JP5839086B2 - Wire electric discharge machining apparatus, control method thereof and program - Google Patents

Description

  The present invention relates to a wire electric discharge machining apparatus, a control method therefor, and a program technique.

  Conventionally, a wire saw is known as an apparatus for slicing a silicon ingot into a large number of thin pieces. Recently, there is a technique for slicing a workpiece into a thin plate using a wire electric discharge machining technique.

  For example, Patent Document 1 discloses a technique for detecting a change in at least one physical state of a wire by analyzing an image captured by a camera disposed adjacent to a winding spool.

  For example, in Patent Document 2, in a wire-cut electric discharge machining apparatus, a dark room in which a contact portion between a traveling wire electrode and an electron passing device is formed in a light-shielded state, and discharge light generated at the contact portion is received to be electrically Disclosed is a technique that can reliably detect the occurrence of discharge light by including a photoelectric element that converts a signal, a means for outputting an operation output in response to an electrical signal, and an operating body that operates according to the operation output. ing.

JP 2013-94959 A JP-A-8-336728

  However, the technique disclosed in Patent Document 1 does not monitor the uniformity of the machining groove.

  Moreover, when it detects with discharge light like the technique disclosed by patent document 2, it is not known in which direction electric discharge machining is progressing, and the uniformity of a process groove is not monitored.

  In the present invention, when electric discharge machining of a workpiece is performed with wires arranged in parallel, the machining progress of the machining groove of the workpiece changes for each wire by changing the discharge state with the workpiece for each of the arranged wires. Therefore, an object of the present invention is to provide a mechanism capable of performing appropriate control when the progress of processing has changed in this way.

The present invention is a wire electric discharge machining apparatus for slicing a workpiece at an interval between wires arranged in parallel, which is taken by a camera that monitors the state of electric discharge machining, and is processed at a plurality of locations by electric discharge machining using the wires arranged in parallel. Based on the image acquisition means for acquiring the image of the workpiece including the groove and the way of arranging the plurality of processing grooves included in the acquired image, whether or not the electric discharge machining is proceeding with the interval between the wires arranged in parallel If the determination means determines that the process is not progressing, the operation related to the progress of the electric discharge machining when the determination means determines the progress is stopped. or and an operation control means for controlling to suppress, after the judging means has passed since it is determined that the left discharge machining of juxtaposed wire spacing is not in progress a predetermined time The image acquisition means acquires an image of the workpiece, and uses the image acquired after the lapse of the predetermined time to analyze again whether or not the electric discharge machining is proceeding with the interval between the wires arranged in parallel. Re-analysis means, and recovery judgment means for judging whether or not a machining defect due to the fact that the electrical discharge machining has not progressed with the wire interval is recovered based on the result of the re-analysis, the recovery When it is determined that the determination unit has recovered, the operation related to the progress of the electric discharge machining controlled to be stopped or suppressed by the operation control unit is returned to normal .

  Further, a waveform for generating a pulse waveform with a waveform intensity corresponding to the machining situation for each of the plurality of machining grooves from the acquired workpiece image, and analyzing the intensity difference based on the progress of the machining situation An intensity generation means, and a machining delay detection means for detecting whether or not a plurality of machining grooves arranged in the acquired image are uniform in the moving direction based on the analyzed intensity difference; , And the determination means makes a determination using a result obtained by the processing delay detection means.

  Further, a waveform for generating a pulse waveform at a waveform interval corresponding to the machining status of each of the plurality of machining grooves from the acquired workpiece image, and analyzing an interval difference based on the progress of the machining status An interval generation unit, and a processing blur detection unit that detects whether or not the arrangement of the processing grooves at a plurality of locations included in the acquired image is uniform in the direction in which the wire vibrates based on the analyzed interval difference. , And the determination means makes a determination using a result obtained by the processing blur detection means.

  Further, the recovery determination means manages a plurality of different processing failure levels for determining whether or not the processing failure due to the fact that the electrical discharge machining has not progressed while maintaining the wire interval, and the different processing failures are managed. According to the level, the operation control means switches a control type to be controlled so as to stop or suppress an operation related to the progress of electric discharge machining.

  In addition, when the recovery determination unit determines that the recovery has not been performed, the operation related to the progress of the electric discharge machining controlled to be stopped or suppressed by the operation control unit is switched to a different control type. To do.

  According to the present invention, when a workpiece is subjected to electric discharge machining with wires arranged side by side, the discharge state of the workpiece is changed for each of the arranged wires, and the machining progress of the machining groove of the workpiece is changed for each wire. Thus, it is possible to provide a mechanism capable of performing appropriate control when the degree of progress of machining has changed in this way.

It is the figure which looked at the wire electric discharge machining system of the present invention from the front. It is the enlarged view which looked at the wire electric discharge machining apparatus of this invention from the front. The inter-electrode state (voltage and current) and the pulse (ON / OFF) cycle of the machining power source in the present invention are shown. It is the figure which showed arrangement | positioning of the electric circuit and various components in this invention. It is the figure which showed arrangement | positioning of the electric circuit and various components in this invention. It is the figure which showed the block diagram for monitoring the discharge condition between the wire electrode and workpiece in the wire electric discharge machining apparatus of this invention. It is the figure which showed an example of the image information which monitored the state when progress of a process was delayed only among one of several process electrode wires from the observation point b side. It is the figure which linked | related the processing progress at the time of normal, and the pulse-train signal (light / dark data) which changes at that time. It is the figure which linked | related the processing progress situation at the time of processing delay generation, and the pulse-train signal (light / dark data) which changes at that time. It is the figure which linked | related the process progress state at the time of the time of a wire shake, and the pulse-train signal (light / dark data) which changes at that time. It is the figure which showed the main flowchart which shows the flow of the monitoring process of the processing condition of this invention. It is the figure which showed the image analysis flowchart of this invention. It is the figure which showed the hardware constitutions of the control computer of this invention. It is the figure which showed the electric circuit in the system which supplies electric power separately for every wire which is a prior art. It is a figure which shows the flowchart which shows the response | compatibility process of the power supply device at the time of the processing delay generation | occurrence | production of this invention. It is a figure which shows the flowchart which shows the response | compatibility process of the wire electric discharge machining apparatus at the time of the process shake generation | occurrence | production of this invention.

  Referring to FIG. FIG. 1 is an external view of a wire electric discharge machining apparatus 1 according to an embodiment of the present invention as viewed from the front. The configuration of each mechanism shown in FIG. 1 is an example, and it goes without saying that there are various configuration examples depending on the purpose and application.

  FIG. 1 shows the configuration of a wire electrical discharge machining system (semiconductor substrate or solar cell substrate manufacturing system) according to the present invention. The wire electric discharge machining system includes a wire electric discharge machining device 1, a power supply device 2, and a machining fluid supply device 50. The wire electric discharge machining system can slice a workpiece into thin pieces by electric discharge at intervals between a plurality of wires arranged in parallel.

  In the wire electrical discharge machining apparatus 1, a workpiece feeding device 3 driven by a servo motor is provided above the wire 103 and can move the workpiece 105 in the vertical direction. In the present invention, the workpiece 105 is sent in the downward (gravity) direction, and electric discharge machining is performed between the workpiece 105 and the wire 103. In the present specification, upper and lower correspond to the upper and lower directions in the direction of gravity, and left and right correspond to the left and right when the wire electric discharge machine is viewed from the front.

  In the power supply device 2, the discharge servo control circuit that controls the servo motor controls the discharge gap to be constant in order to efficiently generate discharge according to the state of discharge, performs work positioning, and discharges Proceed with processing.

  The machining power supply circuit (FIG. 4) supplies a discharge pulse for electric discharge machining to the wire 103, performs control adapted to a state such as a short circuit generated in the discharge gap, and outputs a discharge gap signal to the discharge servo control circuit. Supply.

  The machining fluid supply device 50 feeds machining fluid necessary for cooling the electrical discharge machining part and removing machining chips (scraps) to the workpiece 105 and the wire 103 by a pump, removing machining chips in the machining fluid, and ion exchange. The electrical conductivity (1 μS to 250 μS) is managed and the liquid temperature (around 20 ° C.) is managed. Although water is mainly used, electric discharge machining oil can also be used.

  Grooves are formed in the main rollers 8 and 9 at a predetermined pitch and number so that the workpiece can be processed with a desired thickness, and the tension-controlled wires from the wire supply bobbin are transferred to the two main rollers. It is wound as many times as necessary and sent to the take-up bobbin. A wire speed of about 100 m / min to 900 m / min is used. As the two main rollers rotate in the same direction and at the same speed, one wire 103 sent from the wire feeding portion circulates around the outer periphery of the main rollers (two) and is arranged in parallel. A plurality of wires 103 can travel in the same direction (that is, the travel means).

As shown in FIG. 5, the wire 103 is a single connected wire. The wire 103 is fed from a bobbin (not shown) and fitted into a guide groove (not shown) on the outer peripheral surface of the main roller. After being wound spirally (approximately 2000 times at the maximum), it is wound around a bobbin (not shown).
The wire electric discharge machining apparatus 1 is connected to the power supply unit 2 via an electric wire 513 and is operated by electric power supplied from the power supply unit 2.

As shown in FIG. 1, the wire electrical discharge machining apparatus 1 includes a block 15 that functions as a base of the wire electrical discharge machining apparatus 1, a work feeding device 3 that is installed in an upper portion of the block 15, and an adhesive portion 4. , A workpiece 105, a processing liquid tank 6, a main roller 8, a wire 103, a main roller 9, an electric supply unit 10, and an electric supply 104.
FIG. 2 will be described. FIG. 2 is an enlarged view within a dotted line 16 frame shown in FIG.

  A wire 103 is wound around the main rollers 8 and 9 a plurality of times, and the wires 103 are aligned at a predetermined pitch in accordance with a groove cut in the main roller. The main roller has a structure in which metal is used in the center and the outside is covered with resin.

  A power supply 104 attached to the power supply unit 10 is disposed between the two main rollers and at a position substantially above the center of the main rollers 8 and 9, and the power supply 104 is directed upward. The machining voltage is supplied to the plurality of wires 103 traveling by bringing the exposed surface into contact with the wires.

  The power supply 104 is in contact with 10 of the wires 103 at a time to supply the discharge pulses 503 (FIG. 3) from the machining power supply unit to the 10 wires. The position where the power supply 104 is arranged is provided at a position where the lengths of the wires from both ends of the work 105 are substantially equal (511L1 = 511L2). The power supply 104 is required to be resistant to mechanical wear and have electrical conductivity, and a cemented carbide is used.

  A work 105 attached to the work feeding device 3 is disposed between the two main rollers and substantially below the center of the main rollers 8 and 9, and the work feeding device 3 lowers the work 105. Slicing progresses by feeding in the direction.

  The machining liquid tank 6 is provided at a position below the main roller, the wire 103 and the workpiece 105 are immersed, and the electric discharge machining portion is cooled and the machining chip is removed. The processing liquid tank 6 is for storing the processing liquid and immersing the delivered work.

Although the number of wires 103 that make contact with 10 wires 103 is shown as one, it is needless to say that the number of wires and the total number of electrons can be changed according to the required number.
The block 15 is joined to the work feeding device 3. Further, the workpiece feeding device 3 is bonded (joined) by the workpiece 105 and the bonding portion 4.
In this embodiment, a silicon ingot will be described as an example of the processing material (work 105).
The bonding portion 4 may be anything as long as it is for bonding (joining) the workpiece feeding device 3 and the workpiece 105, and for example, a conductive adhesive is used.

  The workpiece feeding device 3 is a device having a mechanism for moving the workpiece 105 bonded (joined) by the bonding portion 4 in the vertical direction, and the workpiece feeding device 3 is moved downward (gravity direction) while holding the workpiece 105. ), The workpiece 105 can be brought closer to the direction of the wire 103. The work feeding device 3 is disposed at a position lower than the power supply 104. The workpiece feeding device 3 feeds the workpiece 105 in a direction approaching the wire that goes around the main rollers 8 and 9 so that the workpiece 105 to be held is immersed in the machining liquid.

  The processing liquid tank 6 is a container for storing the processing liquid, and is disposed outside the wire that goes around the plurality of main rollers 8 and 9. The working fluid is, for example, deionized water having a high resistance value. By providing the machining fluid between the wire 103 and the workpiece 105, electric discharge occurs between the wire 103 and the workpiece 105, and the workpiece 105 can be shaved.

  A plurality of rows of grooves for winding the wire 103 are formed on the main rollers 8 and 9, and the wire 103 is wound around the grooves. Then, the main roller 8, 9 rotates to the right or left, so that the wire 103 travels. Further, as shown in FIG. 2, the wire 103 is wound around the main rollers 8 and 9 to form a wire row on the upper side and the lower side of the main rollers 8 and 9.

  Also, the wire 103 is a conductor, and the supplied voltage is supplied from the power supply 104 to the wire 103 by contacting the power supply 104 of the power supply unit 10 to which the voltage is supplied from the power supply device 2 and the wire 103. 103 is applied. That is, the power supply 104 applies a voltage to the wire 103.

  Then, an electric discharge occurs between the wire 103 and the workpiece 105, and the workpiece 105 is shaved (electric discharge machining), so that a thin plate-like silicon (silicon wafer) can be formed.

  FIG. 3 will be described. FIG. 3 shows the change of the discharge voltage (Vgn) between the electrodes and the discharge current (Ign) between the electrodes and the ON / OFF operation (timing chart) of Tr1 and Tr2 according to the present invention. The horizontal axis of the graph indicates time.

  First, the transistor Tr1 504 is turned on and an induced voltage is applied. At this time, since the wire 103 and the work 105 (between the electrodes) are insulated, almost no discharge current flows between the electrodes. After that, when a discharge current starts to flow between the electrodes and the discharge is started, the voltage Vgn drops to detect the start of the discharge and turn on Tr2 to obtain a large discharge current between the electrodes. Tr2 is turned off after a predetermined time has elapsed. A series of operations is repeated again after a predetermined time has elapsed since the Tr2 was turned off.

  FIG. 4 will be described. FIG. 4 shows the relationship between the electric circuit 2 and the wire electric discharge machining apparatus 1 in a batch power feeding method in which a machining voltage is fed collectively to a plurality of wires (10 wires) in the present invention. A state is shown in which a wire current as a machining current and a discharge current between the electrodes are flowing. FIG. 4 shows an equivalent circuit of the electric circuit 2 shown in FIG.

  Assuming that the conventional electric circuit 400 shown in FIG. 14 is directly introduced into the electric circuit of the collective power supply method in which a machining voltage is supplied to a plurality of wires (10 wires) at once, a feeding point from the machining power supply unit. In order to control the machining current between the main rollers 8 and 9, Rm is adjusted so that the machining current of the total (10 times) of the wire current supplied to the plurality of wires (10) is supplied. What is necessary is just to install the electric current limiting resistor which is the resistance value divided by the frequency | count of winding (10 times) between a process power supply part and a feeding point. First, a case will be described in which a current limiting resistor having a resistance value fixed to Rm / 10 is installed between the machining power supply unit and the power supply.

  When the discharge state occurs uniformly and simultaneously between all 10 wires and the workpiece, the discharge current is evenly distributed over the 10 wires, and according to the fixed resistance value (Rm / 10). Since the discharge current is supplied between each wire and the workpiece, supply of an excessive discharge current is not a problem.

  However, if the discharge state does not occur uniformly and simultaneously between all 10 wires and the workpiece, the wire current corresponding to the fixed resistance value (Rm / 10) is the wire in the discharge state. Therefore, supply of excessive wire current becomes a problem. That is, when only one of the ten wires is in a discharge state, one wire and a wire current that is 10 times the wire current to be supplied to the workpiece are The wire is broken by being supplied to the workpiece.

  A wiring 513 is an upstream cable having an impedance (resistance) 505 and connected to the processing power supply unit (Vmn) minus side. The wiring 513 supplies a machining voltage to the power supply 104 from the machining power supply unit (Vmn). The wiring 514 has an impedance (resistance) 520 and is a down cable connected to the processing power supply unit (Vmn) plus side.

  The resistance value Rmn 505 of the wiring 513 of the present invention does not fix the resistance value to a predetermined value as in the conventional processing current limiting resistor, and the wire electric discharge machining apparatus in this embodiment is 1 out of 10 wires. Even when only the book is in a discharged state, a mechanism is provided that can control the resistance value to vary depending on the number of discharged books.

  Furthermore, when the resistance value Rmn505 of the present invention is used in a range where the resistance value is sufficiently smaller than the wire resistance Rwn509, the wire resistance Rwn509 becomes dominant in limiting the machining current, and the influence of the resistance value Rmn505. Is almost negligible.

  That is, it is not necessary to provide a current limiting resistor that limits the upper limit of the machining current that flows between the machining power supply unit 501 and the power supply 104 and is a discharge current that is discharged to the workpiece 105 between the electrodes. Alternatively, the resistance value may be smaller than the resistance value obtained by simply dividing Rmn by the number of turns (10 times) around which the main rollers 8 and 9 are wound.

  That is, by using the impedance that is the resistance Rwn 509 of each wire, the wire current Iwn of each wire is stably supplied, so that the concentration of the wire current can be prevented. A resistor (Rwn) 509 is a wire resistance for each wire.

  Here, the wire resistance value from the power supply 104 to the discharge part is a resistance according to the length of the wire from the contact of the traveling wire (one piece) with the supply electron 104 to the discharge part. For example, let Rw1, Rw2,..., Rw10 be the wire resistances when supplying power to 10 wires (the main rollers 8 and 9 are wound 10 turns) in a lump.

  Rm is not a resistor that limits the wire current (Iw) or discharge current (Ig) for each wire as in the conventional method, but Rwn is the wire current (Iw) or discharge current (Ig) for each wire. By setting the limiting resistance, the wire current (Iwn) and the discharge current (Ign) for each wire can be limited. That is, an arbitrary resistance value can be set by changing the distance (length L) between the power feeding point (power supply) and the discharge point (discharge part). That is, when Vmn = 60V, Vgn = 30V, and Rwn = 10Ω, Iwn (Ign) = (60V−30V) / 10Ω = 3A.

  In the above calculation formula, the voltage drop from the feed point to the discharge point due to the wire resistance (Rwn) is set to 30 V, but the discharge from the feed point due to the resistor (Rmn) causing the voltage drop from the machining power supply unit to the feed point is performed. The voltage drop to the point is not considered.

  That is, in the case of the collective power supply method according to the present invention, Iwn is determined by Rwn. Therefore, in order to obtain a desired wire current (Iwn) and discharge current (Ign) for each line, power is supplied from the machining power supply unit. The resistance Rmn that causes a voltage drop to the point is set to have a relationship of Rmn <Rwn.

  The wire resistance Rwn for each wire is calculated from the following three parameters: (1) electrical resistance value ρ depending on the wire material, (2) wire cross-sectional area B, and (3) wire length L. Rwn = (ρ × B ) / L.

  The machining power supply unit 501 supplies a machining voltage Vmn. Here, Vmn is a machining voltage set to supply a machining current necessary for electric discharge machining. Vmn can be set to an arbitrary machining voltage. Furthermore, since the supply amount of the machining current is larger than that in the conventional method, the machining power supply unit 501 supplies larger power (product of the machining voltage and the machining current) than the machining power supply unit 401. The machining power supply unit 501 supplies a machining voltage (Vmn) to the power supply 104.

  The machining power supply unit 502 supplies an induced voltage Vsn. Here, Vsn is an induced voltage set to induce discharge. The machining power supply unit 502 is also used for the purpose of monitoring the state of the discharge voltage (discharge current) between the wire and the workpiece and using it for controlling the workpiece feeding device 3. Vsn can be set to any induced voltage. Furthermore, since the supply amount of the induced current is larger than that in the conventional method, the machining power supply unit 502 supplies larger power than the machining power supply unit 402. The machining power supply unit 502 supplies the induced voltage Vsn to the power supply 104.

  The transistor (Tr2) 503 switches between the ON (conductive) state and the OFF (non-conductive) state of the machining voltage Vmn by switching. The transistor (Tr1) 504 switches between the ON (conductive) state and the OFF (non-conductive) state of the induced voltage Vsn by switching.

  A discharge voltage (Vgn) 507 between the electrodes is a voltage applied between the wire 103 and the workpiece 105 during discharge. For example, let Vg1, Vg2,..., Vg10 be the discharge voltages when supplying power to 10 wires at once.

  A portion where the discharge electrode voltage is applied between the wire 103 and the workpiece 105 by discharge is a discharge portion. In the discharge part, the machining voltage supplied to the plurality of wires traveling by contact with the plurality of wires traveling and the power supply is discharged to the workpiece.

  A discharge current (Ign) 508 between the electrodes is a current that flows between the wire 103 and the workpiece 105 during discharge. For example, Ig1, Ig2,..., Ig10 are discharge currents when power is supplied to 10 wires at once.

  A portion where a discharge current flows between the wire 103 and the workpiece 105 due to the discharge is a discharge portion. In the discharge part, the machining voltage supplied to the plurality of wires traveling by contact with the plurality of wires traveling and the power supply is discharged to the workpiece.

A wire current (Iwn) 510 is individually supplied for each wire. For example, each wire current when power is supplied to 10 wires at once is assumed to be Iw1, Iw2,.
A distance L 511 from the feeding point to the discharging point is the length of the wire from the feeding point (power supply) to the discharge point (work).

  FIG. 5 will be described. FIG. 5 shows that a plurality of wires are collectively fed by a batch feeding type electric circuit 2 that feeds machining voltage currents to a plurality of wires (10) in the present invention. Note that the arrangement of the configuration of the wire electrical discharge machining apparatus 1 shown in FIG. 5 is different from the arrangement of the configuration of the wire electrical discharge machining apparatus 1 shown in FIGS. 1 and 2, but the electrical configuration is the same. I want.

  The power supply 104 contacts a plurality of traveling wires at once. An electric discharge pulse is applied from one electric supply 104 provided at a position facing the workpiece 105 to perform electric discharge machining. One power supply circuit 2 is connected to the number (10) of wires 103 around which the main roller is wound. Hereinafter, the machining current (total of each wire current) flowing in the wire will be described with reference to the arrangement of FIG.

  As shown in FIG. 5, the wire current that flows from the power supply point (position where the power supply 104 and the wire 103 contact) to the discharge point (between the wire 103 and the workpiece 105) flows in two directions of the left and right main rollers. There is wire resistance in each direction. The length 511L1 is the length (distance) between the feeding point and the discharge point when the current flows in the direction of the left main roller, and the wire resistance determined when the length is L1 is Rw1a. The length 511L2 is the length (distance) between the discharge point and the power feeding point when the current flows in the direction of the right main roller. The wire resistance determined when the length is L2 is Rw1b.

  The length that the wire 103 winds the main rollers 8 and 9 once is set to 2 m. Since the power supply 104 and the workpiece 105 are arranged at a distance that is substantially half the length of one turn, the distance between the discharge point and the power supply point (the length L of the wire) is 1 m. Here, the distance of the wire which travels from the power supply to the discharge unit may be longer than 0.5 m.

  The main component of the material of the wire 103 is iron, and the diameter of the wire is 0.12 mm (cross-sectional area 0.06 × 0.06 × πmm 2). Since the wire resistance values Rw1a and Rw1b are the same length (L1 = L2 = 1 m), if each wire resistance value is set to about 20Ω, one wire (Rw1a and Rw1b) The combined wire resistance value of winding the rollers 8 and 9 once is about 10Ω.

  Further, as shown in FIG. 5, in order to make the wire resistance value according to the lengths of L1 and L2 the same resistance value, it is preferable to arrange the power supply 104 so that the lengths of L1 and L2 are the same, but L1 There is no particular problem even if the power supply 104 is arranged so that the difference between the lengths of L2 and L2 differs by about 10% (for example, L1 is 1 m and L2 is 1.1 m). When the discharge voltages Vg1 to Vg10 are substantially equal, since Vmn is applied to each of Rw1 to Rw10, Iw1 to Iw10 are all the same wire current. Here, Vmn is obtained from the voltage drop value (Rw1 × Iw1) due to the wire resistance and the discharge voltage (Vgn). The voltage drop from the power supply 104 to the discharge part is a voltage drop due to the resistance of the traveling wire.

  Rw1 = 10Ω (resistance value from the power supply 104 to the discharge part). If Iw1 = 3A and Vgn = 30V, Vmn is as follows. Vmn = 10 (Ω) × 3 (A) + 30V = 60V. Therefore, the voltage drop from the power supply to the discharge unit is larger than 10 V, and the resistance value from the power supply to the discharge unit may be larger than 1Ω. Note that the voltage drop value due to the wire resistance may be set by the wire parameter according to the relational expression of Rwn = (ρ × B) / L.

  Therefore, when Rmn is calculated when the discharge state occurs uniformly and simultaneously between all the 10 wires and the workpiece, the discharge state occurs in all the wires, and Iw1 = 3A flows through the 10 wires. A total machining current of 10 × 3A = 30 A is required between the machining power supply unit and the power supply point, and the voltage drop between the machining power supply unit and the power supply point is 1 / 100th of Vmn (0.6 V). ), Rmn in this case is as follows. The voltage drop from the processing power supply unit to the power supply 104 is smaller than 1 V, and the voltage drop from the processing power supply unit to the power supply electron may be smaller than the voltage drop from the power supply to the discharge unit. Rmn (resistance value from the processing power supply unit 501 to the power supply 104) = 0.6V / 30A = 0.02Ω. Therefore, the resistance value from the machining power supply unit to the supply electron is smaller than 0.1Ω, and the resistance value from the machining power supply unit to the supply electron may be smaller than the resistance value from the supply electron to the discharge unit. Further, the ratio of the voltage drop from the machining power supply unit to the power supply 104 and the voltage drop from the power supply 104 to the discharge unit is 10 times or more. Furthermore, the ratio of the resistance value from the machining power supply unit to the power supply 104 and the resistance value from the power supply unit to the discharge unit is 10 times or more. Here, when 10 machining currents are obtained in consideration of Rmn, (60V-30V) / ((10Ω / 10 pieces) + 0.02Ω) = 29.41A, and the machining current per wire is 2.941A. It becomes.

  Moreover, even if one wire current flows when the discharge state does not occur uniformly and simultaneously between all 10 wires and the workpiece, the machining current per wire is (60V-30V) / (10Ω + 0.02Ω) = 2.994 A, so that there is no significant difference even when the discharge state occurs uniformly and simultaneously between all ten wires and the workpiece.

As a further effect, when power is supplied to a plurality of N wires (the main rollers 8 and 9 are wound N times) at one location (in a lump), power is supplied individually for each wire. The machining speed is 1 / N compared to the machining speed at the time, but according to the present invention, even when power is supplied to N wires at one place (collective), The same processing speed can be maintained.
FIG. 6 will be described. FIG. 6 is a configuration diagram for monitoring the discharge state between the wire electrode and the workpiece in the wire electric discharge machining apparatus 1 of the present invention.

The locations where the discharge (working part) between the workpiece (workpiece) and the wire electrode can be monitored are the side where the wire electrode approaches the workpiece (observation point a), the side where the wire electrode separates from the workpiece (observation point b), and the wire There are three locations where the electrode is machining the workpiece (observation point c).
Reference numeral 901a denotes a monitoring camera installed at an observation point a, which monitors in real time an image (image) of a machining groove of a workpiece to be electric discharge machined.
Reference numeral 901b denotes a monitoring camera installed at the observation point b, which monitors in real time an image (image) of a machining groove of a workpiece to be electric discharge machined.
Reference numeral 901c denotes a monitoring camera installed at an observation point c (underwater), which monitors in real time an image (image) of a machining groove of a workpiece to be subjected to electric discharge machining.

  By observing either one or two of the observation points a or b, it is possible to grasp the progress of processing by a plurality of wires. Further, by observing the observation point C, it is possible to grasp the machining state inside the workpiece that cannot be seen from the outside.

  As a means for capturing information as an image by installing a camera such as a CCD or a CMOS directly or via an optical fiber as the image pickup / light receiving element, the image pickup / light receiving elements 901a, 901b, 901c are the work of the observation points a, b, c. It fixes to the position which monitors the discharge state between wire electrodes, respectively, and supplies the image information in electric discharge machining to a continuous analysis (image processing) system.

  103z is an example in which only one of the wires 103, which is a plurality of machining electrodes, shows a state in which the progress of machining is delayed. In this example, the length of the machining groove is other than one because the progress of one wire is slow. It is shallower than the groove.

  FIG. 6 is a view as seen from a direction perpendicular to the observation point B. When the lagging direction of the wire 103z that progresses slowly increases, the wire 103z is pushed downward compared to the normal wire position and comes into contact with the workpiece 105. Will break.

  FIG. 7 will be described. FIG. 7 shows an example of image information obtained by monitoring the state when the progress of machining is delayed from only one of the plurality of machining electrode wires 103 from the observation point b side. In this example, 103z is the third wire from the left. Since the progress of this is slow, the length of the processed groove is shorter than the other grooves.

  FIG. 8 will be described. FIG. 8 shows a binarization process of the electrical signal obtained by two-dimensional scanning of the shape of the groove processed by analyzing the acquired image near the processing tip of each wire in the image analysis flowchart of FIG. is there. In the binarized grayscale data, the X axis is the presence or absence of the machining groove, and the Y axis is the length of the machining groove. During normal machining, a pulse train signal (light / dark data) that changes as shown in (1) according to the machining progress is obtained. Since the pulse waveforms at the X-axis and Y-axis positions of the grayscale data are always uniform as in (1), it is determined to be normal (uniform).

  FIG. 9 will be described. FIG. 9 is a diagram in which the electrical signal obtained by two-dimensionally scanning the shape of the groove processed by analyzing the acquired image near the processing tip of each wire in the image analysis flowchart of FIG. 12 is binarized. is there. In the binarized grayscale data, the X axis is the presence or absence of the machining groove, and the Y axis is the length of the machining groove. When machining is delayed, a pulse train signal (grayscale data) that changes as shown in (2) according to the machining progress is obtained. As shown in (2), since the pulse waveform at the Y-axis position of the grayscale data is non-uniform, it is determined that there is an abnormality (processing delay).

FIG. 10 will be described. FIG. 10 is an image analysis flowchart of FIG. 12, in which an electrical signal obtained by two-dimensionally scanning the shape of a groove processed by analyzing an acquired image near the processing tip of each wire is binarized. is there. In the binarized grayscale data, the X axis is the presence or absence of the machining groove, and the Y axis is the length of the machining groove. When a wire shake occurs, a pulse train signal (light / dark data) that changes as shown in (3) according to the processing progress is obtained. As shown in (3), since the pulse waveform at the X-axis position of the grayscale data is not uniform, it is determined that there is an abnormality (wire blur).
FIG. 11 will be described. FIG. 11 is a main flowchart showing a flow of processing status monitoring processing of the present invention.

  In step S101, the wire electrical discharge machining apparatus 1 captures image information from the imaging / light receiving element. That is, the wire electric discharge machining apparatus 1 is photographed by a monitoring camera 901 disposed in the vicinity of the workpiece 105, and a workpiece image including a plurality of machining grooves machined by a plurality of wires is displayed at a predetermined interval (for example, at intervals of 10 seconds). (Image acquisition means).

In other words, here, an image of a work including a plurality of machining grooves photographed by a camera that monitors the state of electrical discharge machining and subjected to electrical discharge machining with a parallel wire is acquired.
In step S102, the wire electric discharge machine 1 is converted / analyzed by the image analysis (image processing) flowchart of FIG.

  In step S103, the wire electric discharge machining apparatus 1 performs an abnormality handling process on the control related to the workpiece feeding and the control related to the machining power performed by the power supply apparatus 2 based on the determination result in S102. Details of step S103 will be described with reference to FIG.

In step S104, the wire electric discharge machining apparatus 1 performs an abnormality handling process on the control related to the travel of the wire executed by the wire electric discharge machining apparatus 1, based on the determination result in S102. Details of step S104 will be described with reference to FIG.
FIG. 12 will be described.
FIG. 12 is an image analysis flowchart of the present invention, and FIGS. 8 to 10 are examples of an acquired image and a pulse signal converted from the acquired image for normal / abnormal analysis.

  When the imaging / light-receiving element is a camera, the image analysis flowchart analyzes the acquired data immediately after obtaining it, and how to arrange the machining grooves in the normal pattern image in which the electrical discharge machining groove arrangement (X or Y direction) is stored in advance. And (image matching) to determine whether the state of discharge is normal / abnormal. Further, the X and Y coordinates emitted by each wire electrode by discharge are analyzed as X and Y coordinate information of the machining groove discharge light in the acquired two-dimensional image, and the arrangement of the machining grooves is specified as shown in FIG. A processing groove delay or a lateral shift due to the processing delay wire 103z may be detected.

In step S <b> 200, the wire electric discharge machining apparatus 1 determines whether the machining that has been successfully completed has been completed in order to determine whether to continue monitoring the state of the machining groove. If the processing has not been completed (No), the process proceeds to S201. If it is determined (Yes) that the processing has been completed, the process proceeds to S208.
In step S201, the wire electric discharge machining apparatus 1 performs the above-described binarization process on the image acquired in S101.

  In the binarization process, first, the wire electric discharge machining apparatus 1 has a difference in height in the waveform intensity in the pulse waveform corresponding to the machining status of the machining grooves at a plurality of positions (Y-axis peak height) for each acquired workpiece image. (Waveform intensity generating means).

  Next, in the binarization process, the wire electric discharge machining apparatus 1 performs, for each workpiece image acquired, an interval difference (X-axis peak interval) in the waveform interval in the pulse waveform corresponding to the machining status of the machining grooves at a plurality of locations. ) Is generated (waveform interval generation means).

  In step S202, the wire electric discharge machining apparatus 1 analyzes the pulse waveform binarized in step S201. That is, the wire electric discharge machining apparatus 1 analyzes information that can determine whether or not the obtained work images are substantially uniform in order to determine whether or not the machining conditions of the plurality of machining grooves are substantially uniform. It detects from a pulse waveform (image analysis means).

  As described above, in step S201 and step S202, a pulse waveform is generated with a waveform intensity corresponding to the machining status for each machining groove at a plurality of locations from the acquired workpiece image, and an intensity difference based on the progress of the machining status. Is being analyzed. Further, in step S201 and step S202, a pulse waveform is generated at a waveform interval corresponding to the machining situation for each of the plurality of machining grooves from the acquired workpiece image, and an interval difference based on the progress of the machining situation is also generated. Analyzing.

  In step S203, the wire electric discharge machining apparatus 1 compares with the normal pulse waveform, and determines whether the number of peaks having the same height (Y axis) as the normal pulse waveform is smaller than a predetermined number. If it is determined that there are few (≠), the process proceeds to S204. If they are determined to be the same (=), the process proceeds to S205 (determination means). In other words, when the wire electric discharge machining apparatus 1 determines that the difference in level of the waveform intensity generated in S201 satisfies the predetermined condition, the machining status of the plurality of machining grooves is not substantially uniform in the direction in which the workpiece moves in S203. It is detected as information that should be judged. That is, here, it is determined whether or not electric discharge machining is proceeding with the interval between the wires arranged side by side based on the arrangement of the machining grooves at a plurality of locations included in the acquired image.

  Here, based on the analyzed intensity difference, it is detected whether or not the way of arranging the plurality of machining grooves included in the acquired image is uniform in the direction in which the workpiece moves (machining delay detection means). . The determination of (≠) or (=) here is made by using the result obtained by detecting the machining delay.

In step S204, the wire electric discharge machining apparatus 1 determines that a machining delay as shown in FIG. 9 has occurred. If a discharge abnormality or partial machining delay is detected in part or all of the monitoring area in step S204, information on the machining abnormality is notified to the pulse power source and the wire saw, and step S103 in FIG. 11 is performed. Alternatively, the necessary response is performed in step S104. For example, an abnormality is displayed on the operation panel, a buzzer is notified, a workpiece delayed in machining is returned, or machining conditions are set to alleviate partial delay. Change automatically or adjust tension of wire electrode.
Here, the pulse power supply is a pulse voltage control unit (not shown) for controlling the set value of the pulse voltage by the machining power supply units 501 and 502 inside the power supply device 2.
Here, the wire saw is a travel speed control unit (not shown) for controlling the set value of the wire travel speed by the main rollers 8 and 9 inside the wire electric discharge machine 1.
Here, the wire saw is a servo voltage control unit (not shown) for controlling the set value of the servo voltage by the workpiece feeding device 3 in the wire electric discharge machining apparatus 1.

  In other words, when information that should be determined to be not substantially uniform is detected in S202, the wire electrical discharge machining apparatus 1 stops or suppresses the operation of any of the wire electrical discharge machining apparatuses related to machining of the workpiece 105 with a plurality of wires. Control is performed (operation control means). If it is determined in step S203 that it is not progressing (≠), control is performed so as to stop or suppress the operation related to the progress of electric discharge machining when it is determined that progress is being made (=). .

  In step S205, the wire electric discharge machining apparatus 1 compares with a normal (or analyzed before a certain time) pulse waveform, and whether the peak coordinate at the same position (X axis) as the normal pulse waveform is deviated from a predetermined position. Judging. The pulse waveform to be compared may be a reference pulse waveform stored in advance. If it is determined that there is a shift (≠), the process proceeds to S206. If it is determined that the positions are the same (=), the process proceeds to S207 (determination means). That is, when the wire electric discharge machining apparatus 1 determines that the interval difference between the waveform intervals generated in S201 satisfies a predetermined condition, in S205, the machining conditions of the plurality of machining grooves are not substantially uniform in the direction in which the wire vibrates. It is detected as information that should be judged.

  That is, also here, it is determined whether or not the electric discharge machining is proceeding with the interval between the wires arranged side by side based on the way of arranging the plurality of machining grooves included in the acquired image.

  Here, based on the analyzed gap difference, it is detected whether or not the arrangement of the plurality of machining grooves included in the acquired image is uniform in the direction in which the wire vibrates (machining blur detection means). . The determination of (≠) or (=) here is made by using the result obtained by detecting the processing blur.

  In step S206, the wire electric discharge machining apparatus 1 determines that the wire shake as shown in FIG. 10 has occurred. If a discharge abnormality or partial wire shake is detected in part or all of the monitoring area in step S206, information on the processing abnormality is notified to the pulse power source and the wire saw, and step S103 in FIG. 11 is performed. Alternatively, a necessary response is performed in step S104. For example, display an error on the operation panel, notify with a buzzer, return the workpiece for which machining has been delayed, automatically change the machining conditions to a setting that reduces partial delay, Adjust the tension.

In other words, when information that should be determined to be not substantially uniform is detected in S202, the wire electrical discharge machining apparatus 1 stops or suppresses the operation of any of the wire electrical discharge machining apparatuses related to machining of the workpiece 105 with a plurality of wires. Control is performed (operation control means). If it is determined in step S205 that it is not progressing (≠), control is performed to stop or suppress the operation related to the progress of electric discharge machining when it is determined that progress is being made (=). .
In step S207, the wire electrical discharge machining apparatus 1 determines that machining is proceeding normally as shown in FIG. 8, continues the machining process as it is, and further continues monitoring.
In step S208, the wire electric discharge machining apparatus 1 ends the monitoring (image analysis).

Further, when the imaging / light receiving element is a line sensor in which a large number of light receiving elements are arranged in a one-dimensional direction, the electric discharge machining state can be observed more simply. The analysis (image processing) system immediately analyzes the data obtained from the line sensor, but the original information is not an image, but is information on the amount of light received by each light receiving element arranged on the line. The light amount of the light receiving element is compared with a light amount in a normal state stored in advance as a reference value. If the light amount is smaller than the reference value, it is determined that the discharge is abnormal.
FIG. 13 will be described. FIG. 13 is a hardware configuration diagram of the control computer 1000 built in the wire electric discharge machining apparatus 1.
The control computer 1000 may be provided separately from the wire electric discharge machine 1.

  In FIG. 13, an MPU (CPU) 1001 comprehensively controls each device and controller connected to the system bus 1004. In addition, the ROM 1002 or the external memory 1011 is necessary for realizing a BIOS (Basic Input / Output System) or an operating system program (hereinafter referred to as an OS) that is a control program of the CPU 1001 and a function executed by each server or each PC. Various programs to be described later are stored.

  The RAM 1003 functions as a main memory, work area, and the like for the CPU 1001. The CPU 1001 implements various operations by loading a program or the like necessary for execution of processing from the ROM 1002 or the external memory 1011 to the RAM 1003 and executing the loaded program.

  An input controller 1005 controls input from a keyboard (KB) 1009 or a pointing device such as a mouse (not shown). The video controller 1006 controls display on the display unit 1010. Note that the display unit 1010 is not limited to a CRT, but may be another display such as a liquid crystal display. These are used by the administrator as needed. Further, the display unit may include a touch panel function in which the user specifies a target position in the display screen with a finger, a pen, or the like.

  The memory controller 1007 is connected via an adapter to a hard disk (HD), flexible disk (FD), or PCMCIA card slot for storing a boot program, various applications, font data, user files, editing files, various data, and the like. Controlling access to an external memory 1011 such as a CompactFlash (registered trademark) memory.

  The communication I / F controller 1008 is connected to and communicates with an external device via a network (communication line) such as a LAN 1012 or WAN, and executes communication control processing in the network. For example, communication using TCP / IP is possible.

  Note that the CPU 1001 can perform display on the display unit 1010 by executing outline font rasterization processing on a display information area in the RAM 1003, for example. Further, the CPU 1001 enables a user instruction with a mouse cursor (not shown) on the CRT.

  Various programs to be described later for realizing the present invention are recorded in the external memory 1011 and are executed by the CPU 1001 by being loaded into the RAM 1003 as necessary. Further, data files and data tables used when executing the program are also stored in the external memory 1011 or the storage unit.

The program in the present invention is a program that can be executed by the control computer 1000 for wire electric discharge machining operation according to the wire electric discharge machining method, and the storage medium of the present invention is stored as a program that can execute the wire electric discharge machining operation. Yes.
(Other embodiments of the present invention)

  As described above, the recording medium on which the program for realizing the functions of the above-described embodiments is recorded is supplied to the wire electric discharge machining apparatus 1, and the system or the computer (or CPU or MPU) in the wire electric discharge machining apparatus is non-temporary. It goes without saying that the object of the present invention can also be achieved by reading and executing a program stored in a typical computer-readable recording medium.

  In this case, the program itself read from the recording medium realizes the novel function of the present invention, and the non-transitory computer-readable recording medium storing the program constitutes the present invention. .

  As a recording medium for supplying the program, for example, a flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, DVD-ROM, BD-ROM, magnetic tape, nonvolatile memory card, ROM , EEPROM, silicon disk, etc. can be used.

  Further, by executing the read program, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program performs the actual processing. Needless to say, a case where the function of the above-described embodiment is realized by performing part or all of the processing is also included.

  Furthermore, after the program read from the recording medium is written to the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, the function expansion board is based on the instructions of the program code. It goes without saying that the case where the CPU or the like provided in the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  Further, the present invention may be applied to a wire electric discharge machining system constituted by a plurality of devices or a wire electric discharge machining apparatus constituted by one device. Further, it goes without saying that the present invention can also be applied to a case where the invention is achieved by supplying a program to a wire electric discharge machining system or a wire electric discharge machining apparatus. In this case, by reading the recording medium storing the program for achieving the present invention into the system or apparatus, the wire electric discharge machining system or the wire electric discharge machining apparatus can enjoy the effects of the present invention. .

Furthermore, by downloading and reading a program for achieving the present invention from a server, database, etc. on a network by a communication program, the system or apparatus can enjoy the effects of the present invention.
In addition, all the structures which combined each embodiment mentioned above and its modification are also included in this invention.
FIG. 14 will be described. FIG. 14 shows an electric circuit 400 and a wire electric discharge machining device 4000 according to an individual feeding system that feeds a machining voltage individually for each wire, which is a conventional system.

  The machining power supply unit 401 supplies a machining voltage Vm. Here, Vm is a machining voltage set to supply a current necessary for electric discharge machining. Vm can be set to an arbitrary machining voltage in the range of 60V to 150V.

  The machining power supply unit 402 supplies an induced voltage Vs. Here, Vs is an induced voltage set for inducing discharge. The machining power supply unit 402 is also used for the purpose of monitoring the voltage (discharge current) state between the wires and the workpiece. Vs can be set to any induced voltage between 60V and 300V.

  The transistor (Tr2) 403 switches between the ON (conductive) state and the OFF (non-conductive) state of the machining voltage Vm by switching. The transistor (Tr1) 404 switches between the ON (conductive) state and the OFF (non-conductive) state of the induced voltage Vs by switching.

  By setting a fixed resistance value (Rm) 405 using a current limiting resistor, the wire current (Iw) for each wire and the discharge current (Ig) between the electrodes are limited. Rm can be set to an arbitrary resistance value of 1Ω to 100Ω. That is, when Vm = 60V (volt), Vg = 30V, and Rm = 10Ω, Iw (Ig) = (60V−30V) / 10Ω = 3A (ampere).

  In the above calculation formula, the voltage drop from the machining power source (Vm) to the feeding point (power supply) is 30 V, but the voltage drop from the feeding point to the discharge point due to the wire resistance (Rw) is not considered. .

  That is, in the case of the conventional individual power feeding method, the value of the machining current Iw is determined by the resistance Rm of the current limiting resistor, so that a desired wire current or discharge current (Ig) is obtained for each wire. Is set so that the wire resistance Rw has a relationship of Rm> Rw.

  By setting a fixed resistance value (Rs) 406 using a current limiting resistor, the induced current that induces discharge is limited. Rs can be set to an arbitrary resistance value of 1Ω to 100Ω.

A discharge voltage (Vg) 407 is a discharge voltage between the electrodes applied between the wire 103 and the workpiece 105 (between the electrodes) during discharge. A discharge current (Ig) 408 is a discharge current between the electrodes that flows between the wire 103 and the workpiece 105 during discharge. The machining current (Iw) 410 is individually supplied for each wire.
FIG. 15 will be described. FIG. 15 is a flowchart showing the processing of the power supply device 2 when a machining delay occurs according to the present invention.
In step S301, the wire electric discharge machining apparatus 1 changes the servo control parameter of the pulse power supply.
In step S302, the wire electrical discharge machining apparatus 1 determines that machining is proceeding normally as shown in FIG. 8, continues the machining process as it is, and further continues monitoring.

  In step S303, the wire electric discharge machining apparatus 1 determines whether or not a predetermined time (for example, 10 minutes) has elapsed since it was determined that the electric discharge machining has not progressed with the interval between the wires arranged in parallel in step S203. Acquire an image of the workpiece after a lapse of time.

  In step S304, the wire electrical discharge machining apparatus 1 uses the image acquired after a predetermined time has passed to reanalyze whether or not electrical discharge machining is proceeding with the interval between the wires arranged in parallel (reanalyzing unit). .

  In step S305, the wire electric discharge machining apparatus 1 determines whether or not the machining defect due to the fact that the electric discharge machining is not progressing with the wire interval is recovered based on the result of the analysis again in step S304 (recovery determination). means).

In step S306, when it is determined that the wire electric discharge machine 1 has recovered in step S305, the operation related to the progress of the electric discharge machining controlled to be stopped or suppressed by the operation control unit is returned to normal. . In the case of recovery, the parameter changed in step S301 is restored.
In step S307, the wire electrical discharge machining apparatus 1 determines that the machining is proceeding normally as shown in FIG. 8, continues the machining process as it is, and further continues monitoring.

In step S308, when it is determined that the wire electric discharge machining apparatus 1 has not recovered in step S305, the operation related to the progress of electric discharge machining controlled to be stopped or suppressed in step S204 is switched to a different control type. The wire electric discharge machining device 1 temporarily stops the discharge and then moves the workpiece position backward.
In step S309, the wire electric discharge machining apparatus 1 restarts machining after ensuring the discharge gap.
In step S310, the wire electric discharge machining apparatus 1 determines whether a predetermined time (for example, 10 minutes) has elapsed, and acquires an image of the workpiece after the predetermined time has elapsed.

  In step S311, the wire electric discharge machining apparatus 1 has a plurality of different machining defect levels (machining) for determining whether or not machining defects due to the fact that the electric discharge machining has not progressed at the wire interval from step S305. (Defect large) is managed.

  In step S312, the wire electric discharge machining apparatus 1 determines whether or not the machining failure due to the fact that the electric discharge machining is not progressing with the wire interval is recovered based on the result of the analysis again in S311 (second step). Recovery judgment means).

In step S313, the wire electric discharge machining apparatus 1 switches the control type that the operation control means controls to stop or suppress the operation related to the progress of the electric discharge machining in accordance with different machining defect levels. The wire electric discharge machine 1 notifies an alarm.
In step S314, the wire electric discharge machine 1 stops electric discharge machining.
FIG. 16 will be described. FIG. 16 is a flowchart showing a corresponding process of the wire electric discharge machining apparatus 1 when machining blur occurs according to the present invention.

In step S401, the wire electrical discharge machining apparatus 1 is often caused by poor control of the wire running state because the main cause of the machining blur is, and when machining blur is detected, the wire running speed and / or the wire tension are set. change.
In step S402, the wire electric discharge machining apparatus 1 determines that machining is proceeding normally as shown in FIG. 8, continues the machining process as it is, and further continues monitoring.

  In step S403, the wire electric discharge machining apparatus 1 determines whether or not a predetermined time (for example, 10 minutes) has elapsed since it was determined that the electric discharge machining has not progressed with the interval between the wires arranged in parallel in step S205. Acquire an image of the workpiece after a lapse of time.

  In step S404, the wire electric discharge machining apparatus 1 analyzes again whether or not electric discharge machining is proceeding with the interval between the wires arranged in parallel using the image acquired after a predetermined time has elapsed (reanalysis means). .

  In step S405, the wire electric discharge machining apparatus 1 determines whether or not the machining failure due to the fact that the electric discharge machining is not progressing with the wire interval is recovered based on the result of the analysis again in step S404.

In step S406, when the wire electric discharge machining apparatus 1 recovers, the wire traveling speed and / or the wire tension changed in step S401 are restored.
In step S407, the wire electrical discharge machining apparatus 1 determines that machining is proceeding normally as shown in FIG. 8, continues the machining process as it is, and further continues monitoring.
In step S408, the wire electric discharge machining apparatus 1 notifies an alarm.
In step S409, the wire electric discharge machine 1 stops electric discharge machining.

DESCRIPTION OF SYMBOLS 1 Wire electrical discharge machining apparatus 2 Power supply device 3 Work feeding apparatus 10 Electric supply unit 103 Wire electrode 104 Electric supply (lump)
105 Workpiece (silicon ingot)
204 Electricity supply (individual)
901 surveillance camera

Claims (7)

A wire electrical discharge machining apparatus for slicing a workpiece at an interval between parallel wires,
Image acquisition means for acquiring an image of a work including a plurality of machining grooves photographed by a camera that monitors the state of electrical discharge machining and subjected to electrical discharge machining with wires arranged in parallel;
Based on how to arrange the machining grooves at a plurality of locations included in the acquired image, a determination unit that determines whether or not electric discharge machining is proceeding with the interval between the wires arranged in parallel,
An operation for controlling to stop or suppress an operation related to the progress of electric discharge machining when the determination means determines that the progress is not made, when the determination means determines that the progress is made. Control means;
With
The image acquisition means acquires the image of the workpiece after a predetermined time has elapsed since it was determined that the electric discharge machining has not progressed with the interval between the wires arranged in parallel.
Re-analyzing means for re-analyzing whether or not electric discharge machining is proceeding with the interval between the wires arranged side by side, using an image acquired after the predetermined time has elapsed;
Based on the result of the re-analysis, recovery judgment means for judging whether or not the machining failure due to the fact that the electrical discharge machining is not progressing with the interval between the wires, and
With
When the recovery determining means determines that the recovery has been performed , the wire electric discharge machining apparatus is configured to restore the operation related to the progress of the electric discharge machining controlled to be stopped or suppressed by the operation control means to normal. . Waveform intensity generation for generating a pulse waveform with a waveform intensity corresponding to the machining situation for each of the plurality of machining grooves from the acquired workpiece image, and analyzing a difference in intensity based on the progress of the machining situation Means,
Based on the analyzed intensity difference, processing delay detection means for detecting whether or not the way of arranging the plurality of processing grooves included in the acquired image is uniform in the direction in which the workpiece moves,
Further comprising
The wire electric discharge machining apparatus according to claim 1, wherein the determination unit makes a determination using a result of the processing delay detection unit. Waveform interval generation for generating a pulse waveform at a waveform interval corresponding to the machining situation for each of the plurality of machining grooves from the acquired workpiece image, and analyzing an interval difference based on the progress of the machining situation Means,
Based on the analyzed interval difference, processing blur detection means for detecting whether or not the way of arranging the plurality of processing grooves included in the acquired image is uniform in the direction in which the wire vibrates,
Further comprising
The wire electric discharge machining apparatus according to claim 1, wherein the determination unit makes a determination using a result obtained by the processing blur detection unit. A plurality of different processing failure levels for determining whether or not the processing failure due to the fact that the electrical discharge machining is not progressing while maintaining the wire interval are managed by the recovery determination means,
The wire electric discharge machining apparatus according to claim 1 , wherein the operation type is controlled so as to stop or suppress the operation related to the progress of electric discharge machining in accordance with the different machining defect level. The operation relating to the progress of electric discharge machining controlled to be stopped or suppressed by the operation control unit is switched to a different control type when the recovery determination unit determines that the recovery is not performed. The wire electric discharge machining apparatus according to claim 1 or 4 . It is a control method by a wire electric discharge machine that slices a workpiece at an interval between wires arranged in parallel,
An image acquisition step in which the image acquisition means of the wire electric discharge machining apparatus acquires an image of a work including a plurality of machining grooves, which are photographed by a camera that monitors the state of electric discharge machining and is electric discharge machined by wires arranged in parallel. ,
The determination means of the wire electric discharge machining apparatus determines whether or not electric discharge machining is proceeding with the interval between the arranged wires based on the arrangement of the plurality of machining grooves included in the acquired image. A decision process;
If the operation control means of the wire electrical discharge machining apparatus determines that the progress is not made by the determination step, it relates to the progress of the electrical discharge machining when the progress is determined by the determination step. An operation control process for controlling to stop or suppress the operation;
Only including,
An image for acquiring an image of the workpiece after a predetermined time has elapsed since the image acquisition means of the wire electric discharge machining apparatus has determined that the electric discharge machining has not progressed at the interval of the wires arranged in parallel in the determination step. Acquisition process;
Reanalyzing means for reanalyzing whether or not the electric discharge machining is proceeding with the interval between the wires arranged side by side, using the image acquired after the predetermined time has elapsed, Process,
A recovery determination step in which the recovery determination means of the wire electric discharge machining apparatus determines whether or not the machining failure due to the fact that the electric discharge machining is not progressing with the wire interval is recovered based on the result of the reanalysis; ,
Including
When it is determined that the recovery is performed in the recovery determination step, the operation related to the progress of the electric discharge machining controlled to be stopped or suppressed in the operation control step is returned to normal . A program that can be read and executed by a wire electric discharge machine that slices a workpiece at an interval between parallel wires,
The wire electric discharge machining apparatus,
Image acquisition means for acquiring an image of a work including a plurality of machining grooves photographed by a camera that monitors the state of electrical discharge machining and subjected to electrical discharge machining with wires arranged in parallel;
Based on how to arrange the machining grooves at a plurality of locations included in the acquired image, a determination unit that determines whether or not electric discharge machining is proceeding with the interval between the wires arranged in parallel,
An operation for controlling to stop or suppress an operation related to the progress of electric discharge machining when the determination means determines that the progress is not made, when the determination means determines that the progress is made. Control means;
To function,
The image acquisition means acquires the image of the workpiece after a predetermined time has elapsed since it was determined that the electric discharge machining has not progressed with the interval between the wires arranged in parallel.
Re-analyzing means for re-analyzing whether or not electric discharge machining is proceeding with the interval between the wires arranged side by side, using an image acquired after the predetermined time has elapsed;
Based on the result of the re-analysis, recovery judgment means for judging whether or not the machining failure due to the fact that the electrical discharge machining is not progressing with the interval between the wires, and
To function,
When the recovery determining means determines that the recovery has been performed , the program restores normal operation related to the progress of electric discharge machining controlled to be stopped or suppressed by the operation control means .

Images