JP4037490B2 - Wire cut electric discharge machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention Wire cut electric discharge machine More specifically, the tension of the wire electrode is detected during the automatic insertion, and the completion of the automatic insertion of the wire electrode is determined by the increase in the tension. Wire-cut electrical discharge machine with configuration About.
[0002]
[Prior art]
The structure along the traveling path of the wire electrode of a conventional wire cut electric discharge machine equipped with an automatic insertion device will be outlined with reference to the schematic diagram of FIG. After the wire electrode 1 is supplied from the wire bobbin 10 and wound around the brake roller 121 and the roller 122 as a group, the wire electrode 1 passes through the disconnection detection limit switch 130, passes through the direction conversion roller 115, It is clamped between the pinch rollers 142 that form a pair. Then, after passing through the buckling detector 150 and passing through the automatic insertion pipe 61 that moves up and down, it is stretched between the upper guide unit 71 and the lower guide unit 72 positioned above and below the workpiece W. Then, the direction is changed by the direction changing roller 75 and the guide block 76, passed through the belt or pipe wire electrode conveying means 77, and taken up between the take-up roller 81 and the pair of pinch rollers 82, and the collection bucket 90. To be discharged. The disconnection detection limit switch 130 is a device that detects, when the wire electrode 1 is disconnected, that the tension of the wire electrode 1 has been lost and slackened by the limit switch.
[0003]
The main part will be further described. The pinch roller 142 is configured to open / close with respect to the feed roller 141 by an opening / closing mechanism 144 such as an air cylinder and to press it. The feed motor 143 that drives the feed roller 141 feeds the wire electrode 1 downstream when automatically inserted, and reverses the wire electrode 1 so as to wind up upstream when the automatic insertion fails. The buckling detector 150 is made of a ring-shaped electric good conductor having an inner diameter sufficiently larger than the diameter of the wire electrode 1, and the insertion of the wire electrode 1 is hindered for some reason during the automatic insertion, so that the wire electrode 1 bends (seats). In this case, the wire electrode 1 and the buckling detector 150 are detected to be electrically short-circuited by a voltage appropriately applied between the wire electrode 1 and the buckling detector 150. is there. The automatic insertion pipe 61 can eject a jet liquid flow downward from its lower end when a liquid flow is supplied by liquid supply means (not shown). The automatic insertion pipe 61 is configured to be movable up and down by an elevating device (not shown), and the delivery roller 141 is configured to send out the wire electrode 1 at substantially the same speed when the automatic insertion pipe 61 is lowered. Moreover, when the automatic insertion pipe 61 is in the raised position, a cutter 67 for cutting the tip of the wire electrode 1 and a tip processing device 68 for removing the cut piece are provided. The upper guide unit 71 and the lower guide unit 72 incorporate a wire guide that slidably guides the wire electrode 1 (not shown). In particular, the wire guide of the upper guide unit 71 is configured to open and close. ing.
[0004]
The back tension, tension, and traveling speed applied to the traveling wire electrode 1 are controlled as follows. A back tension motor 11, which is a torque motor, applies a predetermined torque to the wire bobbin 10, thereby applying a back tension. Accordingly, since a weak tension is applied to the wire electrode 1 traveling between the wire bobbin 10 and the brake roller 121, even if the wire electrode 1 is disconnected during traveling, the wire electrode 1 does not deviate from this traveling path. Also, the brake force set by the brake 123, which is a powder brake or a hysteresis brake, is applied to the brake roller 121, and the tension of the wire electrode 1 that runs while being wound around the brake roller 121 is controlled. Further, in the take-up device 80, the take-up motor 83, which is a speed control motor, controls the rotational speed of the take-up roller 81, whereby the traveling speed of the wire electrode 1 is controlled. Here, the pinch roller 82 is pressed against the take-up motor 83 by a pressing mechanism 84 having a spring.
[0005]
The automatic insertion with the above configuration is performed to pass the end of the wire electrode 1 to the recovery bucket 90 when the electric discharge machining is started or when the wire electrode is disconnected during the electric discharge machining. First, automatic insertion is started after the tip of the wire electrode 1 is cut by the cutter 67 so as to substantially coincide with the tip of the automatic insertion pipe 61. Then, with the wire guide of the upper guide unit 71 opened, the automatic insertion pipe 61 is lowered to the upper surface of the workpiece W or close to the lower guide unit 72 while jetting a jet liquid flow from the automatic insertion pipe 61. . At this time, the brake force of the brake roller 121 is released, and the back tension of the back tension motor 11 is also normally released, and the wire electrode 1 is strongly clamped by the feed roller 141 and the pinch roller 142, and the wire electrode 1 The cut end of is sent downstream. The feeding speed at this end is a low speed substantially the same as the descending speed of the automatic insertion pipe 61. Note that the brake force of the brake roller 121 and the back tension of the back tension motor 11 are released in order to minimize damage to the wire electrode 1 due to this feeding, as will be described later. When the automatic insertion pipe 61 has been lowered, this is stopped and the wire electrode 1 is further fed out at the same speed. Then, the end of the wire electrode 1 is changed in the direction of the direction changing roller 75 and the guide block 76, further conveyed to the wire electrode conveying device 77, and finally taken up between the take-up roller 81 and the pinch roller 82. Then, after a certain period of time has elapsed after starting automatic insertion, the pinch roller 142 of the feed roller 141 is unclamped, the tension of the brake roller 121 is increased stepwise, and the tension applied to the wire electrode 1 is gradually increased to the desired tension. To do. Then, the tension of the wire electrode 1 at the location of the disconnection detection limit switch 130 increases, and the disconnection signal of the disconnection detection limit switch 130 is released. This was detected as a successful automatic insertion. On the other hand, the inconvenience that the insertion was delayed was detected by the buckling detector 150.
[0006]
Since automatic insertion is performed in this way, there are the following problems. The delivery roller 141 and the pinch roller 142 are formed to have a small diameter, and the wire electrode 1 is delivered with a strong feed force by being strongly sandwiched between the pinch rollers 142. For this,
(1) It is difficult to detect changes in the tension and speed of the wire electrode 1 due to the completion of automatic insertion upstream of the delivery roller 141, and the success or failure of automatic insertion is released after the pinch roller 142 of the delivery roller 141 is opened. I had to judge from. The setting time for determination must be set to a time that allows for some margin. In addition, since it took time to sequentially increase the tension of the feed roller 141 in the determination operation, the time spent for the automatic connection work was long.
(2) The wire electrode 1 may bend and wrinkle due to the pinching roller 141 and the pinch roller 142 between them. Further, if the clamping force is insufficient, the wire electrode 1 may slip and wear may occur on the roller surface of the feed roller or pinch roller.
(3) When feeding the wire electrode 1 at a high speed during automatic insertion, the wire electrode 1 must be stopped as fast as possible when a buckling or the like is detected. When a highly responsive motor such as a motor is not used, it is difficult to stop suddenly. Further, since the back tension motor 11 is made free in order to reduce the load applied to the delivery roller 141, even if the delivery roller 141 can be stopped suddenly, the wire electrode 1 is sent out by inertia upstream, The wire may come off the wire travel path.
[0007]
On the other hand, JP-A-2-243222 discloses a discharge provided with a second feed roller and a tension sensor for detecting and controlling the tension of the wire electrode upstream of the feed roller (first feed roller). Processing machines have been proposed. In such an electric discharge machine, the wire electrode sent out by the second feed roller almost cancels the back tension applied to the wire reel, so the above problem (2) is almost solved. . However, in the above proposal, the first feeding roller is the main role of precision control related to automatic insertion. Also, there is no proposal for determining whether or not automatic insertion has succeeded.
[0008]
In addition, in order to cope with processing that requires a better surface finish or processing that uses a finer wire electrode, the tension of the wire electrode is detected, and this is feedback controlled to provide more precise wire electrode The development of a wire-cut electric discharge machine that controls tension is an important issue, and many proposals have been made for this purpose. For example, there are JP-A-57-57211, JP-A-1-199726, JP-A-2-152726, JP-A-2-224925, and Japanese Patent Application No. 9-70732. However, it has not been proposed to determine the completion of the automatic insertion operation.
[0009]
[Problems to be solved by the invention]
Accordingly, the present invention has been made in view of the above circumstances, and during the automatic insertion operation, the wire electrode is fed at a high speed by the servo feed roller, and the tension is detected by the tension detecting means, and the tension value is determined in a predetermined manner. When the reference value is exceeded, it is determined that automatic insertion has been completed, the servo feed motor is switched to tension control the wire electrode, the completion of automatic insertion of the wire electrode is determined faster, and automatic insertion is terminated. Wire cut electric discharge machine The purpose is to provide.
[0010]
[Means for Solving the Problems]
The purpose mentioned above is (1) A wire bobbin capable of applying a back tension and a wire electrode stored in the wire bobbin are wound around a peripheral surface of the roller, and the wire electrode is pressed and pinched between the pinch roller on the entrance side and the exit side of the winding. While the servo feed roller that feeds downstream from the wire bobbin, the automatic insertion means that passes the wire electrode fed by the servo delivery roller from the upper guide unit to the lower guide unit by the jet liquid flow, and the upper side by the automatic insertion means A pulling device for pulling the wire electrode inserted through the guide unit and the lower guide unit and discharging the pulled wire electrode to a recovery bucket; a tension detecting means for detecting the tension of the wire electrode; and Provided downstream, Auxiliary to such an extent that loosening of the wire electrode in the vicinity of the tension detecting means is eliminated while the wire electrode is pressed and pinched with the pinch roller in accordance with the traveling speed of the wire electrode during the dynamic insertion operation. An auxiliary delivery roller that performs smooth delivery, and a wire electrode insertion state detected by at least the tension detection means after the wire electrode has been taken up by the take-up device by an instruction from a numerical controller during automatic insertion operation, and the tension An insertion determination circuit unit for determining that automatic insertion is completed when the tension value of the wire electrode detected by the detection means exceeds a predetermined determination reference value; and the servo according to a command from the numerical controller during automatic insertion operation While controlling the motor of the feed roller to feed the wire electrode, the insertion judgment circuit section is inserted If it is determined that the completion and and a switching circuit section for performing control for switching the tension control of the wire electrode by the motor of the servo feed roller This can be achieved.
[0011]
Also (2) In the above (1), the tension detecting means is disposed between the servo feed roller and the auxiliary feed roller, and includes a guide roller for pressing the traveling wire electrode at the tip of the cantilever, The bending generated in the cantilever due to the reaction force due to the tension of the wire electrode is configured to be detected by a strain gauge. Can also be achieved.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 schematically shows a configuration along the travel route of the wire electrode, and the description of the same configuration as that described in FIG. 6 is omitted. In the present invention, the tension of the wire electrode 1 is controlled by a servo motor, and the servo feed roller 21 corresponds to the brake roller 121 and the feed roller 141 of FIG. This is employed in a wire cut electric discharge machine equipped with at least a servo feed roller 21, a servo feed motor 23 for driving the servo feed roller 21, and a tension detecting means 30.
[0018]
The wire electrode 1 supplied from the wire bobbin 10 is wound around the servo feed roller 21 via the direction changing rollers 15a, 15b and 15c. Back tension is applied to the wire bobbin 10 by the back tension motor 11 even during automatic insertion. Therefore, when buckling occurs during the automatic insertion operation and the servo feed roller 21 is suddenly stopped, the wire bobbin 10 rotates due to inertia, the wire electrode 1 is loosened, and the wire is separated from its travel path. There is no. The servo feed roller 21 having a large diameter is pressed by at least two positions on the entrance side and the exit side by the pinch roller 22a and the pinch roller 22b, so that the wire electrode 1 is against the servo feed roller 21. Without slipping, it is sent downstream at a desired tension or speed. The servo feed roller 21 is driven by a servo feed motor 23, which is a servo motor, and feeds the wire electrode 1 at a predetermined speed as necessary, controls the tension to a constant tension, or suddenly stops as will be described later. . What should be noted here is that the servo feed roller 21 moves the wire electrode 1 in a predetermined manner when an operation of feeding the wire electrode 1 at a high speed and performing automatic insertion (hereinafter referred to as high-speed automatic insertion) is executed. Since the tension is not controlled only by sending the ink downstream at a speed, the wire electrode 1 is not tensioned downstream of the servo delivery roller 21, and a slight pulling force due to the jet liquid flow of the automatic insertion pipe 61 and the auxiliary delivery roller 41 are not applied. Only a slight pulling force is applied, and the tension is slight.
[0019]
Next, the wire electrode 1 is put on a guide roller 31 of a tension detecting means 30 described later, and the direction is changed to a vertical direction, and is sandwiched between an auxiliary feed roller 41 and a pair of pinch rollers 42. . As described above, during execution of the high-speed automatic insertion operation, the wire electrode 1 is hardly tensioned downstream of the servo feed roller 21. Therefore, the auxiliary delivery roller 41 may be provided with a delivery force that is small enough to prevent the wire electrode 1 from slackening upstream, that is, in the vicinity of the tension detection means 30. A very small output AC motor is employed. Further, the pressing force of the opening / closing mechanism 44 of the pinch roller 42 that opens and closes and presses against the auxiliary feed roller 41 may be very small. For example, it is opened and closed by a small-diameter air cylinder. Accordingly, the rotational speed of the auxiliary feed roller 41 always follows the traveling speed of the wire electrode 1. Even when the pinch roller 42 is closed in this way, there is almost no difference in the tension between the upstream and downstream wire electrodes 1 with the auxiliary delivery roller 41 as a boundary, so the downstream wire electrode 1 during high-speed automatic insertion. It is possible to accurately detect the tension change by the upstream tension detecting means 30, and it is possible to always detect the wire tension during automatic insertion. Further, it is possible to eliminate problems such as bending bends on the wire electrode 1 at the position of the auxiliary feed roller 41. The auxiliary feed roller 41 and the pinch roller 42 are not limited to the form of the present embodiment. For example, the wire electrode 1 is restrained with a slight gap and the compressed air is jetted from the slit in the wire feed direction. It may be a ring-shaped guide or the like. Further, when the tension detecting means 30 is not separately provided downstream of the servo delivery roller 21, the traveling resistance of the wire electrode 1 is not generated at the position of the tension detection means 30, so that the auxiliary delivery roller 41 and the pinch roller 42 are provided. It does not have to be, and any wire electrode 1 can be used as long as it can guide the buckle detector 51 without resistance.
[0020]
As shown in FIG. 2, the tension detecting means 30 includes a guide roller 31, a block 32 that pivotally supports the guide roller 31, and a leaf spring that is a cantilever beam that is fixed to the fixed base 34 at the base while the block 32 is attached to the tip. 33 and a strain gauge 35 attached to the leaf spring 33. The guide roller 31 is provided with a V-shaped groove that presses the wire electrode 1 so as not to come off, like the other direction changing rollers 15, and has a shaft 36 at one end of an L-shaped block 32 that is sufficiently rigid with respect to the leaf spring 33. It is pivotally supported by. In such a configuration, the fixed base 34 is attached to the electric discharge machine at a position where the guide roller 31 presses the wire electrode 1, so that the tension causes the leaf spring 33 to be bent. The stress due to this bending is detected by four strain gauges 35 attached to the front and back surfaces of the leaf spring 33. The configuration of the tension detection means 30 is not limited to the form of the present embodiment. In addition, it is not limited to the detection means that actually detects the tension of the wire electrode 1 disposed downstream of the servo feed roller 21, but the load of the feed or take-up load in the servo motor, the feed motor, or the take-off motor that feeds the wire electrode, For example, it may be detected as a fluctuation amount of the current value or as a torsional deformation amount of the motor shaft, and this is converted and detected as a tension.
[0021]
Next, the wire electrode 1 passes through a first buckling detector 51 and a second buckling detector 52 which are appropriately separated as the buckling detection means 50. Each of these has the same structure as the conventional example, but the first buckling detector 51 is fixed, and the second buckling detector 52 is attached to an automatic insertion means 60 described later and moves up and down. By doing so, buckling can be detected by the buckling detector on either side of the upper and lower sides, so that it is easy to detect the buckling even if the mass is very small. Note that the buckling detection means 50 is not limited to the present embodiment, and any device may be used as long as it detects that the automatic insertion has failed and the wire electrode has stopped running by electrical contact or short circuit. It can also be detected from the aforementioned load fluctuation.
[0022]
The automatic insertion means 60 is configured as follows. A gripping device 65 is provided on the upper part of the automatic insertion pipe 61 similar to the conventional one, and a second buckling detector 52 is provided immediately above the gripping device 65, and these are fixed to a lifting platform 62 that moves up and down. The gripping device 65 only needs to be able to clamp the wire electrode 1. For example, a mechanism for pressing and gripping the wire electrode with a rod tip of a small air cylinder 65 a can be employed. A mechanism that opens and closes the fingers by air cylinder drive may be used. The lifting platform 62 is configured to move up and down by an air cylinder 63. Here, the lifting platform 62 is not limited to lifting by the air cylinder 63, but may be lifted by a motor. In the case where the automatic insertion pipe 61 is lowered and the wire electrode 1 is sent out together as will be described later in this alternative embodiment, the lifting motor is adjusted so that the lowering speed of the automatic insertion pipe 61 matches the delivery speed of the wire electrode 1. Since it is rotated, tension control of the servo feed motor 23 as described later is not necessary. The automatic insertion means 60 has been described as an example of an automatic insertion pipe 61 that moves up and down. However, a nozzle is incorporated in the upper guide unit 71, and a jet nozzle type automatic nozzle that automatically inserts a jet liquid flow from this nozzle is shown. Even when the insertion means is employed, the method of the present invention can be employed. The change part by the difference between a pipe jet system and a nozzle jet system is a design change matter of the present invention.
[0023]
Since the configuration downstream from the automatic insertion means 60 is the same as that of the conventional example, this description will be omitted below, and automatic insertion of the servo feed motor 23, tension detection means 30, buckling detectors 51, 52, etc. will be described with reference to FIG. The block configuration of the related control device will be described. Usually, the traveling speed and tension of the wire electrode 1 are input to the numerical control device 300 as a machining program. The numerical control device 300 controls the traveling speed by the take-up motor 83 and the servo feed motor 23 controls the traveling speed. Control the tension. The numerical controller 300 controls the wire delivery control unit 310, and the wire delivery control unit 310 controls the driver 320 that controls the servo delivery motor 23. That is, the wire delivery control unit 310 includes a tension control circuit unit that controls the tension of the wire electrode. In the present invention, in addition to this, the insertion determination circuit unit 315 that determines completion of automatic insertion during the automatic insertion operation and outputs a completion signal and the speed control of the servo feed motor 23 during the automatic insertion operation, A switching circuit unit 316 that switches whether to control is provided. It is preferable that each circuit unit is processed by software.
[0024]
The tension control circuit unit compares the tension set value signal TS from the numerical controller 300 with the tension detection value TM detected by the tension detection means 30 and outputs a tension deviation TD, and the tension deviation A tension compensation circuit unit 313 that outputs TD converted to a speed deviation SD, and a reference speed setting circuit that outputs a reference speed command SR from the speed setting value signal SS and the tension setting value signal TS from the numerical controller 300 311 and an adder circuit 314 that compares the reference speed command SR with the speed deviation SD and outputs a tension converted speed command SC. The tension converted speed command SC is input to the switching circuit 316. In this way, the tension is converted into a speed command for control. Here, the speed set value signal SS is a value corresponding to a speed command for controlling the wire take-up motor 83. When the determination start command TB is input from the numerical control unit 300 immediately after the high-speed automatic insertion operation is started, the insertion determination circuit unit 315 periodically reads the tension detection value TM and performs a predetermined determination as shown in a flowchart described later. Compare with the reference value. When this exceeds a predetermined determination reference value, it is determined that automatic insertion is completed, and an insertion completion signal TF is output. The completion signal TF is also output to the numerical device 300, and the subsequent processing as described later is performed. The switching circuit unit 316 selects and validates one of the input signals from the A and B lines, and usually performs tension control with priority given to the input from the B line. The input to the A line becomes effective when a speed switching command TA is received from the numerical controller 300, and at the same time, the wire electrode feed speed command value SW1 when executing a high-speed automatic insertion operation and the forward transfer speed in the retry operation. Command value SW2 or reverse winding speed command value SW3 is input. When this speed switching command TA is finished or the insertion completion signal TF is received, the input to the A line becomes invalid and the speed control is finished. Naturally, during speed control, the speed of the servo feed motor 23 is fed back to the motor driver 320 by a built-in resolver or encoder. On the other hand, the input to the B line is effective when the A line is not selected. When a tension conversion speed command SC corresponding to a tension value input by a machining program or a insertion completion tension value set in advance as a target value for control after completion of automatic insertion is input, the servo feed motor 23 is set to tension. Be controlled. Here, the insertion completion tension value is larger than the tension before the automatic insertion is completed, and smaller than the tension value required in actual machining. Of course, since the tension is small enough not to be cut even if the tension is applied to the wire electrode having the minimum diameter, there is no disconnection at this stage after the automatic insertion completion determination.
[0025]
If the wire electrode 1 travels during high-speed automatic insertion operation and is bent near the buckling detector, a short circuit signal is generated between the buckling detectors 51 and 52 and the wire electrode 1. This is taken into the numerical control device 300 as a buckling signal BS, and the numerical control device 300 determines that an automatic insertion failure has occurred, and executes a retry operation as shown in a flowchart to be described later.
[0026]
With the above configuration, automatic insertion of the wire electrode is performed as shown in the flowcharts of FIGS. 4 and 5, but the description of the same one as the conventional one is simplified. First, as in the prior art, the take-up motor 83 is activated, a jet liquid flow is ejected, a weak back tension is applied by the back tension motor 11, the auxiliary feed pinch roller 42 is closed, and the auxiliary feed motor 43 is activated (S1, S2). At this time, the end of the wire electrode 1 has not yet been sent out. Next, the wire electrode 1 is clamped by the gripping device 65 (S3), and the servo feed motor 23 is controlled so that the tension of the wire electrode 1 becomes a predetermined set tension described later (S4), while the automatic insertion pipe 61 is covered. The end of the wire electrode 1 is sent out by being lowered by the air cylinder 63 up to the upper surface of the workpiece or close to the lower guide unit 75 (S5). At this time, the weight of the automatic insertion means 60 as a whole and the thrust of the air cylinder 63 are applied to the wire electrode 1 and this is fed back as tension and tension control is performed, so the descending speed of the automatic insertion pipe 61 is controlled as a result of tension control. . Here, a tension converted speed command SC corresponding to the set tension is input to B of the switching circuit unit 316, and the set tension is set to a small value in advance so that the descending speed of the automatic insertion pipe 61 becomes relatively low. It is set and the thrust of the cylinder is adjusted accordingly.
[0027]
After the automatic insertion pipe 61 has been lowered (S6), the clamping of the gripping device 65 is released (S7), and then the servo feed motor 23 is rotated at a high speed so that the end of the wire electrode 1 is moved by the servo feed roller 21. Send out at high speed (S8). At this time, the speed switching command TA is input to the switching circuit unit 316, and the speed command value SW1 input to the A line is valid. Thus, high-speed automatic insertion is executed, but the buckling detectors 51 and 52 detect buckling periodically (just after the routine is omitted in the flowchart) immediately after the start (S9), and tension detection means 30 detects the tension (S10). The tension value detected at this time is a very small tension. The end portion of the wire electrode 1 thus fed out at high speed is inserted into the wire guide of the lower guide unit 72 and finally reaches the take-up device 80 as in the prior art.
[0028]
Here, the pulling speed of the wire electrode 1 by the pulling roller 81 is adjusted to be slightly higher than that by the servo feed roller 21, so that the tension rises when the automatic insertion is successful. When the tension value exceeds a preset determination reference value (S10), the insertion determination circuit unit 315 issues an insertion completion signal TF to the switching circuit unit 316 and the numerical control device 300, so that the switching circuit unit 316 The tension conversion speed command SC corresponding to the insertion completion tension value input to the B line is validated, and the servo feed motor 23 is shifted to tension control (S11). Then, the pinch roller 42 is opened to stop the auxiliary feed motor 43, the automatic insertion pipe 61 is returned to the original position, the jet flow is stopped, and the automatic insertion is finished (S12, S13). If no increase in tension is detected even after a predetermined time T has been set in advance, the servo feed roller 21 and the like are stopped and treated as abnormal (S20, S21, S22). This time t starts to be measured immediately after the automatic insertion is started.
[0029]
When the buckling detector 30 detects buckling as shown in FIG. 5, it is determined that the insertion has failed. In this case, the servo feed motor 23 is stopped (S31), the pinch roller 42 of the auxiliary feed roller 41 is opened and the auxiliary feed roller 41 is stopped (S32), and the torque of the back tension motor 11 is increased. Then, the numerical controller 300 outputs a speed switching command TA to the switching circuit unit 316 and outputs a reverse winding speed command value SW3 to the A line, so that the servo feed motor 23 is reversely rotated at a constant speed to end the wire electrode 1. The part is wound up (S33). After winding up the wire electrode 1 of the fed length (S34), the automatic insertion is retried. First, the torque of the back tension motor 11 is weakened and restored, and the servo feed motor 23 is temporarily stopped (S35). Then, the gripping device 65 is closed, the pinch roller 42 is closed, and the auxiliary feed roller 41 is activated (S36, S37). Next, the numerical controller 300 outputs the speed switching command TA to the switching circuit unit 316 and outputs the forward transfer speed command value SW2 to the A line, so that the servo feed motor 23 moves the end of the wire electrode 1 at a constant speed. (S38). Thus, the wire electrode 1 is fed out by a predetermined amount, the wire electrode 1 is loosened between the buckling detectors 51 and 51 (S39), and then the gripping device 65 is opened and placed on the jet liquid stream ejected at high speed. The end of the wire electrode 1 is inserted at a stroke (S40). Since the bending for the retry is formed in the immediate vicinity of the automatic insertion pipe 61, the subsequent insertion is good.
[0030]
【The invention's effect】
The present invention configured as described above. Wire cut electric discharge machine In this case, the wire electrode insertion state is monitored by the detected tension, and when the detected tension value exceeds a predetermined determination reference value, it is determined that the wire electrode insertion is completed, and the servo feed motor of the servo feed roller is determined. Is switched to tension control, the completion of automatic insertion can be determined more quickly and reliably, and automatic insertion can be terminated early.
[0031]
Also, by monitoring the insertion state of the wire electrode together by buckling, it is possible to quickly determine that the automatic insertion has failed and the progress of the wire electrode has been delayed, and to stop the wire electrode delivery suddenly by the servo delivery motor. Can do. Furthermore, since the back tension may be applied at this time, the wire electrode does not come apart.
[0032]
In addition, the wire electrode is fed out by the large-diameter servo feed roller, and the auxiliary feed roller is fed out by the small-diameter auxiliary feed roller to eliminate the bending of the wire electrode in the vicinity of the tension detecting means. Even if the pinch roller is not opened, the tension detecting means can detect an increase in tension by the take-up device. Further, the wire electrode is not damaged by any of the feeding rollers.
[0033]
Further, in a wire-cut electric discharge machine having an automatic insertion means equipped with an elevating type automatic insertion pipe, the wire electrode feed speed is adjusted between when the automatic insertion pipe is lowered immediately after the start of automatic insertion and after it is lowered. By switching to high speed, the speed of automatic insertion can be increased.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram along a travel route of a wire electrode of an automatic insertion device according to the present invention.
FIG. 2 is a perspective view showing a configuration of tension detecting means according to the present invention.
FIG. 3 is a block diagram of a control device related to automatic insertion according to the present invention.
FIG. 4 is a flowchart showing the control of the automatic control method according to the present invention.
FIG. 5 is a flowchart showing a part of FIG. 4;
FIG. 6 is a schematic configuration diagram along a travel route of a wire electrode of a conventional automatic insertion device.
[Explanation of symbols]
1 Wire electrode
10 Wire bobbins
21 Servo feed roller
23 Servo feed motor
30 Tension detection means
31 Guide roller
33 leaf spring
35 strain gauge
50 Buckling detection means
60 Automatic insertion means
61 Automatic insertion pipe
65 Gripping device
71 Upper guide unit
72 Lower guide unit
80 Pick-up device
90 collection bucket
300 Numerical controller
315 Insertion determination circuit unit
316 switching circuit
1

Claims (2)

A wire bobbin to which a back tension can be applied;
Servo that feeds the wire electrode stored downstream in the wire bobbin downstream from the wire bobbin while winding the wire electrode between the pinch roller on the inlet side and the outlet side of the winding while winding the wire electrode around the peripheral surface of the roller A feeding roller;
Automatic insertion means for inserting the wire electrode delivered by the servo delivery roller from the upper guide unit to the lower guide unit by a jet liquid flow;
A take-up device for taking out the wire electrode inserted into the upper guide unit and the lower guide unit by the automatic insertion means and discharging the taken-out wire electrode to a recovery bucket;
Tension detecting means for detecting the tension of the wire electrode;
Provided on the downstream side of the tension detection means, and in the automatic insertion operation, the wire electrode is rotated in accordance with the traveling speed of the wire electrode and is pressed and pinched between the pinch roller and in the vicinity of the tension detection means. An auxiliary feed roller that performs an auxiliary feed to an extent that eliminates loosening of the wire electrode;
During the automatic insertion operation, the wire electrode tension detected by the tension detection means is detected by detecting the wire electrode insertion state by at least the tension detection means after the wire electrode has been taken up by the take-up device during the automatic insertion operation. An insertion determination circuit unit that determines that automatic insertion has been completed when the value exceeds a predetermined determination reference value;
During the automatic insertion operation, the motor of the servo delivery roller is fed out by controlling the motor of the servo delivery roller according to a command from the numerical control device, and the motor of the servo delivery roller when the insertion determination circuit unit determines that the insertion is completed. A switching circuit unit for performing control to switch to tension control of the wire electrode by,
A wire-cut electric discharge machine characterized by comprising: The tension detecting means is disposed between the servo delivery roller and the auxiliary delivery roller, and includes a guide roller for pressing the traveling wire electrode at the tip of the cantilever, and the reaction force due to the tension of the wire electrode wire-cut electric discharge machine according to claim 1, wherein, characterized in that to constitute a bending caused a cantilever so as to detect by the strain gauges.

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