JP2006231417A - Insertion method for wire electrode and automatic wire connection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely insert a wire electrode into a prepared hole in a short period of time without rewinding the wire electrode to an initial position when the wire electrode is caught. <P>SOLUTION: A feed roller 10 for feeding out the wire electrode 2 is provided to the upper side of an upper wire guide 72. A pipe guide 20, which guides the wire electrode 2 and is capable of freely ascending/descending, is provided between the upper wire guide 72 and the feed roller 10. A jet supply device 50 supplies a jet to a guide pipe 20. A winding roller 30 is a vertically moving means provided between the feed roller 10 and the guide pipe and vertically moving the wire electrode little by little. The winding roller 30 has an eccentric roller 31 and a motor 33 for rotating the eccentric roller. The winding roller 30 repeatedly executes an operation for slightly pulling up the wire electrode 2 while supplying the jet in the guide pipe 20 and an operation for releasing the wire electrode 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wire electrode insertion method and a wire cut electric discharge machining apparatus for automatically inserting a wire electrode into a pilot hole or a machining groove formed in a workpiece when wire electrodes are automatically connected in wire cut electric discharge machining. The present invention relates to an automatic connection device.

  In wire-cut electrical discharge machining, when an unnecessary part (core) is cut out and removed from a workpiece, a wire electrode is inserted into a machining start hole (preparation hole) previously drilled in the workpiece, and the workpiece is removed. It is necessary to connect a wire electrode between a pair of wire guides provided to be sandwiched. Further, when the wire electrode is inadvertently disconnected during processing, the wire electrode needs to be connected again and stretched. Many of the numerically controlled wire-cut electric discharge machining apparatuses are provided with an automatic connection device, and the automatic connection device can automatically insert the wire electrode into the prepared hole.

  In recent precision machining, the prepared hole may have a very small inner diameter that is slightly larger than the wire electrode diameter. Further, when the disconnected wire electrode is inserted, the processed groove may be inserted into the processed groove already formed in the workpiece, but the processed groove is slightly larger than the thickness of the wire electrode by the discharge gap. Most of the wire electrodes are brass wires or tungsten wires having a diameter of 0.3 mm or less, but extremely thin brass wires having a diameter of 0.1 mm or less are often used. Such a wire electrode line has a small rigidity, but is easy to bend and bend easily.

  Therefore, when the diameter or width difference with the wire electrode (hereinafter referred to as clearance) is fed into a pilot hole or machining groove in this way, the tip of the wire electrode is not inserted into the inlet of the pilot hole or machining groove, Alternatively, the wire electrode may be buckled by being caught in the middle of the prepared hole or the processed groove. Moreover, in order to feed as straight as possible, many wire cut electrical discharge machine automatic connection devices have a guide pipe that moves up and down, but the inner diameter of the guide pipe is also very small, so the wire electrode guides It may get caught in the pipe. When the wire electrode buckles due to failure to insert the wire electrode, there is a time lag between the buckling detection of the insertion failure and the delivery of the wire electrode being stopped. In a place where the electrode is not physically constrained by the normal passing locus (traveling route), the electrode jumps out of the traveling route and becomes loose.

  In general, when the insertion of the wire electrode fails, the wire electrode is once wound up and straightened until the slack of the wire electrode is removed by the feed roller, and then the wire electrode is sent out and the insertion is attempted again. This method takes extra time since the wire electrode has to be wound up relatively slowly after winding the wire electrode in order to remove the slackness of the wire electrode, and again, since the wire electrode being sent out has no momentum. There is a high risk of buckling. Therefore, when trying to insert the wire electrode again, a method is considered in which the wire electrode is sent out in a jet flow while the wire electrode is in a relaxed state, and the wire electrode is momentarily passed through the pilot hole while removing the slack. Has been issued. This method is advantageous in that the wire electrode can be easily passed through the pilot hole and the time can be shortened (see Patent Document 1).

  In addition, by providing a buckling prevention mechanism that operates to remove the slack of the wire electrode when the wire electrode is buckled by being caught at the entrance of the pilot hole or the machining groove, the passing position of the wire electrode is set to a normal travel route. A method for forcibly correcting the image so as to be positioned above is known. According to this method, it is possible to reduce the repetition of the operation of inserting the wire electrode, and it is possible to improve work efficiency in automatic connection (see Patent Document 2). Further, there has been considered a method in which compressed air is supplied to give a fine vibration having a predetermined vibration width in the lateral direction to guide the wire electrode to the pilot hole (see Patent Document 3). Furthermore, a method is known in which a pilot hole is automatically searched and the tip of the wire electrode is positioned at the inlet of the pilot hole or the machining groove. According to this method, the wire electrode can be inserted even when the normal travel path of the wire electrode and the axis of the wire electrode that is sent out are shifted from the beginning (see Patent Document 4).

JP 2002-126951 (pages 12-14) Japanese Patent No. 2922272 (page 4) JP 2005-1054 A (pages 6-9) JP-A-4-135423 (pages 4-5)

  The method of feeding the wire electrode together with the jet flow in a slack state is to insert the wire electrode when the clearance between the wire electrode and the pilot hole or machining groove is small, or when the wire electrode is weak and the wire is not very straight and difficult to straighten. The possibility of failure is high, and it is required that the axis of the wire electrode to be fed out and the prepared hole or the machining groove be aligned more strictly. The method of correcting the passage position of the wire electrode so that it is located on the regular travel route requires a special buckling prevention mechanism, the configuration of the automatic connection device becomes relatively complicated, and the momentum to send out the wire electrode is weak Therefore, there is a disadvantage that the wire electrode tends to buckle in the middle of passing through the pilot hole or the machining groove. The method of oscillating the wire electrode or searching for the pilot hole to position the tip of the wire electrode at the inlet of the pilot hole or the machining groove is because the wire electrode is not restrained by the guide pipe before the pilot hole or the machining groove. There is a problem that the wire electrode is easily buckled in the middle of passing through the pilot hole or the machining groove because the wire electrode is difficult to be guided to the hole or the machining groove and the momentum for feeding the wire electrode is weak.

  In these methods, if the wire electrode is caught in the middle of a pilot hole or machining groove, the wire electrode cannot be removed, so the same operation must be performed from the beginning to try again. Don't be. Further, in an automatic connection device that implements such a wire electrode insertion method, in order to make it difficult for the wire electrode to fail to be inserted, the exit of the guide pipe and the entrance of the pilot hole or machining groove are as close as possible. However, the wire-cut electric discharge machine using a so-called die guide as the upper wire guide cannot automatically feed the guide pipe beyond the upper wire guide to the entrance of the pilot hole or machining groove. There is a problem that the success rate of connection decreases.

  In view of the above problems, an object of the present invention is to provide a novel wire electrode insertion method and automatic wire connection device that can reliably insert a wire electrode into a pilot hole or a machining groove in a relatively short time. To do. In particular, to provide a wire electrode insertion method and an automatic wiring device that can more reliably insert a wire electrode into a pilot hole or a machining groove even if the clearance between the wire electrode diameter and the pilot hole or the machining groove is small. With the goal. Several other advantages of the present invention will be specifically described as the embodiments of the invention are described.

  The wire electrode insertion method of the present invention is a wire electrode insertion method that automatically inserts a wire electrode into a pilot hole or a machining groove formed in a workpiece when the wire electrode is automatically connected. Maintaining the state where the wire electrode is slackened between the delivery roller and the guide pipe when bent, the operation of pulling the wire electrode slightly while supplying the jet into the guide pipe and the operation of releasing the wire electrode Repeatedly, the wire electrode is sent out together with the jet flow. Further, the wire electrode insertion method is preferably configured such that the guide pipe or the work piece is repeatedly performed while repeating the operation of slightly lifting the wire electrode while supplying the jet into the guide pipe and the operation of releasing the wire electrode. Is reciprocated horizontally.

  The automatic wire-cutting device of the wire-cut electric discharge machining apparatus according to the present invention is an automatic wire-bonding apparatus of a wire-cut electric discharge machine that automatically inserts a wire electrode into a pilot hole or a machining groove formed in a workpiece. A feed roller provided on the upper side for feeding the wire electrode, a guide pipe which is provided between the upper wire guide and the feed roller and which can be raised and lowered, a jet supply device for feeding a jet to the guide pipe, and a feed roller And a vertically moving means provided between the guide pipe and the guide pipe for vertically moving the wire electrode in small increments. The vertical movement means includes an eccentric roller provided with an eccentric rotation shaft, a motor that rotates the eccentric roller, and a driven roller that is disposed to face the eccentric roller and rotates intermittently according to the rotation of the eccentric roller. It is a winding roller comprising.

  The wire electrode insertion method and automatic wire connection apparatus of the present invention repeat the operations of slightly pulling up the wire electrode and releasing the wire electrode while supplying the jet while the wire electrode is slackened. Gives vertical movement. When the wire electrode is caught in the middle of the guide pipe, pilot hole, or machining groove due to the slight vertical movement of the wire electrode, or when the tip of the wire electrode is slightly detached from the inlet of the pilot hole or machining groove The wire electrode is removed. At this time, since the wire electrode is slack and the jet flow is supplied at the same time, when the wire electrode is caught, the wire electrode is sent out by the jet flow at a stroke as soon as the wire electrode is released. Therefore, even when the wire electrode is caught, it is not necessary to wind up the wire electrode and insert it again, or to search for the pilot hole, and the wire electrode can be reliably inserted into the pilot hole or the processing groove. it can.

  Therefore, the wire electrode can be reliably inserted by a simple operation or a simple configuration, and the time required for automatic connection can be shortened. In particular, even if the wire electrode is buckled, it can be sent out without getting back to the position where the slack of the wire electrode is removed, so there is no need to bring the guide pipe close to the pilot hole or the machining groove, Even if the upper wire guide has a configuration in which the guide pipe cannot pass as in the case of a die guide, the wire electrode can be reliably inserted, so the type of the wire guide is not limited. Further, even if the clearance between the wire electrode and the prepared hole or the machining groove is small, the wire electrode can be inserted reliably. As a result, the present invention has an excellent effect of improving work efficiency in automatic connection.

  FIG. 1 shows an automatic connection device of a wire cut electric discharge machining apparatus according to the present invention. The automatic wire-bonding device 1 includes a feed roller 10 that sends out a wire electrode 2 including a tension mechanism, a guide pipe 20 that can be raised and lowered to guide the wire electrode 2, and a winding roller that is a vertically moving means that moves the wire electrode 2 up and down in small increments 30 and a jet supply device 50 for supplying a high-pressure machining fluid to the guide pipe 20 as a jet. The jet supply device 50 supplies a jet to the guide pipe 20 and supplies the jet to the prepared hole 4 formed in the workpiece 3 through the guide pipe 20.

  The automatic wire connection device 1 also has a tip processing device 40 that cuts and discards the rough tip of the wire electrode 2. The tip processing device 40 holds the cutting device 41 that cuts the wire electrode 2, the disposal box 42 that collects the cutting pieces of the wire electrode 2 that are no longer needed after being cut by the cutting device 41, and the cutting pieces of the wire electrode 2. And a clamping device 43 that conveys to the disposal box 42. The automatic connection device 1 also includes a tip detector 60 that detects the tip of the wire electrode 2 and a buckling detector 70 that detects slackness of the wire electrode 2.

  The wire electrode 2 supply mechanism 5 combines a reel 52 having a brake motor to which a wire bobbin 51 is attached and applies a back tension to the wire electrode 2, a servo pulley 53 that prevents fluctuations in tension, and a tension mechanism that applies tension to the wire electrode. And a breakage detector 54 such as a limit switch that detects the breakage of the wire electrode 2, and a tension detector 55 such as a strain gauge that detects the tension of the wire electrode 2. Further, the discharge mechanism 6 for the wire electrode 2 gives an offset to the traveling path of the wire electrode 2 that is stretched perpendicularly to the workpiece 3 and changes the traveling direction thereof, and the wire electrode 2 with fluid. A conveying device 62 for conveying, a winding roller 63 for winding the wire electrode 2, and a bucket 64 for collecting the used wire electrode 2 are included.

  The wire electrode 2 wound around the wire bobbin 51 is pulled out from the wire bobbin 51, passes through a tension mechanism, and passes through the lower hole 4 from the upper guide unit 7 in which the upper electrical conductor 71 and the upper wire guide 72 are incorporated by the automatic connection device 1. Is inserted. The wire electrode 2 inserted into the lower hole 4 is changed in direction by an idling roller 61 through a lower guide unit 8 in which a lower wire guide and a lower conductive body (not shown) are incorporated. The wire electrode 2 transported by the transport device 62 is captured by the winding roller 63 and is recovered by the bucket 64 by being cut by a cutting machine.

  The feed roller 10 provided on the upper side of the upper wire guide 72 includes a drive roller 12 that rotates forward and backward by a servo motor 11 and a pinch roller 13 that follows the drive roller 12 and presses the wire electrode 2. When the wire electrode 2 is wound up, the feed roller 10 rotates in the reverse direction until the tip of the wire electrode 2 is detected by the tip detector 60. When sending the wire electrode 2, the feed roller 10 rotates forward and slowly sends the wire electrode 2. Further, when the wire roller 2 travels, the feed roller 10 rotates forward at a required speed while receiving a signal from the tension detector 55 and cooperates with the winding roller 63 to apply a predetermined tension to the wire electrode 2. Give.

  The guide pipe 20 is provided between the upper wire guide 72 and the delivery roller 10 and is moved up and down by a lifting device 21 that is operated by an actuator (not shown). When the automatic connection is not performed, the guide pipe 20 rises to the upper limit and stops. When the wire electrode 2 is inserted into the prepared hole 4 or the machining groove, the guide pipe 20 descends to at least directly above the upper wire guide 72 as the wire electrode 2 is fed, and the wire electrode 2 is moved to the upper wire guide 72. invite. When the guide pipe 20 can pass through the upper wire guide 72, the guide pipe 20 descends to a position close to the workpiece 3 with a slight gap, and the wire electrode 2 is previously drilled in the workpiece 3. Guided into the prepared hole 4 or the machining groove already formed in the workpiece 3.

  The winding roller 30 is provided between the feed roller 10 and the guide pipe 20. The winding roller 30 is a vertical movement means for giving a minute vertical movement to the wire electrode in small increments, and repeatedly performs an operation of slightly lifting the wire electrode 2 and an operation of releasing the wire electrode 2. Specifically, the winding roller 30 includes an eccentric roller 31 provided with an eccentric rotation shaft, a driven roller 32 that is disposed so as to be in contact with the eccentric roller 31 and rotates intermittently according to the rotation of the eccentric roller 31, and an eccentric roller 31. The motor 33 rotates the roller 31. The driven roller 32 is separated from the travel path of the wire electrode during processing, and is retracted to a position that does not interfere with the travel of the wire electrode 2. The winding roller 30 is in a state where the wire electrode 2 buckles in the middle of the supply path (traveling path) of the wire electrode 2 and is loosened by protruding from the regular traveling path between the feed roller 10 and the guide pipe 20. Rotate 2 in the direction to wind up.

  Below, the insertion method of the wire electrode 2 of this invention is demonstrated according to operation | movement of the automatic connection apparatus 1 mentioned above. FIG. 2 shows operating states of the feed roller 10 and the winding roller 30 corresponding to the automatic connection process. The member to which the code | symbol corresponding to FIG. 1 was attached | subjected shows the member which has the same function as the member shown by FIG. 1, or has an equivalent effect | action.

  When it is necessary to reconnect the wire electrode 2 due to disconnection or the like, the feed roller 10 is reversed and the wire electrode 2 is wound up until the tip detector 60 detects the tip of the wire electrode 2. Then, the wire electrode 2 is cut by a cutting device 41 such as a cutter, and the cut pieces of the wire electrode 2 that have become unnecessary after being cut are conveyed to the disposal box 42 while being held by the clamp device 43 and discarded.

  As shown in FIG. 2A, the jet electrode is supplied from the jet supply device 50 and the wire electrode is sent out by the feed roller 10 with the axial direction of the wire electrode and the pilot hole or the processing groove aligned. As shown in FIG. 2 (B), when the wire electrode 2 is caught in the middle and buckles and the buckling detector 70 detects the looseness of the wire electrode 2, the feed roller 10 is stopped and the feed roller 10 and A state in which the wire electrode 2 is slackened with the guide pipe 20 is maintained. At the same time, the jet supply device 50 is stopped and the supply of the jet is interrupted. At this time, a control device (not shown) for controlling the feed roller 10 and the buckling detector 70 insert the wire electrode 2 into the prepared hole 4 in consideration of the distance between the upper wire guide 72 and the lower wire guide. It is designed so that the feeding of the wire electrode 2 is stopped when the necessary and sufficient slack length is reached.

  Next, as shown in FIG. 2C, the driven roller 32 is moved from the retracted position to a position in contact with the travel path of the wire electrode 2 while the wire electrode 2 is slack. After that, as shown in FIG. 2D, the eccentric roller 31 of the winding roller 30 is rotated while the jet is supplied from the jet supply device 50 into the guide pipe 20 to slightly lift the wire electrode, Release the wire electrode as shown in (E).

  When the winding roller 30 is actuated, the eccentric roller 31 repeats contacting and moving away from the driven roller 32 as shown in FIGS. 2 (D) and 2 (E). When the eccentric roller 31 is intermittently brought into contact with the driven roller 32, the operation of slightly lifting the wire electrode 2 sandwiched between the eccentric roller 31 and the driven roller 32 and the operation of releasing the wire electrode 2 are repeated alternately. For this reason, the wire electrode 2 is repeatedly pulled up and sent out in a jet stream, and minute pulsations in the vertical direction are generated in the wire electrode 2. This action is similar to the action of a person pinching the wire electrode and pulling it up slightly to poke the tip. Then, the wire electrode 2 is prevented from being caught by the vertical movement of the wire electrode 2 every minute. Alternatively, the tip of the wire electrode 2 is guided to the inlet of the pilot hole 4 by a minute vertical movement of the wire electrode 2 and the restraint force and propulsive force of the jet flow.

  As shown in FIG. 2 (F), the wire electrode 2 from which the obstacle has been removed passes through the pilot hole 4 at once by the jet flow. At the same time, the slack that has occurred between the delivery roller 10 and the guide pipe 20 is eliminated. When the buckling detector 70 stops generating a signal for detecting buckling for a predetermined time, the feed roller 10 is rotated forward to feed the wire electrode 2. The wire electrode 2 is sent to the take-up roller 63 by the transport device 62. And the front-end | tip of the wire electrode 2 is capture | acquired by the winding roller 63, and an automatic connection is completed. Even when the wire electrode 2 to be sent out after removing the obstacle once again gets caught again, as long as the buckling detector 70 outputs a detection signal, the wire electrode 2 repeatedly repeats a minute vertical movement. Because it continues to be given, the obstacle is removed again.

  The wire electrode 2 is held by the delivery roller 10 in a slack state, and the winding roller 30 repeats slight winding and releasing of the wire electrode and tries to send it out by the jet flow. Therefore, the wire electrode moves up and down in small increments. do. Even if the wire electrode is caught in the middle of the guide pipe, pilot hole, or machining groove due to this small vertical movement, even if the tip of the wire electrode is slightly detached from the inlet of the pilot hole or machining groove, the wire electrode is caught. Is removed. Thus, even if the wire electrode 2 is caught in the middle of the pipe guide 20 or the pilot hole 4, it is not necessary to attempt to pass the wire electrode 2 after winding the wire electrode 2 until the slack is removed, and the wire electrode 2 is inserted into the pilot hole 4. Is done.

  As described above, the wire electrode insertion method of the embodiment basically repeats the operations shown in FIG. 2D and FIG. 2E in a short time. The wire electrode 2 can be reliably inserted into the prepared hole 4 and the machining groove by eliminating the wire electrode. In addition, the automatic wire-bonding device of the embodiment is basically strong in the feeding roller 10 that keeps the wire electrode 2 in a relaxed state, the guide pipe 20 that guides the tip of the wire electrode 2 straight, and the wire electrode 2. A jet supply device 50 for providing a restraining force and a propulsive force, and a winding roller 30 including an eccentric roller 31 that moves the wire electrode 2 up and down in small increments by repeatedly pulling up the wire electrode 2 and releasing the wire electrode. Thus, the wire electrode 2 can be inserted into the prepared hole 4 or the processed groove without completely unwinding the wire electrode 2, so that the configuration is simple.

  The wire electrode insertion methods of the above-described embodiments can be combined with other wire electrode insertion methods that can benefit from the present invention. For example, in accordance with the minute vertical movement of the wire electrode 2, it is possible to combine operations in which the workpiece 2 is slightly reciprocated, for example, about several tens of μm to several mm in the XY axis direction (horizontal direction). According to this application method, even when the tip of the wire electrode 2 to be inserted is bent, the wire electrode 2 can be removed and the wire electrode 2 can be inserted into the prepared hole 4 or the machining groove.

  The specific example of the present invention as shown in FIG. 1 shows a preferable configuration for carrying out the present invention. Therefore, the feeding roller 10, the winding roller 30, the tip processing device 40, the buckling detector. Each member such as 70 may have a configuration other than that disclosed in the embodiment as long as it has the same effects as the present invention. For example, instead of the winding roller 30, the same action as the winding roller 30 can be provided by combining the clamping means and an actuator that moves the clamping means up and down for a short distance. Further, for example, the buckling of the wire electrode 2 can be detected also as a counter that measures the delivery time instead of the buckling detector 70 of the embodiment.

  The present invention is applied to an automatic connection device of a wire cut electric discharge machining apparatus. In the present invention, not only a normal wire electrode but also a thin and non-rigid wire electrode can be reliably and efficiently inserted into a pilot hole, a machining groove, and a die guide with a small clearance, and as a result, precision molds and precision parts can be inserted. Contributes to improved processing efficiency and productivity.

It is a front view which shows the general | schematic structure of the whole wire electric discharge machining apparatus provided with the automatic connection apparatus of this invention. It is a schematic diagram which shows operation | movement of the automatic connection apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic connection apparatus 2 Wire electrode 3 Workpiece 4 Prepared hole 5 Supply mechanism 6 Discharge mechanism 7 Upper guide unit 8 Lower guide unit 10 Sending roller 11 Servo motor 12 Driving roller 13 Pinch roller 20 Guide pipe 21 Lifting device 30 Hoisting roller 31 Eccentric roller 32 Followed roller 33 Motor 40 Tip processing device 50 Jet supply device 60 Tip detector 70 Buckling detector 71 Upper current-carrying member 72 Upper wire guide

Claims (4)

In a wire electrode insertion method in which a wire electrode is automatically inserted into a pilot hole or a machining groove formed in a workpiece when the wire electrode is automatically connected, when the wire electrode is buckled, The wire electrode is held in a relaxed state, and while the jet is supplied into the guide pipe, the wire electrode is slightly pulled up and the wire electrode is released repeatedly to repeat the wire electrode. Wire electrode insertion method that sends out the gas along with the jet flow. 2. The guide pipe or the workpiece is reciprocated in a horizontal direction while repeatedly performing an operation of slightly lifting the wire electrode while supplying a jet into the guide pipe and an operation of releasing the wire electrode. The method of inserting a wire electrode as described in 1. In an automatic connection device of a wire-cut electric discharge machining device that automatically inserts a wire electrode into a prepared hole or a machining groove formed in a workpiece, a feed roller that is provided above the upper wire guide and feeds the wire electrode; A guide pipe which is provided between the wire guide and the feed roller and which can be raised and lowered to guide the wire electrode, a jet supply device which supplies a jet to the guide pipe, and a gap between the feed roller and the guide pipe. An automatic wire connection device for a wire cut electric discharge machining apparatus, comprising: a vertical movement means for moving the wire electrode up and down in small increments. The vertical movement means includes an eccentric roller provided with an eccentric rotation shaft, a motor that rotates the eccentric roller, a driven roller that is disposed to face the eccentric roller and rotates intermittently according to the rotation of the eccentric roller. An automatic wire connection device for a wire-cut electric discharge machine according to claim 3, wherein the wire-cut electric discharge machine is a winding roller comprising:

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