Wire electric discharge machine and wire electric discharge machining method

Abstract

The present disclosure is a wire electric discharge machine that moves a wire electrode along a machining path and machines an object to be machined in accordance with machining conditions, the wire electric discharge machine being provided with: a sensor that detects the wire electrode in an intersecting direction that intersects a feeding direction in which the wire electrode is fed; a calculation unit that calculates the amount of displacement on the basis of the detection result of the sensor and the correspondence between the detection result and the amount of displacement of the position of the wire electrode in the intersecting direction; and a calibration execution unit that corrects the correspondence stored in the storage unit on the basis of the detection result when the wire electrode is tilted.

Description

Technical Field

[0001] This disclosure relates to a wire electrical discharge machining (EDM) machine and a wire electrical discharge machining (EDM) method. Background Technology

[0002] Japanese Patent Application Publication No. 2014-133293 discloses a wire electrical discharge machining (EDM) machine that corrects the position of the wire guide based on changes in the hydraulic pressure of the machining fluid, thereby correcting the displacement of the wire electrode. The relationship between the hydraulic pressure of the machining fluid and the displacement of the wire guide is pre-stored in a storage device in the form of a mathematical formula. Summary of the Invention

[0003] The aim is to suppress the reduction in machining accuracy caused by the displacement of the wire electrode during electrical discharge machining.

[0004] The first aspect of this disclosure is a wire electrical discharge machining (EDM) machine that moves a wire electrode along a machining path relative to a workpiece and generates a discharge between the workpiece and the wire electrode according to machining conditions, thereby machining the workpiece. The wire EDM machine includes: a pair of wire guides supporting the wire electrode above and below the workpiece; a sensor that detects the wire electrode at any position between one of the wire guides (i.e., the first wire guide) and the other wire guide (i.e., the second wire guide), along a cross direction intersecting the delivery direction of the wire electrode; a storage unit that pre-stores a correspondence between the sensor's detection results and the displacement of the wire electrode's position in the cross direction; a calculation unit that calculates the displacement based on the detection results and the correspondence stored in the storage unit; and a calibration execution unit that corrects the correspondence stored in the storage unit based on the detection results when the second wire guide is moved relative to the first wire guide, causing the wire electrode to tilt.

[0005] The second aspect of the present invention is a wire electrical discharge machining (EDM) method performed by a wire EDM machine, the wire EDM machine comprising: a pair of wire guides supporting a wire electrode above and below a workpiece; a sensor that detects the wire electrode at any position between one of the wire guides (i.e., the first wire guide) and the other wire guide (i.e., the second wire guide), along a cross direction intersecting the delivery direction of the wire electrode; and a storage unit that pre-stores a correspondence between the sensor's detection results and the displacement of the wire electrode's position in the cross direction. The wire electrical discharge machining (EDM) machine moves the wire electrode along a machining path relative to the workpiece and generates a discharge between the workpiece and the wire electrode according to machining conditions, thereby machining the workpiece. The wire EDM method includes: a calculation step, calculating the displacement based on the detection result and the correspondence stored in the storage unit; and a calibration execution step, correcting the correspondence stored in the storage unit based on the detection result when the wire electrode is tilted by moving the second wire guide relative to the first wire guide. Attached Figure Description

[0006] Figure 1 This is a diagram illustrating one embodiment of a wire electrical discharge machining (EDM) machine.

[0007] Figure 2 This is an enlarged view of the sensor holding section.

[0008] Figure 3 This is a block diagram showing a part of the components of a wire electrical discharge machining (EDM) machine.

[0009] Figure 4A , Figure 4B and Figure 4C This is a graph used to illustrate the sensor detection results corresponding to the displacement of the wire electrode position during processing.

[0010] Figure 5 This is a diagram illustrating the process performed as an adjustment of processing conditions.

[0011] Figure 6A This is a diagram used to illustrate calibration. Figure 6B This is a graph illustrating the correspondence between the sensor's detection results and the displacement.

[0012] Figure 7 This is a flowchart illustrating an example of the processing sequence of a calibration method prior to wire electrical discharge machining.

[0013] Figure 8 This is a flowchart illustrating an example of the processing sequence in a wire electrical discharge machining (WEDM) method. Detailed Implementation

[0014] In existing wire electrical discharge machining (EDM) machines, machining conditions are modified during EDM based on information about the machining path determined by a pre-stored machining program. However, sometimes the actual machined shape differs from the shape indicated by the machining path information. For example, the actual machined shape may differ from the shape indicated by the machining path information due to wire electrode displacement caused by the discharge action or machining hydraulic pressure during EDM.

[0015] Therefore, in cases where multiple cycles of finishing are performed on a workpiece, the amount of machining done in the preceding cycle may become too much or too little. However, if such actual machining shapes are not considered in subsequent electrical discharge machining, the machining accuracy of the workpiece may be reduced.

[0016] Figure 1 This is a diagram illustrating one embodiment of a wire electrical discharge machining (EDM) machine 10. Figure 1 The X, Y, and Z directions shown are orthogonal to each other, with the Z direction being the direction of gravity. However, the positive direction of the Z direction is opposite to the positive direction of gravity. The wire electrical discharge machining (EDM) machine 10 includes a main body 20, a control device 30, and a processing power supply 40. The processing power supply 40 applies a voltage to the electrode space between the wire electrode E and the workpiece W to generate a discharge. Depending on the processing conditions, the wire EDM machine 10 performs electrical discharge machining on the workpiece W through the discharge generated between the electrodes.

[0017] During electrical discharge machining, the control device 30 moves the wire electrode E relative to the workpiece W along the machining path specified by the machining program (machining program 122r described later). The workpiece W is supported on the worktable 62. The relative movement of the wire electrode E and the workpiece W is achieved, for example, by moving the worktable 62 in the X and Y directions.

[0018] The main body 20 of the wire electrical discharge machine 10 has a first wire guide 64 and a second wire guide 66 as a pair of wire guides that are separate from each other. Figure 1 In the example shown, the first wire guide 64 and the second wire guide 66 are located along the direction of gravity (Z direction). Both the first wire guide 64 and the second wire guide 66 can move in the X and Y directions.

[0019] The first wire guide 64 includes a first guide block 68, a first guide wheel 70, and a first nozzle 72. The second wire guide 66 includes a second guide block 74, a second guide wheel 76, and a second nozzle 78. The first wire guide 64 supports the wire electrode E below the worktable 62 and the workpiece W (in the -Z direction relative to the workpiece W). The second wire guide 66 supports the wire electrode E above the worktable 62 and the workpiece W (in the +Z direction relative to the workpiece W).

[0020] The wire electrode E is supplied from the winding tube 80 at a speed determined as one of the processing conditions described later. The wire electrode E is fed via the roller 82 to the second wire guide 66, the workpiece W, and the first wire guide 64. When the second wire guide 66 and the first wire guide 64 are positioned along the direction of gravity (-Z direction), the feeding direction of the wire electrode E is also the direction of gravity (-Z direction).

[0021] The delivered wire electrode E passes through the second wire guide 66, the workpiece W, and the first wire guide 64, and is held by the pinch roller 84 and the feed roller 86. The wire electrode E held by the pinch roller 84 and the feed roller 86 is recovered by the recovery box 88.

[0022] When performing electrical discharge machining on the workpiece W, the machining tank 90 of the main body 20 can also store machining fluid. In this case, the worktable 62, the workpiece W, the first wire guide 64, and the second wire guide 66 are immersed in the machining fluid. The machining tank 90 is mounted on the base 92 of the main body 20. Machining fluid supplied by a machining fluid supply device (not shown) is ejected from the first nozzle 72 of the first wire guide 64 and the second nozzle 78 of the second wire guide 66.

[0023] The sensor holding part 98 is mounted on at least one of the first wire guide 64 and the second wire guide 66. Figure 2 This is an enlarged view of the sensor holding section 98. Two sensors 98x and 98y for detecting the wire electrode E are mounted on the sensor holding section 98. In this embodiment, two sensors 98x and 98y are provided on the first wire guide 64, which supports the wire electrode E below the workpiece W. The sensor holding section 98 functions as a mounting section for mounting the two sensors 98x and 98y on the first wire guide 64.

[0024] Furthermore, each of the two sensors 98x and 98y only needs to detect the wire electrode E at any position from the first wire guide 64 to the second wire guide 66. Therefore, as shown in this embodiment, two sensors 98x and 98y can be provided on the first wire guide 64. However, two sensors 98x and 98y can also be provided on the second wire guide 66, which supports the wire electrode E above the workpiece W. Alternatively, two sensors 98x and 98y can be provided on both the first wire guide 64 and the second wire guide 66.

[0025] In the first wire guide 64, the first guide wheel 70 and the first nozzle 72 are supported by the first guide block 68. A sensor holding part 98 is mounted on the first nozzle 72. Therefore, the two sensors 98x and 98y are located between the first wire guide 64 and the second wire guide 66, and are located slightly away from the position of the wire electrode E supported by the first wire guide 64 in the +Z direction.

[0026] The sensor holding part 98 has a through hole at or near its center for inserting the wire electrode E. The processing fluid ejected from the first nozzle 72 is supplied through this through hole to the electrode space between the wire electrode E and the workpiece W.

[0027] Sensor 98x detects the X-direction electrode E along the first intersection direction (-Z direction) that intersects the output direction of the output electrode E. Sensor 98y detects the Y-direction electrode E along the second intersection direction (-Z direction) that intersects the output direction of the output electrode E.

[0028] In this embodiment, sensor 98x is an optical fiber sensor that detects line electrode E along the X direction. Sensor 98x has a light-emitting fiber 98xt that projects light from a light source in the Y direction, and a light-receiving fiber 98xr that receives light projected by the light-emitting fiber 98xt. The light-emitting end of the light-emitting fiber 98xt and the light-receiving end of the light-receiving fiber 98xr are arranged facing each other in the Y direction. Line electrode E, which extends in the -Z direction, is located between the light-emitting end of the light-emitting fiber 98xt and the light-receiving end of the light-receiving fiber 98xr.

[0029] Similar to sensor 98x, sensor 98y is an optical fiber sensor that detects the line electrode E along the Y direction. Sensor 98y has a light-emitting fiber 98yt that projects light from a light source in the X direction, and a light-receiving fiber 98yr that receives the light projected by the light-emitting fiber 98yt. The light-emitting end of the light-emitting fiber 98yt and the light-receiving end of the light-receiving fiber 98yr are arranged facing each other in the X direction. The line electrode E, which extends in the -Z direction, is located between the light-emitting end of the light-emitting fiber 98yt and the light-receiving end of the light-receiving fiber 98yr.

[0030] Figure 3 This is a block diagram showing a portion of the configuration of a wire electrical discharge machining (EDM) machine 10. The EDM machine 10 also has... Figure 1 The worktable drive unit 102, electrode feed drive unit 104, machining fluid supply device 106, wire guide drive unit 108, and signal processing device 110 are not shown in the diagram. The machining power supply 40 repeatedly applies pulse voltages between the online electrode E and the workpiece W.

[0031] The table drive unit 102 drives the table 62. This allows the wire electrode E to move relative to the workpiece W in the X and Y directions. The table drive unit 102 includes an X-motor, a Y-motor, an X-drive transmission mechanism, and a Y-drive transmission mechanism. The X-motor is used to move the table 62 in the X direction. The Y-motor is used to move the table 62 in the Y direction.

[0032] The X-drive transmission mechanism is used to convert the rotary motion of the X-motor into linear motion in the X direction of the worktable 62. The Y-drive transmission mechanism is used to convert the rotary motion of the Y-motor into linear motion in the Y direction of the worktable 62. Both the X-drive transmission mechanism and the Y-drive transmission mechanism may include a ball screw and a nut engaged with the ball screw. Furthermore, each of the X-motor and Y-motor is equipped with an encoder (rotational position detection sensor) for detecting the rotational position.

[0033] Electrode delivery drive unit 104 has Figure 1 The roller 82, pinch roller 84, and feed roller 86 are shown, along with a delivery motor and a recovery motor (not shown). The delivery motor rotates roller 82. The recovery motor rotates pinch roller 84 and feed roller 86. Each of the delivery motor and recovery motor is equipped with an encoder (rotation position detection sensor) for detecting rotational position.

[0034] Roller 82, by rotating, feeds the wire electrode E wound on the winding tube 80 toward the second wire guide 66, the workpiece W, and the first wire guide 64. Pinch roller 84 and feed roller 86 apply tension to the wire electrode E by clamping it. In this state, pinch roller 84 and feed roller 86 further rotate to feed the wire electrode E toward and collect it back into the recycling bin 88.

[0035] The machining fluid supply device 106 supplies machining fluid to the electrode space between the wire electrode E and the workpiece W. Therefore, the machining fluid from the machining fluid supply device 106 is ejected from the first nozzle 72 of the first wire guide 64 and the second nozzle 78 of the second wire guide 66. Alternatively, the machining fluid may be ejected from only one of the first nozzle 72 of the first wire guide 64 and the second nozzle 78 of the second wire guide 66.

[0036] Furthermore, the processing fluid supply device 106 not only supplies processing fluid to the electrode space between the wire electrode E and the workpiece W, but also supplies processing fluid to the processing tank 90 without passing through the first nozzle 72 and the second nozzle 78. Additionally, the processing fluid supply device 106 may include a wastewater tank and a clean water tank (neither shown). The wastewater tank stores processing fluid containing waste residue discharged from the processing tank 90. ​​The clean water tank stores processing fluid supplied from the wastewater tank, and is processing fluid for which waste residue has been removed by a filter (not shown).

[0037] The wire guide drive unit 108 drives the first wire guide 64 and the second wire guide 66. This allows one of the first wire guide 64 and the second wire guide 66 to move relative to the other in the X and Y directions. Through this relative movement of the first wire guide 64 and the second wire guide 66, the wire electrode E can tilt relative to the direction of gravity (Z direction).

[0038] The wire guide drive unit 108 has an X motor, a Y motor, an X drive transmission mechanism, and a Y drive transmission mechanism for the first wire guide 64 and the second wire guide 66, respectively.

[0039] The X-motor used in the first wire guide 64 is a motor used to move the first wire guide 64 in the X direction. The X-motor used in the second wire guide 66 is a motor used to move the second wire guide 66 in the X direction. The Y-motor used in the first wire guide 64 is a motor used to move the first wire guide 64 in the Y direction. The Y-motor used in the second wire guide 66 is a motor used to move the second wire guide 66 in the Y direction.

[0040] The X-drive transmission mechanism used in the first wire guide 64 is a mechanism for converting the rotary motion of the X-motor into linear motion in the X direction of the first wire guide 64. The X-drive transmission mechanism used in the second wire guide 66 is a mechanism for converting the rotary motion of the X-motor into linear motion in the X direction of the second wire guide 66.

[0041] The Y-drive transmission mechanism used in the first wire guide 64 is a mechanism for converting the rotational motion of the Y-motor into linear motion in the Y direction of the first wire guide 64. The Y-drive transmission mechanism used in the second wire guide 66 is a mechanism for converting the rotational motion of the Y-motor into linear motion in the Y direction of the second wire guide 66.

[0042] The X-axis drive transmission mechanism and the Y-axis drive transmission mechanism may each include a ball screw and a nut that engages with the ball screw. Additionally, each of the X-axis motor and the Y-axis motor is equipped with an encoder (rotational position detection sensor) for detecting rotational position.

[0043] The signal processing device 110 includes a light source 112, a light-receiving element 114, and a signal processing circuit 116. Light emitted from the light source 112 is transmitted within the projection fiber 98xt of the sensor 98x and projected from the projection end through the projection fiber 98xt. If a portion of the projected light is blocked by the line electrode E, the remaining portion of the projected light that is not blocked is received at the light-receiving end of the sensor 98x by the light-receiving fiber 98xr and transmitted within the light-receiving fiber 98xr. The light received by the light-receiving fiber 98xr is detected by the light-receiving element 114.

[0044] The signal processing circuit 116 generates a sensor signal representing the detection result of the sensor 98x based on the detection of light by the light receiving element 114. The detection result of the sensor 98x includes the amount of light received by the light receiving optical fiber 98xr.

[0045] exist Figure 3Only sensor 98x is shown in the diagram; sensor 98y is omitted. In sensor 98y, similarly to sensor 98x, the light-receiving element 114 detects the remaining portion of the light projected from the light source 112 that is not blocked by the line electrode E. Signal processing circuit 116 generates a sensor signal representing the detection result of sensor 98y, which includes the amount of light received by the light-receiving optical fiber 98yr.

[0046] The signal processing circuit 116 transmits a sensor signal representing the detection result of the sensor 98x and a sensor signal representing the detection result of the sensor 98y to the control device 30. Alternatively, the signal processing circuit 116 may also generate a single sensor signal representing the detection results of both the sensor 98x and the sensor 98y, and transmit this sensor signal to the control device 30.

[0047] The control device 30 includes an arithmetic unit 120 and a storage unit 122. The arithmetic unit 120 includes a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). That is, the arithmetic unit 120 includes processing circuitry.

[0048] The storage unit 122 includes volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory) or flash memory. The volatile memory serves as the processor's working memory. The non-volatile memory stores necessary data such as the processing program 122r executed by the processor, processing condition data 122c, and the correspondence between detection results and displacement amounts 122t.

[0049] The machining program 122r determines the machining path when machining the workpiece W. The machining condition data 122c determines the various machining conditions used to machine the workpiece W. Regarding these various machining conditions, use... Figure 5 This will be described later. Correspondence 122t represents the relationship between the detection results of sensors 98x and 98y and the displacement of the position of the line electrode E. Figure 6B To be described later.

[0050] The arithmetic unit 120 includes a machining control unit 150, a calculation unit 152, an adjustment unit 154, and a calibration execution unit 156. The arithmetic unit 120 executes the program stored in the storage unit 122 to realize the machining control unit 150, the calculation unit 152, the adjustment unit 154, and the calibration execution unit 156.

[0051] At least a portion of the processing control unit 150, the calculation unit 152, the adjustment unit 154, and the calibration execution unit 156 can be implemented by integrated circuits such as ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or by electronic circuits containing discrete devices.

[0052] The machining control unit 150 performs control related to the electrical discharge machining of the workpiece W. Specifically, the machining control unit 150 moves the workpiece W and the wire electrode E relative to each other and generates a discharge between them. The machining control unit 150 includes a table drive control unit 182, an electrode feed control unit 184, a machining fluid supply control unit 186, a power supply control unit 188, and a wire guide drive control unit 190.

[0053] The table drive control unit 182 controls the table drive unit 102 to move the table 62 supporting the workpiece W in the X and Y directions. By moving the table 62 in the X and Y directions, the wire electrode E can be moved relative to the workpiece W in the X and Y directions.

[0054] Therefore, the table drive control unit 182 controls the table drive unit 102 to move the wire electrode E relative to the machining path. This machining path is the machining path specified by the machining program 122r, or, as described later, the machining path adjusted by the adjustment unit 154.

[0055] The electrode delivery control unit 184 controls the electrode delivery drive unit 104 to deliver the wire electrode E to the workpiece W and retrieve it into the collection box 88. The delivery speed of the wire electrode E and the tension applied to the wire electrode E are determined as processing conditions. The processing conditions are those specified by the processing condition data 122c, or, as described later, those adjusted by the adjustment unit 154.

[0056] The machining fluid supply control unit 186 controls the machining fluid supply device 106 to supply machining fluid to the electrode space between the wire electrode E and the workpiece W. The power supply control unit 188 controls the machining power supply 40 to apply voltage to the electrode space between the wire electrode E and the workpiece W.

[0057] The wire guide drive control unit 190 controls the wire guide drive unit 108 to move one of the first wire guide 64 and the second wire guide 66 relative to the other in the X and Y directions. By moving the first wire guide 64 and the second wire guide 66 relative to each other in the X and Y directions, the wire electrode E can be tilted relative to the direction of gravity (Z direction).

[0058] The calculation unit 152 acquires the sensor signal transmitted from the signal processing circuit 116 of the signal processing device 110. Based on the detection result of the sensor 98x represented by the acquired sensor signal, the calculation unit 152 calculates the displacement of the position of the line electrode E in the first cross direction (X direction) relative to a reference position. The calculation of the reference position and the displacement relative to the reference position will use… Figure 4A , Figure 4B , Figure 4C This will be explained in detail later. The calculation unit 152 calculates the displacement based on the detection results of the sensor 98x and the correspondence 122t pre-stored in the storage unit 122.

[0059] The calculation unit 152 calculates the displacement of the wire electrode E in the second cross direction (Y direction) relative to a reference position based on the detection result of the sensor 98y represented by the acquired sensor signal. The calculation unit 152 calculates the displacement based on the detection result of the sensor 98y and the correspondence 122t pre-stored in the storage unit 122. Such displacement of the wire electrode E may be caused by, for example, the discharge action or machining hydraulic pressure during electrical discharge machining.

[0060] The wire electrode E should ideally be at a reference position, but it may be displaced due to the discharge action or machining hydraulic pressure. For example, the wire electrode E may be closer to the workpiece W than the reference position, or it may be farther away from the workpiece W. Based on the displacement in the X and Y directions calculated by the calculation unit 152 and the machining position on the machining path, the positional relationship between the wire electrode E and the workpiece W is determined. That is, it can be determined whether the wire electrode E is closer to the workpiece W than the reference position, or farther away from the workpiece W than the reference position.

[0061] When the wire electrode E approaches the workpiece W, the machining amount increases; when the wire electrode E moves away from the workpiece W, the machining amount decreases. Therefore, when the wire electrode E is in a position different from the reference position, the machining amount may increase or decrease, resulting in a decrease in machining accuracy. To prevent this decrease in machining accuracy, the adjustment unit 154 adjusts the machining conditions or the machining path. The machining conditions are adjusted when the wire electrode E is in a position different from the reference position, or the machining path is adjusted to bring the wire electrode E to the reference position.

[0062] By adjusting the processing conditions, the target distance G, which is preset to be the distance between the wire electrode E and the workpiece W after processing, can be changed. Regarding the change of the target distance G, use... Figure 4B , Figure 4C This will be described in detail later. The adjustment unit 154 adjusts the machining conditions based on the displacement in the X and Y directions.

[0063] Based on the adjustment results of the adjustment unit 154, the machining control unit 150 performs electrical discharge machining on the workpiece W. As a result, the distance between the desired linear electrode E and the actual machined workpiece W is close to the adjusted target distance G.

[0064] For example, if the online electrode E is closer to the workpiece W than the reference position, the adjustment unit 154 can reduce the target distance G by an amount corresponding to the displacement in the X and Y directions by adjusting the processing conditions. This prevents excessive machining.

[0065] Furthermore, when the online electrode E is farther from the workpiece W than the reference position, the adjustment unit 154 can increase the target distance G by an amount corresponding to the displacement in the X and Y directions by adjusting the machining conditions. This prevents insufficient machining. Thus, it suppresses the reduction in machining accuracy.

[0066] As described above, the adjustment unit 154 adjusts the machining conditions based on the displacement in the X and Y directions. However, when the machining path is a straight line along the X direction, the adjustment unit 154 may also adjust the machining conditions based solely on the displacement in the Y direction based on the detection result of the sensor 98y. Similarly, when the machining path is a straight line along the X direction, the adjustment unit 154 may also adjust the machining conditions based solely on the displacement in the X direction based on the detection result of the sensor 98x.

[0067] As described above, the adjustment unit 154 can also change the machining path instead of changing the machining conditions. By adjusting the machining path away from the workpiece W using the adjustment unit 154, excessive machining can be prevented. By adjusting the machining path closer to the workpiece W using the adjustment unit 154, insufficient machining can be prevented. In this way, a decrease in machining accuracy can be suppressed.

[0068] As described above, the wire guide drive unit 108 can move the first wire guide 64 and the second wire guide 66 relative to each other in the X and Y directions. This allows the wire electrode E to tilt relative to the direction of gravity (Z direction). Thus, the calibration execution unit 156 corrects the pre-stored correspondence 122t in the storage unit 122 based on the detection results from sensors 98x and 98y when the wire electrode E is tilted.

[0069] Figure 4A , Figure 4B and Figure 4CThese are diagrams illustrating the detection results of sensor 98y corresponding to the displacement of the position Pe of the wire electrode E during machining. In the examples shown in these diagrams, the wire electrode E moves relative to the workpiece W along a machining path that is linear in the positive X direction. While moving relative to the workpiece W, the wire electrode E performs electrical discharge machining on the workpiece W, which is positioned in the positive Y direction.

[0070] exist Figure 4A In the process, the position Pe of the wire electrode E during machining is at the reference position Pr. The reference position Pr is the position Pe of the wire electrode E, supported by the first wire guide 64 and the second wire guide 66 located along the direction of gravity, when the workpiece W is not being machined. Figure 4A In the example shown, during the machining process of the workpiece W, the position Pe of the wire electrode E does not shift from the reference position Pr.

[0071] When the position Pe of the line electrode E does not shift from the reference position Pr, a portion of the light L projected from the projection fiber 98yt of the sensor 98y is blocked by the line electrode E. As a result, the amount of light L received by the light-receiving fiber 98yr at the receiving end of the sensor 98y corresponds to a state where the displacement of the position Pe of the line electrode E is zero. That is, the displacement of 0 can be easily derived from the amount of light received, As.

[0072] The wire electrode E, without displacement from the reference position Pr, processes the workpiece W along the processing path specified by the processing program 122r under the processing conditions specified in the processing condition data 122c. According to these processing conditions, the target distance G is the value Gs. In this case, as... Figure 4A As shown, the processed surface Sp of the processed object W is formed at a position Gs that is equal to the distance G from the reference position Pr to the target.

[0073] When the machining surface Si currently being machined and the predetermined machining surface Su to be machined in the future are machined by the wire electrode E, they are also formed at a position Gs that is equal to the distance G from the reference position Pr.

[0074] exist Figure 4B In the process, the position Pe of the wire electrode E during machining is located at a traveling position Pc that is closer to the workpiece W than the reference position Pr. The offset D of the position Pe of the wire electrode E relative to the reference position Pr is calculated as the displacement of the position Pe of the wire electrode E. That is, in Figure 4B In the example shown, the displacement in the second intersection direction, i.e., the Y direction, is the offset D.

[0075] When the position Pe of the line electrode E is displaced by an offset D from the reference position Pr, a portion of the light L projected from the projection fiber 98yt of the sensor 98y is blocked by the line electrode E. As a result, the amount of light Ac received by the light-receiving fiber 98yr of the sensor 98y at the receiving end corresponds to the state where the position Pe of the line electrode E approaches the workpiece W by the aforementioned displacement. Since the amount of light Ac is greater than the amount of light As when the displacement is zero, it can be determined that the position Pe of the line electrode E is close to the workpiece W.

[0076] That is, based on the amount of light received Ac, it is easy to deduce the case where the position Pe of the line electrode E is close to the workpiece W and the case where the displacement is the offset D.

[0077] Since the position Pe of the wire electrode E is closer to the workpiece W than the reference position Pr, it is necessary to reduce the target distance G as the displacement amount of the offset D. Therefore, the adjustment unit 154 adjusts the processing conditions determined in the processing condition data 122c to reduce the processing amount. According to the adjusted processing conditions, the target distance G becomes a value Gc that is smaller than the displacement amount of the offset D compared to the value Gs.

[0078] In this case, such as Figure 4B As shown, the machined surface Sp of the processed object W is formed at a position Gc, which is equal to the distance G from the travel position Pc. The position of the machined surface Sp is also the position Gs, which is the distance G from the reference position Pr before the change in distance G from the target.

[0079] If processing is performed while maintaining the value Gs without changing the target distance G, the processed surface Sc of the processed object W is formed at a position away from the value Gs from the travel position Pc. That is, the processing amount becomes excessive. However, by adjusting the processing conditions to change the target distance G to the value Gc, excessive processing can be prevented.

[0080] When the machining surface Si currently being machined and the predetermined machining surface Su to be machined in the future are machined by the wire electrode E, they are also formed at a position Gc that is equal to the distance G from the target from the traveling position Pc.

[0081] Additionally, as described above, the adjustment unit 154 can also adjust the machining path specified by the machining program 122r. Figure 4B In the example shown, the adjustment unit 154 causes the machining path to move away from the workpiece W by an offset amount D. As a result, the position Pe of the wire electrode E during machining moves from the current traveling position Pc towards the reference position Pr (see reference). Figure 4A ).like Figure 4A As shown, the processed surface Sp of the processed object W is formed at a position Gs that is equal to the distance G from the reference position Pr to the target.

[0082] exist Figure 4C In the process, the position Pe of the wire electrode E during machining is located at a traveling position Pa that is farther away from the workpiece W than the reference position Pr. The offset D of the position Pe of the wire electrode E relative to the reference position Pr is calculated as the displacement of the position Pe of the wire electrode E. That is, in Figure 4C In the example shown, the displacement in the second intersection direction, i.e., the Y direction, is the offset D.

[0083] When the position Pe of the line electrode E is displaced by an offset D from the reference position Pr, a portion of the light L projected from the projection fiber 98yt of the sensor 98y is blocked by the line electrode E. As a result, the amount of light Aa received by the light-receiving fiber 98yr of the sensor 98y at the receiving end corresponds to the displacement of the line electrode E from the workpiece W. Since the amount of light Aa is less than the amount of light As when the displacement is zero, it can be determined that the position Pe of the line electrode E has moved away from the workpiece W.

[0084] That is, based on the amount of light received Aa, it is easy to deduce the case where the position Pe of the wire electrode E is away from the workpiece W and the case where the displacement is the offset D.

[0085] Since the position Pe of the wire electrode E is farther from the workpiece W than the reference position Pr, the target distance G needs to be increased as the displacement amount of the offset D. Therefore, the adjustment unit 154 adjusts the processing conditions determined in the processing condition data 122c to increase the processing amount. According to the adjusted processing conditions, the target distance G becomes a value Ga that is larger than the displacement amount of the offset D by the ratio Gs.

[0086] At this time, as Figure 4C As shown, the machined surface Sp of the processed object W is formed at a position Ga, which is equal to the target distance G, from the traveling position Pa. The position of the machined surface Sp is also the position Gs, which is the original value of the distance G from the reference position Pr to the target distance G.

[0087] If processing is performed while maintaining the value Gs without changing the target distance G, the processed surface Sa of the processed object W will be formed at the position where it departs from the travel position Pa and leaves the value Gs. That is, the processing amount becomes too small. However, by adjusting the processing conditions to change the target distance G to the value Ga, it is possible to prevent the processing amount from being too small.

[0088] When the machining surface Si currently being machined and the predetermined machining surface Su to be machined in the future are machined by the wire electrode E, they are also formed at a position Ga that is equal to the target distance G from the traveling position Pa.

[0089] Additionally, as described above, the adjustment unit 154 can also adjust the machining path specified by the machining program 122r. Figure 4C In the example shown, the adjustment unit 154 moves the machining path closer to the workpiece W by a displacement amount D. As a result, the position Pe of the wire electrode E during machining moves from the current traveling position Pa to the reference position Pr (see reference). Figure 4A ).like Figure 4A As shown, the processed surface Sp of the processed object W is formed at a position Gs that is equal to the distance G from the reference position Pr to the target.

[0090] As described above, based on the actual position Pe of the wire electrode E detected by the sensor 98y, the offset D of the position Pe of the wire electrode E relative to the reference position Pr is calculated as the displacement of the position Pe of the wire electrode E. Therefore, even if the actual machining shape differs from the machining shape represented by the machining path information determined by the machining program 122r, the machining conditions or machining path can be adjusted to suppress the reduction in machining accuracy.

[0091] In use Figure 4A , Figure 4B and Figure 4C In the above explanation, since the machining path is a straight line in the X direction, the detection result of sensor 98y is used. When the machining path is a straight line in the Y direction, the detection result of sensor 98x is used in the same way as described above. When the machining path is a two-dimensional shape (e.g., a curved shape with corners, etc.), the detection results of sensors 98x and 98y are used in the same way as described above. Therefore, it is possible to calculate the displacement of the position Pe of the line electrode E moving in various machining paths during machining.

[0092] In addition, Figure 4B , Figure 4C In the example shown, the machining conditions or machining path are adjusted when the displacement (offset D) of the position Pe of the online electrode E is greater than zero. However, the machining conditions or machining path can also be adjusted when the displacement is greater than a non-zero threshold. This threshold is determined based on the machining path, machining shape, or required accuracy, etc.

[0093] As described above, the adjustment unit 154 changes the machining amount by adjusting the machining conditions or machining path. Regarding the change in machining amount caused by the adjustment of machining conditions, the following is used... Figure 5 This will be described later. Adjusting the machining path to approach the workpiece W increases the machining quantity. Adjusting the machining path to move away from the workpiece W decreases the machining quantity.

[0094] Figure 5This is a diagram illustrating the process performed as an adjustment of processing conditions. Processing conditions include, for example, processing speed, discharge power, inter-electrode voltage, voltage application time, and / or voltage application stop time.

[0095] The processing speed is the speed at which the wire electrode E and the workpiece W move relative to each other during processing, driven by the worktable drive unit 102 to the worktable 62.

[0096] The discharge power is the power generated between the line electrode E, which is energized by the machining power supply 40, and the workpiece W. The applied voltage between the electrodes is the voltage applied by the machining power supply 40 to the electrodes. The voltage application time is the duration during which the machining power supply 40 applies a pulsed voltage to the electrodes. The voltage application stop time is the time during which the voltage application stops when the machining power supply 40 applies a pulsed voltage to the electrodes.

[0097] The wire electrode delivery speed is the delivery speed at which the wire electrode E is delivered by the electrode delivery drive unit 104. The wire electrode tension is the tension applied to the wire electrode E delivered by the electrode delivery drive unit 104.

[0098] The processing fluid flow rate is the amount of processing fluid supplied from the processing fluid supply device 106 to the electrode space between the linear electrode E and the workpiece W.

[0099] When the machining speed, which is a machining condition, is adjusted by the adjustment unit 154, the machining quantity can be increased by decreasing the machining speed, and the machining quantity can be decreased by increasing the machining speed. The worktable drive control unit 182 of the machining control unit 150 controls the worktable drive unit 102 to move the worktable 62 according to the machining speed adjusted by the adjustment unit 154.

[0100] When the discharge power, which is a processing condition, is adjusted by the adjustment unit 154, the processing amount can be increased by increasing the discharge power and decreased by decreasing the discharge power. The power control unit 188 of the processing control unit 150 controls the processing power supply 40 according to the discharge power adjusted by the adjustment unit 154, so that a discharge occurs between the wire electrode E and the workpiece W.

[0101] When the inter-electrode voltage, which serves as a machining condition, is adjusted by the adjustment unit 154, the machining amount can be increased by increasing the inter-electrode voltage, and the machining amount can be reduced by decreasing the inter-electrode voltage. The power control unit 188 of the machining control unit 150 controls the machining power supply 40 to apply a voltage between the wire electrode E and the workpiece W based on the inter-electrode voltage adjusted by the adjustment unit 154.

[0102] When the voltage application time, which is a processing condition, is adjusted by the adjustment unit 154, the processing amount can be increased by increasing the voltage application time, and the processing amount can be reduced by decreasing the voltage application time. The power control unit 188 of the processing control unit 150 controls the processing power supply 40 to apply voltage between the wire electrode E and the workpiece W according to the voltage application time adjusted by the adjustment unit 154.

[0103] When the voltage application stop time, which is a processing condition, is adjusted by the adjustment unit 154, the processing amount can be increased by reducing the voltage application stop time, and the processing amount can be reduced by increasing the voltage application stop time. The power control unit 188 of the processing control unit 150 controls the processing power supply 40 to apply voltage between the wire electrode E and the workpiece W according to the voltage application stop time adjusted by the adjustment unit 154.

[0104] As described above, the calculation unit 152 calculates the displacement of the position Pe of the wire electrode E based on the detection results of the sensors 98x and 98y and the correspondence 122t pre-stored in the storage unit 122. This correspondence 122t is stored in the storage unit 122 at the time the wire EDM machine 10 leaves the factory. The adjustment unit 154 adjusts the processing conditions or processing path according to the displacement.

[0105] Because electrical discharge machining (EDM) is performed, factors such as degradation of sensors 98x and 98y, residue buildup on sensors 98x and 98y, or positional shifts in sensors 98x and 98y can be considered. Therefore, using the wire EDM machine 10 may reduce the accuracy of the calculation unit 152 in calculating the displacement. In this case, the adjustment unit 154's accuracy in adjusting the machining conditions or machining path will decrease. That is, the machining accuracy may decrease.

[0106] Therefore, the calibration execution unit 156 performs calibration corresponding to the latest state of sensors 98x and 98y, and corrects the correspondence 122t pre-stored in the storage unit 122.

[0107] During calibration, for example, calibration data is acquired whenever one of the first wire guide 64 and the second wire guide 66 moves by a predetermined amount. That is, multiple calibration data are acquired. The calibration data includes data on the displacement of the position Pe of the wire electrode E and data representing the detection result of the sensor 98x or the sensor 98y. Additionally, the displacement in the calibration data may be used... Figure 6A As explained, it is calculated using geometric methods.

[0108] Figure 6A This is a diagram used to illustrate calibration. Figure 6AThis example illustrates the calculation of the displacement Sx of the position Pe of the wire electrode E in the X direction after the second wire guide 66 has moved a distance Mx in the X direction. The second wire guide 66 before moving the distance Mx in the X direction is designated as the second wire guide 66v. In this case, the first wire guide 64 and the second wire guide 66v are located along the Z direction, which is parallel to the direction of gravity. The first wire guide 64 and the second wire guide 66v are separated by a distance Dg.

[0109] The wire electrode E is located at the reference position Pr, parallel to the direction of gravity. The wire electrode E that does not displace from the reference position Pr and is parallel to the direction of gravity is designated as wire electrode Ev. The sensor 98x, which detects the wire electrode E along the X direction, is located a distance Ds away from the first wire guide 64. Additionally, for ease of explanation, in... Figure 6A The Lieutenant General recorded the large size of the 98x sensor.

[0110] like Figure 6A As shown with the line electrode Ev, when the line electrode E is at the reference position Pr, the calibration execution unit 156 acquires the sensor signal transmitted from the signal processing circuit 116 of the signal processing device 110. The detection result of the sensor 98x contained in this sensor signal corresponds to the reference position Pr.

[0111] The calibration execution unit 156, via the wire guide drive control unit 190 of the machining control unit 150, causes the wire guide drive unit 108 to move the second wire guide 66 in the X direction by a movement amount Mx. This moved second wire guide 66 is designated as the second wire guide 66i. Consequently, the wire electrode E tilts in the X direction relative to the Z direction (the direction of gravity). This tilted wire electrode E is designated as the wire electrode Ei.

[0112] Because the line electrode Ei is tilted, at the detection position of the sensor 98x in the direction of gravity, the line electrode E is displaced by a displacement Sx from the reference position Pr in the X direction due to the tilt.

[0113] The calibration execution unit 156 calculates the displacement Sx of the position Pe of the wire electrode E based on the movement Mx of the second wire guide 66 when the wire electrode E is tilted, the distance Dg between the first wire guide 64 and the second wire guide 66v, and the distance Ds between the first wire guide 64 and the sensor 98x. Specifically, the displacement Sx is calculated using equation (1).

[0114] Sx=Mx×(Ds / Dg)・・・(1)

[0115] like Figure 6AAs shown with the wire electrode Ei tilted, the calibration execution unit 156 acquires the sensor signal transmitted from the signal processing circuit 116 of the signal processing device 110. The detection result of the sensor 98x contained in this sensor signal is then compared with the calculated displacement Sx.

[0116] The range of the movement amount Mx of the second wire guide 66 and the number of calibration data points mentioned above are specified by the user of the wire EDM machine 10. For example, the specified range of the movement amount Mx is set to -100 [μm] to 100 [μm] centered on the reference position Pr. In addition, the specified number of calibration data points includes 21 calibration data points at the reference position Pr.

[0117] In this case, calibration data is acquired whenever the reference position Pr is moved by a specified amount of 10 [μm] as shown in Equation (2). That is, the movement amount Mx of the second guide wire 66 and the number of calibration data acquisitions are determined according to the user's specification, and the location for acquiring calibration data other than the reference position Pr is determined by calculation.

[0118] {100-(-100)} / (21-1)=10[μm]・・・(2)

[0119] In this way, by acquiring calibration data for every specified movement of 10 [μm], the corresponding relationship 122tx between the detection result of sensor 98x and the displacement Sx of the position Pe of line electrode E is obtained. Figure 6B This is a graph illustrating the correspondence between the detection result of sensor 98x and the displacement Sx (122tx). Figure 6B In the example shown, the amount of light received, Ax, by the light-receiving fiber 98xr is used as the detection result of sensor 98x. In addition, the range of the movement Mx is set to -100 [μm] to 100 [μm] centered on the reference position Pr.

[0120] Figure 6B The correspondence 122tx shown includes 21 combinations of light-receiving amount Ax and displacement amount Sx, which serve as calibration data acquired every 10 [μm] of movement. The calibration execution unit 156 determines the correspondence 122tx between the detection result of the sensor 98x and the displacement amount Sx in the X direction in this way.

[0121] Similarly, the calibration execution unit 156 determines the correspondence 122ty between the detection result of the sensor 98y and the displacement Sy in the Y direction. The calibration execution unit 156 corrects the correspondence 122t stored in the storage unit 122 to a correspondence 122t that includes the newly determined correspondence 122tx and the correspondence 122ty. As a result, the reduction in machining accuracy can be suppressed.

[0122] In addition, Figure 6A and Figure 6B In the example shown, calibration is performed by moving the second guide wire 66, correcting the correspondence 122t. However, calibration can also be performed by moving the first guide wire 64, correcting the correspondence 122t.

[0123] In addition, Figure 6B In the illustrated correspondence 122tx, whenever the movement Mx changes by a predetermined amount of 10 [μm], the detection result of sensor 98x and the displacement Sx in the X direction are obtained. Based on correspondence 122tx, the differences between the changes in the detection results of sensor 98x and the displacement Sx in the X direction at 20 sets of predetermined amounts of 10 [μm] can be calculated. The average of the 20 changes in the detection results of sensor 98x and the average of the 20 differences in the displacement Sx in the X direction can also be used as the correspondence 122tx associated with the aforementioned predetermined amount of 10 [μm].

[0124] Figure 7 This is a flowchart illustrating an example of the processing sequence of a calibration method prior to wire electrical discharge machining (EDM). This processing sequence is performed, for example, by the arithmetic unit 120 of the control device 30. This processing sequence is performed, for example, before the EDM of the workpiece W begins.

[0125] In step S1, the calibration execution unit 156 determines the movement amount of the first guide wire 64 or the second guide wire 66 and the number of calibration data to be acquired according to user specifications. In step S2, the calibration execution unit 156 determines the acquisition position of the calibration data through calculation.

[0126] In step S3, if the wire electrode E is not located at the reference position Pr, the calibration execution unit 156 causes the wire guide drive control unit 190 of the machining control unit 150 to control the wire guide drive unit 108. The wire guide drive unit 108 drives the first wire guide 64 or the second wire guide 66. As a result, the wire electrode E is located at the reference position Pr. In step S4, the calibration execution unit 156 acquires the detection results of the sensors 98x and / or 98y corresponding to the reference position Pr.

[0127] In step S5, the calibration execution unit 156 causes the guide wire drive control unit 190 to control the guide wire drive unit 108. The guide wire drive unit 108 then drives the first guide wire 64 and the second guide wire 66, which was driven in step S3. As a result, the second guide wire 66 moves by a predetermined amount. In step S6, the calibration execution unit 156 calculates the displacement Sx or Sy of the position Pe of the wire electrode E.

[0128] In step S7, the calibration execution unit 156 acquires the detection result of sensor 98x or sensor 98y corresponding to the displacement Sx or Sy calculated in step S6. In step S8, the calibration execution unit 156 determines whether the detection result of sensor 98x or sensor 98y has been acquired at all calibration data acquisition locations determined in step S2.

[0129] If the result in step S8 is "Yes", the process proceeds to step S9. If the result in step S8 is "No", the process returns to step S5. By repeatedly performing the process from step S5 to step S8, the calibration execution unit 156 can move the second wire guide 66 by a predetermined amount each time. The calibration execution unit 156 can calculate the displacement amount Sx or Sy each time the second wire guide 66 is moved by the predetermined amount, and correlate the displacement amount Sx or Sy with the detection result.

[0130] In step S9, the calibration execution unit 156 corrects the correspondence 122t pre-stored in the storage unit 122. Figure 6B In the example shown, the correspondence 122tx in the X direction of correspondence 122t is the correspondence 122tx between the detection result of sensor 98x and the displacement Sx in the X direction. When the processing of step S9 is completed, this processing sequence ends. Then, the electrical discharge machining of the object W can begin.

[0131] The user of the wire electrical discharge machining (EDM) machine 10 inputs an instruction to start the EDM of the workpiece W into the control unit 30. The machining control unit 150 retrieves the machining program 122r and machining condition data 122c from the storage unit 122. Then, the machining begins... Figure 8 The processing order is shown. Figure 8 This is a flowchart illustrating an example of the processing sequence in a wire electrical discharge machining (WEDM) method. This processing sequence is, for example, performed by the arithmetic unit 120 of the control device 30.

[0132] When this processing sequence begins, electrical discharge machining (EDM) is initiated on the workpiece W. In step S101, the electrode delivery control unit 184 of the machining control unit 150 controls the electrode delivery drive unit 104 to deliver the wire electrode E. In step S102, the table drive control unit 182 of the machining control unit 150 controls the table drive unit 102 to move the table 62. In step S103, the power control unit 188 of the machining control unit 150 controls the machining power supply 40 to apply a voltage between the wire electrode E and the workpiece W.

[0133] In step S104, during the processing of the workpiece W, the calculation unit 152 acquires sensor signals representing the detection results of sensors 98x and 98y from the signal processing device 110. In step S105, the calculation unit 152 calculates the displacement Sx or Sy of the position Pe of the line electrode E relative to the reference position Pr based on the detection results of sensors 98x and 98y.

[0134] In step S106, the adjustment unit 154 determines whether the displacement Sx or Sy of the position Pe of the wire electrode E is greater than a threshold. If the result is "yes" in step S106, the process proceeds to step S107. If the result is "no" in step S106, the process proceeds to step S108. In step S107, the adjustment unit 154 adjusts the processing conditions or processing path during the processing of the workpiece W.

[0135] In step S108, the machining control unit 150 determines whether the electrical discharge machining of the workpiece W has ended. If the result in step S108 is "yes", the process proceeds to step S109. If the result in step S109 is "no", the process returns to step S101.

[0136] In step S109, the power control unit 188 of the machining control unit 150 controls the machining power supply 40 to stop applying voltage between the wire electrode E and the workpiece W. In step S110, the table drive control unit 182 of the machining control unit 150 controls the table drive unit 102 to stop the movement of the table 62. In step S111, the electrode delivery control unit 184 of the machining control unit 150 controls the electrode delivery drive unit 104 to stop the delivery of the wire electrode E. When the processing in step S111 is completed, this processing sequence ends.

[0137] According to this embodiment, based on the detection results of the position Pe of the wire electrode E by sensors 98x and 98y provided on the first wire guide 64 and the correspondence 122t pre-stored in the storage unit 122, the displacement amounts Sx and Sy of the position Pe of the wire electrode E are calculated. The processing conditions or processing path are adjusted based on these displacement amounts Sx and Sy. Based on this adjustment, the workpiece W moves relative to the wire electrode E, and a discharge is generated between the workpiece W and the wire electrode E.

[0138] Therefore, it is possible to suppress the decrease in machining accuracy caused by the displacement of the wire electrode E during electrical discharge machining. Furthermore, based on the detection results when the wire electrode E is tilted by moving the second wire guide 66 relative to the first wire guide 64, the correspondence 122t is corrected. Thus, calibration corresponding to the latest state of sensors 98x and 98y can be performed. That is, even if the states of sensors 98x and 98y change, the decrease in machining accuracy can be suppressed.

[0139] In this embodiment, sensors 98x and 98y are fiber optic sensors. However, other sensors can be used instead of fiber optic sensors. Other sensors include, for example, optical sensors, proximity sensors (eddy current displacement sensors), contact sensors, ultrasonic sensors, image sensors, etc. These sensors can be integrated with the signal processing device 110.

[0140] When using a light sensor, the change in the amount of reflected light or blocked light generated when light is emitted towards the line electrode E can be used to calculate the displacements Sx and Sy of the line electrode E. When using a proximity sensor, the change in impedance caused by the eddy currents generated by the line electrode E can be used to calculate the displacements Sx and Sy of the line electrode E.

[0141] When using a contact sensor, the displacement obtained by the contact sensor in contact with the line electrode E can be used to calculate the displacements Sx and Sy of the line electrode E. When using an ultrasonic sensor, the change in the ultrasonic wave reflected by the line electrode E can be used to calculate the displacements Sx and Sy of the line electrode E. When using an image sensor, the displacement of the line electrode E within an image can be used to calculate the displacements Sx and Sy of the line electrode E.

[0142] The above-described embodiments can also be modified as follows. In the following modifications, descriptions that are repeated in the embodiments are omitted.

[0143] (Modified Example)

[0144] In the above embodiment, the adjustment unit 154 can change the machining amount by adjusting the machining conditions. These machining conditions include, for example, adjusting the machining speed, discharge power, inter-electrode voltage, voltage application time, and / or voltage application stop time. By changing the machining amount, a decrease in machining accuracy can be suppressed.

[0145] Regarding the workpiece W, the requirements for machining speed, machining volume, surface roughness, and machining accuracy differ depending on whether roughing or finishing is being performed. To meet various requirements simultaneously, beyond just machining accuracy, other machining conditions need to be adjusted in addition to those exemplified above. These other machining conditions include, for example, the wire electrode feed rate, wire electrode tension, and / or machining fluid flow rate.

[0146] When the wire electrode feed speed, which is a processing condition, is adjusted by the adjustment unit 154, the discharge frequency can be increased by increasing the wire electrode feed speed, and the discharge frequency can be decreased by decreasing the wire electrode feed speed. The electrode feed control unit 184 of the processing control unit 150 controls the electrode feed drive unit 104 to rotate the roller 82 according to the wire electrode feed speed adjusted by the adjustment unit 154, thereby feeding out the wire electrode E.

[0147] By changing the discharge frequency according to the displacement of the line electrode E (Pe), all the above requirements can be met simultaneously.

[0148] When the wire electrode tension, which is a processing condition, is adjusted by the adjustment unit 154, the vibration of the wire electrode E can be reduced by increasing the wire electrode tension, and the risk of wire electrode breakage can be reduced by decreasing the wire electrode tension. The electrode feed control unit 184 of the processing control unit 150 controls the electrode feed drive unit 104 to rotate the roller 82, the pinch roller 84 and the feed roller 86 according to the wire electrode tension adjusted by the adjustment unit 154, thereby applying tension to the wire electrode E.

[0149] When the vibration of the wire electrode E decreases, the displacement of the position Pe of the wire electrode E decreases. Therefore, it is possible to suppress the reduction in machining accuracy. However, the machining volume may decrease. Additionally, the risk of wire electrode E breaking increases. Therefore, for example, during finishing, by adjusting the wire electrode tension according to the displacement of the position Pe of the wire electrode E, it is possible to simultaneously meet all the above requirements.

[0150] When the flow rate of the machining fluid, which is a machining condition, is adjusted by the adjustment unit 154, the influence of the machining fluid on the wire electrode E increases by increasing the flow rate. Therefore, the machining accuracy may decrease. However, since waste residue is easily removed by the machining fluid, the decrease in machining accuracy can be suppressed, and the machining speed can be increased. For example, by increasing the flow rate of the machining fluid during rough machining, the requirements related to the machining speed can be met with particular priority.

[0151] Reducing the machining fluid flow rate makes it difficult to remove waste residue, which may lead to short circuits between electrodes. In this case, machining accuracy may decrease. However, the influence of the machining fluid on the wire electrode E is reduced. Therefore, the decrease in machining accuracy can be suppressed. For example, by appropriately reducing the machining fluid flow rate during finishing, it is possible to prioritize meeting the requirements related to machining accuracy.

[0152] The machining fluid supply control unit 186 of the machining control unit 150 controls the machining fluid supply device 106 to supply machining fluid to the electrode space between the wire electrode E and the workpiece W, based on the machining fluid flow rate adjusted by the adjustment unit 154. By adjusting the machining fluid flow rate according to the displacement of the position Pe of the wire electrode E, all the above-mentioned requirements can be met simultaneously.

[0153] According to this modified example, the wire electrode feed rate, wire electrode tension, and / or machining fluid flow rate are adjusted as machining conditions. Therefore, various requirements such as machining speed, machining volume, surface roughness, and machining accuracy can be met simultaneously.

[0154] The following notes are also disclosed regarding the above-described embodiments and variations.

[0155] (Postscript 1)

[0156] The wire electrical discharge machining (EDM) machine 10 of this disclosure moves a wire electrode E along a machining path relative to a workpiece W, and generates a discharge between the workpiece and the wire electrode according to machining conditions, thereby machining the workpiece. The wire EDM machine includes: a pair of wire guides 64 and 66 that support the wire electrode above and below the workpiece; and sensors 98x and 98y that are positioned at any position between one of the wire guides (i.e., the first wire guide 64) and the other (i.e., the second wire guide 66), along the path from which the wire electrode is delivered. The sensor detects the wire electrode in the X and Y directions of the cross direction of the output direction; a storage unit 122 pre-stores the correspondence 122t between the sensor's detection results and the displacement amounts Sx and Sy of the wire electrode's position Pe in the cross direction; a calculation unit 152 calculates the displacement amount based on the detection results and the correspondence stored in the storage unit; and a calibration execution unit 156 corrects the correspondence stored in the storage unit based on the detection results when the wire electrode is tilted by moving the second wire guide relative to the first wire guide.

[0157] (Postscript 2)

[0158] In the wire EDM machine described in Appendix 1, the calibration execution unit calculates the displacement based on the movement Mx of the second wire guide when the wire electrode is tilted, the interval distance Dg between the first wire guide and the second wire guide, and the interval distance Ds between the first wire guide and the sensor, and corrects the correspondence stored in the storage unit based on the detection result when the wire electrode is tilted and the displacement.

[0159] (Note 3)

[0160] In the wire EDM machine described in Appendix 2, the calibration execution unit may also calculate the displacement amount each time the second wire guide is moved by a predetermined amount.

[0161] (Note 4)

[0162] In the wire electrical discharge machining machine described in Appendix 2 or 3, the displacement is: the offset D of the position of the wire electrode relative to the reference position when the position of the wire electrode supported by the first wire guide and the second wire guide located at a position along the direction of gravity Z is used as the reference position Pr in the state where the workpiece is not being processed.

[0163] (Note 5)

[0164] In any one of the wire EDM machines described in Appendix 1 to 4, the sensor may also be mounted on the first wire guide.

[0165] (Note 6)

[0166] In any one of the appendices 1 to 5, the wire electrical discharge machine is provided with two sensors. One of the two sensors detects the wire electrode along a first intersecting direction X that intersects the feed direction, and the other sensor may also detect the wire electrode along a second intersecting direction Y that intersects the feed direction and is orthogonal to the first intersecting direction.

[0167] (Note 7)

[0168] The wire electrical discharge machining machine described in any one of Appendices 1 to 6 further includes an adjustment unit 154, which adjusts the machining conditions or the machining path based on the displacement calculated by the calculation unit.

[0169] (Postscript 8)

[0170] In any one of the appendices 1 to 7, the sensor is an optical fiber sensor, which has a light-emitting fiber 98xt, 98yt that projects light L from the light source 112 and a light-receiving fiber 98xr, 98yr that receives the light projected by the light-emitting fiber. The calibration execution unit takes the amount of light As, Ac, Aa, Ax received by the light-receiving fiber when the wire electrode is tilted as the detection result, and corrects the correspondence based on the detection result.

[0171] (Note 9)

[0172] The wire electrical discharge machining method disclosed herein is performed by a wire electrical discharge machining machine, which includes: a pair of wire guides supporting wire electrodes above and below a workpiece; a sensor that detects the wire electrodes at any position between one of the wire guides (i.e., the first wire guide) and the other wire guide (i.e., the second wire guide), along a cross direction intersecting the delivery direction of the wire electrodes; and a storage unit that pre-stores a correspondence between the sensor's detection results and the displacement of the wire electrodes in the cross direction. The wire electrical discharge machining machine moves the wire electrodes relative to the workpiece along a machining path and generates a discharge between the workpiece and the wire electrodes according to machining conditions, thereby machining the workpiece. The wire electrical discharge machining method includes: a calculation step, calculating the displacement based on the detection results and the correspondence stored in the storage unit; and a calibration execution step, correcting the correspondence stored in the storage unit based on the detection results when the wire electrodes are tilted by moving the second wire guide relative to the first wire guide.

[0173] (Postscript 10)

[0174] In the wire discharge machining method described in Appendix 9, in the calibration execution step, the displacement is calculated based on the amount of movement of the second wire guide when the wire electrode is tilted, the interval distance between the first wire guide and the second wire guide, and the interval distance between the first wire guide and the sensor. Based on the detection result when the wire electrode is tilted and the displacement, the correspondence stored in the storage unit is corrected.

[0175] (Postscript 11)

[0176] In the wire electrical discharge machining method described in Appendix 10, during the calibration execution step, the displacement is calculated each time the second wire guide moves by a predetermined amount.

[0177] (Postscript 12)

[0178] In the wire electrical discharge machining method described in Appendix 11, the displacement is: the offset of the position of the wire electrode relative to the reference position when the position of the wire electrode supported by the first wire guide and the second wire guide located in the direction of gravity is used as the reference position in the state where the workpiece is not being machined.

[0179] (Postscript 13)

[0180] In any one of the line electrical discharge machining methods described in Appendices 9 to 12, an adjustment step is further included, in which the machining conditions or the machining path are adjusted based on the displacement calculated in the calculation step.

[0181] (Postscript 14)

[0182] In any one of the line discharge processing methods in Appendices 9 to 13, the sensor is an optical fiber sensor, which has a light-emitting optical fiber that projects light from a light source and a light-receiving optical fiber that receives the light projected by the light-emitting optical fiber. In the calibration execution step, the amount of light received by the light-receiving optical fiber when the line electrode is tilted is taken as the detection result, and the correspondence is corrected based on the detection result.

[0183] This disclosure has been described in detail, but it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit of this disclosure, or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the above embodiments, the order of each action and each process is shown as an example, and is not limited thereto. The same applies to the use of numerical values ​​or mathematical formulas in the description of the above embodiments.

[0184] Symbol Explanation

[0185] 10… wire EDM machine 20… main body

[0186] 30…Control device 40…Processing power supply

[0187] 62… Workbench 64… First wire guide

[0188] 66…Second guide wire device 68…First guide block

[0189] 70…First guide wheel 72…First nozzle

[0190] 74…Second guide block 76…Second guide wheel

[0191] 78… Nozzle 2 80… Winding tube

[0192] 82…roller 84…pinch roll

[0193] 86…feed roller 88…recovery box

[0194] 90…machining groove 92…base

[0195] 98… Sensor holding unit 102… Table drive unit

[0196] 104…Electrode delivery drive unit 106…Processing fluid supply device

[0197] 108…Wire guide drive unit 110…Signal processing device

[0198] 112…Light source 114…Light receiving element

[0199] 116…Signal processing circuit 120…Arithmetic unit

[0200] 122…Storage Department 150…Processing Control Department

[0201] 152…Calculation Department 154…Adjustment Department

[0202] 156…Calibration Execution Unit 182…Stage Drive Control Unit

[0203] 184…Electrode delivery control unit 186…Processing fluid supply control unit

[0204] 188…Power supply control unit 190…Wire guide drive control unit.

Claims

1. A wire electrical discharge machining (EDM) machine that moves a wire electrode along a machining path relative to a workpiece and, according to machining conditions, generates a discharge between the workpiece and the wire electrode to machine the workpiece. The wire electrical discharge machining machine is characterized by having: A pair of wire guides that support the wire electrode above and below the workpiece; A sensor that detects the wire electrode at any position between one of the pair of wire guides, i.e., the first wire guide, and the other wire guide, i.e., the second wire guide, along a cross direction that intersects the delivery direction of the wire electrode. The storage unit stores in advance the correspondence between the detection results of the sensor and the displacement of the position of the line electrode in the cross direction; The calculation unit calculates the displacement based on the detection result and the correspondence stored in the storage unit; as well as The calibration execution unit corrects the correspondence stored in the storage unit based on the detection results when the wire electrode is tilted by moving the second wire guide relative to the first wire guide.

2. The wire electrical discharge machining machine according to claim 1, characterized in that, The calibration execution unit calculates the displacement based on the amount of movement of the second guide wire when the wire electrode is tilted, the interval distance between the first guide wire and the second guide wire, and the interval distance between the first guide wire and the sensor, and corrects the correspondence stored in the storage unit based on the detection result when the wire electrode is tilted and the displacement amount.

3. The wire electrical discharge machining machine according to claim 2, characterized in that, The calibration unit calculates the displacement each time the second guide wire is moved by a predetermined amount.

4. The wire electrical discharge machining machine according to claim 2 or 3, characterized in that, The displacement is: the offset of the position of the wire electrode relative to the reference position when the workpiece is not being processed, with the position of the wire electrode supported by the first wire guide and the second wire guide located in the direction of gravity as the reference position.

5. The wire electrical discharge machining machine according to any one of claims 1 to 4, characterized in that, The sensor is mounted on the first guide wire.

6. The wire electrical discharge machining machine according to any one of claims 1 to 5, characterized in that, Set up two of the aforementioned sensors. One of the two sensors detects the line electrode along a first intersecting direction that intersects the delivery direction, and the other sensor detects the line electrode along a second intersecting direction that intersects the delivery direction and is orthogonal to the first intersecting direction.

7. The wire electrical discharge machining machine according to any one of claims 1 to 6, characterized in that, It also includes an adjustment unit that adjusts the processing conditions or the processing path based on the displacement calculated by the calculation unit.

8. The wire electrical discharge machining machine according to any one of claims 1 to 7, characterized in that, The sensor is an optical fiber sensor, which has a light-emitting optical fiber that projects light from a light source and a light-receiving optical fiber that receives the light projected by the light-emitting optical fiber. The calibration execution unit takes the amount of light received by the light-receiving optical fiber when the line electrode is tilted as the detection result, and corrects the correspondence based on the detection result.

9. A wire electrical discharge machining method, performed by a wire electrical discharge machining machine, characterized in that... The wire electrical discharge machining machine includes: a pair of wire guides that support wire electrodes above and below the workpiece; and a sensor that detects the wire electrode at any position between one of the wire guides (i.e., the first wire guide) and the other wire guide (i.e., the second wire guide), along a cross direction that intersects with the delivery direction of the wire electrode. The system also includes a storage unit that pre-stores the correspondence between the sensor's detection results and the displacement of the wire electrode in the intersecting direction. The wire electrical discharge machining (EDM) machine moves the wire electrode along the machining path relative to the workpiece and, according to machining conditions, generates a discharge between the workpiece and the wire electrode to machine the workpiece. The wire electrical discharge machining method includes: The calculation step involves calculating the displacement based on the detection results and the corresponding relationship stored in the storage unit. as well as The calibration execution step corrects the correspondence stored in the storage unit based on the detection results when the wire electrode is tilted by moving the second wire guide relative to the first wire guide.

10. The wire electrical discharge machining method according to claim 9, characterized in that, In the calibration execution step, the displacement is calculated based on the amount of movement of the second guide wire when the wire electrode is tilted, the interval distance between the first guide wire and the second guide wire, and the interval distance between the first guide wire and the sensor. The corresponding relationship stored in the storage unit is then corrected based on the detection result when the wire electrode is tilted and the displacement.

11. The wire electrical discharge machining method according to claim 10, characterized in that, In the calibration execution step, the displacement is calculated each time the second guide wire moves by a predetermined amount.

12. The wire electrical discharge machining method according to claim 11, characterized in that, The displacement is: the offset of the position of the wire electrode relative to the reference position when the workpiece is not being processed, with the position of the wire electrode supported by the first wire guide and the second wire guide located in the direction of gravity as the reference position.

13. The wire electrical discharge machining method according to any one of claims 9 to 12, characterized in that, It also includes an adjustment step, which adjusts the processing conditions or the processing path based on the displacement calculated in the calculation step.

14. The wire electrical discharge machining method according to any one of claims 9 to 13, characterized in that, The sensor is an optical fiber sensor, which has a light-emitting optical fiber that projects light from a light source and a light-receiving optical fiber that receives the light projected by the light-emitting optical fiber. In the calibration execution step, the amount of light received by the light-receiving optical fiber when the line electrode is tilted is taken as the detection result, and the correspondence is corrected based on the detection result.

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