JPH1148040A - Method and device for wire type electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controlling method and device for a wire type electric discharge machine which can preclude the wire from severance by controlling constant the jetting pressure of a processing liquid. SOLUTION: A processing liquid is jetted at a constant pressure from nozzles 12a and 14a to a part to be processed by discharge machining located between a work 17 and a wire electrode 16, and the rate of flow of the processing liquid is sensed by a rate-of-flow sensing part 53, and a judging part 54 judges whether the obtained rate of flow lies within the normal range predetermined by and stored in a processing condition storing part 52, and an eventual negative judgement should be followed by a reduction of the electric power in pulse form supplied from a power supply for discharge machining 51 to the part to be processed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a wire electric discharge machine, and more particularly to a method and a device for controlling the pressure of a machining fluid jetted from a jet nozzle to an electric discharge machining portion between a workpiece and a wire electrode. The present invention relates to a method and an apparatus for controlling a wire electric discharge machine for preventing wire breakage.

[0002]

2. Description of the Related Art In general, a wire electric discharge machine has a wire guide and a jet nozzle for supplying a machining fluid, and runs a wire electrode along a wire electrode feed path defined by heads provided above and below a work, respectively. On the other hand, the work is mounted on the work mounting table provided on the table, and an intermittent pulse-like electric power is supplied between the work and the wire electrode starting from an initial hole formed on the work or the end face of the work as a starting point to perform a discharging operation. And causes the electric discharge machining operation to proceed from the starting position along a desired trajectory according to the relative movement between the workpiece and the wire electrode. Further, a jet nozzle of a machining fluid is provided at the tip of the upper and lower heads, and the machining fluid is ejected from the jet nozzle to an electric discharge machining portion between the workpiece and the wire electrode, or the workpiece is immersed in the machining fluid. Electric discharge machining is performed.

[0003] At this time, the machining fluid filling the electric discharge machining section is usually jetted from the jet nozzle at a pressure of several Kgf / Cm ² to cool the wire and remove machining dust from the electric discharge machining section. Thereby, smooth and stable electric discharge machining is secured. In other words, the wire is prevented from being broken by the cooling action of the wire and the action of removing the processing waste. This is because the concentration of the processing debris narrows the gap between the workpiece and the wire electrode, causing a concentrated discharge and breaking the wire.

[0004] In order to prevent such wire breakage, the following machining fluid supply control device for a wire electric discharge machine has been disclosed. First, JP-A-63-74525 discloses that
There is disclosed a technique for detecting a machining fluid supply pressure and reducing the intermittent pulse-like power supplied between a workpiece and a wire electrode when the detected pressure is less than a reference value. Second
Japanese Patent Application Laid-Open No. Hei 4-261713 discloses two opposing jet nozzles for jetting a machining fluid in a machining fluid tank above and below an electric discharge machining action part, and respective machining fluid supply passages from the machining fluid tank to the respective jet nozzles. Pumps for changing the discharge amount of the working fluid are provided in the inside, respectively, detecting the jet pressure of the working fluid in each of the working fluid supply passages, and individually controlling the discharge amount of the working fluid so that each detected pressure becomes a predetermined level. Techniques are disclosed.

[0005]

However, the apparatus disclosed in Japanese Patent Application Laid-Open No. 63-74525, for example, starts machining from a jet nozzle toward a work when processing is started from a start hole provided in the work in advance. Since the part where the machining fluid is jetted is in a closed state, the jet pressure of the machining fluid does not decrease and the flow rate decreases, thereby decreasing the machining fluid discharge ability,
In other words, there is a problem that the cooling action of the wire and the action of removing the processing debris are reduced, and the wire is broken.

The apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 4-261713 discloses an apparatus in which, when, for example, processing is started from the outside of a work or a processing path passes near the end face of the work, a jet portion of the working fluid is in an open state. The pressure does not rise to a predetermined level, and the machining fluid is discharged from the jet nozzle mainly to the open portion without sufficiently jetting toward the electric discharge machining portion between the workpiece and the wire electrode, thereby cooling the wire and cutting dust. In some cases, there is a problem that the action of removing the wire is reduced, and in some cases, the wire is broken due to inhalation of air to cause air discharge.

Therefore, the present invention solves the above-mentioned problem, and controls the jet pressure of the machining fluid so that the jet pressure of the machining fluid is constant. An object of the present invention is to provide a method and an apparatus for controlling a wire electric discharge machine, which reduce electric power supplied therebetween and prevent wire breakage.

[0008]

A method for controlling a wire electric discharge machine according to the present invention, which solves the above-mentioned problems, comprises: In a control method of a wire electric discharge machine that supplies electric power in a pulse form to perform electric discharge machining on the work, a flow rate of the machining fluid supplied to the electric discharge machining unit is detected, and the detected flow rate of the machining fluid is set in advance.
It is determined whether or not the flow rate of the detected machining fluid is in the stored appropriate range, and when it is determined that the detected flow rate of the machining fluid is not in the appropriate range, the pulsed power supplied to the electric discharge machining unit is reduced. I do.

A control apparatus for a wire electric discharge machine according to the present invention for solving the above-mentioned problem is to supply a pulsed electric power to the electric discharge machining section while jetting a machining fluid at a constant pressure to an electric discharge machining section of a workpiece by a wire electrode. In a control device of a wire electric discharge machine that performs electric discharge machining of the work, a power supply unit that supplies pulsed electric power to the electric discharge machining unit,
An ejection nozzle for ejecting a machining fluid to the electric discharge machining part, a machining fluid supply pump for supplying a machining fluid in a machining fluid tank to the ejection nozzle, and a flow rate of the machining fluid ejected from the ejection nozzle to the electric discharge machining part And a supply amount of pulsed power supplied from the power supply unit to the electric discharge machining unit, a pressure and a flow rate of the machining fluid supplied from the machining fluid supply pump to the electric discharge machining unit. Machining condition storage means for storing an appropriate range; and determining whether or not the detected flow rate of the machining fluid is within the stored appropriate range. When it is determined that the flow rate is not within the appropriate range, a pulse supplied to the electric discharge machining unit. Discriminating means for sending a command to reduce the electric power to the machining condition storage means.

Further, the machining fluid flow rate detecting means has computing means for computing the machining fluid flow rate from the driving frequency of the machining fluid supply pump and the machining fluid pressure stored in the machining condition storage means.

[0011]

FIG. 1 is a diagram showing an embodiment of a control device for a wire electric discharge machine according to the present invention. The control device of the present embodiment controls the supply of the machining fluid of the wire electric discharge machine using a pressure sensor. As shown in FIG.
The wire electric discharge machine has an upper head 12 and a lower head 14, and a wire electrode 16 supplied from a wire electrode supply reel (not shown) via a traveling path having a guide roller travels between the upper and lower heads 12, 14. It is configured to be. A work 17 mounted and fixed on a work mount (not shown) that can be fed and displaced in a two-dimensional plane is disposed between the upper and lower heads, and an initial hole (small hole) formed in advance in the work 17 is provided. Alternatively, electric discharge machining by the wire electrode 16 is performed with the edge of the work as the starting point of electric discharge machining.

The wire electrode 16 and the work 17 are both connected to an electric discharge machining (pulse) power supply 51, and a discharge occurs when the two oppose each other via a minute gap. The discharge energy is applied to the work 17 by the energy of this discharge. The wire electrode 16 is electrically connected to the electric discharge machining power supply 51 via a power supply (not shown) in the vicinity of the electric discharge machining action portion, and the work 17 is also connected to the electric discharge machining power supply 51 via an appropriate conduction circuit. doing. Then, during the electric discharge machining process, the workpiece 17 is subjected to the feed control together with the work mount in a two-dimensional plane, so that the electric discharge machining proceeds along a desired trajectory, and
From 7, a product having a desired shape is processed.

The upper and lower heads 12 and 14 are provided with jet nozzles 12a and 14a for supplying a machining fluid, and the machining fluid supplied to the jet nozzle 12a is pumped from a cleaning fluid tank 18a of the machining fluid tank 18 by a pump 20. The gas is supplied through piping paths 22a and 22b before and after the pump 20, and is supplied from above to the electric discharge machining section as a jet from the jet nozzle 12a.

The processing liquid supplied to the jet nozzle 14a for supplying the processing liquid is supplied from the cleaning liquid tank 18a to the pump 21a.
And the piping 23 before and after the pump 21
a and 23b, and is supplied from below to the electric discharge machining section as a jet from the jet nozzle 14a. The tips of the jet nozzles 12a and 14a of the upper and lower heads 12 and 14 are formed as circular processing liquid jets, and are configured so that the wire electrode 16 passes through the center.
a and 14a usually have the work 17 and the wire electrode 1
6 is set as close as possible to the surface of the work 17 within a range that does not interfere with the relative displacement with respect to the workpiece 6.
The jet flow of the processing liquid is sufficiently supplied from 2a and 14a to the gap of the processing locus, and the liquid leakage from the gap between the tip of the jet nozzles 12a and 14a and the surface of the work 17 is minimized. The machining fluid is provided with a function of controlling the machining fluid supply operation by the pumps 20 and 21 so that the machining fluid is always supplied in a stable amount in the electric discharge machining operation portion between the workpiece 17 and the wire electrode 16. The machining fluid pumped up by the pumps 20 and 21 from the fluid cleaning fluid tank 18a is jetted to the electric discharge machining section under the optimal command pressure.

Next, the working fluid which has been subjected to a predetermined working fluid action such as cooling or removal of machining debris is collected by a working fluid collecting section 24 provided in the wire electric discharge machine, and is processed through a collecting pipe section 25. The circulating system is returned to the recovered liquid tank 18b of the liquid tank 18, and is sent out from this to the cleaning liquid tank 18a via the pump 26 and the filter 28 for reuse.

Further, the two tanks are connected by an adjusting pipe 29 so that the liquid overflowing from the cleaning liquid tank 18a is gradually returned to the recovery liquid tank 18b. In this case, conventionally, the cleaning liquid is pumped up and the jet nozzles 12a,
The operation of the pumps 20, 21 and 26 is performed so that the flow rate supplied to the recovery liquid tank 4a and the recovery liquid tank 18b flow back to the cleaning liquid tank 18a to contaminate it, and the cleaning liquid does not exceed the level of the regulating pipe 29 and overflow from the cleaning liquid tank 18a. Is adjusted.

Next, control for stabilizing the electric discharge machining operation by controlling the supply amount of the machining fluid in the electric discharge machining section of the wire electric discharge machine will be described below. The control device of the present embodiment controls the optimal amount of the liquid pressure at the position upstream of the ejection port of each of the jet nozzles 12a and 14a in order to control the ejection amount of the machining liquid from the jet nozzles 12a and 14a for supplying the machining liquid. A mechanism for controlling the discharge supply amount by the processing liquid supply pumps 20 and 21 for performing control following the command pressure value is configured.

The NC / power supply unit 50 includes an electric discharge machining power supply 51, a machining condition storage unit 52, a machining fluid flow rate detection unit 53,
The determination unit 54 is provided. The electric discharge machining power supply 51 supplies pulsed electric power to an electric discharge machining portion between the workpiece 17 and the wire electrode 16. The machining condition storage unit 52 stores the electric discharge machining power supply 5
Supply amount of pulsed power supplied from 1 to the electric discharge machining unit,
The pressure of the working fluid supplied to the discharge machining portion from the pump 20, 21 (constant pressure), and stores the appropriate range of the flow rate which is determined by the working fluid of the flow-rate upper limit Q ₁ and the lower limit value Q ₂ of.

The machining fluid flow rate detecting section 53 is provided with the jet nozzle 12
a, flow rate Q of the machining fluid ejected from 14a to the electric discharge machining part
The frequency of the inverters 42 and 43 for driving the pumps 20 and 21 and the processing condition storage 52
Is detected and calculated from the pressure of the working fluid stored in the step (1). The determination unit 54 determines whether the flow rate Q of the machining fluid detected and calculated by the machining fluid flow rate detection unit 53 is within an appropriate range (Q ₁ <Q <Q ₂ ) stored in the machining condition storage unit 52, and When it is determined that there is no (Q <Q ₁ , Q> Q ₂ ), a command to reduce the pulsed power supplied to the electric discharge machining unit is sent to the machining condition storage unit 52.

That is, the piping paths 22b and 2
Pressure sensors 30 and 31 for detecting the working fluid pressure in 3b are provided. The pressure of the working fluid detected by these pressure sensors 30 and 31 is converted into an electric signal, and a feedback control circuit 34 having amplifiers 32 and 33 is provided.
And are fed back to the pressure command value input units 36 and 37 via the control unit 35, respectively.

The pressure command value input units 36 and 37 send command signals corresponding to the difference between the pressure command value and the detected value to the control units 40 and 41 of the pump drive circuits 38 and 39. At this time, the control units 40 and 41 convert the command signal into a pump drive signal, and control the pumping action of the machining fluid supply pumps 20 and 21 by the inverters 42 and 43 to adjust the discharge fluid amount to adjust the discharge fluid amount. 22b and 23
The hydraulic pressure of b is controlled.

FIG. 2 is a diagram showing the relationship between the flow rate of the working fluid and the pressure. In FIG. 2, the horizontal axis represents the flow rate Q (l / min) of the machining fluid per unit time, the vertical axis represents the jet pressure P (Kgf / Cm ² ) of the machining fluid, and f _{1 to} f _n represent the pump drive. Frequency (Hz) of the inverter for use. The relationship between the flow rate, the pressure, and the inverter frequency shown in FIG. 2 is converted into a three-dimensional map and stored in a storage unit, for example, a ROM in advance. As it can be seen from FIG. 2, for example, f ₃ the frequency of the inverter in order to control a constant jet pressure of the working fluid in the setpoint P ₁ ~f
Change it to ₅ . That is, the pressure sensors 30, 31
By controlling the frequency of the inverters 42 and 43 according to the pressure value detected based on the three-dimensional map, the pressure can be controlled to be constant. Conversely, when flow rate sensors (not shown) are provided in the pipe lines 22b and 23b instead of the pressure sensors 30 and 31, the inverters 42, 4 and 4 are operated in accordance with the flow rate values detected based on the three-dimensional map.
By controlling the frequency 3, the pressure can be controlled to be constant.

However, even when the above-described constant pressure control is performed, the wire may be broken. The present invention determines the situation in which such wire breakage may occur based on whether or not the pressure and flow rate of the machining fluid are within an appropriate range. When it is determined that the wire is disconnected, the power supplied from the electric discharge machining power source 51 is reduced to prevent the wire from being broken. The power supplied from the electric discharge machining power supply 51 can be reduced by reducing the applied voltage between the wire electrode 16 and the work 17, shortening the energization time τ _ON , or increasing the pause time τ _OFF .

Next, the electric discharge machining by the wire electric discharge machine will be described in detail with reference to FIGS. FIG. 3 is a diagram showing a specific example of electric discharge machining by a wire electric discharge machine. As shown in FIG. 3, initial holes h _{1 to} h ₅ are previously formed in the work 17 in the z-axis direction perpendicular to the plane of the xy orthogonal coordinates. Also, each part a ₁ , a
_{n, b n, c 1,} c 2, d 1 and e _k indicates the outer periphery abutting the jet nozzle to the respective workpiece surfaces. FIG. 3 also shows that the work 17 is first moved from the start point (x ₁ , y ₁ ) to the end point (x
_n, y ₁₎ to be processed, the second start point (x _1, y ₂₎ from the end point (x _n, is processed to y _2), the third starting point (x _1, y
Machined from ₃₎ to the end point (x _n, y _3), the fourth start point (machined from x _1, y ₄₎ to the end (x _n, y _4), the fifth start point (x _1, y ₅₎ from the end point (x _n, y ₅₎ showing an example of processing up.

FIG. 4 is a cross-sectional view of the electric discharge machining of the workpiece portions shown in FIG. 3, A is a sectional view of _a portion a, B is a sectional view of a _n and b _n unit, C is the cross-section of _one part c Figure, D is a cross-sectional view of c ₂ parts, E is a cross-sectional view and F of d ₁ part is a cross-sectional view of e _k section. A to E show cross-sectional views cut along a plane parallel to the x-axis and viewed from below in FIG. 3, and F show cross-sectional views cut along a plane parallel to the y-axis and viewed from the right in FIG. . 4, a portion of the wire electrode 16 that passes through the jet nozzles 12a and 14a and a portion that is hidden by the work 17 are indicated by broken lines, and an exposed portion that passes through a hole or an open portion of the work 17 is indicated by a solid line. The hatched portion of the workpiece 17 indicates an unprocessed area by a diagonal line from upper right to lower left, and a processing end area by a diagonal line from upper left to lower right.

FIGS. 5 to 9 are views respectively showing first to fifth examples of electric discharge machining of the workpiece 17, wherein the horizontal axis of A and B represents the x-axis displacement, and the vertical axis of A represents the jet nozzles 12a and 14a.
The flow rate Q of the working fluid at a is shown, and the vertical axis of B shows the working fluid pressure P at the jet nozzles 12a and 14a.
Hereinafter, first to fifth electric discharge machining examples will be described in order. Figure 5 is substantially y from the initial hole position h ₁ of the workpiece shown in FIG. 3
FIG. 4 is a diagram showing a first machining example in which electric discharge machining is performed along the x-axis at a constant = y ₁ , where the area inside the outer circumference a ₁ of the jet nozzle is sufficiently larger than the area of the initial hole h _{1 at} the start point, and the jet nozzle is in a closed state. Thus, the pressure of the working fluid is kept constant without decreasing, but the flow rate is significantly reduced. In this case, the cooling action of the wire and the action of removing the processing debris become insufficient due to the decrease in the flow rate of the working fluid, and the wire breaks. Therefore, when detecting this state, the present invention determines that the flow rate of the machining liquid is not within the appropriate range, and reduces the amount of power supply between the wire electrode 16 and the work 17 to prevent wire breakage. After machining at the starting point, the passage area of the machining fluid that can pass through the work gradually increases with the progress of the machining, so the sealing degree of the jet nozzle decreases and the pressure of the machining fluid is kept constant, but the flow rate is The pressure and the flow rate gradually increase until the end point is reached, and a normal machining state is maintained.

FIG. 6 is a view showing a second machining example in which electric discharge machining is carried out along the x-axis at substantially constant y = y ₂ from the initial hole position h _{2 of the} work shown in FIG. 3, and from the start point to the end point. since substantially the same as the first working example shown in FIG. 5 and a description thereof will be omitted, the flow path cross-sectional area is first processed example the ratio of the working fluid can pass through the work in the outer periphery b _n of the jet nozzle at the end And the flow rate increases accordingly.

FIG. 7 shows that y = y ₃ from the initial hole position h ₃ of the work shown in FIG. 3 via the work end face c _2.
Is a diagram illustrating a third working example of discharge machining along the x-axis at a constant, the area of the outer peripheral c ₁ of the jet nozzle deviates from the work 17 at the start point, the jet nozzle pressure of the working fluid becomes the open state decreases The flow rate increases significantly. Then the movement of the workpiece 17 area in the angular c ₂ of the jet nozzle the jet nozzle comes to work end surface c ₂ parts of the point (x _2, y ₃₎ is in contact with substantially half the work 17, the jet nozzle is correspondingly It becomes a closed state, the pressure of the working fluid rises, and the flow rate decreases. In this case, the flow rate of the working fluid decreases but is larger than the predetermined amount.
However, the machining fluid flows out of the open portion of the jet nozzle and the flow rate supplied to the electric discharge machining portion between the wire electrode and the work becomes insufficient. Further, since the pressure of the working fluid increases but is lower than the set value, the flow speed of the working fluid becomes slow. As a result, the effect of cooling the wire and the effect of removing the processing debris become insufficient, and the wire is broken. Therefore, according to the present invention, when this state is detected, it is determined that the flow rate of the machining fluid is not within the appropriate range, and the amount of power supply between the wire electrode 16 and the work 17 is reduced to prevent wire breakage.
Thereafter, as the processing proceeds, the cross-sectional area of the flow path of the processing liquid that can pass through the inside of the work gradually decreases, so that the sealing degree of the jet nozzle increases, the pressure of the processing liquid increases, the flow rate decreases,
Thereafter, both the pressure and the flow rate become substantially constant until the end point is reached, and the normal machining state is maintained.

FIG. 8 is a diagram showing a fourth processing example to electric discharge machining along the x-axis at approximately y = y ₄ constant from the initial hole position h ₄ of the workpiece shown in FIG. 3, the outer periphery of the jet nozzle d is the starting point area within ₁ is sufficiently smaller than the area of the initial hole h _4, the jet nozzle pressure of the working fluid becomes the open state flow does not rise increases significantly. In this case, the flow rate of the working fluid is larger than a predetermined amount, but the working fluid flows out of the opening of the jet nozzle and is insufficiently supplied to the electric discharge working portion between the wire electrode and the workpiece. Further, since the pressure of the working fluid is low, the flow rate of the working fluid is reduced. As a result, the effect of cooling the wire and the effect of removing the processing debris become insufficient, and the wire is broken. Therefore, according to the present invention, when this state is detected, it is determined that the flow rate of the machining fluid is not within the appropriate range, and the amount of power supply between the wire electrode 16 and the work 17 is reduced to prevent wire breakage. After processing at the starting point, a sealed degree of the jet nozzle the jet nozzle by the movement of the x-axis direction enters into the workpiece away from the initial hole h ₄ of the workpiece 17 gradually increases, thus the pressure of the working fluid is increased The flow rate decreases. Thereafter, as the processing proceeds, the cross-sectional area of the flow path of the processing liquid that can pass through the inside of the work gradually decreases, and both the pressure and the flow rate become substantially constant until the end point is reached, so that a normal processing state is maintained.

[0030] Figure 9 is the middle point while electric discharge machining along the x-axis from the initial hole position h ₅ of the workpiece with substantially y = y ₅ constant shown in FIG. 3 (x _k, y _k) the edge e _k of It is a figure which shows the 5th machining example which carries out electric discharge machining via, and since the pressure and flow volume of a machining fluid are substantially the same as the 1st machining example shown in FIG. 5 at a starting point, description is abbreviate | omitted. At the edge e _k of the point (x _k , y _k ), the work 1 has only a certain area in the outer circumference e _{k of the} jet nozzle.
7 and comes off the work 17 only at the remaining portion. The jet nozzle is opened by that much, and the pressure of the working fluid decreases and the flow rate increases. In this case, the flow rate of the machining fluid is large, but the machining fluid flows out from the opening of the jet nozzle and is insufficiently supplied to the electric discharge machining portion between the wire electrode and the workpiece. Further, since the pressure of the working fluid is low, the flow rate of the working fluid is reduced. As a result, the effect of cooling the wire and the effect of removing the processing debris become insufficient, and the wire is broken. Therefore, according to the present invention, when this state is detected, it is determined that the flow rate of the machining fluid is not within the appropriate range, and the amount of power supply between the wire electrode 16 and the work 17 is reduced to prevent wire breakage. Thereafter, as the processing proceeds, the cross-sectional area of the flow path of the processing liquid that can pass through the inside of the work gradually decreases, so that the degree of sealing of the jet nozzle increases, the pressure of the processing liquid increases, the flow rate decreases, and thereafter the end point is reached. Up to this point, the pressure and flow rate are substantially constant, and a normal machining state is maintained.

[0031]

As described above, according to the present invention, it is determined whether or not the flow rate of the machining fluid supplied to the electric discharge machining portion between the wire electrode and the workpiece is within an appropriate range, and the cooling operation of the wire is performed. When it is determined that the flow rate of the machining fluid required for the action of removing the machining debris cannot be maintained in an appropriate range, the power supply amount required for electric discharge machining is reduced, so that disconnection of the wire electrode can be prevented. Further, since the interruption of the processing due to the wire break is prevented, the processing efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a control device of a wire electric discharge machine according to the present invention.

FIG. 2 is a diagram showing a relationship between a flow rate of a working fluid and a pressure.

FIG. 3 is a view showing a specific example of electric discharge machining by a wire electric discharge machine.

[Figure 4] is a cross-sectional view of the electric discharge machining of the workpiece portions shown in FIG. 3, A is a sectional view of _a portion a, B is a sectional view of a _n and b _n unit, C is a cross-sectional view of _a portion c, D is a sectional view of c ₂ parts, E is a cross-sectional view and F of d ₁ part is a cross-sectional view of e _k section.

5A and 5B are diagrams illustrating a first processing example of the work illustrated in FIG. 3, in which A illustrates a change in a flow rate of a working fluid, and B illustrates a change in a pressure of the working fluid.

6A and 6B are diagrams illustrating a second processing example of the work illustrated in FIG. 3, in which A illustrates a change in a flow rate of a working fluid, and B illustrates a change in a pressure of the working fluid.

7A and 7B are diagrams showing a third working example of the work shown in FIG. 3, where A is a diagram showing a change in the flow rate of the working fluid, and B is a diagram showing a change in the pressure of the working fluid.

8A and 8B are diagrams showing a fourth working example of the work shown in FIG. 3, in which A shows a change in the flow rate of the working fluid, and B shows a change in the pressure of the working fluid.

9A and 9B are diagrams showing a fifth working example of the work shown in FIG. 3, in which A shows a change in the flow rate of the working fluid, and B shows a change in the pressure of the working fluid.

[Explanation of symbols]

 12, 14 ... head 12a, 14a ... jet nozzle 16 ... wire electrode 17 ... work 18 ... processing liquid tank 18a ... cleaning liquid tank 18b ... recovery tank 20, 21 ... pump 36, 37 ... pressure command value input section 42, 43 ... Inverter 51: EDM power supply 52: Machining condition storage means 53: Machining fluid flow rate detection means 54: Judgment means

Claims (3)

[Claims] 1. A control method for a wire electric discharge machine which discharges a machining fluid at a constant pressure to an electric discharge machining portion of a workpiece by a wire electrode and supplies pulsed power to the electric discharge machining portion to perform electrical discharge machining of the workpiece. In the above, the flow rate of the machining fluid supplied to the electric discharge machining part is detected, it is determined whether the detected flow rate of the machining fluid is in a preset, stored proper range, and the detected flow rate of the machining fluid is in the proper range. A pulse-like electric power supplied to the electric discharge machining section when it is determined that the electric discharge machining section does not exist. 2. A control device for a wire electric discharge machine which discharges a machining fluid at a constant pressure to an electric discharge machining portion of a work by a wire electrode and supplies pulsed power to the electric discharge machining portion to perform electric discharge machining of the work. A power supply unit for supplying pulsed power to the electric discharge machining unit; an ejection nozzle for ejecting a machining fluid to the electric discharge machining unit; and a machining fluid supply for supplying a machining fluid in a machining fluid tank to the ejection nozzle. A pump, a machining fluid flow rate detecting unit that detects a flow rate of the machining fluid ejected from the ejection nozzle to the electric discharge machining unit, a supply amount of pulsed electric power supplied from the power supply unit to the electric discharge machining unit, Machining condition storage means for storing an appropriate range of pressure and flow rate of the machining fluid supplied from the machining fluid supply pump to the electric discharge machining section; It is determined whether it is within the range, and when it is determined that it is not within the appropriate range,
A determination unit for sending a command to reduce the pulsed power supplied to the electric discharge machining unit to the machining condition storage unit, a control device for the wire electric discharge machine. 3. The machining fluid flow rate detecting means according to claim 2, further comprising: computing means for computing a machining fluid flow rate from the driving frequency of the machining fluid supply pump and the machining fluid pressure stored in the machining condition storage means. Control device of wire electric discharge machine.