Broken wire position estimation device and broken wire position estimation method

Abstract

The wire breakage location estimation device (58) includes: a torque acquisition unit (70) that acquires the torque (Tq) of the winding motor (52); a determination unit (72) that determines whether the rear end (12a) of the wire electrode (12) has passed the winding roller (48); and a rotation angle acquisition unit (74) that acquires the rotation angle (A) of the winding motor (52). RO ); and a wire breakage location estimation unit (76), which determines the rotation angle (A) from the wire electrode (12) breakage to the point where the rear end (12a) passes through the winding roller (48). RO ), estimating the breakage location of the line electrode (12) (P BR ).

Description

Technical Field

[0001] This invention relates to a wire electrical discharge machining (EDM) machine, and more particularly to a device and method for estimating the location of a broken wire electrode. Background Technology

[0002] Japanese Patent Application Publication No. 2019-217559 discloses prior art for wire electrical discharge machining (EDM) machines. The purpose of this prior art is to calculate the breakage location of the wire electrode. Japanese Patent Application Publication No. 2019-217559 also discloses a front-end detection electrode. The front-end detection electrode is disposed in the transport path of the wire electrode. The front-end detection electrode is in contact with the wire electrode. The voltage of the front-end detection electrode varies depending on whether the front-end detection electrode is in contact with the wire electrode.

[0003] In the prior art, the front-end detection electrode is positioned upstream of the breakage location of the wire electrode. The wire electrode is rewound when the breakage occurs. Here, in the prior art, the position where the rewound wire electrode is no longer in contact with the front-end detection electrode is detected based on the change in the voltage of the front-end detection electrode. That is, the prior art detects the front-end position of the wire electrode based on the change in the voltage of the front-end detection electrode. Furthermore, the prior art calculates the breakage location of the wire electrode based on the front-end position of the wire electrode and the amount of rewinding of the wire electrode. Summary of the Invention

[0004] The technology disclosed in Japanese Patent Application Publication No. 2019-217559 has at least the following problems. First, the operator must install the front-end detection electrode in the feed path of the wire electrode. This increases the number of preparation steps for the operator. Second, if the wire electrode upstream of the front-end detection electrode breaks, the front end of the wire electrode is already upstream of the front-end detection electrode at the start of rewinding. Therefore, the front end of the rewinding wire electrode will not reach the front-end detection electrode. Therefore, it is impossible to calculate the breakage location using the technology disclosed in Japanese Patent Application Publication No. 2019-217559. Furthermore, to detect the front end of the wire electrode, it must be rewound (reverse-flowed) in the opposite direction to the feed direction. If the wire electrode is reverse-flowed, it may become entangled due to a momentary impact (beat).

[0005] The purpose of this invention is to provide a device and method for estimating the location of a broken wire, which eliminates the need for a front-end detection electrode and reliably estimates the location of the broken wire electrode.

[0006] A first aspect of the present invention is a wire breakage location estimation device for estimating the breakage location of a wire electrode in a wire electrical discharge machining (EDM) machine. The EDM machine includes: a winding roller that winds the wire electrode, which is fed to and passes through the workpiece; a winding motor that drives the winding roller; and a sensor that outputs a detection signal corresponding to the drive of the shaft of the winding motor. The wire breakage location estimation device includes: a torque acquisition unit that acquires the torque of the winding motor based on the detection signal; a determination unit that, when the wire electrode breaks, determines, based on the torque, whether the rear end of the wire electrode wound by the winding roller has passed through the winding roller; a rotation angle acquisition unit that acquires the rotation angle of the winding motor based on the detection signal; and a wire breakage location estimation unit that estimates the breakage location of the wire electrode based on the rotation angle of the winding motor from the point when the wire electrode breaks until it is determined that the rear end of the wire electrode has passed through the winding roller.

[0007] A second aspect of the present invention is a method for estimating the breakage location of a wire electrode in a wire electrical discharge machining (EDM) machine. The method is characterized by comprising: a winding roller that winds the wire electrode, which is fed to and passes through the workpiece; a winding motor that drives the winding roller; and a sensor that outputs a detection signal corresponding to the drive of the shaft of the winding motor. The method for estimating the breakage location includes: a rotation angle acquisition step, in which the rotation angle of the winding motor is acquired based on the detection signal from the sensor; a torque acquisition step, in which the torque of the winding motor is acquired based on the detection signal from the sensor; a determination step, in the case of a wire electrode breakage, determining, based on the torque, whether the rear end of the wire electrode wound by the winding roller has passed through the winding roller; and a breakage location estimation step, in which the breakage location of the wire electrode is estimated based on the rotation angle of the winding motor from the point of wire electrode breakage until the determination that the rear end of the wire electrode has passed through the winding roller.

[0008] According to the present invention, a device and method for estimating the location of a broken wire electrode are provided, which reliably estimate the location of the broken wire electrode while omitting the front-end detection electrode. Attached Figure Description

[0009] Figure 1 This is a structural diagram of the wire electrical discharge machining machine according to the implementation method.

[0010] Figure 2 This is a structural diagram of the feeding mechanism in the implementation method.

[0011] Figure 3 This is a structural diagram of the wire breakage location estimation device according to the implementation method.

[0012] Figure 4AThis is a diagram of the feeding mechanism when the example wire electrode breaks.

[0013] Figure 4B This is an example from Figure 4A The diagram shows the feeding mechanism after the broken wire electrode passes through the winding roller and pinch roller over time.

[0014] Figure 5 This is a simple example of a graph showing the change in torque of the winding motor before and after the rear end of the wire electrode passes through the winding roller.

[0015] Figure 6 This is a flowchart of the method for estimating the location of a broken wire in an example implementation.

[0016] Figure 7 This is a structural diagram of the device for estimating the location of the broken wire in Modified Example 1.

[0017] Figure 8 This is a diagram showing multiple intervals defined along the delivery path of an example inline electrode.

[0018] Figure 9 The example specifies Figure 8 A table or graph showing the relationship between multiple intervals and the possible causes of line breaks within each interval, along with corresponding solutions.

[0019] Figure 10 This is a flowchart of the method for estimating the location of a broken wire in Example Variation 1. Detailed Implementation

[0020] Hereinafter, preferred embodiments of the wire breakage location estimation device and wire breakage location estimation method of the present invention will be described in detail with reference to the accompanying drawings.

[0021] [Implementation Method]

[0022] Figure 1 This is a structural diagram of the wire electrical discharge machining machine 10 according to the embodiment.

[0023] exist Figure 1 The diagram not only shows the wire electrical discharge machining (EDM) machine 10, but also the X-axis, Y-axis, and Z-axis. The X-axis, Y-axis, and Z-axis are orthogonal to each other. In this embodiment, the X-axis and Y-axis are directional axes parallel to the horizontal plane. In this embodiment, unless otherwise specified, the horizontal direction refers to the XY direction. Furthermore, in this embodiment, the Z-axis is a directional axis parallel to the direction of gravity.

[0024] The wire electrical discharge machine 10 operates by applying a electrode g (refer to) formed between the wire electrode 12 and the workpiece W. Figure 2An industrial machine that generates electrical discharge to perform electrical discharge machining on an object W. The wire electrical discharge machining (EDM) machine 10 includes a machine body 14 and a control device 16. The machine body 14 performs the EDM. The control device 16 controls the machine body 14.

[0025] The main body 14 of the processing machine includes a processing tank 18, a worktable (movable platform) 20, a feed mechanism 22, and a recovery tank 24. The processing tank 18 is a tank for storing processing fluid Lq. The processing fluid Lq is a dielectric liquid. For example, the processing fluid Lq is deionized water.

[0026] The worktable 20 is a pedestal that supports the workpiece W. The worktable 20 is disposed within the machining groove 18. The worktable 20 is capable of moving horizontally. Furthermore, the movable worktable 20 is implemented based on known technology.

[0027] Figure 2 This is a structural diagram of the feed mechanism 22 in the implementation method.

[0028] The feeding mechanism 22 is a mechanism that feeds the wire electrode 12 along a predetermined feed path. The feed path of the wire electrode 12 is the path that sequentially passes through the wire bobbin 30, the feed roller 32, the upper wire guide 38A, the workpiece W, the lower wire guide 38B, and the winding roller 48. Further detailed descriptions of the wire bobbin 30, the feed roller 32, the upper wire guide 38A, the workpiece W, the lower wire guide 38B, and the winding roller 48 will be provided later. The feeding mechanism 22 has a supply system 26 and a recovery system 28. The supply system 26 supplies the wire electrode 12 to the workpiece W. The recovery system 28 recovers the wire electrode 12 that has passed through the workpiece W.

[0029] In addition, Figure 2 The diagram of the worktable 20 supporting the workpiece W is omitted. Additionally, Figure 2 The wire electrode 12 and the workpiece W are depicted adjacent to each other. However, the wire electrode 12 typically passes through a hole penetrating the workpiece W (see reference). Figure 1 ).

[0030] The supply system 26 includes a spool 30, a feed roller 32, two auxiliary rollers 34A, a pipe dies 36A, and an upper wire guide 38A. The spool 30 is a rotatable bobbin. The wire electrode 12 is wound around the spool 30 in a lead-out manner. The feed roller 32 and the two auxiliary rollers 34A are rotatable rollers. The wire electrode 12, leading from the spool 30, is mounted on the feed roller 32. The two auxiliary rollers 34A are positioned between the spool 30 and the feed roller 32. The two auxiliary rollers 34A suppress the deflection of the wire electrode 12. The pipe dies 36A are cylindrical components located downstream of the feed roller 32. The pipe dies 36A guide the wire electrode 12 to the upper wire guide 38A. The upper wire guide 38A is a wire guide that guides the wire electrode 12 from the feed roller 32 to the workpiece W. The upper wire guide 38A is movable in the horizontal direction. An upper electrode pin 40A is provided inside the upper wire guide 38A. The upper electrode pin 40A is connected to a power source (not shown). This power source applies voltage pulses (voltage) to the wire electrode 12 via the upper electrode pin 40A.

[0031] The feed roller 32 and auxiliary roller 34A preferably hold the wire electrode 12 (see reference). Figure 2 Therefore, the possibility of the wire electrode 12 detaching from the feed roller 32 is reduced. Furthermore, the number of auxiliary rollers 34A is not limited to... Figure 2 Examples (2).

[0032] The supply system 26 also includes a torque motor 42 and a feed motor 44. The torque motor 42 is a motor that applies rotational torque to the bobbin 30. This rotational torque is a torque that opposes the feeding direction of the wire electrode 12. This rotational torque applies a force (counter-tension) to the wire electrode 12 in the opposite direction to the feeding direction. The feed motor 44 is, for example, a servo motor. The feed motor 44 is connected to the feed roller 32. The feed motor 44 controls the rotation of the feed roller 32.

[0033] The feed motor 44 has a shaft 44a. Additionally, a sensor 46A is provided on the feed motor 44. The sensor 46A is, for example, a rotary encoder. The sensor 46A outputs a detection signal Si corresponding to the drive of the shaft 44a. A Detection signal Si A Input to control device 16 (refer to) Figure 1 ).

[0034] The recycling system 28 includes a wire guide 38B, an auxiliary roller 34B, a die 36B for lowering the tube, a winding roller 48, and a pinch roller 50. The wire guide 38B is a wire guide that guides the wire electrode 12, which has passed through the workpiece W, towards the winding roller 48. The wire guide 38B is movable in the horizontal direction. A lower electrode pin 40B is provided on the wire guide 38B. The lower electrode pin 40B is connected to a power source (not shown). This power source applies voltage to the wire electrode 12 via the lower electrode pin 40B. Furthermore, the lower electrode pin 40B and the upper electrode pin 40A can also be connected to the same power source. The auxiliary roller 34B is a rotatable roller. The auxiliary roller 34B is located between the wire guide 38B and the winding roller 48. The auxiliary roller 34B suppresses the deflection of the wire electrode 12. The number of auxiliary rollers 34B is not particularly limited. The die 36B for lowering the tube is a cylindrical component located downstream of the wire guide 38B. The lower tube guides the wire electrode 12 toward the winding roller 48 using a die 36B. The winding roller 48 and the pinch roller 50 are both rotatable rollers. The wire electrode 12, having passed through the lower wire guide 38B, is mounted on the winding roller 48. The pinch roller 50, together with the winding roller 48, clamps the wire electrode 12. This reduces the possibility of the wire electrode 12 deflecting.

[0035] The recycling system 28 also includes a winding motor 52. The winding motor 52 is, for example, a servo motor. The winding motor 52 is connected to the winding roller 48. The winding motor 52 controls the rotation of the winding roller 48.

[0036] The winding motor 52 has a shaft 52a. Additionally, a sensor 46B is provided on the winding motor 52. The sensor 46B is, for example, a rotary encoder. The sensor 46B outputs a detection signal Si corresponding to the drive of the shaft 52a. B Detection signal Si B Input to control device 16 (refer to) Figure 1 ).

[0037] The control device 16 includes a motor drive device 54, a motor command device 56, and a disconnection position estimation device 58 (see reference). Figure 1 The motor drive unit 54 drives the torque motor 42, the feed motor 44, and the winding motor 52. The motor command unit 56 outputs a command signal Si to the motor drive unit 54. O .

[0038] The following describes the motor drive device 54, the motor command device 56, and the disconnection position estimation device 58. However, known technologies related to motor control can also be used with respect to the motor drive device 54 and the motor command device 56. Therefore, the description of the motor drive device 54 and the motor command device 56 will be limited to a simple description below.

[0039] The motor instruction device 56 includes a processor and a memory. However, neither the processor nor the memory of the motor instruction device 56 is shown in the figure. A predetermined program is input into the memory of the motor instruction device 56. The processor of the motor instruction device 56 executes the predetermined program. As a result, the motor instruction device 56 outputs an instruction signal Si. O Command signal Si O This is a signal used to specify the rotational speed of the torque motor 42, the feed motor 44, and the winding motor 52. The motor command device 56 can output a command signal Si for specifying the rotational speed of the torque motor 42. O Command signal Si used to specify the rotational speed of feed motor 44 O The command signal Si is used to specify the rotational speed of the winding motor 52. O .

[0040] The motor drive unit 54 suitably includes a motor amplifier (motor driver). The motor drive unit 54 is based on the input command signal Si. O Drive current is supplied to torque motor 42, feed motor 44, and winding motor 52. Torque motor 42, feed motor 44, and winding motor 52 are driven according to the supplied drive current.

[0041] The motor drive unit 54 acquires the detection signal Si A and detection signal Si B The motor drive unit 54 is based on the detection signal Si. A and detection signal Si B Feedback control is implemented. For example, sometimes it is controlled by a command signal Si. O The specified rotational speed of the feed motor 44 differs from the actual rotational speed of the feed motor 44. In this case, the motor drive unit 54 operates based on the detection signal Si. A This adjusts the drive current supplied to the feed motor 44. Consequently, the actual rotational speed of the feed motor 44 is close to that determined by the command signal Si. O The specified rotational speed. Additionally, for example, sometimes it is determined by the command signal Si. O The specified rotational speed of the winding motor 52 differs from the actual rotational speed of the winding motor 52. In this case, the motor drive unit 54 operates based on the detection signal Si. B The drive current supplied to the winding motor 52 is adjusted. As a result, the actual rotational speed of the winding motor 52 is close to that determined by the command signal Si. O The specified rotation speed.

[0042] The motor command device 56 and motor drive device 54, as described above, drive the feed motor 44 and winding motor 52 to feed the wire electrode 12 from the spool 30 to the recovery box 24. Furthermore, the motor command device 56 and motor drive device 54 apply counter-tension to the wire electrode 12 by controlling the torque motor 42. The motor command device 56 and motor drive device 54, by appropriately controlling the feed motor 44, winding motor 52, and torque motor 42, tension the wire electrode 12 between the feed roller 32 and the winding roller 48.

[0043] An electrode gap g is formed between the tensioned wire electrode 12 and the workpiece W (refer to...). Figure 2 The wire electrical discharge machining (EDM) machine 10 applies a voltage to the wire electrode 12 via the upper electrode pin 40A and the lower electrode pin 40B, thereby generating a discharge between the electrodes g. Furthermore, the wire EDM machine 10 moves the wire electrode 12 relative to the workpiece W while generating a discharge between the electrodes g. As a result, the workpiece W is processed into the shape of the finished product. Relatedly, the control device 16 performs movement control of the worktable 20, the upper wire guide 38A, and the lower wire guide 38B, as well as control of the voltage applied to the wire electrode 12.

[0044] Figure 3 This is a structural diagram of the wire break location estimation device 58 in the implementation method.

[0045] The wire break location estimation device 58 includes a display unit 60, an operation unit 62, a storage unit 64, and a calculation unit 66 (see reference). Figure 3 ).

[0046] Display unit 60 is a display that shows information to the operator. Display unit 60 includes, for example, a display screen. Furthermore, display unit 60 can display not only information related to the disconnection location estimation device 58, but also, for example, information related to the motor command device 56. The display screen of display unit 60 may have, for example, a liquid crystal panel. However, the material of the display screen of display unit 60 is not limited to liquid crystal. For example, the material of the display screen of display unit 60 may also include organic EL (OEL: Organic Electro-Luminescence).

[0047] The operation unit 62 is provided for the operator to issue instructions to the wire breakage location estimation device 58. The operation unit 62 includes, for example, a keyboard (multiple operation keys), a mouse, and a touch panel. The touch panel is provided, for example, on the display unit 60. In addition, the operation unit 62 can handle not only operator instructions related to the wire breakage location estimation device 58, but also operator instructions related to the motor command device 56.

[0048] Storage unit 64 includes memory. For example, storage unit 64 includes RAM (Random Access Memory) and ROM (Read Only Memory). The memory of storage unit 64 and the memory (not shown) of motor instruction device 56 may overlap.

[0049] Storage unit 64 stores the wire breakage location estimation program 68. The wire breakage location estimation program 68 is used to ensure that the wire breakage location estimation device 58 reliably estimates the wire breakage location P of the wire electrode 12. BR (Refer to Figure 4A The procedure for estimating the location of a broken wire.

[0050] The arithmetic unit 66 includes a processor. For example, the arithmetic unit 66 includes a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The processor of the arithmetic unit 66 and the processor (not shown) of the motor instruction device 56 may also overlap.

[0051] The calculation unit 66 includes a torque acquisition unit 70, a determination unit 72, a rotation angle acquisition unit 74, a wire break position estimation unit 76, and a display control unit 78. The torque acquisition unit 70, the determination unit 72, the rotation angle acquisition unit 74, the wire break position estimation unit 76, and the display control unit 78 are implemented by the calculation unit 66 executing the wire break position estimation program 68.

[0052] The torque acquisition unit 70 acquires the rotational torque Tq (hereinafter simply referred to as torque Tq) of the shaft 52a of the winding motor 52. Torque Tq is acquired, for example, by the motor drive device 54 or the motor command device 56 based on the detection signal Si from the sensor 46B. B The torque acquisition unit 70 calculates the torque Tq from the motor drive device 54 or the motor command device 56. However, the torque acquisition unit 70 can also calculate the torque Tq based on the detection signal Si. B The torque Tq is calculated. In this case, the torque acquisition unit 70 acquires the detection signal Si. B Detection signal Si B For example, it can be obtained from the electric motor drive unit 54.

[0053] The torque acquisition unit 70 inputs the acquired torque Tq to the determination unit 72.

[0054] The determination unit 72 determines the rear end 12a of the line electrode 12 based on the torque Tq. Figure 4A Whether it has passed through the winding roller 48. The following explains the relationship between the breakage of the wire electrode 12 and the torque Tq in relation to this determination.

[0055] Figure 4A This is a diagram of the feed mechanism 22 when the example wire electrode 12 breaks.

[0056] During the feeding process of the wire electrode 12, the wire electrode 12 rubs against the winding roller 48. Therefore, a frictional force F acts on the wire electrode 12 (refer to...). Figure 2 Frictional force F is the force (load) that opposes the rotation of shaft 52a. Therefore, in the case where frictional force F acts on wire electrode 12 and in the case where frictional force F does not act on wire electrode 12, the drive current of the winding motor 52 required to rotate the winding roller 48 at a specified rotational speed is greater when frictional force F acts on wire electrode 12. The motor drive device 54, in order to follow the command signal Si... O The winding motor 52 is driven by supplying a driving current larger than that provided when the frictional force F does not act on the wire electrode 12. That is, the motor drive device 54 supplies a driving current larger than that provided when the frictional force F does not act to the winding motor 52 in order to maintain the rotational speed and torque Tq of the winding motor 52 within a specified range. During the winding of the wire electrode 12 by the winding roller 48, a frictional force F is generated even after the wire electrode 12 breaks (see reference). Figure 4A ).

[0057] Figure 4B This is an example from Figure 4A The diagram shows the feeding mechanism 22 after the wire electrode 12, which breaks over time, passes through the winding roller 48 and the pinch roller 50.

[0058] The rear end 12a of the wire electrode 12 passes through the winding roller 48, thereby eliminating the frictional force F (see reference). Figure 4B As a result, the load applied to the winding roller 48 decreases. Subsequently, depending on the amount of load reduction, the drive current of the winding motor 52 required to rotate the winding roller 48 at a specified rotational speed decreases. Therefore, the motor drive unit 54 reduces the drive current supplied to the winding motor 52. Here, there is a time difference from the disappearance of the frictional force F to the change in the drive current of the winding motor 52. During this time period, a larger drive current, taking into account the frictional force F, is supplied to the winding motor 52 when the frictional force F is not acting.

[0059] Figure 5 This is a simple example of a graph showing the change in torque Tq of the winding motor 52 before and after the rear end 12a of the line electrode 12 passes through the winding roller 48 (vertical axis: torque Tq, horizontal axis: time). Figure 5 The time point t (hereinafter referred to as the line passage time point) represents the time point at which the rear end 12a of the line electrode 12 passes through the winding roller 48 (between the winding roller 48 and the pinch roller 50).

[0060] exist Figure 5 The chart provides a simple example. Figures 4A-4B The torque Tq changes between the points. The torque Tq increases sharply from the point t when the line passes through. This is because a larger driving current, taking into account the frictional force F, is supplied to the winding roller 48 where the frictional force F is not acting.

[0061] Based on the above, the determination unit 72 will be explained again. In the event of a wire breakage in the wire electrode 12, the determination unit 72 determines whether the rear end 12a of the wire electrode 12 wound by the winding roller 48 has passed through the winding roller 48, based on the rate of change of torque Tq per unit time. For example, if the rate of change exceeds a predetermined threshold after the wire breakage occurs, the determination unit 72 determines that the rear end 12a has passed through the winding roller 48. Furthermore, the threshold is, for example, predetermined based on experiments.

[0062] Furthermore, the winding of the wire electrode 12 by the winding roller 48 refers to the feeding of the wire electrode 12 towards the recycling bin 24 based on the rotation of the winding roller 48. It is not necessary to reverse the direction of the wire electrode 12. The winding motor 52 during the winding process is controlled by the motor drive device 54 and the motor command device 56.

[0063] In order to make the above determination, the determination unit 72 obtains the time of wire breakage of the wire electrode 12. Here, known techniques related to wire breakage detection are used to obtain the time of wire breakage of the wire electrode 12. For example, the wire breakage detection unit (tension sensor) disclosed in Japanese Patent Application Publication No. 2019-217559 is used.

[0064] The rotation angle acquisition unit 74 acquires the rotation angle A of the winding motor 52. RO Rotation angle A RO Capable of detecting signal Si B To calculate. Furthermore, the motor drive unit 54 or the motor command unit 56 can also be based on the detection signal Si. B To calculate the rotation angle A RO . Figure 3 The rotation angle acquisition unit 74 obtains the rotation angle A from the motor drive device 54 or the motor command device 56. RO .

[0065] The rotation angle acquisition unit 74 specifically acquires the rotation angle (rotation amount) A from the time the wire electrode 12 breaks until it is determined that the rear end 12a has passed the winding roller 48. RO The rotation angle A during the period from the breakage of wire electrode 12 to the determination that the rear end 12a has passed the winding roller 48. RO It is input to the disconnection location estimation unit 76.

[0066] The wire breakage location estimation unit 76 calculates the wire length L of the wire electrode 12 from the breakage of the wire electrode 12 to the point where the rear end 12a passes through the winding roller 48. W Line length LW It can obtain the rotation angle A input from the rotation angle acquisition unit 74. RO The calculation is based on the diameter of the winding roller 48. Here, the winding roller 48 is known information. Alternatively, the diameter of the winding roller 48 can also be the radius of the winding roller 48. Next, the wire breakage position estimation unit 76 calculates based on the wire length L. W Presumed location P of the break in the wire electrode 12 in the delivery path BR The wire breakage location estimation unit 76 returns the wire length L upstream from the position of the winding roller 48 in the delivery path of the wire electrode 12. W The length of the line is presumed to be the location of the break point P. BR (Refer to Figure 4A ).

[0067] The breakage location estimation unit 76 will estimate the result (breakage location P). BR Output to display control unit 78.

[0068] The display control unit 78 controls the display unit 60. The display control unit 78 causes the display unit 60 to display the estimation result input from the wire breakage location estimation unit 76. Thus, the operator can grasp the estimated wire breakage location P through the display unit 60. BR The display control unit 78, for example, indicates the broken wire position P. BR The message is displayed. However, the display control unit 78 may also use, for example, a drawing showing the structure of the feed mechanism 22, so that the position P corresponding to the break line in that drawing is shown. BR The designated icons are displayed in the specified areas.

[0069] In this embodiment, the wire breakage location estimation device 58 estimates the wire breakage location P of the wire electrode 12 based on the drive information of the winding motor 52 obtained from the sensor 46B. BR Therefore, the wire breakage location estimation device 58 can estimate the wire breakage location P over the entire range upstream of the winding roller 48 in the delivery path. BR Additionally, the wire break location estimation device 58 determines the break location based on the detection signal Si. B The position of the rear end 12a of the detection wire electrode 12 is determined. Therefore, in this embodiment, it is not necessary to separately provide a front end detection electrode or reverse the wire electrode 12 after wire breakage. Since it is not necessary to reverse the wire electrode 12, the wire electrode 12 will not become entangled due to reversal.

[0070] Figure 6 This is a flowchart of the method for estimating the location of a broken wire in an example implementation.

[0071] The following describes the method for estimating the location of a broken wire. The method is executed by the broken wire location estimation device 58. The broken wire location estimation method includes a rotation angle acquisition step S1, a torque acquisition step S2, a determination step S3, a broken wire location estimation step S4, and a display step S5 (see reference). Figure 6 ).

[0072] The method for estimating the location of a broken wire, for example, automatically starts (START) in the event of a broken wire at wire electrode 12.

[0073] In the rotation angle acquisition step S1, the rotation angle acquisition unit 74 acquires the detection signal Si from the sensor 46B. B Obtain the rotation angle A of the winding motor 52 RO Here, the winding motor 52 continues to rotate to feed the wire electrode 12 to the recycling bin 24. Alternatively, the feed motor 44 can be stopped.

[0074] In the torque acquisition step S2, the torque acquisition unit 70 acquires the torque based on the detection signal Si from the sensor 46B. B Obtain the torque Tq of the winding motor 52.

[0075] In the determination step S3, the determination unit 72 determines, based on the torque Tq, whether the rear end 12a of the wire electrode 12 wound by the winding roller 48 has passed through the winding roller 48.

[0076] If the determination result indicates that the rear end 12a has passed the winding roller 48 (S3: Yes), the process proceeds to the wire breakage position estimation step S4. Conversely, if the determination indicates that the rear end 12a has not passed the winding roller 48 (S3: No), the rotation angle acquisition step S1 and the torque acquisition step S2 are executed again. Thus, the rotation angle A during the period from the occurrence of wire breakage to the rear end 12a of the wire electrode 12 passing the winding roller 48 is obtained. RO .

[0077] In the break-line location estimation step S4, the break-line location estimation unit 76 estimates the break-line location P of the wire electrode 12. BR .

[0078] In step S5, the broken wire position P is estimated based on the broken wire position in step S4. BR Based on the estimated result, the display control unit 78 causes the display unit 60 to display the broken wire position P. BR The above is an explanation of the method for estimating the location of the broken wire in this embodiment.

[0079] [Variation Example]

[0080] The above description illustrates an embodiment of the present invention. Various modifications or improvements can be made to the above embodiment. Furthermore, as can be seen from the scope of the claimed patent, such modifications or improvements can be included within the technical scope of the present invention.

[0081] The following describes variations of the embodiments. However, descriptions that are repeated in the embodiments will be omitted as much as possible in the following description. In the following description, unless otherwise specified, the constituent elements described in the embodiments will be marked with the same reference numerals as in the embodiments.

[0082] (Variation Example 1)

[0083] Figure 7 This is a structural diagram of the wire breakage location estimation device 58A(58) of Modified Example 1.

[0084] The broken wire location estimation device 58A also includes a table 80 and a cause response determination unit 82.

[0085] Table 80 shows the location P of the broken wire of wire electrode 12. BR A table showing the correspondence between the causes of line breakage and the corresponding solutions. Table 80 is pre-stored in storage unit 64.

[0086] Figure 8 This is a diagram showing multiple intervals defined on the delivery path of example online electrode 12.

[0087] The delivery path of the wire electrode 12 is divided into multiple intervals. Figure 8 Six intervals [1] to [6] are shown for dividing the feed path. Interval [1] is the interval from the feed roller 32 to the upper guide 38A. Interval [2] is the interval containing the upper guide 38A. Interval [3] is the interval containing the upper or lower surface of the workpiece W. Interval [4] is the interval containing the portion (central portion) other than the upper and lower surfaces of the workpiece W. Interval [5] is the interval containing the lower guide 38B. Interval [6] is the interval downstream of the lower guide 38B. In addition, the above distinctions are examples for illustration. Therefore, the method of dividing the feed path and the number of intervals are not limited to Figure 8 Examples.

[0088] Figure 9 The example specifies Figure 8 Table 80 shows the correspondence between multiple intervals and the possible causes of line breaks within each interval, as well as the corresponding solutions.

[0089] The candidate cause of the wire breakage of line electrode 12 is based on the breakage location P. BRThe following are examples of possible causes of wire breakage in interval [1]: wear of the upper guide 38A (upper electrode pin 40A), poor cleaning of the upper tube die 36A, and abnormalities near the feed roller 32. In addition, as a solution to the case of wire breakage in interval [1], the following can be mentioned: inspection of the upper guide 38A (upper electrode pin 40A), replacement of the upper guide 38A, cleaning of the upper tube die 36A, inspection of the feed roller 32, and replacement of the feed roller 32.

[0090] exist Figure 9 In Table 80, multiple intervals [1] to [6] are specified in the leftmost column. Figure 9 In Table 80, the reasons for the line breaks corresponding to each interval are specified in the central column. Figure 9 In Table 80, the corresponding solutions for each interval are specified in the rightmost column. However, Figure 9 Table 80 is an example. Therefore, the specific content of Table 80 is not limited to... Figure 9 Examples.

[0091] The cause determination unit 82, for example, can be virtually implemented by the calculation unit 66 executing a prescribed program, similar to the torque acquisition unit 70.

[0092] Cause determination unit 82 determines the broken wire location P estimated by broken wire location estimation unit 76. BR Which interval [1] to [6] does it belong to? Furthermore, the cause determination unit 82, based on this determination result, determines the location P of the broken line. BR The corresponding causes of the disconnection and corresponding solutions. Here, the cause and solution determination section 82 refers to Table 80 as needed.

[0093] In this modified example, the display control unit 78 enables the display unit 60 to display not only the break position P. BR It also displays the cause and response method determined by the cause and response determination unit 82. This allows the operator to efficiently handle wire breakage of the line electrode 12.

[0094] Figure 10 This is a flowchart of the method for estimating the location of a broken wire in Example Variation 1.

[0095] The wire break location estimation device 58A can achieve Figure 10 Method for estimating the location of a broken wire. Figure 10 The method for estimating the location of a broken wire includes steps S1 (obtaining the rotation angle), S2 (obtaining the torque), S3 (judging), S4 (estimating the location of the broken wire), S6 (determining the cause and response), and S7 (displaying).

[0096] The reasons for determining step S6 and display step S7 will be explained below. Furthermore, the explanations of steps S1 (obtaining the rotation angle) to S4 (estimating the break position) are omitted (see the embodiment).

[0097] The cause determination step S6 is performed after the break location estimation step S4. In the cause determination step S6, the cause determination unit 82 determines the break location P, which was estimated in the break location estimation step S4, according to Table 80. BR The corresponding cause of the disconnection and the corresponding solution. Here, the cause and solution determination unit 82 may determine only one of the cause of the disconnection and the solution.

[0098] The display step S7 is executed after the cause response determination step S6. In the display step S7, the display control unit 78 causes the display unit 60 to display the broken wire position P. BR Causes of wire breakage and corresponding solutions. Thus, the method for estimating the location of the wire breakage in this variation is complete (return).

[0099] Alternatively, Table 80 may only include the location P of the broken line. BR The corresponding cause of the disconnection and the corresponding solution. In this case, the cause and solution determination unit 82 determines the cause of the disconnection or the solution.

[0100] (Variation Example 2)

[0101] The determination unit 72 can also determine whether the rear end 12a of the wire electrode 12 has passed the winding roller 48 based on whether the obtained torque Tq has deviated from the range predetermined for the torque Tq.

[0102] (Variation Example 3)

[0103] The torque acquisition unit 70 can also substantially acquire the torque Tq by acquiring a physical quantity that varies according to the torque Tq. The physical quantity that varies according to the torque Tq is not particularly limited as long as it varies according to the torque Tq, such as the drive current of the winding motor 52 or the rotational speed of the winding motor 52.

[0104] (Variation Example 4)

[0105] The wire break location estimation device 58 can also be an electronic device separate from the control device 16 (motor command device 56, motor drive device 54). In this case, the wire break location estimation device 58 obtains the torque Tq or rotation angle A from the control device 16, for example, via a network (wired / wireless). RO .

[0106] (Variation Example 5)

[0107] The above variations can be appropriately combined as long as they are within the range of non-contradiction.

[0108] [Invention obtained from implementation methods]

[0109] The invention described below can be understood from the embodiments and variations thereof.

[0110] <First Invention>

[0111] The first invention is a wire breakage location estimation device (58) that estimates the wire breakage location (P) of the wire electrode (12) in the wire electrical discharge machine (10). BR The wire electrical discharge machining (EDM) machine comprises: a winding roller (48) that winds and feeds the workpiece (W) through the wire electrode of the workpiece; a winding motor (52) that drives the winding roller; and a sensor (46B) that outputs a detection signal (Si) corresponding to the drive of the shaft (52a) of the winding motor. B The wire breakage location estimation device includes: a torque acquisition unit (70) that acquires the torque (Tq) of the winding motor based on the detection signal; a determination unit (72) that, when the wire electrode breaks, determines, based on the torque, whether the rear end (12a) of the wire electrode wound by the winding roller has passed the winding roller; and a rotation angle acquisition unit (74) that acquires the rotation angle (A) of the winding motor according to the detection signal. RO ); and a wire breakage location estimation unit (76), which estimates the wire breakage location of the wire electrode based on the rotation angle of the winding motor from the wire breakage to the point where the rear end of the wire electrode is determined to have passed the winding roller.

[0112] Therefore, a device for estimating the location of a broken wire electrode is provided, which can reliably estimate the location of the broken wire electrode while omitting the front-end detection electrode.

[0113] Alternatively, the determination unit can determine whether the rear end of the wire electrode has passed the winding roller based on the rate of change of the torque per unit time. This allows for the detection of the rear end without relying on the front-end detection electrode and without requiring the wire electrode to reverse.

[0114] Alternatively, the determination unit may determine whether the rear end of the wire electrode has passed the winding roller based on whether the obtained torque deviates from a predetermined range for the torque. This allows for the detection of the rear end without relying on the front-end detection electrode or requiring the wire electrode to reverse.

[0115] Alternatively, the wire breakage location estimation device may further include: a table (80) that establishes a correspondence between the wire breakage location and at least one of the causes of the breakage and the corresponding countermeasures; a cause and countermeasure determination unit (82) that determines, based on the table, at least one of the causes of the breakage and the corresponding countermeasures corresponding to the breakage location estimated by the wire breakage location estimation unit; and a display control unit (78) that causes the display unit (60) to display the determined causes of the breakage and at least one of the countermeasures. Thus, the operator can effectively respond to the situation of wire electrode breakage.

[0116] Alternatively, the wire break location estimation device may be installed in the control device (16) that controls the wire EDM machine.

[0117] <Second Invention>

[0118] A method for estimating the location of a broken wire, wherein the broken wire location (P) of the wire electrode (12) in the wire electrical discharge machine (10) is estimated. BR The wire electrical discharge machining (EDM) machine comprises: a winding roller (48) that winds and feeds the workpiece (W) through the wire electrode of the workpiece; a winding motor (52) that drives the winding roller; and a sensor (46B) that outputs a detection signal (Si) corresponding to the drive of the shaft (52a) of the winding motor. B The method for estimating the location of the broken wire includes: a rotation angle acquisition step (S1), which obtains the rotation angle (A) of the winding motor based on the detection signal of the sensor. RO The process includes: a torque acquisition step (S2), in which the torque (Tq) of the winding motor is acquired based on the detection signal of the sensor; a determination step (S3), in the case of wire electrode breakage, determining whether the rear end (12a) of the wire electrode wound by the winding roller has passed the winding roller based on the torque; and a breakage position estimation step (S4), in which the breakage position of the wire electrode is estimated based on the rotation angle of the winding motor from the time the wire electrode breaks until it is determined that the rear end of the wire electrode has passed the winding roller.

[0119] Therefore, a method for estimating the location of a broken wire electrode with good reliability is provided, which can omit the front-end detection electrode.

Claims

1. A broken wire position estimation device (58) that estimates a broken wire position (P BR ) of a wire electrode (12) that is fed along a prescribed feed path through a work object (W) in a wire electrical discharge machine (10), The wire electric discharge machine is provided with: ​ a winding roller (48) disposed downstream of the work object in the prescribed feed path, which winds the wire electrode that has been fed to the work object and passed through the work object; a winding motor (52) that drives the winding roller; and a sensor (46B) that outputs a detection signal (Si) corresponding to driving of a shaft (52a) of the winding motor B ), The broken wire position estimation device is provided with: a torque acquisition unit (70) that acquires the torque (Tq) of the winding motor from the detection signal; a determination unit (72) that determines, after the wire electrode breaks, whether the rear end (12a) of the wire electrode passes through the winding roller as a result of the wire electrode after breaking being wound by the winding roller; A rotation angle acquisition unit (74) acquires a rotation angle (A) of the winding motor from the detection signal RO ); and a broken wire position estimation unit (76) that estimates the broken wire position of the wire electrode from the rotational angle of the winding motor from when the wire electrode breaks to when the rear end of the wire electrode is determined to have passed through the winding roller.

2. The broken wire position estimation device according to claim 1, wherein the determination unit determines whether the rear end of the wire electrode has passed through the winding roller based on the rate of change per unit time of the torque.

3. The broken wire position estimation device according to claim 1, wherein the determination unit determines whether the rear end of the wire electrode has passed through the winding roller based on whether the acquired torque has deviated from a range that is determined in advance for the torque.

4. The broken wire position estimation device according to any one of claims 1 to 3, further provided with: a table (80) that establishes a correspondence between the broken wire position of the wire electrode and at least one of the broken wire cause and the countermeasure method; a cause countermeasure determination unit (82) that determines at least one of the broken wire cause and the countermeasure method that corresponds to the broken wire position estimated by the broken wire position estimation unit, based on the table; and a display control unit (78) that causes a display unit (60) to display at least one of the determined broken wire cause and the countermeasure method.

5. The broken wire position estimation device according to any one of claims 1 to 3, wherein the broken wire position estimation device is included in a control device (16) that controls the wire electric discharge machine. The wire electric discharge machine is provided with: a winding roller (48) disposed downstream of the work object in the prescribed feed path, which winds the wire electrode that has been fed to the work object and passed through the work object; 6. A broken wire position estimation method of estimating a broken wire position (P of a wire electrode (12) that is fed along a prescribed feed path through a work object (W) in a wire electrical discharge machine (10 BR ), characterized by, a winding motor (52) that drives the winding roller; and The broken wire position estimation method includes: a torque acquisition step (S2) of acquiring the torque (Tq) of the winding motor from the detection signal of the sensor; a sensor (46B) that outputs a detection signal (Si) corresponding to driving of a shaft (52a) of the winding motor B ), a determination step (S3) of determining, after the wire electrode breaks, whether the rear end (12a) of the wire electrode passes through the winding roller as a result of the wire electrode after breaking being wound by the winding roller; and A rotation angle acquisition step (S1) acquires a rotation angle (A) of the winding motor from a detection signal of the sensor RO ); a broken wire position estimation step (S4) of estimating the broken wire position of the wire electrode from the rotational angle of the winding motor from when the wire electrode breaks to when the rear end of the wire electrode is determined to have passed through the winding roller. ​ A broken wire position estimation step (S4) estimates the broken wire position of the wire electrode based on the rotation angle of the winding motor from the wire electrode breaking to the rear end of the wire electrode being determined to have passed the winding roller.

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