JPS59201724A - Working liquid supply device for wire-cut discharge processing machine - Google Patents

Abstract

PURPOSE:To perform the wire discharge processing at extra high accuracy by switching the working liquid pressure just before and after commencement of processing from low to high pressure automatically, and thereby preventing effectively the wire electrode from being cut at the starting time of processing. CONSTITUTION:A groove 5 is formed in a work 2, when a wire electrode 1 intrudes in the work 2 from its end face. In this working liquid control device, the working liquid pressure is low in the initial period of processing, so that an ON signal is given to each solenoid valve, and OFF signal shall be emitted when it is judged that the state of Range IV in the attached diagram is attained. The degree of high or low pressure of the working liquid can be set at option using each adjusting valve. A test of this working liquid supply device of trial make has supported that cutting of wire electrode 1 likely to occur in the initial period of processing can be eliminated. Thus automation for optimum supply of working liquid is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a machining fluid supply device in a wire-cut electric discharge machine.

2. Description of the Related Art Conventionally, a wire-cut electrical discharge machine is known that processes a workpiece by generating electrical discharge in a minute gap between a wire electrode and a workpiece facing the wire electrode.

FIG. 1 is a characteristic diagram showing the relationship between machining speed and machining fluid pressure in a wire-cut electrical discharge machine. The characteristic diagram shown in FIG. 1 shows the relationship between the machining speed F on the vertical axis and the machining fluid pressure Pr on the horizontal axis. Generally, as is clear from the figure, when the hydraulic pressure Pr increases, the machining speed F also increases, and the reason for this is smooth removal of machining chips and cooling effect of the wire electrode. This is due to the increase in However, at the initial stage of machining, a normal wire-cut electric discharge machine machins from the initial hole or from the end face of the workpiece, so it is not possible to use machining fluid pressure at high pressure from the beginning. The reason for this will be explained using FIG. 2.

FIG. 2 is an explanatory diagram showing the machining principle of a conventional wire-cut electrical discharge machine. FIG. 2 shows a state in which the wire electrode 1 is just machining the end face of a workpiece 2, and 3 is a machining fluid spray nozzle. The machining fluid 4 is flowed from the upper and lower machining fluid injection nozzles 3 in the direction shown by the arrow in FIG.

Since the upper and lower surfaces of the workpiece 2 and the end surfaces of the machining fluid injection nozzle 3 are very narrow, the machining fluid 4 scatters backward in the direction shown by arrow A in FIG. As a result, an air discharge occurs in the portion indicated by the broken line B in FIG. 2, and there is a risk that the wire electrode 1 will often break. Therefore, in the past, the pressure of the machining fluid 4 was kept low from the initial stage of machining until the wire electrode 1 fully entered the workpiece 2. For this reason,
After the operator starts machining, it takes time and effort to switch the pressure of the machining fluid 4 from low pressure to high pressure, and it is difficult to decide at what point to switch the machining fluid 4 from low pressure to high pressure. When switching to a high voltage, there was a drawback that the wire electrode 1 would break due to the above-mentioned aerial discharge.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and in wire-cut electric discharge machines,
It has a structure that automatically increases the machining fluid pressure after the discharge starts, which is the start of machining, which saves the operator's effort and allows the machining fluid pressure to be automatically increased at the optimal location. The purpose of the present invention is to provide a machining fluid supply device for a wire-cut electric discharge machine that can be used.

An embodiment of the present invention will be described below with reference to the drawings. Third
The figure is an explanatory diagram showing the basic principle of the wire-cut electric discharge machine of the present invention. In the illustration, 1 is a wire electrode,
Reference numeral 2 indicates a workpiece, and 3 indicates a machining fluid spray nozzle. In FIG. 3, the cross section of the machining fluid spray nozzle 3 is represented by a broken line circle.

The wire electrode 1 is moved in the direction indicated by the arrow A-+B-)C, thereby progressing the processing. Force L that the wire ff1tilxl enters from the end face of the workpiece 2
Along with L, a processing groove 5 is formed in the ]-11 crop.

The distance between position A and position B of wire electromagnetic wire 1 is represented by -t, and the distance between position B of wire electrode 10 and position C is represented by +t. At position A of the wire electrode 1, all the inner diameters of the machining fluid injection nozzles 3 are in the 0PEN state, similarly, at position B, half are in the 0PEN state, and at position C, all are in the CLO8E state. Furthermore, in this invention, the above-mentioned 0PEN and C
In order to make each state of LO8E noticeable, the distance between the upper and lower surfaces of the workpiece 2 and the end surface of the machining fluid injection nozzle 3 is set to be within 'i0.5w. The mode of operation as described above is clearly illustrated in FIG. FIG. 4 is a characteristic diagram showing the relationship between the change in machining fluid pressure at low pressure and the position of the wire electrode corresponding to the wire-cut electric discharge machine of FIG. 3. In FIG. 4, the vertical axis shows the machining fluid pressure Pr, and the horizontal axis shows each distance -
and +t are shown. The 0PEN state of the machining fluid injection nozzle 3, which is the position A of the wire electrode J shown in FIG.
H) in the figure, and similarly, half 0P before and after position B in Figure 3.
The EN state is (n) in Figure 4, and the CLO at position C in Figure 3
The 8E state is shown in FIG. 4 (IV). (Ill
) is because the machining groove 5 is close to the outside of the workpiece 2 when the wire electrode 1 is slightly inside the workpiece 2 from the half-0PEN state of the machining fluid injection nozzle 3 at position B in FIG. This indicates that the machining fluid has escaped to the rear, causing a pressure drop in the machining fluid pressure. As mentioned above, when machining is performed using a machining fluid with low pressure, as shown in Figure 4, 7J
As the machining process progresses, an increase in machining fluid pressure is observed, and
In the state (IV) in the figure, the machining fluid pressure is in equilibrium. Therefore, in the present invention, (
It is sufficient to detect that the machining fluid pressure has increased to the state of (2) and switch the machining fluid pressure from low pressure to high pressure at this point.

FIG. 5 is a schematic configuration diagram C showing a machining fluid supply device for a wire cutter I electric discharge machine which is an embodiment of the present invention. As shown in the figure, the machining fluid 4 indicated by an arrow is sent by a pump P to either path I or (2). 1. Path 1 is provided with a solenoid valve B1 and an adjustment valve 6a, and path 1
is equipped with a solenoid valve B2° adjustment valve 61) and a pressure sensor 7. Path I is for sieve pressure, and path (2) is for low pressure. Processing fluid 4 is UP or DOW indicated by its image and arrow.
The liquid is guided to a machining liquid spray nozzle (not shown) in the N direction.

The signal from the pressure sensor 7 is sent to the machining fluid control device 8.
Judging by this machining fluid control device 8, each electromagnetic valve B1
My father controls all switching of either B2. The electromagnetic valve B1 is closed when it is ON and opened when it is OFF, and the electromagnetic pulp B2 is open when it is ON and closed when it is OFF. The machining fluid control device 8 reads the output of the pressure sensor 7 under microcomputer control, for example, and determines whether the machining fluid pressure has reached an equilibrium state as shown in (IV) in FIG. 4. Since the machining fluid pressure is low at the beginning of machining, the machining fluid control device 8 outputs an ON signal to each of the electromagnetic pulps Bl and B2, and determines that the state (IV) in FIG. 4 has been reached. It is only necessary to output an OFF signal at that point. Here, the degree of low pressure and high pressure of the processing fluid pressure is determined for each adjustment pulp 6a, 61
) can be freely set.

As a result of prototyping and testing the machining fluid supply device for the wire-cut electric discharge machine of the present invention described above, the disconnection of the wire electrode 1, which tends to occur at the beginning of machining, was eliminated, and automation for optimally supplying the machining fluid 4 was achieved. could have been done.

In the above embodiment, the case where control is performed using machining fluid pressure has been explained, but in addition to this, control can also be performed using the volume of machining fluid, and in this case, the decrease in fluid volume is The detection and control are carried out smoothly, and the same effects as in the above-mentioned embodiments are achieved.

As described below, the machining fluid supply device for the wire-cut electrical discharge machine of the present invention is configured to automatically switch the machining fluid pressure from low pressure to high pressure before and after the start of machining.
This has the excellent effect of effectively preventing disconnection of the wire electrode at the start of machining, saving the labor of the operator, and allowing wire electrical discharge machining to be performed with extremely high accuracy.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram showing the relationship between machining speed and machining fluid pressure in a wire-cut electrical discharge machine, Figure 2 is an explanatory diagram showing the machining principle in a conventional wire-cut electrical discharge machine, and Figure 3 is a diagram showing the machining principle of a conventional wire-cut electrical discharge machine. An explanatory diagram showing the basic principle of a wire-cut electrical discharge machine; FIG. 4 is a characteristic diagram showing the relationship between the change in machining speed at low pressure and the position of the wire electrode, which corresponds to the wire-cut electrical discharge machine of FIG. 3; FIG. 5 is a schematic diagram showing a machining fluid supply device for a wire-cut electric discharge machine according to an embodiment of the present invention. In the figure, 1... wire electrode, 2... workpiece, 3
... Machining fluid injection nozzle, 4... Machining fluid, 5... Machining groove, 6a, 6b... Adjustment pulp, 7... Pressure sensor, 8... Machining fluid control device, P...・Pump, B 1
．． , B2... Electromagnetic pulp. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 1 Pr-1111 Figure 2 Figure 3 Figure 4 r

Claims (3)

[Claims] (1) A machining fluid supply device for a wire-cut electrical discharge machine, characterized in that the machining fluid pressure is automatically increased after the start of discharge, which is the start of machining, in the wire-cut electrical discharge machine. (2) The wire-cut electrical discharge machine according to claim 1, wherein the machining fluid pressure is increased by detecting a change in the low machining fluid pressure before the start of machining. Machining fluid supply device. (3) Increasing the machining fluid pressure means that as electrical discharge machining progresses, the low machining fluid pressure increases;
The machining fluid supply device for a wire-cut electric discharge machine according to claim 1, wherein the machining fluid supply device is configured to perform the machining fluid supply after the machining fluid pressure reaches an equilibrium state.