JP5479421B2 - Wire electrode cutting device - Google Patents

Description

  The present invention relates to a wire electrode cutting device for a wire electric discharge machine, and more particularly, to a wire electrode cutting device in which a free end portion of a cut wire electrode has a pointed shape so that automatic tensioning of the wire electrode can be performed quickly and reliably. .

  Patent Document 1 describes a wire electrode automatic tensioning mechanism that includes a slit that receives a wire electrode, holds and releases the wire electrode, and a wire cutting means that cuts the wire electrode in the slit. .

  In Patent Document 2, a current is passed through a wire electrode between a pair of electrons arranged separately along the travel path of the wire electrode, the wire electrode is heated between the electrons and a wire electrode is tensioned to provide a wire. A wire cutting device for a wire electric discharge machine that heat cuts an electrode is disclosed.

Japanese Patent Publication No. 5-21692 Japanese Patent No. 4008435

  In the wire electrode automatic tensioning mechanism described in Patent Document 1, no consideration is given to the shape of the free end of the wire electrode when the wire electrode is cut by the wire cutting device. The free end of the wire electrode is crushed or burred as shown in FIG. 3B and easily caught in the wire path of the upper wire guide, the lower wire guide or the wire electrode insertion hole formed in the workpiece. There is a problem that it is difficult to insert the workpiece into the wire electrode insertion hole.

  In the wire cutting device described in Patent Document 2, since a current is passed through the wire electrode and the wire electrode is heated by the electric resistance of the wire electrode itself, at which position of the wire electrode is cut between passing electrons, or Cutting is indeterminate from the point of view of how it is cut, and therefore the wire electrode cannot be cut well. Furthermore, since the entire wire electrode is heated between the electrons, there is a risk that the wire electrode itself will melt if a large voltage is applied between the electrons. However, the time required for the wire electrode cutting process becomes longer. Furthermore, since the entire wire electrode is heated between the electrons, there is a risk that the tip of the cut wire electrode may be bent illegally due to thermal stress.

  The present invention has a technical problem to solve such a problem of the prior art, and the tip of the cut wire electrode has a pointed shape, and the wire electrode is cut while maintaining rigidity without wrinkles. The purpose is to enable automatic and quick electrode tensioning.

In order to achieve the above-mentioned object, according to the present invention, a wire electrode cutting of a wire electric discharge machine that stretches a tension roller, an upper wire guide, a lower wire guide, and a winding roller in this order and cuts the traveling wire electrode. In the apparatus, the wire electrode is sandwiched between the tension roller and the upper wire guide so as to face each other in a non-contact state, and a pair of cutting electrodes each having a needle-like shape are formed between the cutting electrodes. a voltage generating means for generating an arc discharge to cut the wire electrode, wherein the cutting electrode is provided between the upper wire guide, the wire discharge device for discharging by sandwiching the wire electrode, said voltage generating means the Rutoki to generate arc discharge between the cutting electrode, by reversing the tension roller while sandwiching the wire electrode by the wire discharge device, before The wire electrode cutting apparatus and a control means for applying a tension to the wire electrode.

  According to the present invention, since the pair of cutting electrodes having opposing portions formed in a needle shape are arranged to face each other in a non-contact state with the wire electrode interposed therebetween, the arc is stable in a narrow space, and the wire electrode can be connected even at a low output. Good and can be cut in a short time. Then, the wire electrode is cut at the determined local position. In addition, since the wire electrode is cut in a tensioned state, the tip of the cut wire electrode has a pointed shape while maintaining rigidity without wrinkles. It will surely be possible.

It is the schematic of the wire electric discharge machine by embodiment of this invention. It is the schematic which expands and shows a part of wire electrode cutting device. 1 is an enlarged schematic view showing a tip portion of a wire electrode cut according to the present invention. It is the schematic which expands and shows the front-end | tip part of the wire electrode cut | disconnected by the prior art.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic view of a wire electric discharge machine according to a preferred embodiment of the present invention, FIG. 2 is an enlarged view showing a wire electrode cutting device, and FIG. 3 is a wire electrode cut by the wire electrode cutting device. It is an enlarged view of the free end part.

  In FIG. 1, a wire electric discharge machine 10 is attached to the body of the wire electric discharge machine 10, and a wire bobbin 14 as a supply source of the wire electrode 12, a plurality of pulleys 13, a tension roller 30 and a winding as a wire electrode traveling device. A take-up roller 26 is provided. The wire electrode 12 is pulled and traveled across the workpiece W by the tension roller 30 and the winding roller 26 along the travel path of the wire electrode 12 defined by the plurality of pulleys 13.

  The wire electric discharge machine 10 is further attached to the body of the wire electric discharge machine 10 so as to be movable in the X-axis direction and the Y-axis direction orthogonal to each other, and a table (not shown) for mounting and fixing the work W; The feeders 22 and 24 are provided on the upper and lower sides of the table, and the feeders 22 and 24 apply a predetermined machining voltage between the wire electrode 12 and the workpiece W, while The workpiece W is processed into a desired shape by sending the table in the X-axis direction and the Y-axis direction. The operation of each of the table, the tension roller 30 and the take-up roller 26 and the processing voltage to be applied to the power supply 22 and 24 are controlled by a control device 28. The used wire electrode 12 is recovered from the winding roller 26 to a wire electrode recovery device (not shown).

  The wire electric discharge machine 10 further guides and inserts the wire electrode 12 into a wire electrode insertion hole formed in the workpiece W in advance, and upper and lower wire guides 16 and 18 for holding the traveling wire electrode 12 during processing. A wire conveying jet nozzle 20 that forms an automatic tensioning device that drives the tip of the wire electrode 12 toward the upper wire guide 16 and inserts it into the upper wire guide 16, and a wire conveying jet along the travel path of the wire electrode 12. A wire electrode cutting device 40 disposed between the nozzle 20 and the upper wire guide 16, a wire tip detector 32 disposed above the wire electrode cutting device 40, and a wire electrode cutting device 40 disposed below the wire electrode cutting device 40. A wire discharging device 34 is provided. In the present embodiment, the wire electrode cutting device 40 is provided at a stage before the wire electrode 12 is inserted through the workpiece W.

  The wire discharging device 34 includes a pair of fingers 34a that sandwich the wire electrode 12, and an actuator (not shown) such as a fluid cylinder for opening and closing the fingers 34a, for example, a pneumatic cylinder. Further, as shown by a broken line in FIG. 1, the wire discharging device 34 has an engagement position where the finger 34 a is in the traveling path of the wire electrode 12 and can hold the wire electrode 12, and the finger 34 a shown by a solid line is the wire electrode 12. And an actuator (not shown) such as a pneumatic cylinder that moves the wire discharging device 34 back and forth between the retracted position outside the travel path. When the wire discharge device 34 is in the retracted position, the wire discharge device 34 opens the finger 34a, drops the wire electrode piece held by the finger 34a into a wire electrode piece collection device (not shown), and collects it. You can

  The control device 28 includes a servo motor (not shown) that drives a table (not shown) on which the workpiece W is placed and fixed, and a drive motor (not shown) that drives the tension roller 30 and the take-up roller 26. In addition to a control unit (not shown), high-frequency and high-voltage generation is applied to the machining power supply 36 and the wire electrode cutting device 40 for applying a machining voltage between the wire electrode 12 and the workpiece W via the power supply 16 and 18 A device 38 is included. The high-frequency and high-voltage generator 38 as a voltage generator that generates arc discharge that cuts the wire electrode 12 is a power source that can apply a voltage of 3000 to 5000 V to the wire electrode cutter 40 at a frequency of 10 to 300 kHz, for example. be able to.

  Referring to FIG. 2, in the present embodiment, the wire electrode cutting device 40 includes a pair of cutting electrodes 42 and 44. Each of the cutting electrodes 42 and 44 can be formed, for example, from tungsten or graphite into a round bar shape having a diameter of 2 to 3 mm and needle-like tips 42a and 44a. Further, the cutting electrodes 42 and 44 are arranged to face each other with a predetermined distance d across the traveling wire electrode 12. The distance d can be set to 2 to 3 mm, for example.

  After the unused wire bobbin 14 is mounted on the wire electric discharge machine 10, the wire electrode 12 is manually pulled out from the wire bobbin 14, and sequentially inserted into the tension roller 30 and the wire transport jet nozzle 20, and further downward from the wire transport jet nozzle 20. To the wire discharging device 34. At this time, the tip end portion of the wire electrode 12 is held by the fingers 34a of the wire discharging device 34 in the engagement position. Then, the tension roller 30 is reversed so that the tension acts on the wire electrode 12. The tension is, for example, 50 to 500 g depending on the wire electrode diameter. Next, a high voltage is applied at a predetermined frequency from the high frequency high voltage generator 38 of the control device 28 to the cutting electrodes 42, 44 of the wire electrode cutting device 40, and arc discharge occurs between the tips 42a, 44a of the cutting electrodes 42, 44. Occurs and the tip of the wire electrode 12 is melted. The reverse rotation of the tension roller 30 is stopped, the wire discharging device 34 is moved to the retracted position, and the distal end portion of the cut wire electrode 12 is collected by the wire electrode piece collecting device.

  After the tip portion of the wire electrode 12 is cut by the wire electrode cutting device 40, the tension roller 30 is rotated forward, and a carrier fluid, for example, water is supplied to the wire carrier jet nozzle 20, and the carrier fluid is supplied to the wire carrier jet. By ejecting from the nozzle 20, the wire electrode 12 is driven toward the upper wire guide 16. The wire electrode 12 is sequentially inserted into the wire electrode insertion hole of the workpiece W and the lower wire guide 18 toward the winding roller 26, and the tip portion is captured by the nip of the winding roller 26. In this way, the wire electrode 12 is pulled out from the wire bobbin 14 by the winding roller 26 and can travel in a state where a predetermined tension is applied along the traveling path defined by the plurality of pulleys 13.

  When the wire electrode 12 breaks during electric discharge machining, the break position is usually between the upper and lower wire guides 16 and 18. When the tension roller 30 is reversed and the wire tip detector 32 detects the tip portion of the wire electrode 12 that hangs downward from the wire transport jet nozzle 20, the tension roller 30 is rotated forward by a predetermined amount. When the tip portion of the wire electrode 12 is pinched by the fingers 34 a of the wire discharging device 34, tension is applied to the wire electrode 12 by reversing the tension roller 30. In this state, by applying a predetermined cutting voltage between the cutting electrodes 42 and 44 of the wire electrode cutting device 40, an arc discharge is generated between the needle-like tips 42a and 44a of the cutting electrodes 42 and 44, and the wire The tip portion of the electrode 12 is cut. The distal end portion of the cut wire electrode 12 is discharged by the wire discharge device 34 to the wire electrode piece collection device.

  When the wire tip detector 32 cannot detect the tip portion of the wire electrode 12 for some reason, it can be displayed on the display device (not shown) of the wire electric discharge machine 10 or an alarm sound can be generated. . In that case, the operator of the wire electric discharge machine 10 manually inserts the wire electrode 12 into the wire conveying jet nozzle 20 as described above, and the tip of the wire electrode 12 is held by the finger 34a of the wire discharging device 34. Thus, the tip portion of the wire electrode 12 can be cut by the wire electrode cutting device 40 in a state where the tension is applied to the wire electrode 12 by the tension roller 30.

  Also, when the wire electrode 12 is once cut to change the processing position of the workpiece W, the wire electrode 12 is held by the fingers 34a of the wire discharging device 34, and tension is applied to the wire electrode 12 as described above. In this state, the wire electrode 12 is cut by the wire cutting device 40. The portion of the cut wire electrode 12 on the wire bobbin 14 side is automatically stretched again by the wire transport jet nozzle 20 as described above. The portion of the cut wire electrode 12 on the front end side (winding roller 26 side) is collected by the wire electrode collecting device by the winding roller 26.

  According to the present embodiment, the cutting electrodes 42 and 44 of the wire electrode cutting device 40 are arranged so that the needle-like tips 42a and 44a are opposed to each other. 12 can be cut well in a short time. Moreover, it cut | disconnects in the defined local position. Further, since the wire electrode 12 is cut in a state where tension is applied, the tip of the cut wire electrode has a cusp shape without any wrinkles and with rigidity as shown in FIG. 3A. As a result, the operation of inserting the wire electrode 12 into the upper wire guide 16, the wire electrode insertion hole of the workpiece W, and the lower wire guide 18 by the subsequent wire conveyance jet nozzle 20 is ensured.

DESCRIPTION OF SYMBOLS 10 Wire electric discharge machine 12 Wire electrode 16 Upper wire guide 18 Lower wire guide 20 Wire conveyance jet nozzle 26 Winding roller 28 Control apparatus 30 Tension roller 34 Wire discharge apparatus 36 Processing power supply 38 High frequency high voltage generator 40 Wire electrode cutting apparatus 42 Cutting electrode 44 Cutting electrode

Claims (1)

In the wire electrode cutting device of the wire electric discharge machine that stretches the tension roller, the upper wire guide, the lower wire guide, and the winding roller in this order and cuts the traveling wire electrode,
A pair of cutting electrodes that are arranged in a non-contact state with the wire electrode sandwiched between the tension roller and the upper wire guide, and each opposing portion is formed in a needle shape,
Voltage generating means for generating arc discharge for cutting the wire electrode between the cutting electrodes;
A wire discharging device that is provided between the cutting electrode and the upper wire guide, and pinches and discharges the wire electrode;
Control means for said voltage generating means Rutoki to generate arc discharge between the cutting electrode, by reversing the tension roller while sandwiching the wire electrode by the wire discharge device, applies tension to the wire electrode,
A wire electrode cutting device comprising:

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