Patent Publication Number: US-2021173619-A1

Title: Program editing device and wire electrical discharge machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-221331 filed on Dec. 6, 2019, the contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a program editing device and a wire electrical discharge machine. In particular, the present invention relates to a program editing device that edits a machining program in which a machining path of a wire electrode on a workpiece is defined, and a wire electrical discharge machine that relatively moves the wire electrode based on the machining program. 
     Description of the Related Art 
     Japanese Laid-Open Patent Publication No. 2018-024085 discloses a configuration of a wire electrical discharge machine in which a machining path of movement of a wire electrode relative to a workpiece is divided into a plurality of partial paths (sections or path segments), for which different processing conditions can be set. 
     SUMMARY OF THE INVENTION 
     In electrical discharge machining with a wire electrical discharge machine, the more complicated a machining path set in the machining program, the more likely the shape of the obtained machined product is to be different from the machining path. Some examples of complicated machining paths include a machining path that is composed of a series of angled corners and intricately designed, and a machining path that creates a pseudo-curve consisting of a series of straight line segments. 
     It is therefore an object of the present invention to provide a program editing device and a wire electrical discharge machine capable of improving the accuracy of electrical discharge machining. 
     One aspect of the present invention resides in a program editing device for editing a machining program in which a machining path along which a wire electrode of a wire electrical discharge machine machines a workpiece is defined, wherein the machining program includes a plurality of blocks corresponding to respective multiple partial paths into which the machining path is divided, each of the blocks including path information indicating the corresponding partial path, the program editing device including: an analyzer configured to analyze the machining program and thereby identify a predetermined shape pattern formed by a series of the multiple partial paths in the machining path; an information generator configured to generate shape information corresponding to the identified predetermined shape pattern, and an editor configured to insert the shape information into the machining program. 
     Another aspect of the present invention resides in a wire electrical discharge machine including a wire electrode and configured to move the wire electrode relative to a workpiece along a machining path defined in a machining program, including: a program editing device according to the above aspect of the invention; and an electrical discharge machining unit configured to move the wire electrode relative to the workpiece, along the machining path defined in the machining program edited by the program editing device and perform electrical discharge machining on the workpiece while compensating the machining conditions based on the shape information inserted into the machining program. 
     According to the aspects of the present invention, it is possible to provide a program editing device and a wire electrical discharge machine capable of improving the accuracy of electrical discharge machining. 
     The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing a configuration of a wire electrical discharge machine of an embodiment of the present invention; 
         FIG. 2  is a schematic diagram showing a configuration of a control device; 
         FIG. 3  is a schematic diagram showing a configuration of a program editing device; 
         FIG. 4  is a flowchart showing an example of the flow of a program editing process; 
         FIG. 5  is a diagram showing an example of a state of a machining program before editing; 
         FIG. 6  is a diagram showing a machining path defined by the machining program of  FIG. 5 ; 
         FIG. 7A  is a first example of shape information,  FIG. 7B  is a second example of shape information, and  FIG. 7C  is a third example of shape information; 
         FIG. 8  is a diagram showing a state of the machining program of  FIG. 5  after editing; 
         FIG. 9  is a diagram showing an example of a state of a machining program of a modification 1 before editing; 
         FIG. 10  is a diagram showing a machining path defined by the machining program of  FIG. 9 ; and 
         FIG. 11  is a diagram showing a state of the machining program of  FIG. 9  after editing. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A program editing device and a wire electrical discharge machine of the present invention will be detailed below by describing a preferred embodiment with reference to the accompanying drawings. 
     Embodiment 
       FIG. 1  is a schematic diagram showing a configuration of a wire electrical discharge machine  10  of the embodiment. 
     Referring first to  FIG. 1 , the overall configuration of the wire electrical discharge machine  10  will be described.  FIG. 1  shows a coordinate system having an X-axis, a Y-axis, and a Z-axis which is set in the wire electrical discharge machine  10 . The directions of X and Y axes are orthogonal to each other in a plane, and the Z-axis is orthogonal to each of the X and Y axes. 
     The wire electrical discharge machine  10  includes a wire electrode  12 , a machine main body  14 , a control device  16 , and a program editing device  18 . The wire electrical discharge machine  10  is a machine tool that machines a workpiece W by generating electrical discharge by applying voltage to the electrode gap between the workpiece W and the wire electrode  12  in a dielectric working fluid. 
     The wire electrode  12  is formed of, for example, metal material such as tungsten-based, copper alloy-based, or brass-based material. On the other hand, the workpiece W is formed of, for example, metal material such as iron-based material or superhard material (tungsten carbide). 
     The machine main body  14  includes a supply system  20  that supplies the wire electrode  12  toward the workpiece W, and a collecting system  22  that collects the wire electrode  12  having passed through the workpiece W. 
     The supply system  20  includes a wire bobbin  24 , a torque motor  26 , a brake shoe  28 , a brake motor  30 , a tension detector  32 , and a die guide (upper die guide)  34 . Of these, the wire bobbin  24  has a fresh wire electrode  12  wound thereon. The torque motor  26  applies torque to the wire bobbin  24 . The brake shoe  28  applies a braking force to the wire electrode  12  by friction. The brake motor  30  applies brake torque to the brake shoes  28 . The tension detector  32  detects the magnitude of the tension of the wire electrode  12 . The die guide  34  guides the wire electrode  12  above the workpiece W. 
     The collecting system  22  includes a die guide (lower die guide)  36 , a pinch roller  38 , a feed roller  40 , a torque motor  42 , and a collecting box  44 . Of these, the die guide  36  guides the wire electrode  12  below the workpiece W. The pinch roller  38  and the feed roller  40  hold the wire electrode  12  therebetween. The torque motor  42  applies torque to the feed roller  40 . The collecting box  44  collects the wire electrode  12  conveyed by the pinch roller  38  and the feed roller  40 . 
     The machine main body  14  includes a work-pan  46  capable of storing a dielectric working fluid such as deionized water or oil, which is used during machining. The work-pan  46  is placed on a base  48 . The die guides  34  and  36  are disposed inside the work-pan  46 , and the workpiece W is placed between the die guides  34  and  36 . The die guides  34  and  36  and the workpiece W are immersed in the working fluid stored in the work-pan  46 . 
     The die guide  34  has a support portion  34   a , and the die guide  36  has a support portion  36   a . The support portion  34   a  and the support portion  36   a  support the wire electrode  12 . Further, the die guide  36  includes a guide roller  36   b . The guide roller  36   b  changes the running direction of the wire electrode  12  and then guides the wire electrode  12  to the pinch roller  38  and the feed roller  40 . 
     The die guide  34  ejects a sludge-free clean working fluid toward the electrode gap formed between the wire electrode  12  and the workpiece W. Thus, the electrode gap is filled with the clean liquid suitable for machining, and as a result, reduction in machining accuracy due to sludge generated during machining is prevented. Not only the die guide  34 , but also the die guide  36  may also eject a clean working fluid toward the electrode gap. 
       FIG. 2  is a schematic diagram showing the configuration of the control device  16 . 
     The control device  16  controls the machine main body  14  according to a machining program  56  and machining conditions. The control device  16  includes a storage unit  50   CON  and a computation unit  52   CON . 
     The storage unit  50   CON  stores information, and includes, for example, a hard disk. The storage unit  50   CON  stores therein the machining program  56  and machining conditions. In addition, control software for executing electrical discharge machining is stored. 
     The computation unit  52   CON  processes information, and includes hardware such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), for example. The computation unit  52   CON  includes an electrical discharge machining unit  54 . The electrical discharge machining unit  54  is realized by the computation unit  52   CON  implementing the control software in cooperation with the storage unit  50   CON . The electrical discharge machining unit  54  performs electrical discharge machining on the workpiece W by relatively moving the wire electrode  12  along a machining path  58  set in the machining program  56 , based on the machining conditions. 
     The machining conditions include pulse interval between voltage pulses repeatedly applied to the electrode gap between the wire electrode  12  and the workpiece W, the average voltage applied per unit time across the electrode gap, the relative movement speed between the wire electrode  12  and the workpiece W, the feed rate of the wire electrode  12 , etc. 
     Of the above, the pulse interval is a pause time during which no voltage pulse is applied to the electrode gap between the workpiece W and the wire electrode  12 . The relative movement speed between the wire electrode  12  and the workpiece W is a speed at which the wire electrode  12  is moved relative to the workpiece W. The feed rate is a speed at which the wire electrode  12  travels in a direction in which the wire electrode  12  extends. 
     When the voltage pulses are applied to the electrode gap between the workpiece W and the wire electrode  12 , the electrical discharge machining unit  54  controls an unillustrated power unit in the machine main body  14 , based on the average voltage per unit time, the pulse interval, etc., stored in the storage unit  50   CON . Thus, the voltage pulse is repeatedly applied at a predetermined cycle to the electrode gap between the workpiece W and the wire electrode  12  from the power unit. 
     When the wire electrode  12  is moved relative to the workpiece W, the electrical discharge machining unit  54  controls a motor connected to an unillustrated table on which the workpiece W is fixed. This motor (not shown) moves the table on the XY plane. As a result, the relative positional relationship between the wire electrode  12  and the workpiece W changes, that is, the relative movement of the wire electrode  12  with respect to the workpiece W is implemented. 
     When adjusting the tilt of the wire electrode  12  with respect to the workpiece W, the electrical discharge machining unit  54  controls at least one of an unillustrated motor connected to the die guide  34  and an unillustrated motor connected to the die guide  36 . The motor connected to the die guide  34  moves the die guide  34  on a plane parallel to the XY plane. Similarly, the motor connected to the die guide  36  moves the die guide  36  on a plane parallel to the XY plane. In this manner, the positions of the die guide  34  and the die guide  36  can be made different from each other with respect to at least one of the X-axis direction and the Y-axis direction. Thus, the wire electrode  12  can be tilted with respect to the workpiece W. 
     When the wire electrode  12  is moved in the running direction, the electrical discharge machining unit  54  controls the torque motor  42  by using the feed rate or the like stored in the storage unit  50   CON . Thus, the torque motor  42  applies torque to the wire bobbin  24  and the feed roller  40 , to thereby convey the wire electrode  12  that is in contact with the wire bobbin  24  and the feed roller  40 , in the running direction. The running direction (Z-axis negative direction) of the wire electrode  12  and the direction of movement (X-axis direction, Y-axis direction) of the wire electrode  12  that is relatively moved with respect to the workpiece W intersect each other. 
     Now, the factors that can be considered concerning the machining accuracy in electrical discharge machining will be explained. 
     To begin with, the machining program  56  executed by the electrical discharge machining unit  54  in electrical discharge machining will be described in more detail. The machining program  56  has blocks  62  ( FIG. 5 ) corresponding respectively to a plurality of partial paths (path segments)  60  ( FIG. 6 ) into which the machining path  58  is divided. Each of the blocks  62  has path information indicating the corresponding partial path  60 . The path information includes information indicating the end point of the corresponding partial path  60  and information indicating along what trajectory (i.e., path) the wire electrode  12  should be relatively moved toward the end point (i.e., indicating the shape of the partial path  60 ). 
     For example, in an arcuate partial path  60 , the amount of discharge generated at the electrode gap becomes more unstable than in a linear partial path  60 , so that the gap distance between the wire electrode  12  and the workpiece W is prone to be unstable. In order to deal with this, it is conceivable to cause the electrical discharge machining unit  54  to perform control such as to appropriately adjust the relative movement speed or the pause time when the wire electrode  12  moves along the arcuate partial path  60 . That is, it is considered that the machining accuracy can be improved by changing (compensating) the machining conditions so that the machining conditions are optimized for the shape of the partial path  60  indicated by the path information. 
     However, a complicated machining path  58  has a shape composed of multiple partial paths  60 , so that it may exhibit a geometry in which the gap distance between the wire electrode  12  and the workpiece W tends to be unstable. The geometry is, for example, an angular corner formed by two adjacent partial paths  60 . If the two adjacent partial paths  60  forming an angular corner are both linear, the machining condition for straight lines is applied when referring to the path information on each of the partial paths. In this case, the electrical discharge machining unit  54  fails to cope with the situation in which the gap distance between the wire electrode  12  and the workpiece W becomes unstable, so that there is concern that the machining accuracy may be adversely affected. If it is necessary to finely change the advancing direction of the wire electrode  12  while forming angular corners, there is a risk of further affecting the machining accuracy. Thus, when a complicated machining path  58  is defined in the machining program  56 , it is difficult to perform electrical discharge machining on the workpiece W with high accuracy. 
     To deal with, in the present embodiment, the program editing device  18  described below edits the machining program  56  so that the electrical discharge machining unit  54  can suitably adjust the machining conditions. Hereinafter, the configuration of the program editing device  18  of the present embodiment and the program editing process executed by the program editing device  18  will be described step by step. 
       FIG. 3  is a schematic diagram showing a configuration of the program editing device  18 . 
     The program editing device  18  edits the machining program  56 . The program editing device  18  includes a computation unit  52   EDI , an operation unit  64 , a display unit  66 , and a storage unit  50   EDI . 
     The computation unit  52   EDI  processes information, and includes hardware such as a CPU or GPU, for example. 
     The operation unit  64  is used for inputting information, and includes, for example, a mouse, a keyboard, and a touch panel arranged on the display screen of the display unit  66 . The display unit  66  displays information, and is for example, a liquid crystal display. 
     The storage unit  50   EDI  stores information, and includes, for example, a hard disk. The storage unit  50   EDI  stores editing software for executing a program editing process for editing the machining program  56 . 
     The computation unit  52   EDI  has an analyzer  68 , an information generator  70 , and an editor  72 . Each of these units is realized by the computation unit  52   EDI  executing the editing software. 
     The analyzer  68  reads the machining program  56  from the storage unit  50   EDI  of the control device  16 , and analyzes the read machining program  56 . In the analysis, the analyzer  68  identifies predetermined shape patterns included in the machining path  58 . 
     The analyzer  68  identifies predetermined shape patterns composed of a series of multiple partial paths  60  by recognizing the path information possessed by each of multiple blocks  62 . In the present embodiment, the following two shape patterns correspond to predetermined shape patterns, though is not limited to these. That is, a first-type shape pattern is a “pattern that transitions from a straight line to a curved line or from a curved line to a straight line”. A second-type shape pattern is a “pattern in which two partial paths  60  form an angular corner shape having a predetermined angle”. The predetermined angle is not particularly limited, and may be defined as, for example, an angle included within a predetermined range. 
     The information generator  70  generates shape information  74  ( FIG. 7 ) corresponding to an identified predetermined shape pattern. The shape information  74  contains information indicating a target shape pattern and information regarding partial paths  60  forming the shape pattern, in block  62  units. The number of blocks  62  included in the shape information  74  is not limited, but varies depending on the corresponding shape pattern in the present embodiment. 
     For example, the shape information  74  generated correspondingly to the first-type shape pattern includes, in the present embodiment, blocks  62  indicating information on partial paths  60  forming this first-type shape pattern, i.e., a block  62  indicating information on a partial path  60  located on the upstream side and another block  62  indicating information on a partial path  60  located on the downstream side. 
     The information indicating a partial path  60  is, for example, information indicating the shape of the partial path  60  or information indicating the path length. Further, when the partial path  60  is arc-shaped, information on the curvature of the arc may be included in the information indicating the partial path  60 . The information on the curvature of the arc is, for example, the radius of curvature. 
     Further, similarly to the shape information  74  corresponding to the first-type shape pattern, the shape information  74  generated correspondingly to the second-type shape pattern includes a block  62  indicating information on a partial path  60  located on the upstream side and another block  62  indicating information on a partial path  60  located on the downstream side. The shape information  74  corresponding to the second-type shape pattern further includes yet another block  62  indicating information on the angular corner formed by the upstream-side partial path  60  and the downstream-side partial path  60 . 
     The information on the angular corner is, for example, information indicating whether the corner is an outer corner or an inner corner, or information indicating the angle formed at the corner. Further, when the upstream side partial path  60  and the further upstream side partial path  60  form another angular corner, information on the other angular corner may be included. 
     The editor  72  edits the machining program  56  by inserting the shape information  74  generated by the information generator  70  into the machining program  56 . Thus, in addition to the multiple pieces of path information indicating multiple partial paths  60 , the shape information  74  relating to the predetermined shape pattern composed of the multiple partial paths  60  is also defined in the machining program  56 . 
     The shape information  74  is inserted into the machining program  56  such that the electrical discharge machining unit  54  can grasp the content of the shape information  74  when the relative movement along the most upstream side partial path  60  among the multiple partial paths  60  that constitute the shape pattern indicated by the shape information  74  is performed. More preferably, the shape information  74  is inserted into the machining program  56  such that the electrical discharge machining unit  54  can grasp the content of the shape information  74  immediately before the relative movement along the most upstream side partial path  60  is performed. 
     The above is one example of the configuration of the program editing device  18  for editing the machining program  56 . The edited machining program  56  is stored in the storage unit  50   EDI , and is output to the storage unit  50   CON  of the control device  16  as necessary. Thus, the wire electrical discharge machine  10  can perform electrical discharge machining based on the edited machining program  56 . 
       FIG. 4  is a flowchart showing one example of a processing flow of the program editing process.  FIG. 5  is a diagram showing an example of a state of the machining program  56  before editing. Note that, in  FIG. 5 , a part of the machining program  56  is omitted.  FIG. 6  is a diagram showing a machining path  58  defined by the machining program  56  of  FIG. 5 . Note that, in  FIG. 6 , a part of the machining path  58  is omitted. 
     Next, the flow of the program editing process by the program editing device  18  will be described. The program editing process includes an analyzing step, an information generating step, and an editing step, as shown in  FIG. 4 . Hereinafter, each of these steps will be described sequentially concerning an example of editing the machining program  56  shown in  FIG. 5 . 
     At the analyzing step, a predetermined shape pattern is identified by analyzing the machining program  56 . The analyzer  68  can analyze the machining program  56  and identify a predetermined shape pattern. Next, the identification of a predetermined shape pattern will be described with examples. 
     The machining path  58  illustrated in  FIG. 6  has a series of multiple partial paths  60  ( 60 A,  60 B,  60 C,  60 D). The machining program  56  in  FIG. 5  corresponding to this machining path  58  includes a plurality of blocks  62  ( 62 A,  62 B,  62 C,  62 D). Of these, the block  62 A corresponds to the partial path  60 A, and has path information indicating the partial path  60 A. Similarly, the block  62 B has path information indicating the partial path  60 B, the block  62 C has path information indicating the partial path  60 C, and the block  62 D has path information indicating the partial path  60 D. 
     Here, in the example of  FIG. 6 , the partial path  60 A has a linear shape, and the partial path  60 B has a convex arc shape. Further, the partial path  60 A and the partial path  60 B are connected in this order. In this case, the analyzer  68  analyzes the machining program  56  and thereby identifies the pattern (first-type shape pattern) transitioning from a straight line to a curved line as being formed by the upstream side partial path  60 A and the downstream side partial path  60 B. 
     Further, in the example of  FIG. 6 , the partial path  60 B and the partial path  60 C form an angular corner having a predetermined angle (115 degrees). In this case, the analyzer  68  analyzes the machining program  56  and thereby identifies the pattern (second-type shape pattern) forming the angular corner having the predetermined angle, as being formed by the upstream side partial path  60 B and the downstream side partial path  60 C. 
     In this way, the analyzing step identifies all predetermined shape patterns included in the machining path  58 . 
     At the information generating step, shape information  74  corresponding to the identified predetermined shape pattern is generated based on the result of the analysis obtained at the analyzing step. The shape information  74  may be generated by the information generator  70 . Hereinafter, the generation of the shape information  74  will be described by giving examples. 
     As an instance, for the first-type shape pattern composed of the partial path  60 A and the partial path  60 B, the information generator  70  generates shape information  74 A indicating that the partial path  60 A and the partial path  60 B are connected in series. The shape information  74 A may include information on the path length of each of the partial path  60 A and the partial path  60 B. Further, for the arc-shaped partial path  60 B, information on the curvature of the arc may be also included. 
       FIG. 7A  is a first example of shape information  74 . Note that  FIG. 7A  shows an example of shape information  74 A. 
       FIG. 7A  shows an example of shape information  74 A. The shape information  74 A has two blocks  62 , i.e., a block  62 A A  indicating information on the upstream side partial path  60 A and a block  62 A B  indicating information on the downstream side partial path  60 B. 
     Of the information shown in each of the block  62 A A  and the block  62 A B , the two letters on the right side of “M” denote the sequential order in the machining path  58 . “Mxx” indicates that the block  62 A A  containing it relates to the upstream side partial path  60 . Further, “Myy” indicates that the block  62 A B  containing it relates to the downstream side partial path  60 . In addition, though not shown in  FIG. 7A , “Mww” in  FIG. 7C , which will be described later, indicates that a block containing it is upstream of the block with “Mxx”, and “Mzz” indicates that a block containing it is downstream of the block with “Myy”. The number on the right side of “L” indicates the path length of the partial path  60 , the number on the right side of “R” indicates the value of the radius of curvature, and the number on the right side of “A” indicates the inclination angle with respect to the partial path  60  positioned just anteriorly. Then, regarding the information indicated by the block  62  included in the shape information  74 , the number on the right side of “S” indicates the shape type of the partial path  60 . In the present embodiment, it is assumed, for example, that “S 0  is a straight line”, “S 1  is a convex arc”, “S 2  is a concave arc”, “S 3  is an outer corner (convex angle corner)”, and “S 4  is an inner corner (concave angle corner)”. 
     Based on the above, it is understood that the shape information  74 A indicates that the upstream side partial path  60 A is a straight line having a path length of “7.0138”. The shape information  74 A further indicates that the downstream side partial path  60 B forms an inclination angle of “165” relative to the previous partial path  60 A, and is a “convex arc” having a path length of “2.75” and a radius of curvature of “3”. 
     Referring to another example, for a second-type shape pattern composed of the partial path  60 B and the partial path  60 C, the information generator  70  generates shape information  74 B indicating an angular corner shape formed by the partial path  60 B and the partial path  60 C. The shape information  74 B includes an angle formed between the partial path  60 B and the partial path  60 C. The shape information  74 B may further include, for each of the partial path  60 B and the partial path  60 C, information indicating the path length and information indicating the curvature of the arc. 
       FIG. 7B  is a second example of shape information  74 . Note that  FIG. 7B  shows an example of shape information  74 B. 
       FIG. 7B  shows an example of shape information  74 B. The shape information  74 B has two blocks  62 , i.e., a block  62 B B  indicating information on the upstream side partial path  60 B and a block  62 B c  indicating information on the downstream side partial path  60 C. Further, the shape information  74 B further has a block  62 B BC  indicating information on the angular corner formed between the partial path  60 B and the partial path  60 C. 
       FIG. 7C  is a third example of shape information  74 . Note that  FIG. 7C  shows an example of shape information  74 C. 
       FIG. 7C  shows an example of shape information  74 C. The shape information  74 C has a block  62 C c  indicating information on the upstream side partial path  60 C, a block  62 C D  indicating information on the downstream side partial path  60 D, and a block  62 C CD  indicating information on the angular corner formed between the partial path  60 C and the partial path  60 D. 
     Further, as shown in  FIG. 7C , the shape information  74 C further has a block  62 B′ BC  indicating information regarding the corner formed by the partial path  60  and the partial path  60 B. In this way, when the upstream side partial path  60  ( 60 C) forms an angular corner jointly with the further upstream side partial path  60  ( 60 B), the shape information  74  ( 74 C) can include the information as to the angular corner. 
     In this way, in the information generating step, the associated shape information  74  ( 74 A,  74 B,  74 C,  74 D) is generated for all the identified predetermined shape patterns. 
     In the editing step, the machining program  56  is edited by inserting shape information  74  generated in the information generating step into the machining program  56 . Each piece of shape information  74  is inserted so as to accompany the path information corresponding to the upstream side partial path  60  of the multiple partial paths  60  with which the shape information  74  is associated. Next, editing of the machining program  56  will be described with examples. 
       FIG. 8  is a diagram showing an edited state of the machining program  56  of  FIG. 5 . In  FIG. 8 , a part of the machining program  56  is omitted. 
     For example, the partial paths  60  corresponding to the shape information  74 A are the partial path  60 A and the partial path  60 B. Of these, the partial path  60 A is on the upstream side. Therefore, the editor  72  inserts the shape information  74 A into the machining program  56  so as to accompany the path information (block  62 A) corresponding to the partial path  60 A. 
     Similarly, the editor  72  inserts the shape information  74 B into the machining program  56  so as to accompany the path information corresponding to the partial path  60 B. Further, the editor  72  inserts the shape information  74 C into the machining program  56  so as to accompany the path information (block  62 B) corresponding to the partial path  60 C. 
     In this way, in the editing step, all pieces of generated shape information  74  are inserted to edit the machining program  56 . 
     The machining program  56  after editing is stored in the storage unit  50   CON  of the control device  16 , so that the electrical discharge machining unit  54  can execute it. When performing electrical discharge machining on the workpiece W, the electrical discharge machining unit  54  moves the wire electrode  12  relative to the workpiece W, based on the edited machining program  56 . 
     Here, the electrical discharge machining unit  54 , based on the shape information  74 A, for example, can recognize that the transition from the partial path  60 A to the partial path  60 B is a transition from a straight line to a curved line. Therefore, the electrical discharge machining unit  54  can smoothly change the machining conditions from those suitable for linear relative movement of the wire electrode  12  to those suitable for curved relative movement thereof. 
     Further, the electrical discharge machining unit  54 , based on the shape information  74 B, for example, can recognize that the transition from the partial path  60 B to the partial path  60 C is accompanied with formation of an angular corner having a predetermined angle. Therefore, the electrical discharge machining unit  54  can smoothly change the machining conditions from those suitable for the electrical discharging machining along the partial path  60 B to those suitable for forming the angular corner. The electrical discharge machining unit  54  can also smoothly change the machining conditions from those suitable for forming the angular corner to those suitable for electrical discharge machining along the partial path  60 C. 
     When no machining program editing process of the present embodiment is applied and when, for example, a certain partial path  60  has a short path length, there is concern that optimization of the machining conditions is too late for machining by the wire electrode along the partial path  60 . When the present embodiment is applied to this case, each of the path lengths of the partial paths  60  constituting the predetermined shape pattern can be included in the shape information  74 . Therefore, the electrical discharge machining unit  54  can recognize in advance the presence of a partial path  60  having a short path length, and hence can optimize the timing for adjusting the machining conditions. 
     Though the present embodiment has been described taking an example where the control device  16  and the program editing device  18  are separate from each other, the control device  16  and the program editing device  18  may be integrally configured. That is, the editing software may be stored in the storage unit  50   CON , and the computation unit  52   CON  may execute the above machining program editing process in cooperation with the storage unit  50   CON . 
     Thus, according to the present embodiment, the program editing device  18  and the wire electrical discharge machine  10  capable of improving the accuracy of electrical discharge machining are provided. 
     Modification 
     Though the embodiment has been described as an example of the present invention, it goes without saying that various modifications and improvements can be added to the above embodiment. It is clear from the description of the claims that those added with such modifications and improvements should be incorporated in the technical scope of the present invention. 
     Modification 1 
       FIG. 9  is a diagram showing an example of a state of a machining program  56 ′ of a modification 1 before editing. Note that a part of the machining program  56 ′ is omitted in  FIG. 9 .  FIG. 10  is a diagram showing a machining path  58 ′ defined by the machining program  56 ′ of  FIG. 9 . In  FIG. 10 , a part of the machining path  58 ′ is omitted. 
     As described in the embodiment, predetermined shape patterns are not limited to the two types described in the embodiment. In this modification, one example will be described. 
     In the machining path  58 ′, as shown in  FIG. 10 , a pseudo-curve shape is formed by a series of multiple linear partial paths  60 ′ ( 60 A′,  60 B′, . . . ,  60 P). The analyzer  68  may identify the pseudo-curve shape as a predetermined shape pattern. 
     When the pseudo-curve shape is identified as a predetermined shape pattern, the information generator  70  can generate shape information  74 ′ ( 74 A′,  74 B′, . . . ,  74 J′) according to the pseudo-curve shape. Here, in this modification, the generated shape information  74 ′ is configured to include information indicating a curve shape that approximates to the pseudo-curve shape. 
       FIG. 11  is a diagram showing an edited state of the machining program  56 ′ of  FIG. 9 . Note that a part of the machining program  56 ′ is omitted in  FIG. 11 . 
       FIG. 11  shows an example of shape information  74 ′ that can be generated by the information generator  70  in this modification. The shape information  74 ′ includes information (L0.028) indicating the path length of the partial path  60  constituting part of the pseudo-curve shape, and also includes information (R0.5) indicating the curvature of the curve that approximates to the pseudo-curve. Further, each of the plurality of partial paths  60  forming the pseudo-curve shape is linear in itself, but as the information indicating the shape pattern type, the information (S 1 ) indicating an convex arc is included in the shape information  74 ′. 
     The editor  72  inserts the shape information  74 ′ generated by the information generator  70  into the machining program  56 ′, as information accompanying all the path information corresponding to the plurality of partial paths  60 ′ that constitute the pseudo curve. As a result, the electrical discharge machining unit  54  executing the edited machining program  56 ′ can perform electrical discharge machining by applying the machining conditions for a curved path when the wire electrode  12  advances along the pseudo-curve indicated by the shape information  74 ′. Thus, machining accuracy can be improved. 
     Modification 2 
     The above embodiment and modifications may be arbitrarily combined as long as no inconsistency occurs. 
     Inventions that can be Obtained from the Embodiment 
     The inventions that can be grasped from the above-described embodiment and the modifications thereof will be described below. 
     First Invention 
     The first invention resides in a program editing device ( 18 ) for editing a machining program ( 56 ) in which a machining path ( 58 ) along which a wire electrode ( 12 ) of a wire electrical discharge machine ( 10 ) machines a workpiece (W) is defined. The machining program ( 56 ) includes a plurality of blocks ( 62 ) corresponding to respective multiple partial paths ( 60 ) into which the machining path ( 58 ) is divided, each of the blocks ( 62 ) including path information indicating the corresponding partial path ( 60 ). The program editing device ( 18 ) includes: an analyzer ( 68 ) configured to analyze the machining program ( 56 ) and thereby identify a predetermined shape pattern formed by a series of the multiple partial paths ( 60 ) in the machining path ( 58 ); an information generator ( 70 ) configured to generate shape information ( 74 ) corresponding to the identified predetermined shape pattern; and an editor ( 72 ) configured to insert the shape information ( 74 ) into the machining program ( 56 ). 
     With the above configuration, it is possible to provide a program editing device ( 18 ) that can achieve improved accuracy in electrical discharge machining. 
     The shape information may include information indicating a shape of each of the multiple partial paths ( 60 ) forming the predetermined shape pattern. This can improve machining accuracy. 
     The shape information ( 74 ,  74 ′) may include at least one of information indicating the path length and information indicating the curvature, of the partial path ( 60 ) of the predetermined shape pattern. This can improve machining accuracy. 
     The predetermined shape pattern may include an angular corner shape formed by two adjacent partial paths ( 60 ) of the multiple partial paths, and the shape information ( 74 ) corresponding to the angular corner shape may include information indicating the angle formed by the two adjacent partial paths ( 60 ) forming the angular corner shape. This can improve machining accuracy. 
     The predetermined shape pattern may include a pseudo-curve shape formed of a series of straight linear paths. The shape information ( 74 ′) corresponding to the pseudo-curve shape may include information indicating a curve shape that approximates to the pseudo-curve shape. This can improve machining accuracy. 
     Second Invention 
     A wire electrical discharge machine ( 10 ) which includes a wire electrode ( 12 ) and is configured to move the wire electrode ( 12 ) relative to a workpiece (W) along a machining path ( 58 ) defined in a machining program ( 56 ), includes: a program editing device ( 18 ) described in the above &lt;First Invention&gt;, and an electrical discharge machining unit ( 54 ) configured to move the wire electrode ( 12 ) relative to the workpiece (W), along the machining path ( 58 ) defined in the machining program ( 56 ) edited by the program editing device ( 18 ) and perform electrical discharge machining on the workpiece (W) while compensating the machining conditions based on the shape information ( 74 ,  74 ′) inserted in the machining program ( 56 ). 
     With the above configuration, it is possible to provide a wire electrical discharge machine ( 10 ) that can achieve improved accuracy in electrical discharge machining.