Abstract:
To provide a wire electrode removal device of a wire electric discharge machine, the wire electrode removal device including a wire-electrode guide unit that guides an end on a cut point side of a wire electrode cut by wire-electrode cut devices to outside of a running path, a rewind shaft that pressure-fixes the wire electrode on the cut point side guided by the wire-electrode guide unit with an end face thereof and rewinds the wire electrode on a columnar member having angular portions with subsequent rotational driving thereof, a rewind-shaft drive unit that drives the rewind shaft to perform pressure fixing or pressure releasing of the wire electrode with the rewind shaft, a scraper member that removes a wound wire electrode from the columnar member at a time of pressure releasing of the rewind shaft by the rewind-shaft drive unit, and a collection member that collects the removed wire electrode.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage of International Application No. PCT/JP2012/051818 filed Jan. 27, 2012, the contents of which are incorporated herein by reference in their entirety. 
     FIELD 
     The present invention relates to a wire electrode removal device that removes a wire electrode cut in a wire electric discharge machine. 
     BACKGROUND 
     A wire electric discharge machine generates an electric discharge by applying a pulse voltage between a wire electrode that is laid in a tensioned state between upper and lower wire-electrode guide units, and a workpiece and machines the workpiece into an arbitrary shape as by a jig saw while relatively moving the workpiece and the upper and lower wire-electrode guide units. 
     At the time of a wire electrode connection operation or wire electrode breakage handling during machining by the wire electric discharge machine, a wire electrode needs to be cut and removed, and removal of the wire electrode is performed by a technology described in any of Patent Literatures 1 to 5, for example. 
     CITATION LIST 
     Patent Literatures 
     
         
         Patent Literature 1: Japanese Patent Application Laid-open No. 2005-096049 
         Patent Literature 2: Japanese Patent Application Laid-open No. 63-120034 
         Patent Literature 3: Japanese Patent Application Laid-open No. 63-123632 
         Patent Literature 4: Japanese Patent Application Laid-open No. 2-237724 
         Patent Literature 5: Japanese Patent Application Laid-open No. 2-167622 
       
    
     SUMMARY 
     Technical Problem 
     In Patent Literature 1, a wire electrode cut by a wire-electrode cut device is sandwiched by a driving block and then the driving block is horizontally moved to recover the wire electrode in a predetermined wire-electrode collection box. However, wire electrodes that can be recovered are limited by a horizontal movement distance of the driving block and long wire electrodes cannot be removed. 
     If a long wire electrode remains between a upper wire-electrode guide and a lower wire-electrode guide, it is necessary to rotate a wire feeding roller in an opposite direction to that of feeding to rewind the wire electrode to obtain a wire electrode with the same length as the horizontal movement distance of the driving block or a smaller length, and then cut the wire electrode using the wire-electrode cut device to remove the wire electrode. Therefore, an automatic connection time becomes longer. 
     Furthermore, wire electrodes to be removed are substantially linear and a wire-electrode collection box according to lengths of the wire electrodes is required, which wastes a working space. 
     Patent Literature 2 discloses a wire electrode removal device that sucks and removes long wire electrodes. However, wire electrodes that can be used in a wire electric discharge machine generally have diameters φ from 0.1 to 0.3 and accordingly a large-scaled suction device that can suck thick wire electrodes (φ=0.3, for example) is required even if a thin wire electrode (φ=0.1, for example) is to be sucked, resulting in an excess performance. Furthermore, wire electrodes to be removed are substantially linear and a wire-electrode collection box according to lengths of the wire electrodes is required, which wastes a working space. 
     Patent Literatures 3 and 4 disclose a wire electrode removal device that removes a long wire electrode by feeding a wire electrode being sandwiched by belts or rollers. However, also in the case of Patent Literatures 3 and 4, wire electrodes to be removed are substantially linear and a wire-electrode collection box according to lengths of the wire electrodes is required, which wastes a working space. 
     Patent Literature 5 discloses a technology that enables to remove a long wire electrode by rewinding the wire electrode on a fork-like electrode-sandwiching unit at the time of wire electrode removal. Because the fork-like electrode-sandwiching unit sandwiches the wire electrode, however, when a notch of the fork-like electrode-sandwiching unit is smaller than a wire electrode diameter, the notch cannot be located at a wire-electrode running position not to interfere with the wire electrode during electric discharge machining and accordingly a movement distance of the fork-like electrode-sandwiching unit needs to be increased, which prevents downscaling of a cylinder. Meanwhile, when the fork-like electrode-sandwiching unit is made larger than a wire electrode diameter to downscale the cylinder, the wire electrode cannot be securely sandwiched and cannot be rewound. 
     When the wire electrode is to be rewound by the folk-like electrode-sandwiching unit, a rotation-position detection device needs to be mounted on a motor to prevent the wire electrode from being unwound due to its own spring property and falling from the folk-like electrode-sandwiching unit, or to install the notch of the folk-like electrode-sandwiching unit not to be in contact with the wire electrode during electric discharge machining, which complicates the mechanism. 
     Furthermore, the fork-like electrode-sandwiching unit pulls the wire electrode up in an outer-peripheral tangent direction of the fork-like electrode-sandwiching unit and thus the center of a wire guide is located at the notch of the fork-like electrode-sandwiching unit. Accordingly, the wire electrode can be rewound roughly perpendicularly to the wire guide but cannot be rewound exactly perpendicularly thereto, which may cause breakage of the wire electrode. 
     The present invention has been achieved to solve the above problems, and an object of the present invention is to provide a wire electric discharge machine and a wire electrode removal device that can remove long wire electrodes, reduce an automatic connection time, and minimize the possibility of breakage of wire electrodes. 
     Another object of the present invention is to downscale a wire-electrode collection box by compactly wrapping up removed wire electrodes to ensure a working space. 
     Solution to Problem 
     There is provided a wire electric discharge machine according to the present invention including: a wire-electrode cutting unit that is placed on a running path of a wire electrode to cut the wire electrode; and a removal unit that removes a wire electrode cut by the wire-electrode cutting unit from the running path, wherein the removal unit includes a wire-electrode guide unit that guides an end on a cut point side of the wire electrode cut by the wire-electrode cutting unit to outside of the running path, a rewind shaft that pressure-fixes the wire electrode on the cut point side guided by the wire-electrode guide unit with an end face thereof, and rewinds the wire electrode on a columnar member having angular portions with subsequent rotational driving, a rewind-shaft drive unit that drives the rewind shaft to perform pressure fixing or pressure releasing of the wire electrode with the rewind shaft, a scraper member that removes the wound wire electrode from the columnar member at a time of pressure releasing of the rewind shaft by the rewind-shaft drive unit, and a collection member that collects the removed wire electrode. 
     Advantageous Effects of Invention 
     The present invention has unprecedented significant effects such that long wire electrodes can be removed, an automatic connection time can be reduced, the possibility of breakage of wire electrodes is minimized, and that removed wire electrodes are compactly wrapped up to downscale a wire-electrode collecting box and to ensure a working space. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an explanatory diagram of a wire electrode automatic-connection device and a wire electrode removal device in a wire electric discharge machine. 
         FIG. 2  is a perspective view of a configuration of the wire electrode removal device. 
         FIG. 3  is an operation explanatory diagram of an operation of the wire electrode removal device. 
         FIG. 4  is an operation explanatory diagram of an operation of the wire electrode removal device. 
         FIG. 5  is an operation explanatory diagram of an operation at the time of rewinding and removing a wire electrode. 
         FIG. 6  is a perspective view for explaining an operation of the wire electrode removal device. 
         FIG. 7  is a perspective view for explaining an operation of the wire electrode removal device. 
         FIG. 8  is a configuration diagram of a configuration of a rewind shaft and a rewind shaft scraper. 
         FIG. 9  depicts a configuration of a rewind-wire-electrode guide. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A wire electrode removal device and a wire electric discharge machine according to the present invention will be explained below in detail with reference to the accompanying drawings. 
     First Embodiment 
       FIGS. 1 and 2  are explanatory diagrams of a wire electrode automatic-connection device and a wire electrode removal device in a wire electric discharge machine. 
     A wire electrode  1  is fed with rotation of a wire-electrode feed roller  3  to be laid in a tensioned state between an upper wire-electrode guide unit  4  and a lower wire-electrode guide unit  5  that determine a position of the wire electrode, an electric discharge is generated due to a pulse voltage applied between a workpiece  2  and the upper and lower wire-electrode guide units  4  and  5 , and the workpiece is machined into an arbitrary shape as by a jig saw while the workpiece  2  and the upper and lower wire-electrode guide units  4  and  5  are relatively moved. 
     During machining, the wire electrode  1  is passed through a machining start hole of the workpiece  2  from the upper wire-electrode guide unit  4  and is automatically connected to a wire-electrode collection roller  27  that collects the wire electrode  1 , by the wire electrode automatic-connection device including the wire-electrode feed roller  3  and a wire-electrode guide pipe  6 . 
     The wire electrode  1  needs to be cut at the end of the machining, at the time of breakage of the wire electrode that is performing machining, when connection by the wire-electrode automatic-connection device fails because the wire electrode  1  is jammed on the upper wire-electrode guide unit  4 , the lower wire-electrode guide unit  5 , or the workpiece  2 , or the like. Accordingly, there is provided a wire-electrode cut device that cuts the wire electrode  1  through electric heating while pressing the wire electrode  1  against a conducting cut member  7  using a cut-wire-electrode holder  8  in association with an operation of a cut cylinder  9 . 
     The wire-electrode cutting method can be other methods instead of electric heating, such as cutting by a blade. 
     When the wire electrode  1  is broken during electric discharge machining, the wire electrode  1  remaining on a collection side from a breaking point, that is, on a side of the wire-electrode collection roller  27  is collected and removed by the wire-electrode collection roller  27  in a wire-electrode running direction during the wire electric discharge machining. 
     On the other hand, the wire electrode  1  remaining on a wire feed side from the breaking point, that is, between the wire-electrode cut device and the lower wire-electrode guide unit  5 , or the like is cut by the wire-electrode cut device, and the wire electrode remaining between the wire-electrode cut device and the lower wire-electrode guide unit  5  needs to be removed. The cut wire electrode  1  can be removed by the wire-electrode cut device explained in the present embodiment, and then the remaining wire electrode can be passed again through the machining start hole of the workpiece by the wire-electrode automatic-connection device. 
     Also when connection by the wire-electrode automatic-connection device at an initial stage of the machining is not successfully performed, as well as when the wire electrode  1  is broken during electric discharge machining, the wire electrode is cut and the cut wire electrode  1  needs to be removed by the wire electrode removal device in the same manner as mentioned above. 
     In the wire electrode removal device, a rewind-wire-electrode guide  10  serving as a wire-electrode guide unit placed at a wire-electrode running position rotates around a rewind-wire-electrode guide shaft  11  to guide the wire electrode  1  cut by the wire-electrode cut device to a rewind shaft unit, the wire electrode  1  is sandwiched between a rewind shaft  16  having angular portions and a rewind roller  21  in the rewind shaft unit, the rewind roller  21  is rotated to cause the rewind shaft  16  to follow, and the wire electrode  1  is wound on the rewind shaft  16  to rewind the wire electrode  1  perpendicularly to the wire guide and remove the wire electrode  1 . 
     When being rewound, the wire electrode  1  is held and applied with load by a rewind-wire-electrode holding upper-unit  14  and a rewind-wire-electrode holding lower-unit  15  to be pressed against the angular portions of the rewind shaft  16 . The wire electrode  1  is plastically deformed to reduce the spring property of the wire electrode itself, so that a long wire electrode is removed with being compactly wrapped up. 
     A configuration of the wire electrode removal device according to the present embodiment is explained next in detail. 
     In the drawings, reference sign  10  denotes the rewind-wire-electrode guide located at a wire-electrode running position, which rotatingly moves around the rewind-wire-electrode guide shaft  11  through interaction with a pinion  12  mounted on the rewind-wire-electrode guide shaft  11  with a horizontal movement of a rewind-wire-electrode guide cylinder  13  with a rack. 
     The rewind-wire-electrode guide  10  has a through hole formed along a wire-electrode running path, through which the wire-electrode guide pipe  6  passes at the time of automatic connection, and the wire electrode  1  is run on the wire-electrode running path to perform electric discharge machining, during a wire-electrode non-removal time when the rewind-wire-electrode guide cylinder  13  with a rack does not horizontally move. 
     The rewind-wire-electrode guide  10  has a substantially L-shaped member having a notch formed therein, and has such a function that the notch of the L-shaped member is inclined to fall over the rewind shaft unit and guides the wire electrode  1  to the rewind shaft unit during a wire-electrode removal time when the rewind-wire-electrode guide cylinder  13  with a rack horizontally moves. 
     During wire electrode removal, the wire electrode  1  is positioned and held by the rewind-wire-electrode holding lower-unit  15  provided in the rewind shaft unit and the rewind-wire-electrode holding upper-unit  14  of the rewind-wire-electrode guide  10  formed at a position facing the rewind-wire-electrode holding lower-unit  15  to be applied with load at the time of sliding when the wire electrode  1  is to be rewound, which is explained later. 
     While the rewind-wire-electrode holding upper-unit  14  and the rewind-wire-electrode holding lower-unit  15  are suitably made of a high hardness material such as a ceramic material to slide the wire electrode  1 , a rubber material or a resin material that can apply higher load to the wire electrode can be alternatively used. While the shape of these units is suitably a V-shaped groove for positioning, an inclined shape, a circular shape, or the like can be alternatively used. 
     In addition, while the rewind-wire-electrode holding upper-unit is attached to the rewind-wire-electrode guide and is arranged to operate together with the rewind-wire-electrode holding lower-unit with rotational driving, it is needless to mention that a cylinder for holding a rewind wire electrode different from the rewind-wire-electrode guide cylinder can be arranged to hold the wire electrode. 
     A configuration of the wire electrode removal device on the side of the rewind shaft unit is explained next with reference to  FIG. 2 . 
     Reference sign  16  denotes the rewind shaft, for example, in a box shape suitable for sandwiching the wire electrode, having angular portions for rewinding and removing the wire electrode  1 . The rewind shaft  16  is effective in pressing the wire electrode  1  against thereto to plastically deform the wire electrode  1 , and reducing the spring property of the wire electrode itself as long as the rewind shaft  16  has angular portions such as a triangular shape, a star shape, or a plate shape. Reference sign  17  denotes a rewind shaft housing that keeps the rewind shaft  16  therein, which is fixed to a rewind shaft bearing  18  that enables rotation of the rewind shaft  16  and can be horizontally moved by a rewind shaft cylinder  19  serving as a rewind-shaft drive unit, together with the rewind shaft bearing  18 . 
     Reference sign  20  denotes a rewind shaft scraper through which the rewind shaft  16  passes and that scrapes the wire electrode  1  wound around the rewind shaft  16 , from the rewind shaft  16 . 
     Reference sign  21  denotes the rewind roller that is located at a position facing the rewind shaft  16  to sandwich the wire electrode  1  by working together with the rewind shaft  16  and to cause the rewind shaft  16  to follow. The rewind roller  21  is fixed to a rewind roller shaft  22  and rotated by driving of a rewind motor  23 . The rewind motor  23  can be directly connected to the rewind shaft  16  to directly rotate the rewind shaft  16  by driving of the rewind motor  23 . 
     Reference sign  24  denotes a removed-wire-electrode guide member that guides the scraped wire electrode  1  to a wire-electrode collection box  25 . An air flow path can be provided to the removed-wire-electrode guide member  24  to blow the scraped wire electrode  1  to the wire-electrode collection box  25 . 
     Reference sign  26  denotes wire-electrode holding rollers that are driven at the time of wire electrode cutting and hold the wire electrode  1  to facilitate the cutting. The wire-electrode holding rollers  26  serve as a guide when the wire electrode is pulled perpendicularly to the lower wire-electrode guide at the time of wire electrode removal. 
     An operation of cutting and removing a wire electrode performed in the wire electric discharge machine according to the present invention is explained next. 
     When wire electrode automatic connection fails or the wire electrode  1  is broken due to electric discharge machining, the wire electrode  1  is cut by the wire-electrode cut device including the conducting cut member  7 , the cut-wire-electrode holder  8 , and the cut cylinder  9  (see  FIG. 3 ). 
     An end of the wire electrode  1  cut by the wire-electrode cut device is in a state where it passes through the through hole of the rewind-wire-electrode guide  10  and is supported thereby. 
     A horizontal movement of the rewind-wire-electrode guide cylinder  13  with a rack is then converted into a rotational movement by the pinion  12 , which rotates the rewind-wire-electrode guide  10  by substantially 90 degrees on the rewind-wire-electrode guide shaft  11 , so that the end of the cut wire electrode  1  is guided to the rewind shaft unit in a state where it is sandwiched by the wire-electrode holding rollers  26  (see  FIG. 4 ). 
     A cross-sectional view of the rewind-wire-electrode guide  10  in a state of being guided to the rewind shaft unit is shown in  FIG. 5 . 
     As shown in  FIG. 5 , the wire electrode  1  on the side of the cut end is supported by the through hole of the rewind-wire-electrode guide  10  and by a sandwiching point between the rewind-wire-electrode holding upper-unit  14  and the rewind-wire-electrode holding lower-unit  15  shown in the right part of  FIG. 5 . 
     The rewind-wire-electrode holding upper-unit  14  and the rewind-wire-electrode holding lower-unit  15  ideally have a V-groove shape. The spring property of the wire electrode  1  itself can be reduced more and the wire electrode  1  can be wrapped up more compactly in a case where a position of winding on the rewind shaft  16  is limited, which is explained later. 
     Thereafter, the wire electrode  1  guided to the rewind shaft unit is located at the notch of the rewind-wire-electrode guide  10 , the rewind shaft  16  is horizontally driven by the rewind shaft cylinder  19 , the rewind shaft  16  is inserted into the notch, and the wire electrode  1  is sandwiched between an end face of the rewind shaft  16  and the rewind roller  21  placed at a position facing the rewind shaft  16  (see  FIG. 6 ). 
     Sandwiching of the wire-electrode holding rollers  26  is released and then the rewind motor  23  attached to the rewind roller shaft  22  is rotatingly driven with the wire electrode sandwiched, which causes the rewind roller  21  to rotate and the rewind shaft  16  to follow. As a result, the wire electrode  1  to be removed is rewound on the rewind shaft  16  and thus even a long wire electrode can be rewound. 
     Because the wire electrode  1  is sandwiched between the rewind-wire-electrode holding upper-unit  14  and the rewind-wire-electrode holding lower-unit  15  at that time, the wire electrode  1  can be effectively rewound on the rewind shaft  16  with sufficient load applied by the rewind shaft  16  having the angular portions to the wire electrode  1  to be plastically deformed, and the rewound wire electrode  1  is compactly wrapped up because of plastic deformation (see  FIG. 7 ). 
     When the rewind shaft  16  has a smaller diameter, the wire electrode  1  can be more compactly wrapped up during rewinding of the wire electrode  1  on the rewind shaft  16 . 
     When the rewind shaft  16  and the rewind shaft scraper  20  have a concave polygonal shape with concave and convex portions and the rewind shaft  16  is placed to fit the rewind shaft scraper  20  as shown in  FIG. 8 , the wire electrode  1  wound on the rewind shaft  16  can be more reliably scraped. 
     After the rewind-wire-electrode guide  10  is returned to the original position, the rewind shaft  16  is horizontally driven by the rewind shaft cylinder  19  and the wire electrode  1  wound on the rewind shaft  16  is scraped from the rewind shaft  16  by the rewind shaft scraper  20 . The removed wire electrode  1  is guided by the removed-wire-electrode guide member  24  to the wire-electrode collection box  25 . 
     To guide the removed wire electrode  1  to the wire-electrode collection box  25 , an air flow path can be provided to the removed-wire-electrode guide member  24  to blow the scraped wire electrode  1  to the wire-electrode collection box  25 . 
     According to the present embodiment, the scraped wire electrode is compactly wrapped up and the wire-electrode collection box  25  can be downscaled. 
     The position of the wire electrode  1  is remained by the wire-electrode holding rollers  26  without changing from the wire running position and the wire electrode can be rewound perpendicularly to the upper wire-guide unit, thereby preventing breaking of the wire electrode during rewinding. 
     While pressure fixing or releasing of the wire electrode by driving of the rewind shaft  16  in the horizontal direction has been explained, the direction of the driving is not limited to the horizontal direction and any direction such as a vertical direction can be applied to the present embodiment as long as a mechanism that can appropriately perform pressing, releasing, and rotation of the wire electrode is used. 
     Second Embodiment 
     In the first embodiment, when the cut wire electrode  1  is to be rewound on the rewind shaft  16 , the wire electrode  1  is sandwiched between the rewind-wire-electrode holding upper-unit  14  and the rewind-wire-electrode holding lower-unit  15  and is rewound with load applied thereto. At that time, when an air pressure to the rewind-wire-electrode guide cylinder  13  with a rack is variable according to the diameter of the wire electrode  1  to enable adjustment of the load, thereby performing load adjustment by the rewind-wire-electrode holding upper-unit  14  and the rewind-wire-electrode holding lower-unit  15  according to the diameter of the wire electrode  1 , breaking of the wire electrode during rewinding is also prevented and how the rewound wire electrode  1  is wrapped up can be adjusted. 
     The same effect is obtained when the wire electrode  1  is sandwiched by the wire-electrode holding rollers  26 , load is applied to the wire electrode  1 , and the load is adjusted during rewinding. 
     Third Embodiment 
       FIG. 9  is an enlarged view of relevant parts of the rewind-wire-electrode holding upper-unit  14  and the rewind shaft  16 . In a third embodiment of the present invention, concave portions as shown in  FIG. 8  are formed on the rewind shaft  16 . When the cut wire electrode  1  is rewound while being sandwiched between the rewind-wire-electrode holding upper-unit  14  and the rewind shaft  16  during rewinding of the wire electrode  1  on the rewind shaft  16 , the wire electrode  1  can be rewound being folded on the angular portions of the rewind shaft  16 . 
     Similarly to the second embodiment, the air pressure to the rewind-wire-electrode guide cylinder  13  with a rack can be variable to adjust load and how the rewound wire electrode  1  is wrapped up can be adjusted by load adjustment according to the diameter of the wire electrode  1 . 
     INDUSTRIAL APPLICABILITY 
     The present invention relates to a wire electric discharge machine including a wire electrode removal device, and in the present invention, long wire electrodes can be removed, an automatic connection time can be reduced, the possibility of breakage of wire electrodes is minimized, and removed wire electrodes are compactly wrapped up to downscale a wire-electrode collecting box to ensure a working space.