Patent Publication Number: US-2023141769-A1

Title: Workpiece switching jig and cutting system

Description:
FIELD 
     Embodiments described herein relate generally to a workpiece switching jig and a cutting system. 
     BACKGROUND 
     A wire electric discharge machine is known as one of the cutting machines for cutting a workpiece. In a wire electric discharge machine, a workpiece (workpiece to be processed) is placed in a work tank filled with a working fluid, and the workpiece can be cut by utilizing the discharge phenomenon that occurs between a conductive wire electrode and the workpiece. 
     If a cut-off portion cut off from the workpiece by the wire electric discharge machine is dropped into the work tank, when an arm is operated to move the wire, the arm interferes with the cut-off portion dropped into the work tank, and the mechanism including the arm may be damaged. Therefore, various techniques have been proposed to prevent the cut-off portion from dropping into the work tank. For example, Patent Literature 1 discloses a method in which a robot holds the workpiece and the cut-off portion. In this method, it is necessary to make the movement of the robot follow the movement of the wire, which makes the control complicated, and may be a factor that makes the processing accuracy less than the processing accuracy of the wire electric discharge machine. In addition, the robot may come into contact with a structure of the wire electric discharge machine during processing and damage the structure. Limiting the operating range of the robot can reduce the possibility that the robot comes into contact with the wire electric discharge machine, but it also limits the operating range of the wire, and thus reduces the processing range. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Unexamined Patent Application Publication No. 61-8224 
     SUMMARY OF INVENTION 
     Technical Problem 
     Therefore, it is desired to easily collect the cut-off portion cut off from the workpiece. 
     Solution to Problem 
     A workpiece switching jig according to one aspect of the present disclosure is attachable to and detachable from a cutting machine and holds a workpiece to be cut by the cutting machine. The workpiece switching jig includes a jig main body configured to hold the workpiece, a cut-off portion basket configured to receive a cut-off portion cut from the workpiece by the cutting machine, and an arm configured to support the cut-off portion basket with respect to the jig main body. 
     Advantageous Effects of Invention 
     According to this aspect, the cut-off portion can be easily collected for each cutting process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side view showing a configuration of a cutting system according to the present embodiment. 
         FIG.  2    is a plan view of the cutting system shown in  FIG.  1   . 
         FIG.  3    is a view shows a table of a wire electric discharge machine shown in  FIG.  1   . 
         FIG.  4    is a perspective view showing an example of a workpiece switching jig shown in  FIG.  2   . 
         FIG.  5    is a plan view of the workpiece switching jig shown in  FIG.  3   . 
         FIG.  6    is an end view of an A-A′ section showing an example of a cut-off portion basket shown in  FIG.  5   . 
         FIG.  7    is an end view of the A-A′ section showing another example of the cut-off portion basket shown in  FIG.  5   . 
         FIG.  8    is an end view of the A-A′ section showing another example of the cut-off portion basket shown in  FIG.  5   . 
         FIG.  9    is an end view of a B-B′ section showing an example of the cut-off portion basket shown in  FIG.  5   . 
         FIG.  10    is an end view of the B-B′ section showing another example of the cut-off portion basket shown in  FIG.  5   . 
         FIG.  11    is a perspective view showing another example of the cut-off portion basket shown in  FIG.  5   . 
         FIG.  12    is a view showing an example of a structure for adjusting the relative position of the cut-off portion basket with respect to a jig main body shown in  FIG.  3   . 
         FIG.  13    is a view showing another example of the structure for adjusting the relative position of the cut-off portion basket with respect to the jig main body shown in  FIG.  3   . 
         FIG.  14    is a view showing another example of the structure for adjusting the relative position of the cut-off portion basket with respect to the jig main body shown in  FIG.  3   . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a cutting system according to the present embodiment will be described with reference to the drawings. In the following description, constituent elements having substantially the same function and configuration are denoted by the same reference numeral, and a repetitive description will be given only where necessary. 
     (Configuration of Cutting System  10 ) 
     As shown in  FIGS.  1  and  2   , a cutting system  10  according to the present embodiment includes a wire electric discharge machine  30  that cuts a workpiece W, a storage shelf  50  that stores a plurality of workpiece switching jigs  20  in a state of holding the workpiece W, a robot arm mechanism  40  that transports the workpiece switching jigs  20  between the storage shelf  50  and the wire electric discharge machine  30 , and a disposal bucket  60  in which a cut-off portion W 2  cut off from the workpiece W is discarded. Typically, the robot arm mechanism  40  is arranged between the storage shelf  50  and the wire electric discharge machine  30 , and the disposal bucket  60  is arranged on the transport path of the workpiece switching jigs  20  between the robot arm mechanism  40  and the storage shelf  50 . 
     The wire electric discharge machine  30  can be replaced with another cutting machine such as a saw blade cutting machine having a function of cutting the workpiece W. Further, the robot arm mechanism  40  can be replaced with another type of transport loader mechanism having a function of transporting the workpiece switching jigs  20 . 
     (Cutting Procedure Using Cutting System  10 ) 
     The cutting procedure of the workpiece W using the cutting system  10  according to the present embodiment is as follows. The storage shelf  50  stores a plurality of workpiece switching jigs  20  in a state of holding the workpiece W before cutting. 
     First, the robot arm mechanism  40  holds a workpiece switching jig  20  stored in the storage shelf  50 , transports the workpiece switching jig  20  into a work tank  31  of the wire electric discharge machine  30 , and attaches the workpiece switching jig  20  to a chuck member  35  of a table  33  in the work tank  31  (see  FIG.  3   ). When the workpiece switching jig  20  is attached to the chuck member  35 , the wire electric discharge machine  30  starts cutting the workpiece W. Upon completion of the cutting by the wire electric discharge machine  30 , the workpiece switching jig  20  in a state of holding a workpiece W 1  after cutting and a cut-off portion W 2  cut off from the workpiece W before cutting is removed from the chuck member  35  of the table  33  in the work tank  31  and transported to and stored in the storage shelf  50  by the robot arm mechanism  40 . 
     The cut-off portion W 2  held by the workpiece switching jig  20  is released to the disposal bucket  60  by a disposal operation performed by the robot arm mechanism  40  above the disposal bucket  60  during transport of the workpiece switching jig  20  from the wire electric discharge machine  30  to the storage shelf  50 . Since the disposal bucket  60  is arranged on the transport path of the workpiece switching jig  20  between the wire electric discharge machine  30  and the storage shelf  50  which stores the workpiece switching jig  20  after cutting, the time required for discarding the cut-off portion W 2  held by the workpiece switching jig  20  can be shortened, and the reduction in work efficiency can be suppressed. Further, since the worker does not need to collect the cut-off portion W 2  from the workpiece switching jig  20  stored in the storage shelf  50 , the cutting system  10  can be operated unattended without imposing a workload on the worker. 
     Also, since the workpiece switching jig  20  has a function of holding the workpiece W 1  after cutting and the cut-off portion W 2  cut off from the workpiece W before cutting, the cut-off portion W 2  can be collected together with the workpiece switching jig  20  holding the cut-off portion W 2  each time cutting is performed. Since the cut-off portion W 2  does not remain in the work tank  31 , the risk that the cut-off portion W 2  interferes with the operation of the wire electric discharge machine  30  can be reduced. The collection operation of the workpiece switching jig  20  by the robot arm mechanism  40  or the worker (or the collection operation of the workpiece W 1  after cutting corresponding to the collection operation of the workpiece switching jig  20 ) is included in the cutting procedure of the conventional cutting system, and does not significantly lower the work efficiency of the conventional cutting process since addition of a new step for collecting the cut-off portion W 2  is not required. 
     (Description of Workpiece Switching Jig  20 ) 
     Hereinafter, the workpiece switching jig  20  will be described in detail. 
     As shown in  FIGS.  4  and  5   , the workpiece switching jig  20  has a jig main body  21  that holds a workpiece W before cutting, a cut-off portion basket  25  that receives a cut-off portion W 2  cut off from the workpiece W, and an arm  23  that supports the cut-off portion basket  25  with respect to the jig main body  21 . 
     In the jig main body  21 , a fixture for attaching the workpiece switching jig  20  to the chuck member  35  of the base portion  33  of the wire electric discharge machine  30  is detachably attached to a vise that holds and fixes a workpiece W between two members. 
     Specifically, the jig main body  21  has a rectangular plate-shaped main body base  210 . Hereinafter, an axis parallel to the longitudinal direction of the main body base  210  is referred to as an X-axis, an axis parallel to the lateral direction of the main body base  210  is referred to as a Y-axis, and an axis parallel to the thickness (height) direction of the main body base  210  is referred to as a Z-axis. 
     A block-shaped fixed portion  211  is provided on the surface of the main body base  210  on one end side, and a block-shaped support portion  212  is provided on the surface on the other end side. The fixed portion  211  and the support portion  212  are spaced apart along the X-axis. Actually, the main body base  210 , the fixed portion  211 , and the support portion  212  are integrally molded. 
     The support portion  212  is provided with a screw hole penetrating in a direction parallel to the X-axis. A rod  213  is inserted and screwed into the screw hole. A handle  214  is provided at the rear end of the rod  213 , and a block-shaped movable portion  215  is connected to the front end of the rod  213 . The movable portion  215  is supported movably along the X-axis on the main body base  210 . By arranging the workpiece W between the fixed portion  211  and the movable portion  215  and rotating the handle  214  so that the movable portion  211  approaches the fixed portion  215 , the worker can sandwich and fix the workpiece W between the fixed portion  211  and the movable portion  215 . The main body base  210 , the fixed portion  211 , the support portion  212 , the rod  213 , the handle  214 , and the movable portion  215  constitute the vise. 
     A flange  216  is provided on one end surface of the main body base  210 , and an attachment portion is detachably connected via the flange  216 . The attachment portion has a block-shaped attachment base  217 . The fixture  219  is supported on one side surface of the attachment base  217 . A flange  218  is provided on the other side surface of the attachment base  217  opposite to the side surface on which the fixture  219  is provided. The attachment portion is connected to the main body base  210  by fastening its flange  218  to the flange  216  of the main body base  210  with a bolt or the like in a state where the flange  218  is joined to the flange  216 . By configuring the attachment portion provided with the fixture  219  to be attachable to and detachable from the vise composed of the main body base  210  and the like, only the attachment portion needs to be replaced even when the chuck member  35  to which the workpiece switching jig  20  is connected is changed, and the versatility of the workpiece switching jig  20  can be improved. 
     The arm  23  has an L-shaped appearance. The cut-off portion basket  25  is connected to the front end of the arm  23 , and the rear end of the arm  23  is attached to the jig main body  21 . The arm  23  is attached to the jig main body  21  such that a first arm portion  231  constituting the arm  23  is parallel to the Y-axis, a second arm portion  236  constituting the arm  23  is parallel to the X-axis, and the cut-off portion basket  25  at the front end of the arm  23  is arranged at a position where the cut-off portion basket  25  can receive the cut-off portion W 2  cut off from the workpiece W. For example, when the workpiece W is a round bar as in the present embodiment, the cut-off portion basket  25  is arranged between the fixed portion  211  and the movable portion  215  of the jig main body  21  by the arm  23 . 
     The shape and size of the arm  23  and the attachment position of the arm  23  to the jig main body  21  can be discretionarily determined as long as a gap for passing a wire  37  of the wire electric discharge machine  30  can be provided between the jig main body  21  and the cut-off portion basket  25  and the cut-off portion basket  25  can be arranged at a position where the cut-off portion basket  25  can receive the cut-off portion W 2  cut off from the workpiece W. Therefore, the external shape of the arm  23  is not limited to an L-shape, and may be bent, curved, or any combination of these shapes. 
     The cut-off portion basket  25  is shaped like a box with an open top. A space for receiving the cut-off portion W 2  is demarcated by a bottom plate and a side plate constituting the box. The cut-off portion basket  25  has an inner surface shape consistent with the cut-off portion W 2 . For example, in the case where a round bar as the workpiece W is fixed to the jig main body  21  so as to be parallel to the Y-axis (see  FIG.  3   ), the cut-off portion basket  25  is composed of four side plates  252 ,  253 ,  254 , and  255  so that a space for receiving the cut-off portion W 2  is rectangular in plan view, as shown in  FIG.  5   . As shown in  FIG.  6   , the bottom plate  251  is configured to curve convexly along the X-axis. 
     The shape of the cut-off portion basket  25  is not limited to the above as long as it is consistent with the cut-off portion W 2 . For example, when the workpiece W is a squire bar having a rectangular cross section, the bottom plate  251  is flat as shown in  FIG.  7   . Further, when the workpiece W is a bar having a triangular cross section, the bottom plate  251  is configured to project in a V-shape as shown in  FIG.  8   . As a result, the cut-off portion W 2  cut off from the workpiece W can be stabilized in the cut-off portion basket  25 , and the possibility of dropping from the workpiece switching jig  20  during transport can be reduced. 
     The bottom plate  251  of the cut-off portion basket  25  has an opening  259  for draining the working fluid filled in the work tank  31  of the wire electric discharge machine  30 . Typically, the opening  259  is one opening, but may include a plurality of openings or be reticulated. The shape of the opening  259  is typically rectangular, but may be another shape such as a circle. Of course, when a cutting machine that cuts the workpiece W without submerging the workpiece W in the work tank  31  filled with the working fluid is used, the opening  259  is not necessarily required. 
     In the cut-off portion basket  25 , of the side plate, the side plate portion on the side close to the jig main body  21  is lower than the other side plate portions. For example, in the case of the cut-off portion basket  25  having a rectangular shape in plan view as shown in  FIG.  5   , of the four side plates  252 ,  253 ,  254 , and  255 , one side plate  252  on the side close to the jig main body  21  is lower than the other side plates  253 ,  254 , and  255  as shown in  FIG.  9   . Accordingly, the workpiece W can be brought closer to the bottom plate  251 , the possibility that the cut-off portion W 2  falls outside the cut-off portion basket  25  can be reduced. In particular, when cutting is performed with the workpiece W submerged in the work tank  31  filled with the working fluid, the cut-off portion W 2  cut off from the workpiece W may not fall directly below, so that the side plate is partially lowered to bring the workpiece W as close as possible to the bottom plate  251  is very effective in reliably accommodating the cut-off portion W 2  in the cut-off portion basket  25 . Further, by making the other side plate portions higher, even if the cut-off portion W 2  cut off from the workpiece W flies in all directions in reaction to cutting, the cut-off portion W 2  can be prevented from falling outside the cut-off portion basket  25 . 
     As shown in  FIG.  10   , the cut-off portion basket  25  may have an inclined plate  257  that guides the cut-off portion W 2  to the bottom plate  251 . The inclined plate  257  is arranged so as to be inclined from the edge of one side plate  252  close to the jig main body  21  of the four side plates  252 ,  253 ,  254 , and  255  toward the bottom plate  251 . Since the cut-off portion W 2  cut off from the workpiece W can be slid down along the inclined plate  257  toward the bottom plate  251  at a slow speed, the possibility that the cut-off portion W 2  falls directly to the outside of the cut-off portion basket  25  and the possibility that the cut-off portion W 2  bounces on the bottom plate  251  and goes out to the outside of the cut-off portion basket  25  can be reduced in comparison with the configuration without the inclined plate  257 . In addition, since the cut-off portion W 2  reaches the bottom plate  251  in an inclined posture along the inclined plate  257 , a part of the cut-off portion W 2 , such as a corner of the cut-off portion W 2  can be engaged with the opening  259  formed in the bottom plate  251 , and the cut-off portion W 2  can be more stably accommodated in the cut-off portion basket  25 . 
     Also, as shown in  FIG.  11   , the height of the entire side plate may be made smaller than the thickness of the cut-off portion W 2  from the viewpoint of making it easier to drop the cut-off portion W 2  from the cut-off portion basket  25  during the disposal operation of the cut-off portion W 2  held by the workpiece switching jig  20  by the robot arm mechanism  40 . Further, if the cut-off portion W 2  has a circular cross section as in the present embodiment, the cut-off portion basket  25  can be configured to have the side plate so as to have a cross-sectional shape that widens from the bottom to the open top, such as a V-shape or semicircle, in order to facilitate rolling of the cut-off portion W 2  along the side plate. 
     In addition, the cut-off portion basket  25  may be detachably attached to the arm  23 . The versatility of the workpiece switching jig  20  can be improved by preparing multiple types of cut-off portion baskets  25  having different shapes and sizes, selecting a cut-off portion basket  25  corresponding to the workpiece W, and attaching the cut-off portion basket  25  to the arm  23 . 
     In the workpiece switching jig  20  according to the present embodiment, the relative position of the cut-off portion basket  25  with respect to the jig main body  21  can be adjusted. As a structure for achieving this, a structure in which the attachment position of the arm  23  with respect to the jig main body  21  can be changed can be employed. 
     As shown in  FIG.  12   , the jig main body  21  has a plurality of screw holes  220  for attaching the arm  23  so that the attachment position of the arm  23  with respect to the jig main body  21  can be changed. The screw holes  220  are provided on the back surface of the jig main body  21  so as to be dispersed along the X-axis and the Y-axis. The first arm portion  231  on the rear end side of the arm  23  is provided with a plurality of through holes  240 . The worker can attach the arm  23  to the jig main body  21  by screwing in a state where a through hole  240  selected from the through holes  240  provided in the arm  23  is aligned with a screw hole  220  selected from the screw holes  220  provided in the jig main body  21 . By changing at least one of the screw hole  220  of the jig main body  21  and the through hole  240  of the arm  23 , the position of the cut-off portion basket  25  with respect to the jig main body  21  can be adjusted in the X-axis direction and the Y-axis direction. Here, the X-axis direction corresponds to a direction in which the cut-off portion basket  25  approaches/moves away from the jig main body  21 , and the Y-axis direction corresponds to a direction perpendicular to the direction in which the cut-off portion basket  25  approaches/moves way from the jig main body  21 . 
     In order to adjust the position of the cut-off portion basket  25  with respect to the jig main body  21  in the X-axis direction and the Y-axis direction, a plurality of attachment structures (screw holes or through holes) may be provided in at least one of the jig main body  21  and the arm  23 . 
     As shown in  FIG.  13   , when it is desired to adjust the position of the cut-off portion basket  25  with respect to the jig main body  21  in the Z-axis direction, a spacer member  70  having a thickness corresponding to the adjustment width may be interposed between the jig main body  21  and the arm  23 . As described with reference to  FIG.  12   , it is also possible to have a structure for adjusting the position of the cut-off portion basket  25  with respect to the jig main body  21  in the Z-axis direction by changing the attachment position of the arm  23  with respect to the jig main body  21 . In this case, for example, a plurality of screw holes are provided in a side surface of the jig main body  21 , the arm  23  is composed of three arm portions parallel to the three orthogonal axes, respectively, and a plurality of through holes are provided in the arm portion along the Z-axis. 
     As long as the arm  23  can be attached to the jig main body  21 , the attachment structure is not limited to screws, and any structure such as a bolt-nut structure or a fitting structure can be employed. 
     In the above-described configuration, the relative position of the cut-off portion basket  25  with respect to the jig main body  21  is adjusted by changing the attachment position of the arm  23  with respect to the jig main body  21  and by interposing the spacer member  70  between the jig main body  21  and the arm  23 ; however, the arm  23  may have a structure for adjusting the position of the cut-off portion basket  25  with respect to the jig main body  21 . 
     As shown in  FIG.  14   , the first and second arm portions  231  and  236  constituting the arm  23  each have an extensible mechanism. As the extensible mechanism, any mechanism such as a mechanism utilizing a slide bar, a ball screw mechanism, or a slide rail mechanism, can be used. Here, a slide rail mechanism will be described as an example of the extensible mechanism. The first arm portion  231  has a first fixed rail  232  attached to the jig main body  21  at its rear end portion and a first moving rail  233  slidably supported on the first fixed rail  232 . The second arm portion  236  has a second fixed rail  237  connected to the first moving rail  233  and a second moving rail  238  slidably supported on the second fixed rail  237  and provided with the cut-off portion basket  25  at its front end. According to the above configuration, the position of the cut-off portion basket  25  with respect to the jig main body  21  can be adjusted in the Y-axis direction by changing the extension length of the first arm portion  231  arranged along the Y-axis. Similarly, the position of the cut-off portion basket  25  with respect to the jig main body  21  can be adjusted in the X-axis direction by changing the extension length of the second arm portion  236  arranged along the X-axis. When the arm  23  itself has a structure capable of adjusting the position of the cut-off portion basket  25  with respect to the jig main body  21 , it is advantageous from the viewpoint of ease of adjustment to configure the arm  23  in an L-shape and to attach the arm  23  to the jig main body  21  so that the first arm portion  231  and the second arm portion  236  constituting the arm  23  are parallel to the Y-axis and the X-axis, respectively. 
     If it is desired to adjust the position of the cut-off portion basket  25  with respect to the jig main body  21  in the Z-axis direction, the arm  23  may be composed of three arm portions arranged along the three orthogonal axes, respectively, and the arm portion arranged along the Z-axis may be extended or contracted. The attachment structure of the arm  23  to the jig main body  21  described with reference to  FIGS.  12  and  13    may be combined with the extensible structure of each arm portion  231 ,  236  constituting the arm  23  described with reference to  FIG.  14   . Accordingly, by interposing the spacer member  70  between the arm  23  and the jig main body  21  illustrated in  FIG.  14   , the position of the cut-off portion basket  25  with respect to the jig main body  21  can be adjusted in the Z-axis direction. 
     The arm  23  may be composed of multiple types of small components having a coupling structure. By changing the combination or the number of components constituting the arm  23 , the shape and size of the arm  23  can be discretionarily changed, and thereby the relative position of the cut-off portion basket  25  with respect to the jig main body  21  can be adjusted. 
     While some embodiments of the present invention have been described, these embodiments have been presented as examples, and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention and are included in the scope of the claimed inventions and their equivalents. 
     EXPLANATION OF REFERENCE NUMERALS 
     
         
           20 : workpiece switching jig,  21 : jig main body,  210 : main body base,  211 : fixed portion,  212 : support portion,  213 : rod,  214 : handle,  215 : movable portion,  216 ,  218 : flange,  217 : attachment base,  219 : fixture,  23 : arm,  231 : first arm portion,  236 : second arm portion,  25 . cut-off portion basket,  251 : bottom plate,  252 ,  253 ,  254 ,  255 : side plate,  259 : opening