JP3399736B2 - Wire electric discharge machine and wire electric discharge method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire electric discharge machine and a wire electric discharge machining method for performing electric discharge machining by applying a pulse voltage between a work piece and a wire electrode arranged to face the work piece. The present invention relates to a wire electric discharge machine and a wire electric discharge machining method for realizing efficient electric discharge machining by switching electrical machining conditions according to changes in the plate thickness of a workpiece and changes in machining conditions.

[0002]

2. Description of the Related Art Generally, in a power supply circuit of a wire electric discharge machine, a machining speed is improved by controlling ON / OFF of a switching element with a very short width in order to supply a machining current having a high peak value. I am trying to

By the way, the machining volume of the wire electric discharge machine per unit time is obtained by: machining groove width × sheet thickness × line machining speed, and further, the machining volume per unit time is
It depends on the processing energy (current value) and the value specific to the material of the wire electrode and the workpiece. Therefore, the relationship between the processing speed and the processing current is as shown in the graph of FIG. 11, and the plate thickness of the workpiece is expressed by the following equation (1). That is, plate thickness = K × processing energy / processing speed (1) K: a constant.

In wire electric discharge machining, a tension of several hundred g to several kg is applied to a thin wire electrode in order to maintain machining accuracy, and there is a maximum current value that can be passed through the wire electrode. If it exceeds this, disconnection occurs. Here, considering this current value as a current density, the current value at the wire break limit is determined by the length of the wire electrode processed portion, so that there is an optimum processing condition depending on the plate thickness of the workpiece. Generally, the wire breakage limit is highest at a plate thickness of 40 to 60 mm, and the wire breakage limit becomes lower when the plate thickness is thinner than this and due to the cooling efficiency when the plate thickness is thicker.

From the above, it is necessary to control the processing conditions according to the plate thickness in order to perform efficient processing without causing wire breakage, and as a conventional example related to the above technique, As disclosed in Japanese Patent Publication No. 2-29453, there is proposed a wire electric discharge machine which calculates a plate thickness from a machining feed rate and a machining current and switches electrical machining conditions according to the plate thickness.

FIG. 12 is a block diagram showing the structure of a conventional wire electric discharge machine. In the figure, 1 is a wire electrode, 2 is a work as a workpiece, 3 is a processing power source for supplying power to the wire electrode 1, 4 is an integrator, 5 is a reference voltage V1 and an output from the integrator 4. 6 is a differential amplifier for amplifying the difference between the input and output, and 6 is a voltage frequency converter for inputting the output from the operational amplifier 5 and converting the voltage frequency thereof. 57 is for comparing the reference voltage V2 and the output from the integrator 4 for integration. While the output of the device 4 is larger, the output α is "1".

Further, 58 is an analog switch which is turned on while the output α from the comparator 57 is "1", 9 is an integrator for inputting the output from the analog switch 58, and 10 is an analog signal from the integrator 9. A to digital signal
A / D converter, 59 is a numerical controller, 12X and 12Y are X and Y axis servo units, 13X and 13Y are X and Y axis motors for relatively moving the wire electrode 1 and the workpiece 2, and R1 to R1. R3 is a resistance.

The integrator 4 smoothes the voltage between the wire electrode 1 and the work 2 divided by the resistors R1 and R2, and its output corresponds to the average machining voltage. . The differential amplifier 5 amplifies the difference between the output from the integrator 4 and the reference voltage V1 and adds it to the voltage frequency converter 6, and the numerical controller 59 distributes the pulse signal from the voltage frequency converter 6 to the motor 13X. , 13Y are created and added to the servo units 12X, 12Y. As a result, the relative feed operation between the wire electrode 1 and the work 2 is performed at a speed such that the average machining voltage becomes constant. Since the above-described operation is well known, detailed description will be omitted.

The comparator 57 compares the output from the integrator 4 with the reference voltage V2. While the reference voltage V2 is smaller, the discharge between the wire electrode 1 and the work 2 is normally performed. Of the analog switch 58, the output α is set to "1", and the output is set to "0" while the arc state is maintained while the reference voltage V2 is higher.
And the numerical controller 59.

Therefore, the current signal from the current detecting resistor R3 is applied to the integrator 9 via the analog switch 58 only when the discharge between the wire electrode 1 and the work 2 is normally performed. It will be. The integrator 9 smoothes the current signal applied via the analog switch 58 and applies it to the A / D converter 10, and its output corresponds to the true machining current.

The numerical control device 59 is the same as the motor 13 described above.
In addition to controlling X and 13Y, the output of the voltage frequency converter 6, the output of the A / D converter 10, the material of the work 2 and the wire electrode 1 input from an external keyboard (not shown), etc. Based on the constant K and the machining groove width d
The process shown in the flowchart of FIG. 13 is performed at regular intervals. The processing groove width d is obtained in advance by performing test processing before processing.

Next, the operation of the above conventional wire electric discharge machine will be described with reference to the flowchart of FIG. The numerical control device 59 displays the constant time (step S
In 1), it is determined whether or not the output α from the comparator 57 is "1" (step S2). If the output α is "1" (affirmation in step S2), the output of the voltage frequency converter 6 is first output. The relative feed speed F between the wire electrode 1 and the workpiece 2 is obtained based on the above (step S3), and the true machining current IT is obtained based on the output from the A / D converter 10 (step S4). The plate thickness h of the work is obtained by performing the calculation shown in the following formula (2) (step S5).

That is, Thickness of work piece h = K × IT / (F · d) (2) K: A constant determined by the workpiece and the wire electrode material F: Relative feed rate between wire electrode and workpiece IT: True machining current d: Processed groove width Is.

In a memory (not shown) inside the numerical controller 59, as shown in FIG.
Corresponding to n (however, h (n-1) <hn), no-load voltages Vs1 to Vsn, peak currents Ip1 to Ipn, on times Ton1 to Tonn, off times Toff1 to To.
ffn is stored. When the numerical control device 59 obtains the plate thickness h by the above equation (2), it compares the plate thickness h with the plate thicknesses h1 to hn stored in the memory, and based on the comparison result, the electrical processing conditions. Is switched (step S6).

In this case, if h1 <h <h2, the numerical control device 59 indicates that the electrical machining conditions Vs1, I corresponding to the plate thickness h1.
p1, Ton1, Toff1 are read out, and control signals b, c, d for controlling no-load voltage, peak current, and on / off time are created based on these conditions, added to the machining power source 3, and switching of electrical machining conditions. Is to do. As a result, the electrical machining conditions can be switched according to the plate thickness of the workpiece 2, and efficient electrical discharge machining can be realized.

[0016]

However, although there are limit current values depending on the material and diameter of the wire electrode and the plate thickness of the workpiece, the working conditions are generally not uniform. For example, as shown in FIG.
As shown in Fig. 5, in the processing of a workpiece of 60 mm, the processing condition is good, the processing energy can be large and the processing speed is fast, and the processing condition is bad. There is a situation like the slower area B.

Therefore, when the end surface, the corner portion, and the machining liquid nozzle of the workpiece to which the machining liquid is not jetted efficiently cannot be in close contact with each other, it is necessary to weaken the electric machining conditions to prevent the disconnection. The wire electric discharge machine does not disclose any configuration capable of changing the electric machining conditions according to these situations. As a result, in the above-mentioned conventional example, in order to cope with these situations, if a strong machining condition is set, the wire breaks when the machining condition is bad, and conversely, if a weak machining condition is set, the machining speed decreases. There is a problem that the processing efficiency is reduced.

The present invention has been made to solve the above-mentioned problems, and in a wire electric discharge machine, an optimum machining condition is selected with respect to a change in the plate thickness of the work piece or a change in the working condition. By doing so, it is an object of the present invention to obtain a wire electric discharge machine and a wire electric discharge machining method capable of preventing wire breakage and efficiently performing electric discharge machining.

[0019]

In order to achieve the above object, a wire electric discharge machine according to the present invention applies a pulse voltage between a work piece and a wire electrode arranged to face the work piece. In a wire electric discharge machine for performing electric discharge machining by means of machining, a machining speed detecting means for detecting a relative machining speed between the workpiece and the wire electrode, and an energy value calculating means for calculating an energy value of the discharge pulse. , Compound
For different machining speed values and several different discharge pulses
Several different electromachining condition strengths corresponding to energy values
Is stored in advance and the inclination of the machining speed value with respect to the energy value is
The same electrical processing condition strength is stored in the same area.
However, the strength of the electromachining process varies depending on the energy value.
It has a memory that stores the
Machining speed detected by the step and the energy value
The memo using the energy value calculated by the calculating means
Electrical condition strength to obtain the corresponding electrical machining condition strength from
Output from the degree converting means and the electrical condition intensity converting means.
And a control means for switching to the electromachining condition corresponding to the strength of the electromachining condition .

In the wire electric discharge machine according to the present invention, the plate thickness is calculated from the machining speed data and the energy value,
Select the electrical condition strength from the relationship between the plate thickness and energy,
Since the electrical condition corresponding to the electrical condition strength is switched,
It is possible to select the optimum machining conditions, and as a result, it is possible to prevent disconnection and to perform efficient electric discharge machining.

A wire electric discharge machine according to the next invention is a wire electric discharge machine for performing electric discharge machining by applying a pulse voltage between a work piece and a wire electrode arranged to face the work piece. Machining speed detecting means for detecting the relative machining speed of the workpiece and the wire electrode, energy value calculating means for calculating the energy value of the discharge pulse for each predetermined period, a plurality of different plate thickness values and a plurality of It has a memory in which a plurality of different electric machining condition intensities are stored in advance corresponding to energy values of different discharge pulses, and machining speed data detected by the machining speed detecting means and energy calculated by the energy value calculating means. Value and
And the plate thickness was determined based on the electric conditions intensity conversion means for acquiring the electrical machining conditions intensity corresponding from the memory using the computed energy value by said energy value computing means, said electrical condition intensity conversion means And a control means for switching to the electromachining condition corresponding to the electromachining condition strength output from.

A plurality of wire electric discharge machines according to the present invention are provided.
Energy of Different Thickness and Multiple Discharge Pulses
The different electrical machining condition strengths in advance corresponding to the gee value.
Memorize, and from this stored data, plate thickness and energy value
The electrical processing condition strength corresponding to the
Switch to electrical conditions that correspond to the processing condition strength.
As a result , disconnection can be prevented and efficient electrical discharge machining can be performed.

The wire electric discharge machining method according to the next invention is
In a wire electric discharge machining method for performing electric discharge machining by applying a pulse voltage between a work piece and a wire electrode arranged to face the work piece, a relative machining of the work piece and the wire electrode a first step of detecting the speed, a second step of calculating the energy value of the discharge pulse, the
The processing speed data detected in the first step and the second processing
The energy value calculated by
Machining speed value and energy of several different discharge pulses
Pre-store multiple different electromachining condition strengths corresponding to the values
And the slope of the machining speed value with respect to the energy value is the same.
Although the same electric processing condition strength is memorized in the region,
The electrical processing condition strength that varies depending on the ghee value is stored.
Based on the stored data, the corresponding electrical processing condition strength can be determined.
The third step of obtaining and the electricity obtained in the third step
Switching to electrical machining conditions corresponding to the condition machining strength 4th
The process of and is included.

In the wire electric discharge machining method according to the present invention, the plate thickness is calculated from the machining speed data and the energy value, the electrical condition strength is selected from the relationship between the plate thickness and energy, and the electrical condition strength is met. Since the electrical conditions are switched, you can select the optimum processing conditions, and as a result,
It is possible to prevent disconnection and perform efficient electric discharge machining.

The wire electric discharge machining method according to the next invention is
In a wire electric discharge machining method for performing electric discharge machining by applying a pulse voltage between a work piece and a wire electrode arranged to face the work piece, a relative machining of the work piece and the wire electrode A first step of detecting a speed, a second step of calculating an energy value of a discharge pulse for each predetermined period, machining speed data detected in the first step, and
And the plate thickness was determined based on the energy values calculated in the second step, the second by using the computed energy value in step, a plurality of different thickness values and the energy of the different discharge pulses A third step of obtaining the corresponding electromachining condition strength from the stored data in which a plurality of different electromachining condition strengths are stored in advance and the electric condition machining strength obtained in the third step. And a fourth step of switching to a corresponding electromachining condition.

The wire electric discharge machining method according to the present invention, multiple
Energy of different thickness values and different discharge pulses
Predict multiple different electromachining condition strengths corresponding to the rugged value.
The thickness and energy from this stored data.
The electric processing condition strength corresponding to the value is acquired, and the acquired electric
Switch to electrical conditions that correspond to the strength of the gas processing conditions
Therefore, disconnection can be prevented, and efficient electric discharge machining can be performed.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a wire electric discharge machine and a wire electric discharge method according to the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing the configuration of a wire electric discharge machine according to Embodiment 1.
In the figure, 1 is a wire electrode, 2 is a workpiece, 7 is a discharge start detection circuit that detects a machining voltage between electrodes, 8 is a pulse control circuit that controls the switching operation of a machining power supply 11, and 11 is a Wire electrode 1 and work piece 2
A machining power supply that supplies a discharge current pulse to and, and an energy value calculator 14 that calculates machining energy.

Further, 20 is a table on which the workpiece 2 is placed, 21a and 21b are X-axis and Y-axis drive motors for positioning the relative positions of the wire electrode 1 and the workpiece 2, and 2a and 21b.
2 is an axis drive control device that controls the X-axis and Y-axis drive motors 21a and 21b, 23 is an average machining voltage detection device that detects an average machining voltage, and 24 is an axis movement command to the axis drive control device 22 and the pulse control circuit 8. And an NC control device for sending a processing condition parameter.

FIG. 2 is a connection diagram of the processing power source according to the first embodiment. In the figure, 1101 is a DC power supply (E
1) 1102 is a sub switching element (TR1), 11
03 is a current limiting resistor, 1104 is a diode,
The negative electrode of the DC power supply 1101 is connected to the cathode of the diode 1104, the anode of the diode 1104 is connected to the wire electrode 1, the positive electrode of the DC power supply 1101 is connected to one end of the current limiting resistor 1103, and the current limiting resistor 11
The other end of 03 is connected to the drain of the sub switching element (TR1) 1102, and the sub switching element (TR1) 1
The source of 102 is connected to the workpiece 2, and the gate of the 102 is connected to the pulse control circuit 8.

Reference numeral 1105 denotes a DC power source (E2), 11
Reference numeral 06 is a main switching element (TR2), 1107 is a diode, and the negative electrode of the DC power supply 1105 is the diode 1
107, the anode of the diode 1107 is connected to the wire electrode 1, the positive electrode of the DC power supply 1105 is connected to the drain of the main switching element (TR2) 1106, and the main switching element (TR2) 1106.
The source is connected to the work piece 2 and the gate is connected to the pulse control circuit 8.

Reference numeral 1108 denotes a direct current power source, 1109 denotes a diode, the positive electrode of the direct current power source 1108 is connected to the anode of the diode 1109, the cathode of the diode 1109 is connected to the wire electrode 1, and the direct current power source 1108 is used.
The positive electrode of is connected to the workpiece 2.

FIG. 3 is a block diagram showing a detailed structure of the energy value calculation unit 14, and in FIG.
Reference numeral 1 is an energy value conversion circuit for inputting a signal from the pulse control circuit 8, 1402 is a processing energy value addition circuit for adding processing energy of a predetermined cycle, and 1403 is a timer for setting a calculation cycle of the processing energy value addition circuit 1402. . The input of the energy value conversion circuit 1401 is connected to the signal SG2 of the pulse control circuit 8, converts the pulse width data of the signal SG2 into an energy value, and the output is connected to the input 1402a of the processing energy value addition circuit 1402.

The output 140 from the timer 1403
3a is connected to the reset input of the processing energy value adding circuit 1402 and the trigger input of the latch circuit 1404.
Further, the output 1402b from the processing energy value adding circuit 1402 is connected to the data input of the latch circuit 1404, and the output from the latch circuit 1404 is the NC controller 24.
Connected to.

Next, the operation of the first embodiment will be described. In FIG. 1, machining path information and machining electrical condition parameters are input to the NC controller 24 from an NC program or an operation panel (not shown). The input processing electrical condition parameter is output to the pulse control circuit 8. The pulse control circuit 8 generates a drive signal having a predetermined current peak, pulse width, and rest time based on the machining electrical condition parameter, and controls the machining power supply 11.

The machining power source 11 is driven by this drive signal, and a predetermined current pulse is held in the upper and lower parts of the workpiece 2 by the wire guide 1
Is supplied to the machining gap between the workpiece 2 and the workpiece 2, and water or a water-based machining liquid is generally supplied to the machining gap to perform electric discharge machining.

Next, the average machining voltage detecting device 23 detects the average voltage during the machining process, and based on this voltage, the electrode 1 or the electrode 1 or the workpiece 1 is maintained so that the relative position between the electrode 1 and the workpiece 2 is kept constant. The feed control of the workpiece 2 is executed. That is, when the detected average voltage is equal to or higher than the predetermined value, the feed speed of the electrode 1 or the workpiece 2 is increased, and when the average voltage is equal to or lower than the predetermined value, the feed speed of the electrode 1 or the workpiece 2 is decreased. As described above, the NC controller 24 calculates the feed rate, outputs a positioning command to the axis drive controller 22 based on the machining path information, and controls the positioning of the table 20 by the X-axis drive motor 21a and the Y-axis drive motor 21b. A desired shape is processed by performing.

Further, the NC control unit 24 is the shaft drive motor 2
In addition to controlling 1a and 21b, operation panel (not shown)
Based on the constant K determined by the material of the work 2 and the wire electrode 1 input from the etc., from the machining speed data calculated inside the NC control device 24 and the energy data e calculated by the energy value calculator 14. The process shown in the flowchart of 6 is performed at regular intervals.

Next, FIG. 4 is a timing chart showing the operation of the pulse control circuit 8 shown in FIGS. In the figure, 40a is a machining voltage waveform, 40b is a machining current waveform, 40c is a pulse signal SG1 for driving the sub switching element (TR1) 1102, 40d is a pulse signal SG2, 4 for driving the main switching element (TR2) 1106.
0e is a signal S for determining the magnitude of the time until the discharge starts and the predetermined time Tc after SG1 is set to "1".
It is G3.

First, SG1 is set to "1" and SG3 is set to "0" at the timing of processing start, and the sub-switching element (TR1) 1102 is turned on by SG1, so that the workpiece 2 is processed with respect to the wire electrode 1. Is applied with the voltage E1 of the DC power supply 1101, and SG1 is set to "1".
If the predetermined time Tc is exceeded after that, SG3 is controlled to be "1".

Next, when the discharge starts, the divided voltage value Vg (see FIG. 2) by the resistors 71 and 72 and the set voltage V
The discharge start is detected by comparing with 1, and at this timing S
G1 is set to "0" and SG2 is set to "1" to drive the main switching element (TR2) 1106, and the DC power supply 1105 starts supplying the machining current between the electrodes. At this time, if SG3 is "0", ON1 for a predetermined time, "1"
In this case, SG2 is set to "1" for a predetermined time ON2, then SG2 is set to "0" to stop the supply of the machining current, and after the pause time OFF, the operation of setting SG1 to "1" again is performed. repeat.

Generally, the time Td when SG1 becomes "1" is compared with a predetermined time Tc, and Td≤Tc (immediate discharge pulse).
ON when 1, and O when Td> Tc (normal discharge pulse)
The processing speed can be improved by selecting N2 and setting ON1 <ON2. At this time, the discharge current waveform is a pulse waveform with a high peak value and a short width, such as 40b.

This is the sub switching element (TR1) 1
After the voltage E1 is applied by driving 102, a minute current limited by the current limiting resistor 1103 flows into the machining gap at the start of discharge, and when discharge is detected, the main switching element (TR2) 1106 is driven to supply power from the power source 1105. This is because after the current rises on the low impedance circuit and after the driving of the main switching element (TR2) 1106 is stopped, the current flows to the DC power supply 1108 and instantly falls.

Next, FIG. 5 shows the energy value calculation unit 14
Is a timing chart showing the operation of
50a is an output pulse 1403a from the timer 1403
50b is a timing chart of the output 1402b of the processing energy value addition circuit 1402, and 50c is energy data e which is the added value of the processing energy for each sampling time held in the latch circuit 1404. 3 and 5, the energy value conversion circuit 1401
Is the main switching element (TR2) 1 of the pulse control circuit 8
ON time of drive pulse SG2 of 106 (ON1 or O
Based on N2), it is converted into a processing energy value for each current pulse and output.

Here, the current waveform as shown in FIG.
Since the current peak value peculiar to the circuit exists with respect to the impedance and the current pulse width in the circuit, the processing energy value per discharge pulse should be obtained from the product of the arc potential and the integrated value of the current pulse. You can In addition,
The processing power supply 11 is not limited to the one shown in FIG. 2 and may be any one capable of obtaining the energy value as described above.

By the way, the processing energy value adding circuit 14
02 starts addition of the energy value for each machining pulse by the output pulse 1403a given at the set period T of the timer 1403, and outputs the addition result 1402b to the latch circuit 1404. The latch circuit 1404 holds the output 1402b of the processing energy value adding circuit 1402 at the rising edge of the output 1403a of the timer 1403 connected to the trigger input.

Further, the processing energy value adding circuit 1402
Performs a reset operation at the fall of the output 1403a of the timer 1403 so that the latch circuit 1404 latches the addition result 1402b and then clears the addition value. Then, the added value of the processing energy for each sampling time held in the latch circuit 1404 is output to the NC control device 24 as energy data e.

Next, the operation of selecting the electrical condition strength will be described with reference to the flow chart shown in FIG. N
In a memory (not shown) inside the C control device 24, FIG.
Pulse width Ip corresponding to the electrical condition intensities E1 to E8 shown in
1 to Ip8, parameters of the rest times Toff1 to Toff8, and the electrical condition strength selectable for each plate thickness shown in FIG. 8 are stored.

Here, the electric condition strength E is E1 <E2 <... <E8 as strength as a processing condition, and the energy data e read from the energy value calculation unit 14 is as follows.
There is a relationship of e1 <e2 <e3 <e4. First, NC
The controller 24 repeats the operation (step S
10) Calculate the relative feed speed between the wire electrode 1 and the workpiece 2, that is, the processing speed f (step S1).
1).

Next, the energy data e output from the energy value calculator 14 is read (step S12),
The plate thickness h is calculated (step S13). Next, the NC control device 24 selects the electrical condition intensity from the calculated plate thickness h and the energy data e based on the rules shown in FIGS. 7 and 8 (step S14), and the pulse width Ip corresponding to the electrical condition intensity is selected. And the rest time Toff are output to the pulse control circuit 8. Therefore, the electrical condition is switched based on various conditions (S step 15).

For example, if the energy data e input from the energy value calculator 14 is e = e4 and the plate thickness calculated by the NC controller 24 is h = 60 mm, E8 is selected as the electrical condition strength, and The pulse width Ip8 and the pause time Toff8 corresponding to the condition strength E8 are output to the pulse control circuit 8. Even if the plate thickness h is calculated to be 60 mm, if the processing condition is bad and the energy data e output from the energy value calculation unit 14 is a value of e = e2, the electrical condition strength is selected to be E6, which is weaker than E8, The pulse width Ip6 and the rest time Toff6 are output to the pulse control circuit 8.

With the configuration as shown in the first embodiment, even if the plate thickness of the work piece 2 is suddenly changed or the working condition such as the work near the end face of the work piece is changed, The appropriate electrical condition strength is selected from the relationship between the processing speed and energy, and the electrical condition parameters are changed.When the machining conditions are poor, weak electrical conditions can be set to prevent wire breakage, and the machining fluid nozzle can be in close contact. When the possible machining conditions are good, strong electrical conditions are set, so that the machining speed does not decrease, and efficient machining processing is realized.

Here, in the first embodiment, the electric condition strength is set to eight kinds in FIG. 7, but the number of strengths different from eight kinds may be set. In addition, although two types of parameters, that is, the pulse width and the dwell time, are used as the parameters of the electrical condition to be changed for each electrical condition strength, other parameters such as the average machining voltage Vg and the no-load voltage Vs may be changed. .

Further, in FIG. 8, the plate thickness is divided into five types, but it may be divided into a number different from the five types. Further, although the electrical condition strength selection rule that can be selected for each plate thickness in FIG. 8 is defined based on the energy data e, it may be defined based on the processing speed data f or the processing speed data f and the energy data e. good.

(Second Embodiment) In the first embodiment,
Although the electric condition strength is selected by the NC control device 24, the technical feature of the second embodiment is that the electric condition strength is selected without the NC control device 24.

FIG. 9 is a block diagram showing the structure of the wire electric discharge machine according to the second embodiment. In the figure, 15
Is an electrical condition intensity conversion unit (ROM) that inputs the processing speed data f and the energy data e and outputs the electrical condition intensity, and 16 is the electrical condition intensity E from the electrical condition intensity conversion unit 15.
Is an electric condition conversion unit (ROM) for inputting and outputting electric condition parameters.

FIG. 10 shows the contents of the electric condition strength conversion unit 15 and the contents of the electric condition conversion unit 16 stored in the NC control device 24 in the first embodiment (see FIG. 7). Remember the same.

Next, the operation of the second embodiment will be described. The electrical condition intensity conversion unit 15 outputs the electrical condition intensity E with the machining speed data f calculated by the NC control device 24 and the energy data e calculated by the energy value calculation unit 14 as data selected as an input address. Next, the electrical condition conversion unit 16 determines the electrical condition strength E
To output the corresponding electrical condition parameter to the pulse control circuit 8.

The electrical condition selecting operation at the start of machining will be described. For example, if Ip1 and Toff1 corresponding to E1 are set as the initial values of the electrical condition parameters, the machining process proceeds and the machining speed data f And the energy data e are calculated, and these data are input to the electrical condition intensity conversion unit 15 and the electrical condition conversion unit 16 to select the electrical condition intensity and the electrical condition parameter corresponding thereto.

Here, the contents of the electrical condition intensity conversion section 15 will be described. As shown in FIG. 10, it is a matrix for selecting the electrical condition intensity from the processing speed and energy, and FIG. 6 according to the first embodiment. The processing performed by the flowchart shown in is stored in the ROM in advance. That is, the relationship between processing speed and energy is shown in Fig. 1.
As can be seen from the fact that it can be expressed by the graph shown in Fig. 1, the plate thickness can be specified from the processing speed and energy, so the ROM input address is the processing speed and energy, and the electrical condition strength is set at the location specified by the input address. If the value of E is described, the same operation as the flowchart of the first embodiment can be realized.

As described above, by constructing the wire electric discharge machine as shown in the second embodiment, the workpiece 2
Even if the plate thickness of changes sharply or changes in the processing conditions such as processing near the end surface of the workpiece, the electrical condition strength is selected from the relationship between the processing speed and energy, and the electrical condition parameters are changed. When the machining condition is bad, the electrical condition is set weak to prevent wire breakage, and when the machining condition that the machining liquid nozzle can be closely attached is set to the strong electrical condition, efficient electrical discharge machining can be realized. .

In addition, since the operation of selecting the electric condition strength is performed without the NC controller 24, the electric condition can be selected quickly, so that it is possible to quickly respond to the change in the plate thickness and the change in the working condition. You can The NC control device 24
The contents of the ROMs of the electrical condition intensity conversion unit 15 and the electrical condition conversion unit 16 may be stored in the memory inside the NC control device 24 if the transfer speeds of and are sufficiently high.

[0063]

As described above, in the wire electric discharge machine according to the present invention, the electric condition is set weak when the working condition is bad, and the electric condition is set strong when the working condition is good. While preventing this, it is possible to suppress a decrease in processing speed and improve processing efficiency.

The wire electric discharge machine according to the next invention is N
Since the electric condition strength is selected without going through the C control device, the electric condition can be changed in a shorter time according to the change of the work sheet thickness and the working situation, and the wire speed can be prevented while preventing the wire breakage. Can be suppressed to a minimum.

Further, in the wire electric discharge machining method according to the present invention, like the wire electric discharge machine, the electric condition is set weak when the machining condition is bad, and the electric condition is strongly set when the machining condition is good. Therefore, it is possible to prevent the wire breakage and suppress the reduction of the processing speed, and it is possible to improve the processing efficiency.

The wire electric discharge machining method according to the next invention is
Similar to the wire electric discharge machine, since the electrical condition strength is selected without going through the NC control device, it is possible to change the electrical condition according to the change in the workpiece plate thickness and the machining situation in a shorter time, and It is possible to minimize the reduction in processing speed while preventing wire breakage.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wire electric discharge machine according to a first embodiment.

FIG. 2 is a circuit diagram showing a connection state of a processing power source according to the first embodiment.

FIG. 3 is a block diagram showing a detailed configuration of an energy value calculation unit according to the first embodiment.

FIG. 4 is a timing chart showing the operation of the pulse control circuit according to the first embodiment.

FIG. 5 is a timing chart showing the operation of the energy value calculation unit according to the first embodiment.

FIG. 6 is a flowchart showing an operation of the wire electric discharge machine according to the first embodiment.

FIG. 7 is an explanatory diagram showing stored contents of a memory of the NC control device according to the first embodiment.

FIG. 8 is an explanatory diagram showing stored contents of a memory of the NC control device according to the first embodiment.

FIG. 9 is a block diagram showing a configuration of a wire electric discharge machine according to a second embodiment.

FIG. 10 is a graph showing the contents of an electrical condition strength conversion unit according to the second embodiment.

FIG. 11 is a graph showing the relationship between processing speed and energy.

FIG. 12 is a block diagram showing a configuration of a conventional wire electric discharge machine.

13 is a flowchart showing the operation of the conventional wire electric discharge machine shown in FIG.

FIG. 14 is an explanatory diagram showing the contents of a memory of the conventional wire electric discharge machine shown in FIG.

FIG. 15 is a graph showing a region A in which the processing condition is good and the processing energy can be increased and the processing speed is fast, and a region B in which a large amount of energy cannot be input and the processing speed is slow because the processing condition is bad.

[Explanation of symbols]

1 wire electrode, 2 workpiece, 7 discharge start detection circuit, 8 pulse control circuit, 11 machining power supply, 14 energy value calculation unit, 15 electrical condition intensity conversion unit, 16
Electrical condition conversion unit, 20 table, 21a X-axis drive motor, 21b Y-axis drive motor, 22-axis drive control device, 23 average machining voltage detection device, 24 NC control device, 1401 energy value conversion circuit, 1402 machining energy value addition circuit , 1403 timer, 1404
Latch circuit

Continuation of the front page (56) Reference JP-A-5-305517 (JP, A) JP-A-53-131598 (JP, A) JP-A 1-216725 (JP, A) JP-A-51-13498 (JP , A) JP-A-7-1244 (JP, A) JP-B-2-29453 (JP, B2) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23H 7/02 B23H 7/04

Claims (4)

(57) [Claims] 1. A wire electric discharge machine for performing an electric discharge machining process by applying a pulse voltage between a work piece and a wire electrode arranged opposite to the work piece, wherein the work piece and the wire electrode are provided. Machining speed detecting means for detecting a relative machining speed, an energy value calculating means for calculating an energy value of the discharge pulse, a plurality of different machining speed values and a plurality of different discharge pulses
Depending on the energy value of
Degree is stored in advance, and the machining speed value
Areas with the same inclination store approximately the same electrical processing condition strength.
Depending on the energy value, different electromachining conditions
It has a memory that stores strength and detects the machining speed.
Processing speed and energy value detected by means
The energy value calculated by the calculation means is used to
Electrical conditions to obtain corresponding electrical processing condition strength from Mori
Strength conversion means and electrical processing conditions output from the electrical condition strength conversion means
A wire electric discharge machine comprising: a control means for switching to an electric machining condition corresponding to strength . 2. A wire electric discharge machine for performing an electric discharge machining process by applying a pulse voltage between a work piece and a wire electrode arranged opposite to the work piece, wherein the work piece and the wire electrode are provided. Corresponding to a plurality of different plate thickness values and a plurality of different discharge pulse energy values, and a machining speed detecting means for detecting the relative machining speed of A plate having a memory in which a plurality of different electromachining condition intensities are stored in advance , and obtained based on the machining speed data detected by the machining speed detecting means and the energy value calculated by the energy value calculating means. Electric condition strength for acquiring the corresponding electric machining condition strength from the memory using the thickness and the energy value calculated by the energy value calculating means. A wire electric discharge machine comprising: a conversion unit; and a control unit that switches to an electric machining condition corresponding to the electric machining condition strength output from the electric condition strength conversion unit. 3. A wire electric discharge machining method in which a pulse voltage is applied between a work piece and a wire electrode arranged to face the work piece to perform electric discharge machining, wherein the work piece and the wire electrode are provided. First step for detecting the relative machining speed of the discharge pulse, a second step for calculating the energy value of the discharge pulse, the machining speed data detected in the first step, and the second step .
Using the energy value calculated in the process of
Different machining speed values and energy of several different discharge pulses
The different electrical machining condition strengths in advance corresponding to the gee value.
Memorized, the slope of the machining speed value with respect to the energy value is the same.
Almost the same electrical machining condition strength is stored in the same area, but
The electrical processing condition strength that differs depending on the magnitude of the energy value is recorded.
From the stored memory data, the corresponding electrical processing condition strength
Corresponding to the third step of acquiring the degree and the electrical condition processing strength obtained in the third step.
And a fourth step of switching to electrical machining conditions . 4. A wire electric discharge machining method for performing electric discharge machining by applying a pulse voltage between a work piece and a wire electrode arranged opposite to the work piece, wherein the work piece and the wire electrode are provided. First step of detecting the relative machining speed of the first and second steps of calculating the energy value of the discharge pulse for each predetermined period
Process, the processing speed data detected in the first process and the second process
Of a thickness determined based on the computed energy value in step, by using the energy values calculated by the second step, the energy value of a plurality of different thickness values and a plurality of different discharge pulses Corresponding to the third step of acquiring the corresponding electromachining condition strength from the stored data in which a plurality of different electromachining condition strengths are stored in advance, and the electric condition machining strength obtained in the third step. A fourth step of switching to electrical machining conditions, and a wire electric discharge machining method comprising: