JPH0425090B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a method in which a pair of machining liquid jet nozzles through which a wire electrode is inserted are opposed to each other, and an intermittent voltage pulse is applied between the workpiece and the wire electrode, which are interposed between both nozzles. The present invention relates to a wire cut electrical discharge machining device that applies pressurized machining fluid to the machining section from both nozzles, and provides means for supplying machining fluid to the machining section that is particularly suitable for high-speed cutting and that enables good machining. Concerning what you have.

In wire cut electric discharge machining, in order to perform high-speed machining, it is necessary to increase the hydraulic pressure or flow rate of the machining fluid in the machining part, and to reduce the generation of bubbles in the machining part and the entrainment of air bubbles from the outside. It is necessary to keep the temperature low in order to increase the liquid flow in the machining part to prevent the occurrence of air discharge, to quickly remove machining debris, and to prevent wire electrode breakage accidents.

On the other hand, in wire cut electric discharge machining, the cross-sectional area of the machining groove relative to the tip surface of the machining fluid injection nozzle increases at locations where the machining feed direction changes, such as at bending points in the machining contour shape, and at locations away from the machining part. The flow rate of the machining fluid flowing in the machining grooves may increase, causing concentrated discharge or short circuits. In addition, atmospheric discharge or concentrated discharge may occur due to gas generated during machining or air drawn in from around the nozzle tip. This may cause marks or breakage of the wire electrode, leading to deterioration in processing accuracy.

The present invention makes it possible to increase the hydraulic pressure, flow rate, and flow rate (hereinafter referred to as machining fluid pressure, etc.) of the machining fluid in the machining section, thereby sufficiently cooling the wire electrode and machining gap and removing machining debris. The wire cut discharge has a structure that enables high-speed machining by increasing the machining current and maintaining the desired supply state of machining fluid to the machining part even when machining conditions change. The purpose is to provide processing equipment.

In order to achieve this object, the wire cut electric discharge machining apparatus of the present invention includes a main nozzle in which one or both of a pair of machining fluid injection nozzles forms a main jet coaxial with the wire electrode, and a main jet in which one or both nozzles form a main jet coaxial with the wire electrode; It is composed of one or more sub-nozzles that form assist jets to prevent the workpiece, and means for individually setting the machining fluid injection pressure of each nozzle arranged on both sides of the workpiece, and the electric discharge machining state of the machining gap and short circuit. The machining fluid injection pressure of each nozzle may vary depending on the occurrence state of the machining fluid, or depending on changes in the machining area before and after the bending point of the machining contour shape or the cross-sectional area of the machining groove with respect to the nozzle tip. It is characterized by comprising means for controlling changes in relation to each other so that the relationship is maintained.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. First, the configuration of the nozzle section in this embodiment will be explained with reference to FIGS. 1 and 2. 1st
In the figure, 1 is a wire electrode, and 2 and 3 are an upper arm and a lower arm to which guide rollers 4 and 5 of the wire electrode 1 are attached, and these are attached to a column or the like of the main body of the apparatus (not shown). Support members 6 and 7 are attached to the arms 2 and 3 so that their vertical positions can be adjusted by manual handles or motors 8 and 9;
0 is a current-carrying pin as an upper current-carrying device that applies voltage to the wire electrode 1 by contacting the wire electrode 1 which is pressed and displaced by a wear-resistant and usually insulating pressing pin 10' attached to the support member 6; 1
Reference numeral 1 denotes a current-carrying roller serving as a lower current-carrying device that also serves as a lower guide roller, and since it is energized by contacting with the wire electrode 1 subjected to wire cut electric discharge machining, a fixed current-carrying pin for the upper clean wire electrode 1 is used. 10 is a rotating roller, and the pin 10 is used to increase the contact area.
The diameter is large enough for
This is carried out by applying brush current to the roller 11 or the rotating shaft of the roller 11. 12 and 13 are respectively attached to support members 6 and 7 so that minute positions can be adjusted;
Alternatively, it is a hollow cylindrical nozzle body that is fixedly attached, and openings 14 and 15 are formed in the upper and lower end surfaces of the upper nozzle body 12, and the lower opening 1
5, an upper nozzle 22 is attached to the upper nozzle 22 so as to be movable up and down in the axial direction of the wire electrode by interposing a spring 22A as necessary, and to be fixed to the flange 22a so as not to fall off. The upper nozzle 22 may be fixedly attached to the nozzle body 12 as in the embodiments described later, or may be formed integrally with the nozzle body 12. Further, inside the nozzle body 12, a die-shaped upper positioning guide 18 for the wire electrode 1 is provided at the lower end, and a machining liquid passage hole 2 is provided.
A hollow cylindrical guide holder 20 having a diameter of 0a is attached so as to be concentric with the opening 14 and the nozzle 22, and is further provided with a pressurizing fluid for introducing a predetermined pressurized machining fluid into the nozzle body 12. A supply hose 25 is provided connected to the nozzle body 12.

On the other hand, a micro opening 16 through which the wire electrode 1 is inserted is also provided at the lower end of the lower nozzle main body 13, and a lower nozzle 23 is installed at the upper part so as to face the upper nozzle 22, and the wire electrode 1 is inserted inside. A guide holder 21 having a die-shaped lower positioning guide 19 at the upper end and having a machining liquid passage hole 21a is disposed so as to be concentric with the lower nozzle 23 and the opening 16. A pressurized supply hose 26 is connected to the nozzle body 13 and is connected to the nozzle body 13 to introduce a pressurized machining fluid having a higher pressure than the upper nozzle body 12 as described later.

The machining fluid introduced into the nozzle bodies 12, 13 from the pressurized supply hoses 25, 26 cools the wire electrode 1 passing therethrough, and also cools the wire electrode 1 passing through the openings 14, 16.
It flows out to the current-carrying pin 10 and the current-carrying roller 11 to cool them, and also serves to cool the guides 18 and 19.

Note that when the current-carrying roller 11 is sufficiently cooled by the flowing down of the machining fluid injected from the nozzles 22 and 23 to the machining section 27, the lower end opening 16 of the nozzle body 13 is opened just enough to allow the wire electrode 1 to pass through. In some cases, it may be made small enough to be used as a seal, or it may be further sealed. That is, as will be described later, in the case of the configuration of the illustrated embodiment, the supply pressure of the machining fluid at the lower nozzle 23, that is, the lower nozzle body 13 side, is set higher than that at the upper part, and it is necessary to maintain this pressure. Opening 1 for some reason
6 is sufficiently small or sealed. The workpiece 24 interposed between the upper nozzle 22 and the lower nozzle 23 is fixed to the processing table 31, and the processing table 31 is connected to the motors 32, 33.
This makes it possible to freely control and move the wire electrode 1 along a predetermined contour shape on a plane perpendicular to the axis of the wire electrode 1 under the control of a numerical controller. Further, the wire electrode 1 is unwound from a storage reel provided in a column or the like of the apparatus main body (not shown) via a brake roller, etc., extends downward via a guide roller 4 of an upper arm 2, and is guided by a lower arm 3. The material is wound up or collected via the roller 5 and a take-up roller (not shown) onto a take-up reel such as a column body or a collection container. Then, electrical discharge machining is performed by applying intermittent voltage pulses between the workpiece 24 and the wire electrode 1 while jetting machining liquid from the nozzles 22 and 23 to the machining section 27.

However, the difference between this embodiment nozzle and the conventional nozzle is in the structure of the lower nozzle 23. The lower nozzle 23, whose plan view is shown in FIG. The main nozzle 44 generates a main jet 50 with high injection pressure, etc., and the main jet is bent as shown at 50' (i.e., the action of the jet machining liquid by the upper nozzle 22 and the workpiece 24 in the machining section 27). Shape effect due to machining progressing with the cut surface and the wire electrode 1 of the relevant part becoming arched or arched on the opposite side to the machining feed direction, and gravity due to upward flow in the vertical direction It consists of a sub-nozzle 45 that generates an assist jet 51 outside the main jet, that is, as a coaxial jet wrapped around the main jet. The sub nozzle 45 is attached to the main nozzle 44 movable with respect to the lower nozzle body 13,
Preferably, a plurality of pressurized supply hoses 46 having the same tip opening or fixedly installed with one slightly retracted from the other depending on the processing purpose etc. and distributing the same shape for supplying processing liquid to the inside of the sub-nozzle are arranged around the sub-nozzle. It is connected to. The main nozzle 44 is fitted into the upper end opening 13A of the lower nozzle body 13 so as to be slidable in the direction of the wire electrode 1, and between a flange 44a formed at the lower end of the main nozzle 44 as necessary and the opening edge of the main body 13. A spring 47 is interposed as necessary. Note that, as shown in FIG. 3, the direction in which the machining fluid is injected into the nozzle 45 by the pressurized supply hose 46 connected to the sub-nozzle 45 is directed away from the center of the sub-nozzle 45 to generate a swirling flow. This allows the assist jet to be ejected evenly and prevents uneven pressure.

FIG. 4 is a diagram showing the machining fluid supply system in this embodiment, and as shown in this diagram, each nozzle 2
A system for supplying machining fluid to 2, 44, and 45 is provided separately and independently. That is, each pipe 71, 72, 73 connected to each pressurized supply hose 25, 26, 46 is provided independently, and each pipe 71, 72, 73 is provided with a liquid supply tank 77, respectively.
Variable machining fluid supply pumps 74, 75, and 76 are provided to forcefully feed machining fluid from the nozzle to each nozzle, and these pumps are configured to be controlled by an NC device (or CNC device) 78. These variable machining fluid supply pumps 74 to 76 control the rotation speed, torque, etc. of a motor as a drive source, and the pump blades, swash plate, etc. to control the pressure, etc. of the supplied machining fluid. , or one that controls both the motor and pump swash plate. 79, 80, 81 are stop valves or pressure/flow control valves provided in each pipe 71, 72, 73, and 82, 83, 84 are throttle valves 8.
5, 86, and 87, respectively. In addition, 88 is a processing tank, 89 is a drainage tank, 90
9 is a drain pipe that connects both tanks; 91 is a dust removal device that includes a pump 92 and a filter 93 and removes dust from the dirty machining fluid in the drain tank 89 and sends it to the liquid supply tank 77;
4 is an ion removal device having a pump 96 operated by the output of the conductivity meter 95 and an ion exchange resin 97.

FIG. 5 shows an example of a control device that controls the machining fluid supply pumps 74 to 76, and the electric motors 74M, 75M, 7 of each pump 74, 75, 76
The firing angle, on/off time, etc. of the thyristors and transistors constituting the rectifier circuit or inverter 98, 99, 100 provided between the 6M and the AC power source 101 are controlled by the NC device (or CNC device) 78. It was designed to do so. As shown in FIG. 6, the NC device (or CNC device) 78 has a voltage between the wire electrode 1 and the workpiece 24 (shown at A) between V _l and V _p , which means electric discharge. The discharge detection circuit 102 sometimes turns on the output as shown in C, and turns on the output for a short time t ₁ from when the voltage between electrodes rises to below the voltage between electrodes V _p in a normal discharge state as shown in B. a timing pulse generation circuit 103 that takes the outputs of both circuits 102 and 103, and an AND circuit 104 that takes the logical product of the outputs of both circuits 102 and 103;
The CPU 106 is a PIO (multipurpose input/output device).
107, and stores the count value in memory 1.
From comparison with the data stored in 08, the rectifier circuit or inverters 98 to 100 are controlled via the PIO 107 so that the count value is equal to or less than a predetermined value.

In this configuration, the pressure of the machining fluid supplied from the pressurized supply hose 25 from the upper nozzle body 12 into the upper nozzle 22 is set to, for example, 3 to 10 Kg/cm ² , and the pressure of the machining fluid supplied from the lower nozzle body 13 into the main nozzle 44 is set to a pressure of 3 to 10 Kg/cm 2 .
Adjust the pressure of the machining fluid supplied from 6 to, for example, 7 to 20 kg/
cm ² , machining is performed by setting the pressure of the machining fluid supplied from the pressurized supply hose 46 into the sub-nozzle 45 to, for example, 5 to 10 Kg/cm ² , and the main jet 50 from the main nozzle 44 is converted into an assist jet from the sub-nozzle 45. 51 prevents the main jet from collapsing (bending), increases both the pressure and flow rate of the machining fluid in the machining section 27, prevents air from being sucked into the main jet 50 from the surroundings, and prevents bubbles from being sucked into the main jet 50. By suppressing the occurrence, processing speed can be increased.

In the above case, the machining fluid supply pump 74, By controlling 75 and 76, the main nozzle 44 is
The machining fluid injection pressure, etc. of the upper nozzle 22 and the sub nozzle 45 can be set to the highest level, and the upper nozzle 22 and the sub nozzle 45 can be set lower than the main nozzle 44 and approximately the same, or one of them can be set higher within several kg/cm ² . In many cases, the machining fluid injection flow rate is highest at the sub-nozzle 45, which has the possibility of having the largest opening.

In this case, the lower nozzle 23 is the main nozzle 44
By the action of the flange portion 44a and the like provided as necessary, the machining liquid is projected from the lower nozzle body 13 and presses the tips of the main nozzle 44 and the sub nozzle 45 against the lower surface of the workpiece 24. The state of proximity or contact between the tip of each nozzle and the lower surface of the workpiece 24 is, for example, the main nozzle 4
When the fluid pressure in step 4 is increased, the nozzle tip and the bottom surface of the workpiece come into close contact at a certain fluid pressure value, but when the fluid pressure is further increased, the nozzle tip and the workpiece come into close contact at a certain fluid pressure value. The relationship between the settings of the machining fluid injection pressure of the nozzles 22, 44 and 45, the thickness of the workpiece 24, the machining conditions that change the machining groove, such as a minute gap being formed between the bottom surface, Even due to changes in the machining contour shape (the total area of the machining grooves facing the opening surfaces of the nozzles 22, 44, and 45) during machining, the pressure contact may change from a slightly separated state to a slightly stronger pressure contact. However, by setting the high and low values of the machining fluid injection pressure, etc. in each of the nozzles 22, 44, and 45 in the relationship as described above in the configuration and arrangement of the above-mentioned embodiment, the machining average can be adjusted. By increasing the current, high-speed machining can be stably continued without disconnection of the wire electrode 1.

Therefore, when machining is performed with the machining fluid injection pressures of the nozzles 22, 44, and 45 set to a desired good relative relationship, the counter 1
If the count value per unit time in 05 exceeds a predetermined value, there is a risk that the discharge state will shift to an abnormal discharge state such as atmospheric discharge, concentrated discharge, or steady arc discharge, and the supply of machining fluid to the machining part may be interrupted. It is necessary to enhance the cleaning effect of the machining gap by increasing the amount to promote renewal of the machining fluid and removal of machining debris. In such a case, simply increasing the fluid pressure of the main nozzle 44 will not work.
The relative relationship between the hydraulic pressures of the nozzles 22, 44, and 45 is disrupted, and the hydraulic pressure of the nozzle 22 is relatively insufficient, causing the jet flow from the main nozzle 44 to excessively blow up onto the upper surface of the workpiece, causing electrical discharge. make the situation unstable,
Due to the relative lack of hydraulic pressure in the sub-nozzle 45, the effect of preventing the main jet from bending is no longer sufficient, and even if the hydraulic pressure in the main nozzle 44 is increased, the desired result cannot be obtained. Therefore, in the present invention, in addition to increasing the hydraulic pressure of the main nozzle 44, each pump 74,
75 and 76 are controlled in relation to each other. As a result, even if the machining conditions change, the supply state of the machining fluid to the machining section can be maintained in a desired favorable state, and stable high-speed machining can be performed.

In addition, in the case of this embodiment, the nozzles 22 and 23
are both movable in the axial direction of the wire electrode 1 relative to the nozzle bodies 12 and 13, and the upper nozzle 22 presses the tip of the nozzle 22 against the surface of the workpiece 24 against a spring 22A provided as necessary, or
The machining liquid flows into the nozzle body 12 so as to maintain a minute gap G.
The lower nozzle 23 is supplied with a predetermined pressure or the like to cause the nozzle 22 to protrude like a piston, while the lower nozzle 23 is supplied with the nozzle main body 13 and jetted from the nozzle 23 due to the injection pressure of the machining fluid, which causes the tip of the nozzle 23 to (Tip surfaces of main nozzle 44 and sub nozzle 45)
is in complete pressurized contact with the lower surface of the workpiece 24, and the machining liquid jetted from the nozzles 44 and 45 is transferred to the nozzle 4.
5 and the lower surface of the workpiece 24 to the extent possible to prevent leakage and spouting into the surroundings, or to prevent air from being sucked into the machining liquid spouted from the abutting portion. . Therefore, the workpiece 24 of the nozzle 23 or even the nozzle 22
The nozzles 22 and 23 are usually made of synthetic resin or coated with synthetic resin, and more preferably made of electrically insulating, low friction and abrasion resistant synthetic resin so that the relative movement for processing feed is not inhibited by pressurized contact with the nozzles 22 and 23. etc., and also a flexible elastic body for sealing the injection opening of the nozzle 23, especially the nozzle 45.
A ring may be provided.

Figure 7 is a diagram showing the relationship between the machining fluid flow rate and the wire electrode temperature under certain electrode and workpiece conditions.As can be seen from this figure, as the machining fluid flow rate increases, effective contact with the wire electrode is made. This allows the temperature of the wire electrode to be changed significantly, and it can be understood from this that the temperature of the wire electrode can be lowered by increasing the flow rate of the machining fluid in the machining section 27. In addition, FIG. 8 shows the hydraulic pressure of the machining fluid (the pressure inside the nozzle body 13 is the injection pressure, and the machining fluid pressure inside the nozzle body 13 is the pressure inside the main body 12, for example).
It is set to 1.5 to 5 times. ) and the amount of bubbles generated in the machining section when the machining current is changed to 10A, 15A, and 18A.Increasing the liquid pressure suppresses the generation of bubbles, and this shows that the present invention It is understood that by increasing the pressure of the machining fluid in the machining section, the amount of bubbles generated can be reduced, the machining speed can be increased, and the possibility of wire electrode breakage can be reduced.

In this embodiment, an example was shown in which atmospheric discharge and concentrated discharge were avoided, but the machining fluid supply pump 74
In addition to this, various other methods such as those described in Japanese Patent Publication No. 54-33400 can be adopted as a method for controlling .about.76 according to the discharge state. For example, out of a certain number of discharge pulses applied between poles, count the number of pulses for which the arc voltage (voltage during discharge) is below the reference voltage, that is, the number of short-circuit pulses, and count the number of short-circuit pulses when the value becomes below a certain value. and each nozzle 22,
By controlling the machining fluid supply pumps 74 to 76 in relation to each other so that the respective hydraulic pressures 44 and 45 are maintained in the relative relationship at the time of setting, it is possible to prevent the wire electrode from being cut. In addition, the ratio of the number of pulses where the arc voltage is within a certain voltage range is determined, and each nozzle 22, 44, and 45 is
The machining fluid supply pumps 74 to 76 may be controlled in relation to each other so that each fluid pressure is maintained in the relative relationship at the time of setting, and the machining fluid pressure etc. may be controlled so that appropriate electric discharge machining can be performed. .

In addition, it is possible to deal with changes in the machining area before and after the bending point of the machining contour shape and changes in the cross-sectional area of the machining groove facing the nozzle tip surface (the cross-sectional area of the flow path through which the machining fluid flows). The machining fluid supply pumps 74 to 76 may be controlled so as to obtain a machining fluid pressure of the same amount. The pump control for changes in the cross-sectional area of the machining fluid flow path may be performed simultaneously with the pump control based on the discharge state.

In addition, in the case of the above-mentioned embodiment, the machining fluid injection pressure etc. of the upper nozzle 22 and the lower main nozzle 44 are, for example,
The ratio is set to a constant ratio such as 1:1.5 or 1:2.0, and the machining fluid injection pressure of each nozzle 22 and 44 is simultaneously changed and controlled depending on the electrical discharge machining state while maintaining that ratio. , pumps 74 and 7
5 may be used as one common pump.

9 to 11 show other embodiments of the present invention, in which an assist jet 51' for preventing bending of the main jet 50 is sent from the processing groove 30 to the processing area as a sub-nozzle of the lower nozzle 23'. a first sub-nozzle 45' that forms a sharp machining fluid jet that is inclined with respect to the axis of the wire electrode toward 27;
A second sub-nozzle 5 that forms a machining fluid jet 52 that wraps around the assist jet 51' and prevents air from being sucked into the machining section 27 by the assist jet 51'.
It consists of 3. Second sub nozzle 53
is fixed to a mounting ring 55 attached to the lower nozzle body 13 via a bearing 54, and an external gear 56 that is integral with the mounting ring 55 is connected to the output shaft of a motor 57 attached to the support member 7. It meshes with a pinion 58 provided in the. The first sub-nozzle 45' is attached to the second sub-nozzle 53, and a flexible pressurized supply hose 46' is connected to the part that protrudes outward from the second sub-nozzle 53. A pipe 59 forming a pressurized machining fluid supply port is fixedly installed, and a flexible pressurized supply hose 60 is connected to the pipe 59. With this configuration, by operating the motor 57, the first sub-nozzle 45' can vertically rotate together with the second sub-nozzle 53 around the nozzle body 13 over a range of 360 degrees or more.

Further, in this embodiment, the upper nozzle 22', which is the other nozzle whose machining fluid injection pressure etc. are set lower than that of the other nozzle, is constituted by a fixed nozzle integrated with the nozzle body 12. around,
In the illustrated embodiment, on the lead-in side of the wire electrode 1,
A lower nozzle 23 serving as one nozzle having a machining fluid injection pressure set higher than that of the other nozzle.
This prevents the coaxial main jet and assist jet along the wire electrode 1 from flowing from the machining groove 30 formed in the workpiece 24 to a location away from the machining section 27 and leaking to the outside as shown by the dotted line 34. , a disk-shaped pad 36 having a diameter sufficiently larger than the outer diameter of the upper nozzle 22' is normally provided so that the machining liquid at a predetermined flow rate and flow rate can flow into the machining section 27 with sufficient pressure.

The upper nozzle part of this embodiment is the machining fluid injection nozzle 2.
2' is a fixed nozzle that is integrated with the nozzle body 12 as described above, and the pad 36 has nozzle 2 in the center.
2', a disk-shaped upper member 37 having a plurality of machining fluid outflow holes 42 circumferentially arranged around it, a rising edge 38a formed around it, and a nozzle 22 in the center. A circular lower member 3 having a machining fluid inflow hole 39 (this hole may be divided into a plurality of holes in the circumferential direction) having a diameter larger than the outer diameter of .
The upper end of the rising edge 38a of the lower member 38 is fixed to and integrated with the outer periphery of the upper member 37, or the rising edge 38a is integrated with the lower member 38 placed on the upper surface of the workpiece 24. is fitted into the upper member 37 so as to be movable and adjustable in one axial direction of the wire electrode, thereby forming a hollow disk shape, and as shown in the figure, for example, two pieces are screwed into threaded grooves provided on the outer periphery of the nozzle 22'. The nozzle 22' is installed by clamping the mounting hole of the upper member 37 with the nuts 40 and 41.
mounted on. Further, a plurality of holes 43 for draining machining fluid are arranged in the circumferential direction on the rising edge 38a.

In addition, in this embodiment, the lower end face opening 16 of the lower nozzle body 13 is connected to the cylindrical guide holder of the guide 19 so that the main nozzle 44 can easily jet the machining fluid under high machining fluid jet pressure. 21', that is, the guide holder 2
There is no hole 21a on the outer periphery of the wire electrode 1, and a minute amount of machining fluid leaks from the inside of the holder 21' to the energizing roller 11 side through the minute gap between the guide 19 of the wire electrode 1 and the die. All of the supplied pressurized machining fluid is injected from the main nozzle 44 to the machining section 27 coaxially along the wire electrode 1 . Note that the spring 47 between the main nozzle 44 and the nozzle body 13 is not provided, and the nozzle 44
The nozzle 44 is pushed up against the gravity acting on the body 13 and the sliding resistance between the nozzle 44 and the main body 13, and the tip surface of the nozzle 44 is pressed against the lower surface of the workpiece 24.

At least the lower member 38 of this pad 36 is made of a flexible or non-flexible synthetic resin material, and is attached to the workpiece 24 in close contact with the workpiece 24 or through a slight gap G as shown in the figure. Processing is carried out while facing 24. Also, this pad 37 is attached to the lower member 3.
8 can be attached to the nozzle 22' without obstructing the flow of processing liquid through the hole 39, the surrounding rising edge 38a and the upper member 37 can be omitted.

FIG. 11 shows the machining fluid supply system in this embodiment, which includes machining fluid supply pumps 74, 75, 76', and 76'' for each nozzle. That is, the upper nozzle 22' A machining fluid supply system including machining fluid supply pumps 74 and 75 is provided for the main nozzle 44 of the lower nozzle, and valves are provided for the first and second sub nozzles 45' and 53 that replace the sub nozzle 45, respectively. 81', 81'' and machining fluid supply pumps 76', 7
6'' and bypass piping 84', 84'' having throttle valves 86', 87'', and these machining fluid supply pumps 76', 76'' are also connected to the NC device (or
(CNC device) 78.

In this configuration, the pressure of the machining fluid supplied from the pressurized supply hose 25 from the upper nozzle body 12 into the upper nozzle 22' is set to, for example, 3 to 10 Kg/cm ² , and the pressure of the machining fluid is supplied from the lower nozzle body 13 into the main nozzle 44 through the pressurized supply hose. For example, set the pressure of the machining fluid supplied from 26 to 7 to 20.
Kg/cm ² , and the pressure of the processing fluid supplied from the pressurized supply hose 46' into the first sub-nozzle 45' is, for example, 20 kg/cm 2 .
~60Kg/cm ² , and the pressure of the machining fluid supplied from the pressurized supply hose 60 into the second sub-nozzle 53 is, for example, 5~60Kg/cm 2 .
15Kg/cm ² , and the NC device follows changes in the coordinates of the machining section 27 as machining progresses so that the tip of the first sub-nozzle 45' faces the machining groove 30 or the tip faces the machining groove 30. The main jet 50 from the main nozzle 44 is supported by the sharp assist jet 51' from the first sub-nozzle 45', thereby preventing the main jet 50 from collapsing ( bending) is prevented, and the pressure, flow rate, and flow rate of the machining fluid in the machining section 27 are increased. Also, the second sub nozzle 53
The assist jet 51 and the main jet 5 are caused by the jet 52 surrounding the assist jet 51'.
Processing speed can be increased by eliminating the blowing of air into the 0 from the surroundings and suppressing the generation of bubbles.

In addition, in the illustration, there is a gap between the main nozzle 44 and the second sub-nozzle 53, and from the gap,
It appears that there is a possibility that air may be blown into the jet from one or both of the nozzles from the surroundings, but if the gap is formed sufficiently small and filled with the flowing machining fluid, the air may be The above-mentioned air blowing can be prevented by creating a state or configuration in which there is almost no liquid in the blowing region, or by setting a larger amount of liquid in the jet stream 52 of the second sub-nozzle 53.

Furthermore, if the pad 36 is provided, the machining liquid leaking through the part of the machining groove 30 away from the machining part 27 is blocked by the lower member 38 of the pad 36 as shown by the dotted line 34, Lower member 3 as shown
Enter into the pad 36 through the hole 39 of No. 8, and insert the upper member 37.
It is discharged from the hole 42 or the rising edge 38a, that is, the hole 43 on the outer periphery. In addition, the hole 3 of the lower member 38
The jet machining liquid that reaches the upper surface of the workpiece 24 around it, which would normally not flow out from the lower member 38, is also surrounded by the lower surface of the lower member 38 or the gap formed between the lower surface and the upper surface of the workpiece 24. Except for those that flow out to the machined groove 30 side because the dissipation and outflow to the
A part or most of it is connected to the pad 36 from the hole 39.
This facilitates the formation of a liquid stream flowing into and exiting from the holes 42 and 43. By creating such a flow of machining fluid in addition to the main jet collapse prevention effect, the fluid pressure in the machining section 27 around the wire electrode 1 can be further increased and the flow rate can be increased, so that the machining average current can be increased. Even if the processing area 2 is increased,
The temperatures of the wire electrode 7 and the wire electrode 1 can be kept low, processing can be performed at a higher speed than in the previous embodiment, and there is less risk of accidents such as cutting of the wire electrode due to generation of bubbles.

In this case, the lower member 38, which is placed on the upper surface of the workpiece 24 so as to be able to fit and move at the rising edge 38a with respect to the pad 36 or the upper member 37, is held slightly by the machining fluid jet from below. In some cases, the gap G may be formed in equilibrium, and in this embodiment, an equilibrating disk 48 is provided at the tip of the nozzle body 12 to deflect the machining fluid ejected upward from the hole 42 in the horizontal direction. However, this disc 48 may also be configured to serve as the tip surface of the nozzle body 12.

In this embodiment, as in the previous embodiment, a machining fluid supply system having a machining fluid supply pump is provided for each nozzle, so settings such as the pressure of machining fluid ejected from each nozzle can be performed independently. In addition, depending on changes in the discharge state and machining path,
By controlling each pump in conjunction with each other so that the machining fluid injection pressure of each nozzle is maintained in the relative relationship at the time of setting, the supply state of machining fluid to the machining section can be controlled even if the machining state changes. Stable high-speed machining can be performed while maintaining the desired good condition.

Note that in this embodiment, the first sub nozzle 4
5' are arranged around the main nozzle 44 along with second sub-nozzles 53, for example, 3 to 8, and a stop valve is provided in the machining fluid supply system for each of the first sub-nozzles 45' and the second sub-nozzles 53. If the machining liquid is spouted from the selected first sub-nozzle 45' and second sub-nozzle 53 to the machining section by opening and closing the stop valve, the rotation angle of each of these sub-nozzles 45', 53 can be changed. The range is also smaller,
The amount of deflection of the pressurized supply hoses 46', 60 can be reduced, and damage thereof can be prevented. When a plurality of first sub-nozzles 45' are provided, the second
The sub-nozzle 53 has a ring shape surrounding the main nozzle 44, and the machining fluid injection port is connected to each first sub-nozzle 4.
They may be provided in the vicinity of 5', respectively.
Further, the second sub-nozzle 53 is a ring-shaped nozzle coaxially surrounding the main nozzle 44, and both nozzles 44 and 53 are integrally connected, and one first sub-nozzle 4 is connected to the second sub-nozzle 53.
5' so that the desired assist jet 51' is always formed by the first sub-nozzle 45'.
The nozzles 44, 45' and 53 may be integrally configured to be rotated in a controlled manner around the nozzle body 13, and various modifications are possible.

In addition, although the above-described embodiments have all been described with reference to the case where the two nozzles face each other vertically, the present invention can also be applied to the case where the two nozzles are arranged so as to face each other in the horizontal direction. Furthermore, in the above embodiments, the sub-nozzle is provided on one nozzle (lower nozzle), but the sub-nozzle may be provided only on the other nozzle (upper nozzle) or on both nozzles. Also, a machining fluid supply system having separate machining fluid supply pumps is provided corresponding to each nozzle.

As described above, in the apparatus of the present invention, at least one of the pair of opposing nozzles is configured with a main nozzle and a sub-nozzle to prevent the main jet from bending, so that the machining fluid pressure in the machining section is etc., making it possible to perform high-speed machining.In addition, a machining fluid supply system with separate machining fluid supply pumps for each nozzle has been installed, making it easy to set the machining fluid jet pressure, etc. for each nozzle. This makes it possible to perform machining under optimal machining fluid conditions. In addition, the machining fluid injection pressure of each nozzle is changed and controlled in relation to each other so that the correlation at the time of setting is maintained according to the discharge state or changes in the machining path such as before and after the bending point of the machining contour shape. Therefore, it is possible to prevent excess or deficiency of machining fluid, aerial discharge, concentrated discharge, short circuit, etc., and perform highly accurate machining with stable high-speed machining.

[Brief explanation of drawings]

1 to 6 show an embodiment of the wire cut electrical discharge machining apparatus of the present invention, in which FIG. 1 is a longitudinal sectional view of the nozzle part, FIG. 2 is a plan view of the lower nozzle, and FIG. 3 is the lower nozzle. 4 is a diagram of the machining fluid supply system, FIG. 5 is a control circuit diagram of the machining fluid supply pump, FIG. 6 is a waveform diagram to explain its operation, and FIG. 7 is a machining fluid supply system diagram. Relationship diagram between flow rate and electrode temperature,
Fig. 8 is a diagram showing the relationship between the hydraulic pressure of the machining fluid and the amount of bubbles generated, Fig. 9 is a longitudinal cross-sectional view of a nozzle section of another embodiment of the present invention, Fig. 10 is a plan view of the lower nozzle, and Fig. 11 The figure is a diagram of the machining fluid supply system of this embodiment. 1... Wire electrode, 22, 22'... Upper nozzle,
23, 23'... lower nozzle, 24... workpiece,
27... Processing section, 44... Main nozzle, 45,
45', 53...Sub nozzle, 74-76...Machining fluid supply pump.

Claims (1)

[Claims] 1. A wire electrode is updated and moved in the axial direction between a pair of positioning guides arranged at intervals, and a workpiece is moved through a minute gap from a direction perpendicular to the axial direction of the wire electrode. The machining fluid is injected and supplied from a pair of machining fluid injection nozzles which are placed opposite to each other on both sides of the workpiece and coaxially with the wire electrode, and are intermittently provided between the wire electrode and the workpiece. In wire cut electric discharge machining, machining is performed by electric discharge generated by applying a voltage pulse, and a relative machining feed is applied between the wire electrode and the workpiece on the plane in the orthogonal direction, the pair of machining One or both of the liquid injection nozzles are composed of a main nozzle that forms a main jet coaxial with the wire electrode, and one or more sub-nozzles that form an assist jet that prevents the main jet from bending; Means for individually setting the machining fluid jetting pressure of each of the nozzles arranged on both sides of the object, and a time of setting the machining fluid jetting pressure of each of the nozzles according to a change in the machining path of the discharge state or the machining contour shape. 1. A wire-cut electric discharge machining apparatus comprising means for controlling changes in relation to each other so that a relative relationship between the two is maintained. 2. The sub-nozzle supplies machining fluid from the machining groove to the machining part as a sharp assist jet inclined with respect to the axis of the wire electrode, and forms a machining fluid jet that prevents air suction by the assist jet. The wire-cut electrical discharge machining apparatus according to claim 1, comprising another sub-nozzle and a unique machining fluid supply pump corresponding to the other sub-nozzle.