Control device for wire electric discharge machine, control program for wire electric discharge machine, and control method for wire electric discharge machine

Abstract

A control device (2) for a wire electric discharge machine (1) controls the wire electric discharge machine (1) for applying a voltage between a wire electrode (11) and an object to be machined (4) to generate electric discharge, thereby performing removal machining on the object to be machined (4). When a wire electric discharge machine (1) detects a short circuit on the basis of a value to be monitored, which is at least one of a machining current and a machining voltage during machining, power supply to a wire electrode (11) is stopped and machining is interrupted, and the wire electrode (11) is moved at a predetermined retreat distance in an offset direction in which the distance between the wire electrode (11) and a machining surface of an object to be machined (4) increases. After the wire electrode (11) has been withdrawn for a predetermined withdrawal time, the wire electrode (11) is made to approach the machining surface again and resume machining.

Description

Technical Field

[0001] The present invention relates to a control device for a wire electric discharge machine for removing a processing object by generating electric discharge between a wire electrode and the processing object, a control program for the wire electric discharge machine, and a control method for the wire electric discharge machine. Background Art

[0002] The wire EDM generates discharge by generating a voltage between the wire electrode and the object to be processed, thereby removing the object to be processed. In the wire EDM, in order to obtain the desired shape and the desired surface roughness, the wire electrode is usually rotated multiple times along the trajectory of the desired shape to repeat the processing. During the repeated processing, the offset of the wire electrode relative to the desired shape is continuously changed at each repetition, and the input processing energy is continuously reduced, thereby gradually reducing the surface roughness. At this time, as the input processing energy decreases, the processing amount decreases, and therefore the distance between the wire electrode and the object to be processed is continuously shortened. If the wire electrode vibrates and processing chips are generated in this state, the wire electrode and the object to be processed may contact and cause a short circuit.

[0003] Patent Document 1 discloses a technique for retracting a wire electrode in order to release the short circuit when a short circuit is detected. In the technique disclosed in Patent Document 1, when a short circuit is detected, the wire electrode is retracted by a predetermined distance, and if the short circuit is not released at this time, it is determined that a short circuit has occurred in a direction perpendicular to the traveling direction of the wire electrode, and the retracting direction and retracting distance of the wire electrode are determined.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 5-77109 Summary of the invention

[0005] However, according to the above-mentioned conventional technology, the time from when the wire electrode is retracted until the machining is resumed, i.e., the machining reset time, is not taken into consideration. If the machining reset time is short, machining chips may not be sufficiently removed, or the vibration of the wire electrode may not converge, resulting in repeated short circuits, thereby causing a problem of reduced machining accuracy.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for a wire electrical discharge machine that can suppress a decrease in machining accuracy even when a short circuit occurs.

[0007] In order to solve the above-mentioned problems and achieve the purpose, the control device of the wire electric discharge machine involved in the present invention controls the wire electric discharge machine, and the wire electric discharge machine applies a voltage between a wire electrode and a processing object to generate discharge, thereby removing the processing of the processing object. The control device of the wire electric discharge machine is characterized in that when the wire electric discharge machine detects a short circuit based on at least one of the processing current and the processing voltage during processing, that is, the monitoring object value, the power supply to the wire electrode is stopped to interrupt the processing, and the wire electrode is moved by a predetermined retreat distance in an offset direction in which the distance between the wire electrode and the processing surface of the processing object increases, thereby retreating the wire electrode, and after a predetermined retreat time has passed after the wire electrode is retreated, the wire electrode is brought close to the processing surface again to resume the processing.

[0008] Effects of the Invention

[0009] The control device for a wire electrical discharge machine according to the present invention has an effect of being able to suppress a decrease in machining accuracy even when a short circuit occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a diagram showing the configuration of the wire electrical discharge machining system according to the first embodiment.

[0011] Figure 2 This is an explanatory diagram of the causes of machining lines during finishing.

[0012] Figure 3 It is an explanatory diagram of the evacuation process and the reprocessing process when a short circuit occurs in the first embodiment.

[0013] Figure 4 This is a flowchart for explaining the processing control operation involved in the second embodiment.

[0014] Figure 5 It is a diagram showing the configuration of a wire electrical discharge machining system according to a third embodiment.

[0015] Figure 6 It is an explanatory diagram of the escape process and the reprocessing process when a short circuit occurs in the third embodiment.

[0016] Figure 7 This is a flowchart for explaining the processing control operation involved in the third embodiment.

[0017] Figure 8 This is a diagram showing a first example of a short circuit to be detected in the fourth embodiment.

[0018] Fig. 9 This is a diagram showing a second example of a short circuit to be detected in the fourth embodiment.

[0019] Fig.10 It is a diagram showing the retreat direction and the re-approach direction of the wire electrode in the fifth embodiment.

[0020] Fig.11 This is a diagram showing the structure of a learning device related to a wire electrical discharge machine.

[0021] Fig.12 is a diagram showing an example of a neural network.

[0022] Fig.13 This is a flowchart related to the learning process of the learning device.

[0023] Fig.14 This is a diagram showing the structure of an inference device related to a wire electrical discharge machine.

[0024] Fig.15 This is a flowchart related to the inference processing of the inference device.

[0025] Fig.16 This is a diagram showing a first example of the hardware configuration of the wire electrical discharge machining system.

[0026] Fig.17 It is a diagram showing a second example of the hardware configuration of the wire electrical discharge machining system. DETAILED DESCRIPTION

[0027] Hereinafter, a control device for a wire electrical discharge machine, a control program for a wire electrical discharge machine, and a control method for a wire electrical discharge machine according to embodiments of the present invention will be described in detail with reference to the drawings.

[0028] Implementation method 1.

[0029] Figure 1 1 is a diagram showing a configuration of a wire electrical discharge machining system 100 according to Embodiment 1. The wire electrical discharge machining system 100 includes: a wire electrical discharge machining machine 1 that performs a removal process on a machining object 4; a control device 2 that controls the wire electrical discharge machining machine 1; a power supply device 3 that supplies power to the wire electrical discharge machining machine 1; and a detection unit 5 that detects a state of the wire electrical discharge machining machine 1.

[0030] The wire electrical discharge machine 1 has a function of performing a removal process on a processing object 4. The wire electrical discharge machine 1 includes a wire electrode 11, a position adjustment unit 12 that adjusts the relative position between the wire electrode 11 and the processing object 4, and a power supply unit 13 that supplies power from a power supply device 3 to the wire electrode 11 to provide processing energy.

[0031] The wire discharge machining machine 1 repeatedly performs multiple processes until a processed shape corresponding to a desired shape is obtained. The first process performed among the multiple processes is called rough processing, which is a process that places more emphasis on processing speed than on shape accuracy. The second and subsequent processes among the multiple processes are called finishing processing. Finishing processing is performed more than or equal to one time, and when it is repeated multiple times, finishing processing is performed in a manner that gradually improves the shape accuracy.

[0032] The control device 2 gives a position command indicating the relative position between the wire electrode 11 and the object 4 to the position adjustment unit 12 of the wire electrical discharge machine 1 and gives a power supply command to the power supply device 3 , thereby controlling the removal process of the object 4 by the wire electrical discharge machine 1 .

[0033] The detection unit 5 detects at least one of the machining current and the machining voltage, that is, a monitoring target value, and outputs the detected monitoring target value to the control device 2 .

[0034] The control device 2 can detect a short circuit between the wire electrode 11 and the object 4 based on the monitoring target value output by the detection unit 5. When a short circuit is detected, the control device 2 sequentially performs a retraction process of the wire electrode 11 and a re-machining process of resuming machining after the retraction process.

[0035] Here, a description will be given of machining defects that occur when a short circuit occurs during finish machining. Figure 2 This is an explanatory diagram of the cause of machining streaks in finishing. Finishing requires less machining energy than roughing to make the surface roughness finer, so the wire electrode 11 is closer to the machining surface than roughing. Figure 2 In the example shown, finishing machining is performed while the wire electrode 11 is moved in the machining direction D1. In this state, when machining chips 41 are generated and contact the wire electrode 11, the machining chips 41 may contact the machining object 4 because the distance between the wire electrode 11 and the machining surface of the machining object 4 is close. In this case, a short circuit occurs between the wire electrode 11 and the machining object 4. If machining is continued in this state and the machining chips 41 are removed, the short circuit can be resolved, but since no discharge occurs in the short-circuited portion, the machining object 4 is not cut, and the cut remaining portion of the machining object 4 becomes convex compared to the normally machined surface, and is recognized as a machining streak 42.

[0036] Figure 3 1 is an explanatory diagram of the avoidance process and the reprocessing process when a short circuit occurs in the first embodiment. Figure 3In the example shown, machining is performed while the wire electrode 11 is moved in the machining direction D1. Here, if the machining chips 41 contact the wire electrode 11 and a short circuit occurs, the control device 2 detects the short circuit based on at least one of the machining current and the machining voltage, that is, the monitoring object value. If a short circuit is detected, the control device 2 stops the power supply to the wire electrode 11 and interrupts the machining, and causes the wire electrode 11 to retreat in the retreat direction D2. The retreat direction D2 is an offset direction in which the distance of the wire electrode 11 from the machining surface of the machining object 4 increases, and is preferably set to a direction obliquely backward relative to the machining direction D1 so that the distance relative to the inclined surface 45 connecting the previous machining surface 43 and the machining surface 44 being machined also increases. In addition, the retreat path is set so as not to contact the machining surface during retreat. The control device 2 moves the wire electrode 11 by a predetermined retreat distance. In this way, the short circuit can be eliminated.

[0037] If the short circuit can be eliminated, the control device 2 resumes the processing of the processing object 4. At this time, the control device 2 makes the wire electrode 11 retreat, and then after a predetermined retreat time, makes the wire electrode 11 approach the processing surface. The reapproach direction D3 at this time is, for example, the opposite direction of the retreat direction D2. The control device 2 resumes the power supply to the wire electrode 11 until the wire electrode 11 and the processing object 4 approach to a distance at which discharge occurs for the applied processing voltage and processing current. In this way, it is possible to suppress the occurrence of discharge on the processing surface 44 that has been processed again and suppress over-processing.

[0038] Implementation method 2.

[0039] Figure 4 1 is a flowchart for explaining the machining control action involved in Embodiment 2. After machining starts, the control device 2 obtains at least one of the machining current and the machining voltage as a monitoring object value (step S101). The control device 2 determines whether a short circuit is detected based on the obtained monitoring object value (step S102). Here, the control device 2 can determine that a short circuit has occurred when the change amount of the obtained monitoring object value exceeds a predetermined threshold value.

[0040] When a short circuit is not detected (step S102: No), the control device 2 returns to the process of step S101. When a short circuit is detected (step S102: Yes), the control device 2 stops the power supply to the wire electrode 11 (step S103) to interrupt the machining.

[0041] The control device 2 determines the retraction direction D2 based on the state of the wire electrical discharge machine 1 at the time of interrupting machining (step S104 ). The control device 2 moves the wire electrode 11 in the retraction direction D2 by a predetermined retraction distance (step S105 ).

[0042] Here, the control device 2 estimates the length of the processing stripe 42 generated by the short circuit in the processing direction D1 and estimates the starting point of the processing stripe 42 in consideration of the control delay from the occurrence of the short circuit to the retreat of the wire electrode 11 (step S106). The control device 2 uses the estimated starting point of the processing stripe 42 as the starting point of the reprocessing and determines a re-approaching trajectory for approaching the starting point of the processing stripe 42 from the position of the retreating wire electrode 11 (step S107).

[0043] After the wire electrode 11 starts to retreat, the control device 2 determines whether a predetermined retreat time has passed (step S108). If the retreat time has not passed (step S108: No), the control device 2 returns to the process of step S108. If the retreat time has passed (step S108: Yes), the control device 2 moves the wire electrode 11 according to the re-approach trajectory (step S109). After moving the wire electrode 11, the control device 2 resumes power supply (step S110) and resumes machining.

[0044] Implementation method 3.

[0045] Figure 5 1 is a diagram showing a configuration of a wire electrical discharge machining system 100 - 1 according to Embodiment 3. The wire electrical discharge machining system 100 - 1 includes a wire electrical discharge machining machine 1 - 1 instead of the wire electrical discharge machining machine 1 of the wire electrical discharge machining system 100 , and includes a control device 2 - 1 instead of the control device 2 of the wire electrical discharge machining system 100 .

[0046] The wire electrical discharge machine 1-1 includes a wire electrode 11, a position adjustment unit 12, a power supply unit 13, a machining fluid supply unit 14 for supplying machining fluid between the wire electrode 11 and the machining object 4, and a wire conveying speed adjustment unit 15 for adjusting the conveying speed of the wire electrode 11. The machining fluid is a liquid supplied between the wire electrode 11 and the machining object 4 by the wire electrical discharge machine 1-1 during machining, and is supplied for the purpose of discharging machining chips 41 or cooling the wire electrode 11 which generates heat during machining.

[0047] The control device 2-1 has, in addition to the function of the control device 2, a function of adjusting the flow rate of the machining fluid and the conveying speed of the wire electrode 11 in order to improve the discharge capability of the machining chips 41 when a short circuit is detected in the wire electric discharge machine 1-1. Specifically, when the wire electrode 11 is retracted when a short circuit is detected, the control device 2-1 instructs the machining fluid supply unit 14 to increase the flow rate of the machining fluid compared to before the adjustment, and instructs the wire conveying speed adjustment unit 15 to increase the conveying speed of the wire electrode 11 compared to before the adjustment. In the third embodiment, the control device 2-1 adjusts both the flow rate of the machining fluid and the conveying speed of the wire electrode 11 when a short circuit is detected, but the control device 2-1 may control at least one of the flow rate of the machining fluid and the conveying speed of the wire electrode 11. In addition, when the control device 2-1 retracts the wire electrode 11, it can increase the flow rate of the machining fluid and the conveying speed of the wire electrode 11, discharge the machining chips 41, and then restore the flow rate of the machining fluid and the conveying speed of the wire electrode 11 to their original states, or it can continue to use the adjusted flow rate and conveying speed after resuming machining.

[0048] Figure 6 This is an explanatory diagram of the retreat process and re-processing process when a short circuit occurs in Embodiment 3. When the wire electrode 11 is moved in the processing direction D1, discharge occurs between the wire electrode 11 and the processing object 4, thereby removing the processing object 4, and the removed processing object 4 may become processing chips 41 and adhere to the processing surface. In the finishing process, since the distance between the wire electrode 11 and the processing surface is short, it may contact with the processing chips 41 and cause a short circuit.

[0049] Here, after the short circuit occurs, a control delay DW may occur until the wire electrode 11 is retracted. In addition, when the machining chips 41 are continuously generated, the machining line 42 may have a certain length l. Here, the height of the machining line 42 is denoted as h.

[0050] If the short circuit is detected, the control device 2-1 estimates the control delay DW and the length l of the processing stripe 42, and estimates the starting point Ps of the processing stripe 42 based on the control delay DW and the length l of the processing stripe 42. After the control device 2-1 suspends the processing by retracting the wire electrode 11, it brings the wire electrode 11 close to the estimated starting point Ps when resuming the processing.

[0051] In addition, when the control delay DW is generated, since the section of the control delay DW has already been processed, if the processing is performed again, overcutting will occur. Therefore, the control device 2-1 estimates the section where the processing stripes 42 are generated and need to be processed again, that is, the reprocessing section 51, and the section that has already been processed and does not need to be processed again, that is, the non-reprocessing section 52, based on the control delay DW, the length l of the processing stripes 42, the starting point Ps of the processing stripes 42, and the diameter of the wire electrode 11. After resuming the processing, the wire electrode 11 is powered from the starting point Ps of the processing stripes 42 to the reprocessing section 51 to perform processing. When passing through the reprocessing section 51, the power supply to the wire electrode 11 is stopped and the processing current is cut off. The processing current is kept cut off until the wire electrode 11 moves through the non-reprocessing section 52. Then, if the wire electrode 11 passes through the non-reprocessing section 52, the control device 2-1 starts to power the wire electrode 11 again and resumes the processing.

[0052] Figure 7 3 is a flowchart for explaining the processing control operation involved in the third embodiment. Figure 7 The processing shown is Figure 4 The same parts are denoted by the same reference numerals and the description thereof will be omitted.

[0053] Regarding the processing from step S101 to step S104, Figure 4 Before starting the retreat, the control device 2 - 1 changes the flow rate of the machining fluid and the conveying speed of the wire electrode 11 (step S120 ). At this time, the control device 2 - 1 increases the flow rate of the machining fluid and the conveying speed of the wire electrode 11 compared to before the change, thereby improving the discharge capability of the machining chips 41 .

[0054] The control device 2-1 is in operation with Figure 4 After the same process as step S105, replace Figure 4 Instead of step S106, the starting point Ps of the processing stripe 42 and the length l of the processing stripe 42 are estimated (step S121). Based on the estimated starting point Ps and the length l of the processing stripe 42, the control device 2-1 determines a reapproach trajectory in such a way that the wire electrode 11 approaches the starting point Ps of the processing stripe 42 (step S122).

[0055] Regarding the processing from step S108 to step S110, Figure 4 In addition, regarding the actions after power is restored in step S110, as shown in FIG. Figure 6 As described above, the control device 2 - 1 performs control so that machining is performed in the remachining section 51 and machining is not performed in the non-remachining section 52 .

[0056] Implementation method 4.

[0057] Figure 8 This is a diagram showing a first example of a short circuit to be detected in the fourth embodiment. Fig. 9 2 is a diagram showing a second example of a short circuit to be detected in the fourth embodiment. Figure 8 and Fig. 9 In FIG. 1 , the horizontal axis represents time or a position on the processing object 4, and the vertical axis represents at least one of a processing current and a processing voltage. Figure 8 It includes a normal processing waveform 61 and an instantaneous short-circuit waveform 62 - 1 . Fig. 9 It includes a normal processing waveform 61 and a continuous short-circuit waveform 62 - 2 .

[0058] like Figure 8 As shown, when a short circuit occurs instantaneously, the instantaneous short circuit waveform 62 - 1 exhibits at least one of an instantaneous decrease and increase in at least one of the machining current and the machining voltage relative to the normal machining waveform 61 .

[0059] like Fig. 9 As shown in FIG. 6 , when a short circuit continuously occurs, the continuous short circuit waveform 62-2 takes at least one of a continuous decrease and increase in at least one of the machining current and the machining voltage relative to the normal machining waveform 61. In the fourth embodiment, both a momentary short circuit and a continuous short circuit are judged as a short circuit. Therefore, when the change amount of the monitored object value is greater than or equal to the threshold value, the control device 2 Figure 8 The change is instantaneous, or Fig. 9 The changes shown are continuous and are all judged as short circuits.

[0060] Furthermore, the control device 2 may estimate the height h of the machining line 42 based on the behavior of at least one of the machining current and the machining voltage during the short circuit, and change the machining conditions during the remachining based on the estimated height h of the machining line 42 .

[0061] Implementation method 5.

[0062] Fig.101 is a diagram showing the retreat direction D2 and the reapproach direction D3 of the wire electrode 11 in the fifth embodiment. The retreat direction D2 of the wire electrode 11 is a deviation direction in which the distance from the processing object 4 increases. The retreat trajectory of the wire electrode 11 is determined based on the processing trajectory so that the wire electrode 11 does not contact the processing surface. The reapproach direction D3 of the wire electrode 11 has a vector element parallel to the processing direction D1, and the wire electrode 11 is reapproached obliquely relative to the processing surface from the rear of the processing direction D1. When the wire electrode 11 is short-circuited, the wire electrode 11 moves in the processing direction D1, so the wire electrode 11 forms a curved shape behind the processing direction D1. When the processing is restored, the wire electrode 11 is closest to the processing surface in the curved shape when the short circuit occurs, so the wire electrode 11 is closest to the processing surface from the rear of the processing direction D1, thereby suppressing the wire electrode 11 from contacting the processing surface.

[0063] Implementation method 6.

[0064] In the sixth embodiment, an example in which information used for controlling the wire electrical discharge machine 1 is learned using machine learning will be described.

[0065] <Learning Stage>

[0066] Fig.11 It is a block diagram of a learning device 70 related to the wire electrical discharge machine 1. In the following, in Embodiment 6, the learning related to the wire electrical discharge machine 1 is described, but the learning related to the wire electrical discharge machine 1 - 1 may be performed.

[0067] The learning device 70 includes a learning data acquisition unit 71 and a model generation unit 72. The learning data acquisition unit 71 acquires learning data including condition information indicating conditions for machining performed by the wire electrical discharge machine 1 and information used for remachining a machining streak 42, which is a cut residual portion of the machining object 4 generated when a short circuit occurs in the wire electrical discharge machine 1.

[0068] Here, the condition information is the specification of the wire EDM 1, the elements of the object 4 to be processed, the settings of the wire EDM 1 during processing, and includes, for example, at least one of the thickness of the object 4 to be processed, the electrode diameter of the wire electrode 11, the processing trajectory, the processing conditions, the processing current, and the processing voltage. The “information used for reprocessing the processing stripes 42” acquired by the learning data acquisition unit 71 includes, for example, at least one of the control delay DW of the wire EDM 1, the length l of the processing stripes 42, the retreat trajectory, the reapproach trajectory, and the height h of the processing stripes 42.

[0069] The model generation unit 72 generates a trained model that infers "information used for reprocessing the processing stripes 42" according to the learning data created based on the combination of the condition information output from the learning data acquisition unit 71 and the information used for reprocessing the processing stripes 42. Here, the learning data is data that associates the condition information and the "information used for reprocessing the processing stripes 42" with each other.

[0070] The information used for reprocessing the processing stripes 42 is inferred by the trained model generated by the model generation unit 72, including, for example, at least one of the starting point Ps of the processing stripes 42, the reprocessing interval 51, the non-reprocessing interval 52, the processing conditions during reprocessing, the retreat trajectory, and the re-approach trajectory.

[0071] The learning algorithm used by the model generation unit 72 may be a known algorithm such as a teacher-trained learning, a non-teacher-trained learning, or a reinforcement learning. As an example, a case where a neural network is applied will be described.

[0072] The model generation unit 72 learns information used for reprocessing the processing stripes 42 by so-called teacher learning, for example, according to a neural network model. Here, teacher learning refers to a method of giving a data set of input and a result as a label to the learning device 70, thereby learning the features existing in these learning data and inferring the result based on the input.

[0073] A neural network is composed of an input layer consisting of multiple neurons, an intermediate layer consisting of multiple neurons, and an output layer consisting of multiple neurons. The intermediate layer is also called a hidden layer. The intermediate layer can be 1 layer or more than 2 layers.

[0074] For example, if it is Fig.12 In the three-layer neural network shown, multiple inputs are input to the input layer (X1-X3), and the values ​​are multiplied by weight W1 (w11-w16) and input to the intermediate layer (Y1-Y2), and the result is further multiplied by weight W2 (w21-w26) and output from the output layer (Z1-Z3). The output result changes according to the values ​​of weight W1 and weight W2. Fig.12 is a diagram showing an example of a neural network.

[0075] In the present application, the neural network learns the information used for reprocessing the processing stripes 42 through so-called supervised learning according to the learning data created based on the combination of condition information obtained by the learning data acquisition unit 71 and the information used for reprocessing the processing stripes 42.

[0076] That is, the neural network adjusts the weights W1 and W2 to perform learning so that condition information is input to the input layer and the result output from the output layer is close to "information used for reprocessing the processing stripes 42".

[0077] The model generation unit 72 generates a trained model by executing the above learning and outputs the model.

[0078] The trained model storage unit 73 stores the trained model output from the model generation unit 72 .

[0079] Next, use Fig.13 , the learning process of the learning device 70 is explained. Fig.13 This is a flowchart related to the learning process of the learning device 70.

[0080] The learning data acquisition unit 71 acquires the condition information and the information used for reprocessing the processing stripes 42 as learning data (step S201). In addition, the learning data acquisition unit 71 simultaneously acquires the condition information and the information used for reprocessing the processing stripes 42, but the condition information and the information used for reprocessing the processing stripes 42 can be input in association with each other, and the condition information and the information used for reprocessing the processing stripes 42 can be acquired at different timings. For example, when the condition information includes a plurality of information, each of the plurality of information included in the condition information can be acquired at different timings, and when the information used for reprocessing the processing stripes 42 includes a plurality of information, each of the plurality of information included in the information used for reprocessing the processing stripes 42 can be acquired at different timings.

[0081] The model generating unit 72 performs learning processing, that is, according to the learning data created based on the combination of the condition information obtained by the learning data acquiring unit 71 and the information used for reprocessing the processing stripes 42, through the so-called taught learning, the information used for reprocessing the processing stripes 42 is learned to generate a trained model (step S202).

[0082] The trained model storage unit 73 stores the trained model generated by the model generation unit 72 (step S203 ).

[0083] <Effective use stage>

[0084] Fig.14 1 is a block diagram of an estimation device 74 related to the wire electrical discharge machine 1. The estimation device 74 includes an estimation data acquisition unit 75 and an estimation unit 76.

[0085] The estimation data acquisition unit 75 acquires condition information indicating conditions of machining performed by the wire electrical discharge machine 1 as estimation data.

[0086] Specifically, the condition information acquired by the inferred data acquisition unit 75 includes specifications of the wire discharge machine 1, elements of the processing object 4, settings of the wire discharge machine 1 during processing, etc., for example, including at least one of the plate thickness of the processing object 4, the electrode diameter of the wire electrode 11, the processing trajectory, the processing conditions, the processing current, and the processing voltage.

[0087] The inference unit 76 infers the "information used for reprocessing the machining stripe 42, which is the remaining cut portion of the machining object 4 generated when a short circuit occurs in the in-line electric discharge machining machine 1" obtained by using the trained model. Specifically, the information inferred by the inference unit 76 includes at least one of the starting point Ps of the machining stripe 42, the reprocessing section 51, the non-reprocessing section 52, the machining conditions during reprocessing, the retreat trajectory, and the re-approach trajectory. The inference unit 76 inputs the condition information obtained by the inference data acquisition unit 75 to the trained model, thereby being able to output the "information used for reprocessing the machining stripe 42" inferred based on the condition information.

[0088] In the present embodiment, the estimation is performed using the trained model learned by the model generation unit 72 of the wire electrical discharge machine 1 , but the trained model may be obtained from another wire electrical discharge machine or the like and the estimation may be performed based on the trained model.

[0089] Next, use Fig.15 , a process for obtaining “information used for reprocessing the processing stripe 42” using the inference device 74 will be described. Fig.15 This is a flowchart related to the inference processing of the inference device 74.

[0090] The estimation data acquisition unit 75 acquires condition information as estimation data (step S211). The estimation unit 76 inputs the condition information to the trained model stored in the trained model storage unit 73 (step S212) to obtain "information used for re-processing the processing stripes 42".

[0091] The inference unit 76 performs data output processing for outputting the "information used for reprocessing the machining stripes 42" obtained by the trained model to the control device 2 of the wire electrical discharge machine 1 (step S213). The control device 2 of the wire electrical discharge machine 1 uses the output "information used for reprocessing the machining stripes 42" to bring the wire electrode 11 closer to the machining surface (step S214). For example, when the "information used for reprocessing the machining stripes 42" is the starting point Ps of the machining stripes 42, the reprocessing section 51, the non-reprocessing section 52, the machining conditions during reprocessing, the retreat trajectory, and the reapproach trajectory, the control device 2 retreats the wire electrode 11 by the retreat distance according to the retreat trajectory shown in the inference result, and after the retreat time has passed, moves the wire electrode 11 to the starting point Ps shown in the inference result according to the closest trajectory, performs machining from the starting point Ps to the reprocessing section 51, and stops the power supply to the wire electrode 11 during the non-reprocessing section 52, thereby stopping the machining. In this way, the machining stripes 42 can be removed.

[0092] In addition, in the present embodiment, the case where the supervised learning is applied to the learning algorithm used by the model generation unit 72 is described, but the present invention is not limited to this. Regarding the learning algorithm, in addition to the supervised learning, reinforcement learning, unsupervised learning, semi-supervised learning, etc. can also be applied.

[0093] The learning device 70 and the inference device 74 are used to learn the "information used for re-processing the processing stripes 42" of the wire electric discharge machine 1, but may be connected to the wire electric discharge machine 1 via a network, for example, and may be a separate device from the wire electric discharge machine 1. In addition, the learning device 70 and the inference device 74 may be built into the wire electric discharge machine 1. Furthermore, the learning device 70 and the inference device 74 may exist on a cloud server.

[0094] In addition, the model generation unit 72 can learn the "information used for reprocessing the processing stripes 42" according to the learning data created for multiple wire discharge machines 1. In addition, the model generation unit 72 can obtain learning data from multiple wire discharge machines 1 used in the same area, and can also learn the "information used for reprocessing the processing stripes 42" using learning data collected from multiple wire discharge machines 1 operating independently in different areas. In addition, the wire discharge machine 1 that collects the learning data can be added to the object in the middle, or removed from the object. In addition, the learning device that has learned the "information used for reprocessing the processing stripes 42" for a certain wire discharge machine 1 can be applied to other wire discharge machines 1 different from it, and the "information used for reprocessing the processing stripes 42" for the other wire discharge machine 1 can be relearned and updated.

[0095] In addition, as a learning algorithm used in the model generation unit 72, deep learning that learns the extraction of feature quantities themselves can also be used, and machine learning can also be performed according to other well-known methods such as genetic programming, functional logic programming, support vector machines, etc.

[0096] Implementation method 7.

[0097] In the seventh embodiment, a hardware configuration example of a wire electrical discharge machining system is described. Fig.16 1 is a diagram showing a first example of the hardware configuration of a wire discharge machining system. The wire discharge machining system includes a control device 2, a power supply device 3, and a second control device 6. The control device 2 is a numerical control device. The power supply device 3 may include, for example, Figure 1 The second control device 6 includes a learning device 70 , an estimation device 74 , and a trained model storage unit 73 .

[0098] Regarding the wire electrode 11, the wire electrode 11 is supplied from the wire electrode spool 81, and is conveyed to the processing section 88 via the wire electrode conveying roller 83. In addition, if the upper power supply 13a and the lower power supply 13b are powered from the power supply device 3, a processing current is supplied to the wire electrode 11. The position of the wire electrode 11 is maintained by the upper guide 86 and the lower guide 87. After the wire electrode 11 processes the processing object 4 placed on the platform T in the processing section 88, it is recovered to the wire electrode recovery box 82 via the lower roller 84. The conveying speed of the wire electrode 11 is controlled by the wire travel speed control motor 85. Fig.16In the structure shown, position commands are input from the control device 2 to the X-axis motor 89 and the Y-axis motor 90, and the positions of the stage T on the X-axis and the Y-axis are changed, thereby controlling the relative position of the wire electrode 11 with respect to the processing object 4. In this case, the process of retracting the wire electrode 11 corresponds to the process of moving the stage T so that the relative distance of the wire electrode 11 with respect to the processing object 4 becomes the retraction distance, thereby moving the wire electrode 11 with respect to the processing object 4 by the retraction distance.

[0099] In addition, the functions of the control device 2 and the second control device 6 are implemented using a processing circuit. The processing circuit can be dedicated hardware or a control circuit having a processor and a memory such as a CPU (Central Processing Unit). In the case where the processing circuit is dedicated hardware, the processing circuit is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or a combination thereof. In addition, in the case where the above-mentioned processing circuit is implemented by a control circuit using a CPU, the control circuit has a processor and a memory also referred to as a CPU, an arithmetic device, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), etc. The memory is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (registered trademark) (Electrically EPROM), a magnetic disk, a floppy disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disk), etc.

[0100] When the processing circuit is implemented by a control circuit, the processing circuit is implemented by the processor reading out and executing the control program corresponding to the processing of each structural element stored in the memory. In addition, the memory is also used as a temporary memory in each processing executed by the processor. The control program is, for example, a computer program for causing the wire EDM 1 to execute the following steps, namely, when the wire EDM 1 detects a short circuit based on at least one of the machining current and the machining voltage during machining, that is, the monitoring object value, the step of stopping the power supply to the wire electrode 11 and interrupting the machining; the step of retreating the wire electrode 11 by moving the wire electrode 11 by a predetermined retreat distance in the offset direction in which the distance between the wire electrode 11 and the machining surface of the machining object 4 increases; and the step of reapproaching the wire electrode 11 to the machining surface again and resuming the machining after a predetermined retreat time has passed after the wire electrode 11 has retreated. In addition, the control program can be provided in a state stored in a storage medium, or can be provided via a communication channel such as the Internet.

[0101] Fig.17 This is a diagram showing a second example of the hardware configuration of the wire discharge machining system. Fig.17 , mainly for Fig.16 The different parts are explained in Fig.16 In the first example shown, the relative position between the wire electrode 11 and the object 4 is controlled by moving the stage T on which the object 4 is placed. Fig.17 In the second example shown, a position command is input from the control device 2 to the upper guide 86 and the lower guide 87 to change the position of the wire electrode 11 , thereby controlling the relative position between the wire electrode 11 and the object 4 .

[0102] In addition, use Fig.16 and Fig.17The two examples shown illustrate the hardware structure of the wire discharge machining system, but the hardware structure of the wire discharge machining system is not limited to the examples shown in the figure. For example, in the above-mentioned first and second examples, the control device 2 is a numerical control device, and the second control device 6 is a device different from the numerical control device, but the numerical control device may also have the function of the second control device 6. Alternatively, in the above-mentioned first and second examples, the second control device 6 has a learning device 70, an inference device 74, and a trained model storage unit 73, but part of these functions may also be set in a device different from the second control device 6 and the control device 2. For example, as described above, the functions of the learning device 70 and the trained model storage unit 73 can be implemented on a cloud server. In addition, part of the functions of the control device 2 may also be performed by a device different from the numerical control device. In addition, in the above-mentioned first and second examples, the power supply device 3 has a detection unit 5, but if the detection unit 5 can detect at least one of the machining current and the machining voltage, it may not be built into the power supply device 3.

[0103] The configuration described in the above embodiment is merely an example, and may be combined with other known technologies, the embodiments may be combined with each other, and part of the configuration may be omitted or changed without departing from the gist.

[0104] Description of the label

[0105] 1. 1-1 Wire EDM, 2. 2-1 Control device, 3 Power supply device, 4 Processing object, 5 Detection unit, 6 Second control device, 11 Wire electrode, 12 Position adjustment unit, 13 Power supply unit, 13a Upper power supply unit, 13b Lower power supply unit, 14 Processing fluid supply unit, 15 Wire conveying speed adjustment unit, 41 Processing chips, 42 Processing stripes, 43, 44 Processing surface, 45 Inclined surface, 51 Reprocessing section, 52 Non-reprocessing section, 61 Normal processing waveform, 62-1 Instantaneous short-circuit waveform, 62-2 Continuous short-circuit waveform, 70 Learning device , 71 learning data acquisition unit, 72 model generation unit, 73 trained model storage unit, 74 inference device, 75 inference data acquisition unit, 76 inference unit, 81 wire electrode spool, 82 wire electrode recovery box, 83 wire electrode conveying roller, 84 lower roller, 85 wire travel speed control motor, 86 upper guide, 87 lower guide, 88 processing unit, 89X-axis motor, 90Y-axis motor, 100, 100-1 wire discharge machining system, D1 processing direction, D2 retreat direction, D3 re-approach direction, Ps starting point, T platform.

Claims

1. A control device for a wire electric discharge machine, the control device controlling the wire electric discharge machine, the wire electric discharge machine applying a voltage between a wire electrode and a processing object to generate electric discharge, thereby performing a removal process on the processing object, The control device of the wire electric discharge machine is characterized in that When the wire electrical discharge machine detects a short circuit based on at least one of a machining current and a machining voltage during machining, that is, a monitoring target value, stopping the power supply to the wire electrode to interrupt the machining, The wire electrode is retracted by moving the wire electrode by a predetermined retraction distance in an offset direction in which a distance between the wire electrode and a processing surface of the processing object increases, After the wire electrode is retracted and a predetermined retraction time has elapsed, the wire electrode is brought close to the machining surface again to resume the machining.

2. The control device for the wire electrical discharge machine according to claim 1, characterized in that: When the machining is resumed after the wire electrode has retreated, the power supply to the wire electrode is resumed after the wire electrode and the object are brought close to a distance at which discharge occurs in response to the applied machining voltage and machining current.

3. The control device for a wire electrical discharge machine according to claim 1 or 2, characterized in that: The short circuit is detected based on at least one of an amount of change in the monitored value and a duration of time in which the amount of change in the monitored value exceeds a predetermined threshold value.

4. The control device for a wire electrical discharge machine according to claim 1, wherein: Based on a control delay time from detection of the short circuit to retreat of the wire electrode and a length of a machining line which is a cut-off portion of the object caused by the short circuit estimated based on the monitoring target value, the machining line portion is re-machined.

5. The control device for the wire electrical discharge machine according to claim 4, characterized in that: Based on the control delay time and the length of the processing stripes, the starting point of the processing stripes, the reprocessing interval for performing the reprocessing of the processing object, and the non-reprocessing interval for not performing the reprocessing are estimated, and based on the estimation result, the position of the wire electrode during the reprocessing and the power supply to the wire electrode are controlled.

6. The control device for a wire electrical discharge machine according to claim 1, wherein: When the short circuit is detected, the flow rate of the machining fluid supplied between the object to be machined and the wire electrode is increased compared to before the short circuit is detected.

7. The control device for a wire electrical discharge machine according to claim 1, wherein: The machining conditions when resuming the machining are changed based on the amount of change in the monitored value when the short circuit is detected.

8. The control device for a wire electrical discharge machine according to claim 7, characterized in that: Based on the change in the monitored object value when the short circuit is detected, the height of the processing stripe, i.e., the remaining cut portion of the processing object caused by the short circuit, is estimated, and the processing conditions when resuming the processing are changed according to the estimated value of the height of the processing stripe.

9. The control device for a wire electrical discharge machine according to claim 1, wherein: Also provided is a learning device, the learning device having: a learning data acquisition unit that acquires learning data including condition information indicating conditions for machining performed by the wire electrical discharge machine and information used for remachining machining streaks that are residual portions of the machining object generated when a short circuit occurs in the wire electrical discharge machine; as well as A model generating unit generates a trained model for estimating information used for re-machining the machining line based on the condition information of the wire electrical discharge machine, using the learning data.

10. The control device for a wire electrical discharge machine according to claim 1, wherein: Also provided is an inference device, the inference device having: an estimation data acquisition unit that acquires condition information indicating conditions of machining performed by the wire electrical discharge machine as estimation data; and an inference unit that uses a trained model for inferring information used for reprocessing a machining stripe, which is a cutting residue of the machining object generated when a short circuit occurs in the wire electric discharge machine, based on the condition information, and outputs information used for reprocessing the machining stripe based on the condition information input from the inference data acquisition unit, The processing is resumed using the inference result of the inference device.

11. The control device for a wire electrical discharge machine according to claim 9 or 10, characterized in that: The condition information includes at least one of the plate thickness of the object to be processed, the electrode diameter of the wire electrode, a processing trajectory, a processing condition, the processing current, and the processing voltage.

12. The control device for a wire electrical discharge machine according to claim 9 or 10, characterized in that: The information used to reprocess the processing stripes includes the starting point of the processing stripes, the interval for reprocessing corresponding to the part generating the processing stripes, namely the reprocessing interval, the interval for not processing after starting the reprocessing, namely the non-reprocessing interval, the processing conditions during reprocessing, and at least one of the retreat trajectory and the re-approach trajectory.

13. A control program for a wire electrical discharge machine, the program controlling the wire electrical discharge machine for applying a voltage between a wire electrode and a processing object to generate electrical discharge, thereby performing a removal process on the processing object, The control program of the wire EDM is characterized by: When the wire electrical discharge machine detects a short circuit based on at least one of a machining current and a machining voltage during machining, that is, a monitoring target value, The wire electrical discharge machine is caused to perform the following steps: stopping the power supply to the wire electrode to interrupt the processing; The wire electrode is retracted by moving the wire electrode by a predetermined retraction distance in an offset direction in which a distance between the wire electrode and a processing surface of the processing object increases; and After a predetermined retraction time has elapsed after the wire electrode has been retracted, the wire electrode is brought close to the machining surface again to resume the machining.

14. A method for controlling a wire electrical discharge machine, the method comprising: controlling the wire electrical discharge machine, the wire electrical discharge machine applying a voltage between a wire electrode and a processing object to generate discharge, thereby performing a removal process on the processing object, The control method of the wire electric discharge machine is characterized in that: When the wire electric discharge machine detects a short circuit based on at least one of a machining current and a machining voltage during machining, that is, a monitoring target value, the method includes the following steps: stopping the power supply to the wire electrode to interrupt the processing; The wire electrode is retracted by moving the wire electrode by a predetermined retraction distance in an offset direction in which a distance between the wire electrode and a processing surface of the processing object increases; and After a predetermined retraction time has elapsed after the wire electrode has been retracted, the wire electrode is brought close to the machining surface again to resume the machining.

Images