-cut electric discharge machining equipment, Figure 2 is a characteristic diagram showing an example of the pressure flow characteristics of the conventional machining fluid supply circuit and pump, and Figure 3 is FIG. 4 is a cross-sectional view showing the relationship between the processing area and the nozzle in a conventional device when the thickness of the workpiece is reduced; FIG. 4 is a schematic diagram showing the configuration of a processing fluid supply circuit according to an embodiment of the present invention; ,
FIG. 5 is a characteristic diagram showing an example of the pressure-flow rate characteristics of the pump and the machining fluid supply circuit that have changed due to the implementation of the present invention. The same members in each figure are given the same reference numerals, 14 is a machining area, 18 is a machining fluid, 34 is a machining fluid pipe, 46
is a pressure compensated flow control valve.

Claims (1)

[Scope of Claims] 1. A wire electrode that is provided to face a workpiece and generates electrical discharge in a machining area between the workpiece and the workpiece, and a machining fluid pipe that pumps machining fluid from a machining fluid tank using a pump. A wire-cut electric discharge machining apparatus comprising: a machining fluid supply circuit that supplies the machining fluid to the machining area through a nozzle; and a valve disposed in the machining fluid pipe line to adjust the amount of the machining fluid to a set amount, A wire-cut electric discharge machining apparatus characterized in that a flow rate control device is provided in the machining fluid supply circuit to prevent the machining fluid from flowing at a flow rate exceeding a preset flow rate. 2. A wire-cut electric discharge machining apparatus according to claim 1, characterized in that the flow rate control device is a pressure-compensated flow rate control valve. 3. A wire cut electric discharge machining apparatus according to claim 1, wherein the flow rate control device is formed by a sensor that detects a change in flow rate or a change in fluid pressure, and a solenoid valve operated by the sensor. 4. A wire-cut discharge device according to claim 1, characterized in that the flow rate control device is formed by a sensor that detects a change in flow rate and a control device that controls the motor rotation speed of the pump based on a signal from this sensor. Processing equipment.