JPWO2008050405A1 - Wire electrical discharge machine - Google Patents

Abstract

The wire electric discharge machine of the present invention includes an upper power supply state in which a high-frequency pulse voltage is applied to the wire electrode only from an upper power supply unit disposed on the upper side of the workpiece, and a lower power supply disposed on the lower side of the workpiece. The lower power supply state in which a high-frequency pulse voltage is applied to the wire electrode from only the part and the both-side power supply state in which a high-frequency pulse voltage is applied to the wire electrode in synchronization with each other from both the upper power supply unit and the lower power supply unit By controlling the power feeding so as to be mixed during the period, the short-circuit between the wire electrode and the workpiece and the wire breakage are suppressed, and the productivity can be easily improved.

Description

  The present invention relates to a wire electric discharge machine that generates a discharge between a wire electrode and a workpiece to process the workpiece into a predetermined shape.

  In a wire electric discharge machine, a high frequency pulse voltage is applied to a wire electrode, and at this time, the work piece is removed little by little by an electric discharge generated between the wire electrode and the work piece, and the work piece is shaped into a predetermined shape. Process. The wire electrode travels in a predetermined direction, for example, a vertical direction by a pair of upper and lower wire guides, and the machining fluid is supplied around the wire electrode while the workpiece is processed. For example, the workpiece can be precisely machined by causing the discharge to occur while moving the table on which the workpiece is placed in a predetermined direction by numerical control.

  In order to accurately and stably process a workpiece by wire electric discharge machining, it is important to process the workpiece while keeping the distance between the wire electrode and the workpiece within a predetermined range. If the short circuit occurs, electric discharge will not occur, so machining will stop. In addition, a concentration of electric discharge (hereinafter referred to as “concentrated electric discharge”) occurs due to accumulation of machining waste or the like between the wire electrode and the workpiece, and the wire electrode is disconnected as a result of locally excessive discharge energy. (Hereinafter referred to as “wire breakage”) often occurs. When the wire breakage occurs, the wire electrode must be guided again by the wire guide, which greatly reduces productivity. Thus, various techniques for preventing wire breakage have been devised.

  For example, in Patent Document 1, two or more energizing terminals for supplying a pulse voltage from a machining power source to a wire electrode are provided above and below the workpiece, and energization switching is performed between each energizing terminal and the machining power source. There is described an electric discharge machining apparatus in which a switch is provided and the energization switching switch is controlled to be switched each time a plurality of continuous pulse voltages are applied from a machining power source to one energization terminal. In this electrical discharge machining apparatus, the discharge location between the wire electrode and the workpiece periodically moves up and down, so that heat generation of the wire electrode can be suppressed even when a large current is applied. Since the discharge points with the workpiece are also dispersed, wire breakage is prevented.

  Further, in Patent Document 2, electrons for supplying a machining pulse to the wire electrode are provided on the upper side and the lower side of the workpiece, and between the upper side electron and the workpiece and on the lower side. A wire-cut electric discharge machining apparatus in which a machining pulse power source is provided between each workpiece and the workpiece is described. In this wire-cut electric discharge machining apparatus, concentration of discharge points is prevented by causing a pulse current to flow asynchronously from the upper and lower electrons to the wire electrode, and as a result, wire breakage is prevented.

  In Patent Document 3, two contacts are provided along the wire electrode so as to be located at both ends of the processing area of the workpiece (workpiece), and a discharge position between the wire electrode and the workpiece is disclosed. Accordingly, an electric discharge machining apparatus that supplies a machining current to one or both of the two contacts is described. In this electric discharge machining apparatus, a contact to which a machining current is to be supplied is changed in accordance with the discharge position to prevent local heating due to concentrated discharge, and as a result, wire breakage is prevented.

JP 59-47123 A JP-A-1-97525 Japanese Examined Patent Publication No. 6-61663

  Each of the electrical discharge machining devices described in Patent Documents 1 to 3 is useful for improving productivity by preventing wire breakage, but in order to improve productivity in wire electrical discharge machining. It is desirable to prevent wire breakage and to prevent a short circuit between the wire electrode and the workpiece. According to the inventors' experiments, the short circuit is applied with a voltage of several pulses to the wire electrode via either the energizing terminal disposed above the workpiece or the energizing terminal disposed below. It can happen just by doing.

  Therefore, as in the electric discharge machining apparatus described in Patent Document 1, the above short-circuiting is efficiently performed only by alternately supplying power from one power supply terminal to the wire electrode and supplying power from the other power supply terminal to the wire electrode. It cannot be suppressed well. As in the wire-cut electric discharge machining apparatus described in Patent Document 2, the power supply from one power supply terminal to the wire electrode and the power supply from the other power supply terminal to the wire electrode are performed asynchronously, or described in Patent Document 3 The same applies to the case where the power supply from one power supply terminal to the wire electrode and the power supply from the other power supply terminal to the wire electrode are changed according to the discharge position as in the electrical discharge machining apparatus that has been provided. The short circuit cannot be efficiently suppressed. When the wire electrode and the workpiece are short-circuited, the electric discharge does not occur, so that the electric discharge machining itself stagnates and the average machining speed decreases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a wire electric discharge machine that can easily improve productivity by suppressing short-circuiting and wire breakage between a wire electrode and a workpiece.

  The wire electric discharge machine of the present invention that achieves the above object is arranged above and below the workpiece while supplying a machining fluid between the wire electrode that runs in the thickness direction of the workpiece and the workpiece. A wire electric discharge machine that applies a high-frequency pulse voltage to a wire electrode through a pair of power supply units and processes the workpiece by an electric discharge generated between the wire electrode and the workpiece. A high-frequency pulse voltage is applied to the upper power supply unit disposed above the workpiece through the first switching element unit, and the second switching is performed to the lower power supply unit disposed below the workpiece. A main power source for applying a high-frequency pulse voltage via the element portion; a first pulse oscillator for supplying a pulse signal for controlling the opening / closing operation of the first switching element portion to the first switching element portion; and a second switching element portion The second switch A second pulse oscillator that supplies a pulse signal for controlling the opening / closing operation of the chucking element portion, and the opening / closing operations of the first switching element portion and the second switching element portion, respectively, and the high frequency pulse is applied to the wire electrode only from the upper feeding portion An upper power supply state in which voltage is applied, a lower power supply state in which a high frequency pulse voltage is applied to the wire electrode only from the lower power supply portion, and a high frequency on the wire electrode in synchronization with each other from both the upper power supply portion and the lower power supply portion A storage unit storing power supply control data for power supply control so that both-side power supply states to which a pulse voltage is applied are mixed, and controls the operations of the first pulse oscillator and the second pulse oscillator based on the power supply control data. And a pulse oscillation control unit.

  When the upper power supply state or the lower power supply state described above, a short circuit between the wire electrode and the workpiece is likely to occur, but if the upper power supply state and the lower power supply state appear alternately, the wire electrode and the workpiece Since the position of the discharge point in between changes in the plate thickness direction (thickness direction) of the workpiece, the occurrence of concentrated discharge can be suppressed and wire breakage can be prevented. In addition, since the discharge between the wire electrode and the workpiece is stabilized when the power supply is on both sides, a short circuit between the wire electrode and the workpiece can be prevented.

  In the wire electric discharge machine of the present invention, since the pulse oscillation control unit controls the operations of the first pulse oscillator and the second pulse oscillator based on the power supply control data, the upper power supply state and the lower power supply are performed during the electric discharge machining. The state and the both-side power feeding state can be mixed in an arbitrary pattern. Appropriate power supply control data according to the planned electric discharge machining conditions, for example, is obtained in advance by experiments and stored in the storage unit, thereby suppressing short-circuiting and wire breakage between the wire electrode and the workpiece. Can do. Therefore, it is easy to improve productivity.

FIG. 1 is a configuration diagram schematically showing an example of a wire electric discharge machine of the present invention. FIG. 2 is a schematic diagram showing the relationship between the waveform of the pulse signal supplied from each pulse oscillator shown in FIG. 1 to the first switching element unit or the second switching element unit and the power supply state to the wire electrode. FIG. 3 is a configuration diagram schematically showing an example of the main power source having a first main power source and a second main power source in the wire electric discharge machine of the present invention. FIG. 4 is a graph schematically showing the relationship between the discharge position and the discharge current value when the wire electric discharge machine shown in FIG. FIG. 5 is a configuration diagram schematically showing an example of a wire electric discharge machine according to the present invention that can prevent a wire breakage due to an impedance deviation between power feeding circuits. FIG. 6 is a configuration diagram schematically showing another example of the wire electric discharge machine of the present invention that can prevent wire breakage due to impedance deviation between power feeding circuits. FIG. 7 is a configuration diagram schematically showing still another example of the wire electric discharge machine according to the present invention that can prevent wire breakage due to impedance deviation between power feeding circuits. FIG. 8 schematically shows an example of the wire electrical discharge machine of the present invention that can adjust the supply condition of the high-frequency pulse voltage to each power supply circuit in accordance with the impedance of each of the upper and lower power supply circuits. FIG. FIG. 9 shows another example of the wire electric discharge machine of the present invention that can adjust the supply condition of the high-frequency pulse voltage to each power supply circuit in accordance with the impedance of each of the upper and lower power supply circuits. FIG. FIG. 10 is a configuration diagram schematically showing an example of the wire electric discharge machine of the present invention to which a wire disconnection avoidance function is added. FIG. 11 is a schematic diagram showing an example of a power feeding pattern when a power feeding ratio return function is added to the pulse oscillation control unit of the wire electric discharge machine shown in FIG. FIG. 12 is a configuration diagram schematically showing an example of the wire electric discharge machine of the present invention to which a short circuit prevention function is added. FIG. 13 shows operations of the first pulse oscillator and the second pulse oscillator according to the flow rate of the machining liquid supplied from the machining liquid supply device to each of the upper nozzle and the lower nozzle in the wire electric discharge machine of the present invention. It is a block diagram which shows roughly an example to which the function which controls is added. FIG. 14 shows a data conversion unit for converting the appearance pattern of the upper power supply state, the lower power supply state, and the both-side power supply state input from the input unit into the power supply control data in the wire electric discharge machine of the present invention. It is a block diagram which shows an example of what was provided roughly. FIG. 15 is a configuration diagram schematically showing an example of the wire electric discharge machine of the present invention in which only one switching element unit is provided in one power feeding unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wire electrode 20a Upper side electric power feeding part 20b Lower side electric power feeding part 25a, 28a 1st switching element part 25b, 28b 2nd switching element part 30 Main power supply 30a 1st main power supply 30b 2nd main power supply 35a 1st pulse oscillator 35b 2nd pulse Oscillator 50 Voltage detection device 55 Table drive device 57 Speed measurement device 60 Work fluid supply device 65a Upper nozzle 65b Lower nozzle 70 Impedance measurement unit 75 Disconnection sign detection unit 80, 80A to 80D Machine body 85 Storage unit 90, 90a to 90f Arithmetic / Control Unit 95, 95a to 95f Pulse Oscillation Control Unit 100 Plate Thickness Determination Unit 105 Flow Rate Comparison Unit 110, 110A to 110J Control Device 130, 140, 150, 160, 170, 180, 190 Wire Electric Discharge Machine 200, 210, 220, 230, 40 a wire electric discharge machine W workpiece

  Hereinafter, embodiments of a wire electric discharge machine of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram schematically showing an example of a wire electric discharge machine of the present invention. A wire electric discharge machine 130 shown in the figure includes a processing machine main body 80 that performs electric discharge machining of the workpiece W into a predetermined shape under numerical control, a control device 110 that numerically controls the operation of the processing machine main body 80, and a wire Alternatively, an input unit 115 that is connected to the control device 110 wirelessly and inputs commands, data, and the like to the control device 110, and displays the commands, data, and the like that are input to the control device 110 or the operating status of the processing machine body 80, etc. And a display unit 120.

  The processing machine main body 80 applies a high-frequency pulse voltage to the wire electrode 1 that travels in the plate thickness direction of the workpiece W, and causes the workpiece W to be discharged by electric discharge generated between the wire electrode 1 and the workpiece W. Process. The workpiece W is placed on a table 5 movable on the XY plane (horizontal plane), and the wire electrode 1 travels across the workpiece W in the thickness direction in a state where tension is applied. .

  In order to run the wire electrode 1 in a predetermined direction, a wire bobbin 10, a tension roller 12a, a guide roller 14a, and a wire guide 16a are disposed above the table 5, and a wire guide 16b and a guide roller 14b are disposed below the table 5. , And a tension roller 12g. The wire electrode 1 wound around the wire bobbin 10 is pulled out by the tension roller 12a, guided in the vertical direction by the guide roller 14a, the wire guide 16a, the wire guide 16b, and the guide roller 14b, and then pulled by the tension roller 12b. Then, it is recovered in the wire recovery box 18. As a result of the speed at which the wire electrode 1 is taken out by the tension roller 12b being set faster than the speed at which the wire electrode 1 is drawn by the tension roller 12a, the wire electrode 1 causes the workpiece W to move in a state where tension is applied. Drive across the thickness direction.

  In addition, a pair of power feeding units 20 a and 20 b are arranged separately above and below the table 5 in order to apply a high-frequency pulse voltage to the wire electrode 1. A power feeding unit 20a disposed above the table 5 (hereinafter referred to as “upper power feeding unit 20a”) is located above the wire guide 16a, and a power feeding unit 20b disposed below the table 5 (hereinafter referred to as “ The lower power supply portion 20b ") is located below the wire guide 16b. A first switching element unit 25a having at least one switching element is connected to the upper power supply unit 20a, and a main power supply 30 and a first pulse oscillator 35a are connected to the first switching element unit 25a. A second switching element unit 25b having at least one switching element is connected to the lower power supply unit 20b, and a main power supply 30 and a second pulse oscillator 35b are connected to the second switching element unit 25b. . The main power supply 30 is also connected to the central portion of the workpiece W in the plate thickness direction.

  The main power supply 30 supplies a voltage of a predetermined height to each of the first switching element unit 25a and the second switching element unit 25b during operation, and the first pulse oscillator 35a and the second pulse oscillator 35b A pulse signal for controlling the opening / closing operation of the switching element units 25a and 25b is supplied to the first switching element unit 25a or the second switching element unit 25b. The operations of the first pulse oscillator 35a and the second pulse oscillator 35b are controlled by a pulse oscillation control unit 95, which will be described later, so that the switching element units 25a and 25b are opened and closed in a predetermined pattern. The above-described high-frequency pulse voltage can be applied to the wire electrode 1 from the power supply unit 20b or to the wire electrode 1 from both the upper power supply unit 20a and the lower power supply unit 20b.

  In starting or resuming the electric discharge machining of the workpiece W, first, in order to detect whether or not the gap between the wire electrode 1 and the workpiece W is within a predetermined area, the sub power supply A relatively low pulse voltage from 40 is supplied to the upper power supply unit 20a through the third switching element unit 45a and to the lower power supply unit 20b through the fourth switching element unit 45b. At this time, each of the third switching element unit 45a and the fourth switching element unit 45b is closed in synchronization with each other. Then, the potential difference between each of the power feeding units 20a, 20b and the workpiece W is detected by the voltage detection device 50, and the main power supply 30 operates only when the detection result is within a predetermined range. On the other hand, when the detection result is not within the predetermined range, the width of the gap between the workpiece W and the wire electrode 1 is adjusted by moving the table 5. In order to move the table 5, a table driving device 55 is connected to the table 5. The table driving device 55 moves the table 5 in a predetermined direction even during the electric discharge machining of the workpiece W. The table 5 includes a speed sensor (not shown) such as a linear encoder or a rotary encoder, and a speed measuring device (not shown) determines the driving speed of the table 5 based on the detection result of the speed sensor. Measure and transmit the measurement result to the calculation / control unit 90 described later.

  Further, in order to prevent the wire electrode 1 from being overheated at the time of electric discharge machining of the workpiece W and to prevent the wire electrode 1 from being disconnected, at the time of electric discharge machining of the workpiece W, from the machining liquid supply device 60 to the upper nozzle 65a A machining fluid is supplied between the workpiece W and the wire electrode 1 via the lower nozzle 65b. The upper nozzle 65a is disposed above the workpiece W, and the lower nozzle 65b is disposed below the workpiece W. The machining fluid supply device 60 has a flow rate measurement function for separately measuring the machining fluid supply amount (flow rate) to the upper nozzle 65a and the machining fluid supply amount (flow rate) to the lower nozzle 65b.

  On the other hand, the control device 110 that controls the operation of the processing machine main body 80 includes a storage unit 85, a calculation / control unit 90, and a pulse oscillation control unit 95.

  The storage unit 85 stores numerical control data used for controlling operations of the table driving device 55, the machining fluid supply device 60, and the like, and each of the first switching element unit 25a and the second switching element unit 25b. Power supply control data for controlling the form of power supply to the wire electrode 1 by defining the opening / closing operation is stored. The power supply control data is set so as to prevent short circuit and wire breakage between the wire electrode 1 and the workpiece W under standard electric discharge machining conditions. Data for opening and closing the first switching element portion 25a with the switching element portion 25b open, data for opening and closing the second switching element portion 25b with the first switching element portion 25a open, and the first switching element portion 25a And data for opening and closing each of the second switching 25b in synchronization with each other.

  The power supply control data stored in the storage unit 85 may be only one type, and when it is expected or scheduled to produce a plurality of types of products by the wire electric discharge machine 130, they are associated with each product. Further, a plurality of types of power supply control data may be used.

  The arithmetic / control unit 90 first activates the sub power supply 40 when a command for instructing the operation start of the wire electric discharge machine 130 is input from the input unit 115 described later. Then, it is determined whether or not the detection result of the voltage detection device 50 is within a predetermined range. When the detection result is within the predetermined range, the main power supply 30 is activated. Thereafter, the operations of the table driving device 55 and the machining fluid supply device 60 are controlled based on the numerical control data stored in the storage unit 85. At the time of electric discharge machining of the workpiece W, the operation of the table driving device 55 is controlled based on the numerical control data to move the table 5 in a predetermined direction, and each nozzle 65a from the machining liquid supply device 60 is based on the numerical control data. , 65b is supplied with a machining fluid at a predetermined flow rate.

  Further, the calculation / control unit 90 obtains the energy of the high-frequency pulse voltage applied from the wire electrode 1 to the workpiece W based on the detection result of the potential difference by the voltage detection device 50, and the table 5 by the speed measurement device described above. The processing speed is obtained based on the driving speed of Then, the plate thickness of the workpiece W is sequentially calculated from the energy of the high-frequency pulse voltage, the processing speed, etc., and the control data corresponding to the plate thickness is read from the numerical control data and applied to the wire electrode 1. The energy of the high frequency pulse voltage is feedback controlled. Specifically, the pulse interval of the high frequency pulse voltage to be applied is feedback controlled. Further, the calculation / control unit 90 controls the operation of the display unit 120 to display the command or data input to the control device 110 or the operation status of the processing machine body 80 on the display 120.

  The pulse oscillation control unit 95 starts operation under the control of the arithmetic / control unit 95, reads predetermined power supply control data stored in the storage unit 85, and based on the power supply control data, the first pulse oscillator The operation of each of 35a and the second pulse oscillator 35b is controlled. When a plurality of types of power supply control data are stored in the storage unit 85, the user designates desired power supply control data using the input unit 115 prior to electric discharge machining of the workpiece W. At this time, the power supply control data stored in the storage unit 85 is displayed on the display unit 120 so that the user can easily select desired power supply control data.

  As described above, the power supply control data read by the pulse oscillation control unit 95 includes data for opening and closing the first switching element unit 25a with the second switching element unit 25b open, and opening the first switching element unit 25a. The data for opening and closing the second switching element unit 25b while the data for opening and closing each of the first switching element unit 25a and the second switching 25b in synchronization with each other is included. Therefore, during the period during which electric discharge machining is performed on the workpiece W, an upper power supply state in which a high frequency pulse voltage is applied only to the wire electrode 1 from the upper power supply unit 20a, and a high frequency pulse voltage to the wire electrode 1 from only the lower power supply unit 20b. And a both-side power supply state in which a high-frequency pulse voltage is applied to the wire electrode 1 from both the upper power supply unit 20a and the lower power supply unit 20b are mixed in a predetermined pattern.

  FIG. 2 is a schematic diagram showing the relationship between the waveform of the pulse signal supplied from the pulse oscillators 35 a and 35 b to the first switching element unit 25 a or the second switching element unit 25 b and the power supply state to the wire electrode 1. .

  As shown in the figure, the pulse signal supplied from the first pulse oscillator 35a to the first switching element unit 25a has a pulse waveform in which the low level L and the high level H are repeated at a predetermined cycle, and from the second pulse oscillator 35b. When the pulse signal supplied to the second switching element unit 25b remains at the low level L, the first switching element unit 25a opens and closes while the second switching element unit 25b is open, resulting in the upper power supply state UF. . Conversely, the pulse signal supplied from the first pulse oscillator 35a to the first switching element unit 25a remains at the low level L, and the pulse signal supplied from the second pulse oscillator 35b to the second switching element unit 25b is at the low level. When the pulse waveform repeats L and high level H in a predetermined cycle, the second switching element section 25b opens and closes while the first switching element section 25a is open, so that the lower power supply state LF is entered. When the pulse signal supplied from the first pulse oscillator 35a to the first switching element unit 25a and the pulse signal supplied from the second pulse oscillator 35b to the second switching element unit 25b have a pulse waveform synchronized with each other, Since the first switching element unit 25a and the second switching element unit 25b open and close in synchronization with each other, the both-side power supply state BF is obtained.

  The present inventors have found that the frequency of occurrence of short circuit between the wire electrode 1 and the workpiece W and the difficulty of occurrence of wire breakage are determined by the material and wire diameter of the wire electrode 1, the quality of the working fluid used, the nozzles 65a, Although the supply amount of the processing liquid from 65b, the material of the workpiece W, the shape of the product to be manufactured from the workpiece W, and the like vary depending on the processing conditions, the above-described power supply states are switched in a short cycle. It was clarified by experiments that short-circuiting frequently occurred and the machining speed was not easily increased. It has also been experimentally clarified that wire breakage is likely to occur when the number of pulses under each power supply state is increased too much.

  For example, the sum of the number of high-frequency pulse voltages applied to the wire electrode 1 under the upper power supply state and the number of high-frequency pulse voltages applied to the wire electrode 1 under the lower power supply state When the number of high-frequency pulse voltages applied to 1 is the same as the number of pulses, if the number of pulses under each power supply state is less than 3, short-circuiting between the wire electrode 1 and the workpiece W occurs frequently and the machining speed is greatly increased. May decrease. Further, when the number of pulses under each power supply state is 10,000 or more, the position of the discharge point between the wire electrode 1 and the workpiece W is not so dispersed in the thickness direction of the workpiece W, and the wire Disconnection may occur easily.

  Furthermore, the inventors of the present invention increase the frequency of occurrence of a short circuit between the wire electrode 1 and the workpiece W when the ratio of the number of pulses under the double-sided power supply state in the total number of pulses applied to the wire electrode 1 is too small. It has been experimentally clarified that wire breakage tends to occur when the amount is too large. For example, if the ratio is less than 50%, a short circuit is likely to occur, and if it is 95% or more, a wire breakage is likely to occur.

  Considering these, it can be seen that the short circuit and the wire breakage between the wire electrode 1 and the workpiece W can be suppressed by appropriately mixing the upper power supply state, the lower power supply state, and the both-side power supply state.

  In the above-described wire electric discharge machine 130, as a result of the pulse oscillation control unit 95 controlling the operations of the first pulse oscillator 35a and the second pulse oscillator 35b based on the power supply control data stored in the storage unit 85. The power supply is controlled so that the upper power supply state, the lower power supply state, and the both-side power supply state are mixed in a predetermined pattern. Therefore, by obtaining appropriate power supply control data by experiment and storing them in the storage unit 85 in advance, it is possible to suppress short-circuiting and wire breakage between the wire electrode 1 and the workpiece W, respectively. Therefore, it is easy to improve productivity in the wire electric discharge machine 130.

Embodiment 2. FIG.
In the wire electric discharge machine of the present invention, the main power source can be divided into a first main power source and a second main power source in order to suppress overheating of the wire electrode at the center portion in the plate thickness direction of the workpiece. .

  FIG. 3 is a configuration diagram schematically illustrating an example of a wire electrical discharge machining apparatus in which the main power source includes a first main power source and a second main power source. In the wire electric discharge machining apparatus 140 shown in the figure, the main power supply 30 has a first main power supply 30a and a second main power supply 30b. The first main power supply 30a is connected to the upper power feeding part 20a via the first switching element part 25a and is connected to the upper part in the plate thickness direction of the workpiece W. The second main power source 30b is connected to the lower power feeding unit 20b via the second switching element unit 25b and is connected to the lower part of the workpiece W in the plate thickness direction. The operations of the first main power supply 30a and the second main power supply 30b are controlled by the calculation / control unit 90a.

  Since the configuration of the wire electric discharge machine 140 other than the above is the same as that of the wire electric discharge machine 130 shown in FIG. 1, the constituent members shown in FIG. 3 are the same as those shown in FIG. 1. Are denoted by the same reference numerals as those used in FIG. 1 and description thereof is omitted. Note that the processing machine main body constituting the wire electric discharge machine 140 is given a new reference number 80A, and the control device is given a new reference number 110A.

  In the wire electric discharge machine 140 configured as described above, the first main power supply 30a is connected to the upper part in the plate thickness direction of the workpiece W, and the second main power supply 30b is connected to the lower part of the workpiece W in the plate thickness direction. Therefore, the impedance from the first main power supply 30a to the discharge point and the impedance from the second main power supply 30b to the discharge point in the both-side power supply state are respectively the thickness of the workpiece W at the position of the discharge point. The closer to the center of the direction, the larger. As a result, the discharge current value between the wire electrode 1 and the workpiece W decreases as the position of the discharge point approaches the central portion of the workpiece W in the plate thickness direction.

FIG. 4 is a graph schematically showing the relationship between the discharge position (discharge point position) and the discharge current value when the wire electric discharge machine 140 is in a double-sided power supply state. The solid line L _{1 in} the figure shows the above relationship. For reference, the above relationship in the wire electric discharge machine 130 shown in FIG. 1 is indicated by a broken line L ₂ in FIG. The discharge current value indicated by the solid line L ₁ and the discharge current value indicated by the broken line L ₂ are obtained under the same processing conditions.

  As is clear from FIG. 4, in both of the wire electric discharge machines 130 and 140, the discharge current value between the wire electrode and the workpiece is such that the position of the discharge point approaches the central portion in the plate thickness direction of the workpiece. However, the degree of the decrease is larger in the wire electric discharge machine 140 than in the wire electric discharge machine 130. The discharge current value itself at the center portion in the plate thickness direction of the workpiece is also smaller in the wire electric discharge machine 140 than in the wire electric discharge machine 130 under the same machining conditions.

  Generally, in a wire electric discharge machine, overheating of the wire electrode at the time of electric discharge machining is suppressed by supplying a machining fluid between the wire electrode and the workpiece. Compared to the upper part and lower part in the plate thickness direction of the workpiece, cooling with the machining liquid is less likely to occur, so the wire electrode may overheat at the center of the workpiece in the plate thickness direction and cause wire breakage. Often there is.

  However, in the wire electric discharge machine 140 shown in FIG. 3, the discharge current value when the both-side power feeding state is set decreases as it approaches the central portion in the plate thickness direction of the workpiece W. It is easy to suppress excessive overheating of the wire electrode 1 even in the central portion in the direction. Therefore, it is easier to prevent the wire breakage than the wire electric discharge machine 130 (see FIG. 1) described in the first embodiment.

  Therefore, according to the wire electric discharge machine 140, like the wire electric discharge machine 130, the upper electrode feeding state, the lower electric power feeding state, and the both-side electric power feeding state are mixed in a predetermined pattern, so that the wire electrode 1 and the workpiece W As compared with the wire electric discharge machine 130, it is easy to suppress wire breakage. As a result, it becomes easy to improve productivity as compared with the wire electric discharge machine 130.

Embodiment 3 FIG.
In the wire electric discharge machine, when the Z-axis height (relative height of the upper power feeding part) or the thickness of the workpiece changes, the distance from the discharge point to each power feeding part changes, and accordingly the upper power feeding part The power supply circuit (hereinafter referred to as “upper power supply circuit”) that reaches the discharge point via the power supply circuit and the power supply circuit (hereinafter referred to as “lower power supply circuit”) that reaches the discharge point via the lower power supply portion. Occurs. Such a bias in impedance causes a difference in the magnitude of the discharge current in each power supply circuit, and wire breakage is likely to occur in a power supply circuit having a large discharge current (a power supply circuit having a small impedance).

  In the wire electric discharge machine of the present invention, by adjusting the supply condition of the high-frequency pulse voltage to each of the upper power supply circuit and the lower power supply circuit according to the bias of the impedance between the upper power supply circuit and the lower power supply circuit, It can be configured to prevent wire breakage caused by impedance deviation between power supply circuits.

  FIG. 5 to FIG. 7 are configuration diagrams schematically showing an example of a wire electric discharge machine that can prevent wire breakage caused by impedance deviation between power feeding circuits. Among the constituent members shown in these drawings, those common to the constituent members shown in FIG. 1 are denoted by the same reference numerals as those used in FIG. 1 and description thereof is omitted.

  A wire electric discharge machine 150 shown in FIG. 5 includes a control device 110B having a pulse oscillation control unit 95a. The pulse oscillation control unit 95a reads the data of the Z-axis height (the height of the upper power supply unit 20a with respect to the lower power supply unit 20b) stored in advance in the storage unit 85 by the user, or is stored in the storage unit 85. The Z-axis height is determined from the numerical control data, and the Z-axis height is compared with a reference value to determine the magnitude relationship between the impedances in the upper power supply circuit and the lower power supply circuit. Then, the power supply control data read from the storage unit 85 is modified by, for example, computation so that the discharge current value in the power supply circuit with a small impedance approaches the discharge current value in the power supply circuit with a large impedance, and the modified power supply control data is Based on this, the pulse oscillation controller 95a controls the operations of the first pulse oscillator 35a and the second pulse oscillator 35b.

  For example, the discharge current value is adjusted by adjusting the energy of the high frequency pulse voltage supplied to the wire electrode 1 by changing the pulse length or pulse interval in the high frequency pulse voltage or changing the number of pulses to be supplied. be able to. When each of the first switching element unit 25a and the second switching element unit 25b has a plurality of switching elements, the energy of the high-frequency pulse voltage supplied to the wire electrode 1 is adjusted by changing the number of switching elements to be opened. You can also Note that the Z-axis height assumed when the power supply control data is created is used as the reference value, and the reference value is stored in advance in the storage unit 85, for example. This wire electric discharge machine 150 is particularly suitable when a flat object is used as the workpiece W.

  A wire electric discharge machine 160 shown in FIG. 6 includes a control device 110C having an arithmetic / control unit 90b and a pulse oscillation control unit 95b. Similar to the calculation / control unit 90 (see FIG. 1) shown in FIG. 1, the calculation / control unit 90b uses the energy of the high-frequency pulse voltage applied from the wire electrode 1 to the workpiece W, the processing speed, and the like. It has a function of sequentially calculating the thickness of the workpiece W, and sends the calculation result to the pulse oscillation control unit 95b. FIG. 6 shows a speed measuring device 57 not shown in FIG.

  The pulse oscillation control unit 95b compares the above calculation result sent from the calculation / control unit 90b with a reference value to obtain the magnitude relationship between the impedances in the upper and lower power feeding circuits. Then, the power supply control data read from the storage unit 85 is modified by, for example, computation so that the discharge current value in the power supply circuit with a small impedance approaches the discharge current value in the power supply circuit with a large impedance, and the modified power supply control data is Based on this, the pulse oscillation controller 95b controls the operations of the first pulse oscillator 35a and the second pulse oscillator 35b. As the reference value, the plate thickness assumed when the power supply control data is created is used, and the reference value is stored in advance in the storage unit 85, for example. This wire electric discharge machine 160 is suitable not only when a flat plate-like object is used as the workpiece W but also when a recess or a hole is formed in the workpiece W in advance.

  A wire electric discharge machine 170 shown in FIG. 7 includes a control device 110D having an arithmetic / control unit 90c, a pulse oscillation control unit 95c, and a plate thickness determining unit 100, and the storage unit 85 has a three-dimensional workpiece. Further data is stored. The arithmetic control unit 90 c controls the operation of the plate thickness determining unit 100, and the plate thickness determining unit 100 includes the above three-dimensional data and numerical control data stored in the storage unit 85 (numerical values for the table driving device 55. The electrical discharge machining location is specified based on the control data), the thickness of the workpiece W at the electrical discharge machining location is obtained, and the thickness data is sent to the pulse oscillation control unit 95b. The pulse oscillation control unit 95c compares the plate thickness data sent from the calculation / control unit 90c with a reference value, and obtains a magnitude relationship between the impedances of the upper power supply circuit and the lower power supply circuit. Then, the power supply control data read from the storage unit 85 is modified by, for example, computation so that the discharge current value in the power supply circuit with a small impedance approaches the discharge current value in the power supply circuit with a large impedance, and the modified power supply control data is Based on this, the pulse oscillation control unit 95c controls the operations of the first pulse oscillator 35a and the second pulse oscillator 35b. As the reference value, the plate thickness assumed when the power supply control data is created is used, and the reference value is stored in advance in the storage unit 85, for example. This wire electric discharge machine 170 is suitable not only when a flat plate is used as the workpiece W but also when a recess or a hole is formed in the workpiece W in advance.

  In each of the above-described wire electric discharge machines 150, 160, and 170, the supply condition of the high-frequency pulse voltage to each of the upper power supply circuit and the lower power supply circuit is adjusted according to the magnitude relationship (bias) of the impedance between the power supply circuits. Therefore, it is easy to prevent a wire disconnection caused by an impedance deviation between power feeding circuits. Therefore, according to these wire electric discharge machines 150, 160, and 170, the upper power supply state, the lower power supply state, and the both-side power supply state are mixed in a predetermined pattern as in the wire electric discharge machine 130 shown in FIG. As a result, it is possible to prevent a short circuit between the wire electrode 1 and the workpiece W, and it is easier to suppress wire disconnection than the wire electric discharge machine 130. As a result, it becomes easy to improve productivity as compared with the wire electric discharge machine 130.

Embodiment 4 FIG.
In the wire electric discharge machine of the present invention, the supply condition of the high-frequency pulse voltage to each power supply circuit is adjusted in accordance with the impedance of the upper power supply circuit and the impedance of the lower power supply circuit, so that the impedance is uneven between the power supply circuits. It can be configured to prevent the resulting wire breakage.

  FIGS. 8 and 9 schematically illustrate an example of a wire electric discharge machine that can adjust the supply conditions of the high-frequency pulse voltage to each power supply circuit according to the impedance of the upper power supply circuit and the impedance of the lower power supply circuit, respectively. FIG. Among the constituent members shown in these drawings, those common to the constituent members shown in FIG. 1 are denoted by the same reference numerals as those used in FIG. 1 and description thereof is omitted.

  A wire electric discharge machine 180 shown in FIG. 8 includes a machine main body 80B having an impedance measuring unit 70 and a control device 110E having a pulse oscillation control unit 95d. The impedance measurement unit 70 measures the impedance between the main power supply 30 and the upper power supply unit 20a in the upper power supply circuit and the impedance between the main power supply 30 and the lower power supply unit 20b in the lower power supply circuit, respectively. The actual measurement result is transmitted to the pulse oscillation control unit 95d. The pulse oscillation control unit 95d compares the actual measurement result by the impedance measurement unit 70 with a reference value, and obtains the magnitude relationship between the impedances in the upper and lower power supply circuits. Then, the power supply control data read from the storage unit 85 is modified by, for example, computation so that the discharge current value in the power supply circuit with a small impedance approaches the discharge current value in the power supply circuit with a large impedance, and the modified power supply control data is Based on this, the pulse oscillation controller 95d controls the operations of the first pulse oscillator 35a and the second pulse oscillator 35b. As the reference value, the impedance assumed when the power supply control data is created is used, and the reference value is stored in advance in the storage unit 85, for example.

  A wire electric discharge machine 190 shown in FIG. 9 includes a control device 110F having a pulse oscillation control unit 95e. The storage unit 85 includes an upper power supply circuit measured in advance by a manufacturer or user of the wire electric discharge machine 190, and The impedance of each lower power feeding circuit is stored in advance. Specifically, actual measurement data of impedance between the main power supply 30 and the upper power supply unit 20a in the upper power supply circuit, and actual measurement data of impedance between the main power supply 30 and the lower power supply unit 20b in the lower power supply circuit, and Are stored in advance. The pulse oscillation control unit 95e directly compares the measured data of each impedance stored in the storage unit 85 or compares it with a reference value, thereby comparing the magnitude relationship between the impedances in the upper feeding circuit and the lower feeding circuit. Ask for. Then, the power supply control data read from the storage unit 85 is modified by, for example, computation so that the discharge current value in the power supply circuit with a small impedance approaches the discharge current value in the power supply circuit with a large impedance, and the modified power supply control data is Based on this, the pulse oscillation controller 95e controls the operations of the first pulse oscillator 35a and the second pulse oscillator 35b. As the reference value, the impedance assumed when the power supply control data is created is used, and the reference value is stored in advance in the storage unit 85, for example.

  In each of the wire electric discharge machines 180 and 190 described above, the supply condition of the high-frequency pulse voltage to each power supply circuit is adjusted according to the impedance of the upper power supply circuit itself and the impedance of the lower power supply circuit itself. It is easy to prevent wire breakage due to impedance deviation (magnitude relationship) between the two. Therefore, these wire electric discharge machines 180, 190 have the same technical effects as the wire electric discharge machines 150, 160, 170 described in the third embodiment.

Embodiment 5 FIG.
The wire electric discharge machine of the present invention prevents the wire breakage in the operations of the first pulse oscillator and the second pulse oscillator when a wire breakage sign (hereinafter referred to as “breakage sign”) is detected. It is possible to add a wire disconnection avoidance function to be controlled.

  FIG. 10 is a configuration diagram schematically showing an example of a wire electric discharge machine to which a wire disconnection avoidance function is added. The wire electric discharge machine 200 shown in the figure includes a processing machine body 80C having a disconnection sign detection unit 75 and a control device 110G having a pulse oscillation control unit 95f. The storage unit 85 includes the first embodiment. In addition to the power supply control data described in (4) (hereinafter referred to as “basic power supply control data” in the present embodiment), power supply control data (hereinafter referred to as “wire supply control data”) for avoiding wire disconnection when there is a disconnection sign. Further, “disconnection avoidance power supply control data”) is stored. 10 that are the same as those shown in FIG. 1 are assigned the same reference numerals as those used in FIG. 1 and descriptions thereof are omitted.

  The disconnection sign detection unit 75 is electrically connected to the upper power supply unit 20a, the lower power supply unit 20b, and the workpiece W. For example, from the current shunt ratio between the upper power supply circuit and the lower power supply circuit. The position of the discharge point is obtained, and it is determined that there is a sign of wire breakage when a concentrated discharge in which the discharge point is concentrated at one place is detected, and this is referred to as a predetermined signal (hereinafter referred to as “disconnection sign detection signal”). ) Is sent to the pulse oscillation control unit 95f.

  The pulse oscillation control unit 95f that has received the disconnection sign detection signal modifies the feed control data by reading the disconnection avoidance feed control data from the storage unit 85, and based on the disconnection avoidance feed control data, the first pulse oscillator 35a. And the operation | movement of each of the 2nd pulse oscillator 35b is controlled, and a wire disconnection is avoided. For example, each of the first pulse oscillator 35a and the second pulse oscillator 35b is controlled so that the upper power supply state and the lower power supply state appear alternately, whereby the positions of the discharge points are dispersed over time and the wire breaks. To avoid.

  Since the wire electric discharge machine 200 has the above-described wire breakage avoidance function, it is easier to prevent the wire breakage than the wire electric discharge machines described in the first to fourth embodiments. Therefore, according to the wire electric discharge machine 200, as in the wire electric discharge machine 130 shown in FIG. 1, the upper power supply state, the lower power supply state, and the both-side power supply state are mixed in a predetermined pattern, so that the wire electrode 1 And the workpiece W can be prevented from being short-circuited, and wire breakage can be easily suppressed as compared with the wire electric discharge machine 130. As a result, it becomes easy to improve productivity as compared with the wire electric discharge machine 130.

  When a wire breakage avoidance function is added to the wire electric discharge machine, the pulse oscillation control unit has a predetermined ratio, that is, basic power supply control data, when the long-term (about 1 to 2 seconds) field of view is reached. Based on the above, the function of returning the power supply ratio in each of the upper power supply state, the lower power supply state, and the both-side power supply state when the operations of the first pulse oscillator and the second pulse oscillator are controlled (hereinafter referred to as “power supply ratio return function”) .) Can be added.

FIG. 11 is a schematic diagram illustrating an example of a power supply pattern when a power supply ratio return function is added to the pulse oscillation control unit 95f described above. In the example shown in the figure, until the time T ₁ is the basic power supplying control data pulse oscillation control unit 95f based on is controlling a first pulse generator 35a and the second pulse oscillator 35b each operation. Under the basic power supply control data, the operation of performing the both-side power supply state for two cycles after performing the upper power supply state and the lower power supply state for each cycle is repeated.

When disconnection sign detection signal from the disconnection sign detection unit 75 to the pulse oscillation control unit 95f at time T ₁ is sent, pulsed control unit 95f is the first pulse oscillator 35a based on power supply control data for disconnection avoidance and second The operation of each of the pulse oscillators 35b is started, and the operation of each of the first pulse oscillator 35a and the second pulse oscillator 35b is controlled so that the upper power supply state and the lower power supply state appear alternately. When the disconnection sign detection signal from the disconnection sign detection unit 75 ceases at time T _2, the pulse oscillation control unit 95f is to express power supply rate return function, upper feeding state, the lower powered state, and both powered state, respectively The operation of each of the first pulse oscillator 35a and the second pulse oscillator 35b is controlled so that the power supply ratio according to is the power supply ratio under the basic power supply control data.

Specifically, since the both-side power supply state is not performed for one cycle from time T ₁ to time T ₂ , the ratio of the upper power supply state, the lower power supply state, and the both-side power supply state is 1: 1: 2. so as to control the first pulse oscillator 35a and the second pulse oscillator 35b each operation, each to appear one by one period upper feeding state and the lower powered state between the time T _2, until time T _3, and both sides The power supply state appears for 8 cycles. As a result, the power supply ratio in each of the upper power supply state, the lower power supply state, and the both-side power supply state is returned to the power supply ratio under the basic power supply control data.

The power supply ratio recovery function provided to the pulse oscillation control unit 95f includes a function of calculating a power supply ratio under the basic power supply control data, an upper power supply state, a lower power supply state under the disconnection avoidance power supply control data, And the function of counting the number of occurrences of each power supply state, and the deviation of the power supply ratio caused by performing power supply under the power supply control data for disconnection avoidance, that is, the deviation from the power supply ratio under the basic power supply control data. A function to calculate and a function to correct the deviation are included. Pulse oscillation control unit 95f, the time T ₃ thereafter controls the first pulse oscillator 35a and the second pulse oscillator 35b each operation based on the basic power supplying control data again.

Embodiment 6 FIG.
In the wire electric discharge machine of the present invention, the short circuit between the wire electrode and the workpiece is detected so that the short circuit is prevented or the short circuit is prevented when the short circuit is detected. A function for controlling the operations of the 1-pulse oscillator and the second-pulse oscillator (hereinafter referred to as “short-circuit prevention function”) can be added.

  FIG. 12 is a configuration diagram schematically showing an example of a wire electric discharge machine to which a short circuit prevention function is added. A wire electric discharge machine 210 shown in the figure includes a control device 110H having an arithmetic / control unit 90d and a pulse oscillation control unit 95g, and the storage unit 85 is short-circuited when there is an indication of a short circuit or a short circuit. Further, power supply control data (hereinafter referred to as “short-circuit prevention power supply control data”) for preventing the short circuit or eliminating the short circuit is stored. Of the constituent members shown in FIG. 12, those common to the constituent members shown in FIG. 1 are assigned the same reference numerals as those used in FIG.

  The calculation / control unit 90d performs a sign of short circuit between the wire electrode 1 and the workpiece W or a short circuit based on the potential difference between the power supply units 20a and 20b and the workpiece W detected by the voltage detection device 50. To detect. Specifically, the discharge voltage value is calculated from the potential difference between each of the power supply units 20a, 20b and the workpiece W detected by the voltage detection device 50, and this value is the material of the wire electrode 1 and the material of the workpiece W. If the average discharge voltage value falls below a preset average discharge voltage value based on the quality of the machining fluid and the magnitude of the high-frequency pulse voltage applied to the wire electrode 1, it is determined that a short circuit has occurred or a short circuit has occurred. When a short circuit sign or a short circuit is detected, the calculation / control unit 90d sends a predetermined signal (hereinafter referred to as a “short circuit / prediction detection signal”) to the pulse oscillation control unit 95g. The average discharge voltage value is obtained by the manufacturer or user of the wire electric discharge machine 210 and stored in the storage unit 85 in advance.

  Upon receiving the short circuit / predictive detection signal from the calculation / control unit 90d, the pulse oscillation control unit 95g modifies the power supply control data by reading out the power supply control data for short circuit prevention from the storage unit 85, and uses the power supply control data for short circuit prevention. Based on this, the operation of each of the first pulse oscillator 35a and the second pulse oscillator 35b is controlled to prevent a short circuit between the wire electrode 1 and the workpiece W or a short circuit between the wire electrode 1 and the workpiece W. Let go. For example, the discharge between the wire electrode 1 and the workpiece W is stabilized by controlling the operations of the first pulse oscillator 35a and the second pulse oscillator 35b so as to be in a power supply state on both sides, whereby the wire electrode 1 The short circuit between the wire electrode 1 and the workpiece W is eliminated.

  Since the wire electric discharge machine 210 has the above-mentioned short-circuit prevention function, the wire breakage 1 and the workpiece W are prevented from being short-circuited as compared with the wire electric discharge machines described in the first to fifth embodiments. Is easy. Therefore, according to the wire electric discharge machine 210, the wire electrode 1 can be obtained by mixing the upper power supply state, the lower power supply state, and the both-side power supply state in a predetermined pattern like the wire electric discharge machine 130 shown in FIG. And the workpiece W can be prevented from being short-circuited, and it is easier to suppress a short-circuit between the wire electrode 1 and the workpiece W than the wire electric discharge machine 130. As a result, it becomes easy to improve productivity as compared with the wire electric discharge machine 130. In addition, also when adding a short circuit prevention function to a wire electric discharge machine, the power supply ratio return function described in the fifth embodiment can be added to the pulse oscillation control unit.

Embodiment 7 FIG.
The wire electric discharge machine of the present invention has a function of controlling the operations of the first pulse oscillator and the second pulse oscillator in accordance with the flow rate of the machining liquid supplied from the machining liquid supply device to each of the upper nozzle and the lower nozzle. Can be added.

  FIG. 13 is a configuration diagram schematically illustrating an example of a wire electric discharge machine to which the above functions are added. The wire electric discharge machine 220 shown in the figure includes a control device 110I having an arithmetic / control unit 90e, a pulse oscillation control unit 95h, and a flow rate comparison unit 105. Among the structural members shown in FIG. 13, those common to the structural members shown in FIG. 1 are assigned the same reference numerals as those used in FIG.

  The arithmetic / control unit 90e controls the operation of the machining fluid supply device 60 based on the numerical control data (numerical control data for the machining fluid supply device 60) stored in the storage unit 85. Data about the flow rate of the machining liquid supplied from the supply device 60 to the upper nozzle 65 a and the flow rate of the machining liquid supplied to the lower nozzle 65 b are sent to the flow rate comparison unit 105. The flow rate comparison unit 105 to which these data are sent compares each data with a reference value and sends the result to the pulse oscillation control unit 95h. The flow rate comparison unit 105 has, as the reference value, data on the flow rate of the machining fluid assumed when the power supply control data is created, for example.

  The pulse oscillation control unit 95h reads the power supply control data from the storage unit 85 and controls the operations of the first pulse oscillator 35a and the second pulse oscillator 35b, while the flow rate of the machining liquid is determined from the comparison result by the flow rate comparison unit 105. When there is a nozzle that is determined to exceed the reference value, the power supply control data is modified by, for example, calculation. That is, of the high-frequency pulse voltage supplied to the wire electrode 1 from the power supply unit on the same side as the nozzle in which the flow rate of the machining liquid is determined to exceed the reference value in the upper power supply unit 20a and the lower power supply unit 20b. The power supply control data is modified so that the power supply ratio is lowered. The operation of each of the first pulse oscillator 35a and the second pulse oscillator 35b is controlled based on the modified power supply control data.

  When wire electrical discharge machining is performed on the workpiece, the flow rate of the machining fluid supplied from the machining fluid supply device to each of the upper nozzle and the lower nozzle is not constant throughout the electrical discharge machining. The flow rate of the machining fluid is different between the straight movement path and the arcuate movement path. Further, the flow rate of the processing liquid may be different between the upper nozzle 65a and the lower nozzle 65b. When the flow rates of the machining fluid are different between the upper nozzle 65a and the lower nozzle 65b, the machining fluid flows into the machining groove (the gap between the wire electrode 1 and the workpiece W) from the nozzle having a large machining fluid flow rate. Is less than the amount of machining fluid flowing into the machining groove from the nozzle having a low machining fluid flow rate, and it becomes easier for machining waste to accumulate in the machining groove on the nozzle side where the flow rate of machining fluid is large. As a result, the discharge frequency increases on the nozzle side where the flow rate of the machining fluid is large, and wire breakage is likely to occur.

  In the wire electric discharge machine 220 shown in FIG. 13, when there is a nozzle for which the flow rate of the machining liquid is determined to exceed the reference value, it is supplied to the wire electrode 1 from the power feeding unit on the same side as the nozzle. Since the operation of each of the first pulse oscillator 35a and the second pulse oscillator 35b is controlled so that the feeding ratio of the high-frequency pulse voltage is low, the flow rate of the machining liquid supplied to each of the upper nozzle 65a and the lower nozzle 65b Even when fluctuates, wire breakage is suppressed.

  Therefore, according to the wire electric discharge machine 220, the wire electrode 1 can be obtained by mixing the upper power supply state, the lower power supply state, and the both-side power supply state in a predetermined pattern as in the wire electric discharge machine 130 shown in FIG. And the workpiece W can be prevented from being short-circuited, and wire breakage can be easily suppressed as compared with the wire electric discharge machine 130. As a result, it becomes easy to improve productivity as compared with the wire electric discharge machine 130.

  As described above, the wire electric discharge machine of the present invention has been described by exemplifying seven forms, but the present invention is not limited to the seven forms described above. For example, only a mixed pattern (appearance pattern) of the upper power supply state, the lower power supply state, and the both-side power supply state is input from the input unit so that the user can easily store desired power supply control data in the storage unit. Thus, a data conversion unit can be provided in the control device so that desired power supply control data is stored in the storage unit.

  FIG. 14 is a configuration diagram schematically illustrating an example of a wire electric discharge machine in which the data conversion unit is provided in the control device. In the control device 110J of the wire electric discharge machine 230 shown in the figure, when a mixed pattern (appearance pattern) of the upper power supply state, the lower power supply state, and the both-side power supply state is input from the input unit, the appearance pattern is displayed. A data conversion unit 108 is provided for generating the corresponding power supply control data. The power supply control data created by the data conversion unit 108 is stored in the storage unit 85 via the calculation / control unit 90f. The pulse oscillation control unit 95 controls the operations of the first pulse oscillator 35a and the second pulse oscillator 35b based on the power supply control data. 14 that are the same as those shown in FIG. 1 are assigned the same reference numerals as those used in FIG. 1 and description thereof is omitted.

  Although not shown in the drawings, in the wire electric discharge machine of the present invention, the first switching element unit and the second switching element unit to which the main power source is connected may be separate members from the main power source. And it can also be used as a component of the main power supply. Similarly, the third switching element unit and the fourth switching element unit to which the sub power source is connected can be separate members from the sub power source, or can be a constituent member of the sub power source. The same applies to each of the first pulse oscillator and the second pulse oscillator, which can be a constituent member of the main power source or the sub power source or a constituent member of the pulse oscillation control.

  Furthermore, only one switching element unit can be provided in one power feeding unit. FIG. 15 is a configuration diagram schematically illustrating an example of a wire electric discharge machine in which only one switching element unit is provided in one power feeding unit. In the processing machine main body 80D of the wire electric discharge machine 240 shown in the figure, one switching element part 28a (hereinafter referred to as “first switching element part 28a”) is provided corresponding to the upper power feeding part 20a. Switching element units other than the one switching element unit 28a are not connected to the upper power feeding unit 20a. Similarly, one switching element portion 28b (hereinafter referred to as “second switching element portion 28b”) is provided corresponding to the lower power feeding portion 20b, and the switching element portions other than the second switching element portion 28b are located below. It is not connected to the side power feeding unit 20b. The individual switching element units 28 a and 28 b are shared by the main power supply 30 and the sub power supply 40. A first pulse oscillator 35a is connected to the first switching element section 28a, and a second pulse oscillator 35b is connected to the second switching element section 28b.

  The first switching element unit 28 a can be a separate member from either the main power supply 30 or the sub power supply 40, or can be a constituent member of the main power supply 30 or the sub power supply 40. Similarly, the second switching element portion 28b can be a separate member from both the main power supply 30 and the sub power supply 40, or can be a constituent member of the main power supply 30 or the sub power supply 40.

  Regardless of how many switching element portions are provided in one power supply unit, the wire electric discharge machine of the present invention can arbitrarily mix the upper power supply state, the lower power supply state, and the both-side power supply state during the electric discharge machining ( Therefore, it is possible to appropriately change the amount of electric discharge machining in the plate thickness direction of the workpiece while preventing a short circuit or wire breakage between the wire electrode and the workpiece. It is also possible to improve the processing accuracy. If the power supply ratio in the upper power supply state is increased, electric discharge machining can be advanced in the upper part in the plate thickness direction of the workpiece, and if the power supply ratio in the lower power supply state is increased in the lower part in the plate thickness direction in the work piece. Since electric discharge machining can proceed, machining accuracy in the plate thickness direction of the workpiece can be improved by appropriately combining these power supply states.

  Moreover, since the plate | board thickness of the workpiece in an electric discharge machining location can be calculated | required using the three-dimensional data of a workpiece like the wire electric discharge machine 170 shown in FIG. 7, the said three-dimensional data is used. In a wire electric discharge machine having the function of obtaining the thickness of the workpiece at the electrical discharge machining location, the thickness of the workpiece is determined from the energy of the high-frequency pulse voltage applied to the workpiece from the wire electrode and the machining speed. It is also possible to omit the function of calculating. The wire electric discharge machine of the present invention can be variously modified, modified, combined, etc. in addition to those described above.

Claims (13)

A high frequency is applied to the wire electrode via a pair of power feeding portions disposed above and below the workpiece while supplying a machining fluid between the wire electrode traveling in the plate thickness direction of the workpiece and the workpiece. A wire electric discharge machine that applies a pulse voltage and processes the workpiece by electric discharge generated between the wire electrode and the workpiece,
A high-frequency pulse voltage is applied to the upper power supply unit disposed above the workpiece among the pair of power supply units via the first switching element unit, and the lower power supply unit is disposed below the workpiece. A main power source that applies a high-frequency pulse voltage to the side power feeding unit via the second switching element unit, and a first pulse that supplies a pulse signal for controlling the opening / closing operation of the first switching element unit to the first switching element unit An oscillator,
A second pulse oscillator for supplying a pulse signal for controlling an opening / closing operation of the second switching element unit to the second switching element unit;
Specifying the opening / closing operation of each of the first switching element unit and the second switching element unit to apply a high-frequency pulse voltage to the wire electrode only from the upper feeding unit, and from only the lower feeding unit A lower power supply state in which a high-frequency pulse voltage is applied to the wire electrode and a both-side power supply state in which a high-frequency pulse voltage is applied to the wire electrode in synchronization with each other from both the upper power supply unit and the lower power supply unit are mixed. A storage unit in which power supply control data for power supply control is stored, and
A pulse oscillation control unit for controlling operations of the first pulse oscillator and the second pulse oscillator based on the power supply control data;
A wire electric discharge machine characterized by comprising: The main power supply
A first main power source connected to the upper power feeding unit via the first switching element unit and connected to an upper portion in the plate thickness direction of the workpiece;
A second main power source connected to the lower power feeding unit via the second switching element unit and connected to the lower part in the plate thickness direction of the workpiece;
The wire electric discharge machine according to claim 1, comprising:   The pulse oscillation control unit includes an impedance between a main power source and an upper power supply unit in an upper power supply circuit that reaches a discharge point from the main power source through the first switching element unit and the upper power supply unit, and Depending on the impedance between the main power source and the lower power supply part in the lower power supply circuit that reaches the discharge point via the two switching element parts and the lower power supply part, the discharge current value in the power supply circuit with the smaller impedance is The power supply control data is modified to approach the discharge current value in the power supply circuit having the larger impedance, and the operations of the first pulse oscillator and the second pulse oscillator are controlled based on the modified power supply control data. The wire electric discharge machine according to claim 1. The storage unit further stores data about the Z-axis height that was assumed when the power supply control data was created,
The pulse oscillation control unit, based on the Z-axis height when the workpiece is subjected to electric discharge machining and the data about the Z-axis height stored in the storage unit, in the upper feeding circuit Determining the magnitude relationship between the impedance and the impedance in the lower power supply circuit;
The wire electric discharge machine according to claim 3. A table that can move in two axial directions with the workpiece placed thereon;
A table driving device for moving the table in the biaxial direction;
A speed measuring device for measuring the driving speed of the table;
A voltage detection device for detecting a potential difference between each of the upper power feeding unit and the lower power feeding unit and the workpiece;
A processing speed is calculated based on the driving speed of the table measured by the speed measuring device, and a high-frequency pulse voltage applied to the workpiece from the wire electrode based on a potential difference detected by the voltage detection device An operation / control unit that calculates the thickness of the workpiece using the processing speed and the energy of the high-frequency pulse voltage;
Further comprising
The pulse oscillation control unit determines a magnitude relationship between the impedance in the upper feeding circuit and the impedance in the lower feeding circuit based on the thickness of the workpiece calculated by the calculation / control unit.
The wire electric discharge machine according to claim 3. A table that can move in two axial directions with the workpiece placed thereon;
A table driving device for moving the table in the biaxial direction;
A calculation / control unit for controlling the operation of the table driving device;
A plate thickness determining unit for calculating a plate thickness of the workpiece at a location where electric discharge machining is performed;
In addition, the storage unit further stores numerical control data for numerically controlling the operation of the table driving device and three-dimensional data of the workpiece,
The arithmetic / control unit controls the operation of the table driving device based on the numerical control data,
The plate thickness determining unit calculates the plate thickness of the workpiece at a location where electric discharge machining is performed based on the numerical control data and the three-dimensional data,
The pulse oscillation control unit determines a magnitude relationship between the impedance in the upper feeding circuit and the impedance in the lower feeding circuit based on the thickness of the workpiece calculated by the plate thickness determining unit.
The wire electric discharge machine according to claim 3. An impedance measurement unit that actually measures the impedance in the upper power supply circuit and the impedance in the lower power supply circuit;
The pulse oscillation control unit determines a magnitude relationship between the impedance of the upper power supply circuit and the impedance of the lower power supply circuit based on the actual measurement result of the impedance measurement unit.
The wire electric discharge machine according to claim 3. The storage unit stores in advance the measured data of each of the impedance in the upper power supply circuit and the impedance in the lower power supply circuit,
The pulse oscillation control unit, based on the measured data of the impedance in the upper power supply circuit and the impedance in the lower power supply circuit stored in the storage unit, the impedance in the upper power supply circuit and the lower power supply Determining the magnitude relationship with the impedance in the circuit;
The wire electric discharge machine according to claim 3. A disconnection sign detection unit that is connected to the upper power supply unit, the lower power supply unit, and the workpiece to detect a wire disconnection sign;
The pulse oscillation control unit is configured to control the power supply so that a position of a discharge between the wire electrode and the workpiece is dispersed over time when the disconnection sign detection unit detects a sign of wire disconnection. Modifying the data and controlling the operations of the first pulse oscillator and the second pulse oscillator based on the modified power supply control data;
The wire electric discharge machine according to claim 1.   The pulse oscillation control unit modifies the power supply control data so that the upper power supply state and the lower power supply state appear alternately when the wire breakage sign detection unit detects a wire breakage sign. The wire electric discharge machine according to claim 9. A voltage detection device for detecting a potential difference between each of the upper power feeding unit and the lower power feeding unit and the workpiece;
A calculation / control unit that determines whether there is a short circuit between the wire electrode and the workpiece or a sign of the short circuit based on a detection result by the voltage detection device;
Further comprising
The pulse oscillation control unit is configured to control the power supply so that a discharge between the wire electrode and the workpiece is stabilized when the arithmetic / control unit determines that the short circuit or the sign of the short circuit is present. Modifying the data and controlling the operations of the first pulse oscillator and the second pulse oscillator based on the modified power supply control data;
The wire electric discharge machine according to claim 1.   The pulse oscillation control unit modifies the power supply control data so as to be in the both-side power supply state when the arithmetic / control unit determines that the short circuit or the sign of the short circuit exists. 11. A wire electric discharge machine according to item 11. An upper nozzle disposed above the workpiece;
A lower nozzle disposed below the workpiece;
A working fluid supply device for supplying a working fluid to each of the upper nozzle and the lower nozzle;
An operation / control unit for controlling the operation of the machining fluid supply device to supply a predetermined flow rate of the machining fluid to each of the upper nozzle and the lower nozzle from the machining fluid supply device;
A flow rate comparison unit for obtaining a magnitude relationship between the amount of machining fluid supplied to each of the upper nozzle and the lower nozzle and the amount of machining fluid assumed when creating the power supply control data;
And further having
The storage unit further stores numerical control data for numerically controlling the operation of the machining fluid supply device,
The calculation / control unit controls the operation of the machining fluid supply device based on the numerical control data,
The pulse oscillation control unit, when there is a nozzle having a larger amount of machining fluid supplied than the amount of machining fluid supplied when the power supply control data is created as a result of the comparison by the flow rate comparison unit, The power supply control data is modified so that the power supply ratio from the power supply unit on the same side to the wire electrode is low, and the operations of the first pulse oscillator and the second pulse oscillator are performed based on the modified power supply control data. Control,
The wire electric discharge machine according to claim 1.

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