Method and apparatus for calculating pivot point position

Abstract

A fulcrum position calculation method according to the present invention is used to calculate a fulcrum position of a wire electrode (18) of a wire electric discharge machining machine (10) and includes: acquiring a relative position from a storage unit (32) in which is stored the relative position between a fulcrum position corresponding to a first angle, which is the angle of inclination of the wire electrode (18), and a fulcrum position corresponding to each of a plurality of angles differing from the first angle; inclining the wire electrode (18) to the first angle; measuring the fulcrum position corresponding to the first angle; and calculating the fulcrum position corresponding to each angle on the basis of the relative position and the measured fulcrum position corresponding to the first angle.

Description

Technical Field

[0001] The present disclosure relates to a fulcrum position calculation method and a fulcrum position calculation device.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2006-035395 discloses a wire electrical discharge machining machine. The wire electrical discharge machining machine performs taper machining on a workpiece.

Summary of the Invention

[0003] When taper machining is performed, it is necessary to accurately obtain the fulcrum positions of the wire electrodes in two wire guides. Recently, a better fulcrum position calculation method and a fulcrum position calculation device have been eagerly awaited.

[0004] A first aspect of the present disclosure is a fulcrum position calculation method for calculating the fulcrum positions of wire electrodes in two wire guides of a wire electrical discharge machining machine. The fulcrum position calculation method includes a relative position acquisition step of acquiring the relative position from a storage unit that stores the relative position between the fulcrum position corresponding to a first angle, which is the angle of inclination of the wire electrode with respect to a reference line, and the fulcrum positions corresponding to each of a plurality of angles different from the first angle; a fulcrum position measurement step of inclining the wire electrode at the first angle with respect to the reference line and measuring the fulcrum position corresponding to the first angle; and a fulcrum position calculation step of calculating the fulcrum positions corresponding to each angle based on the measured fulcrum position corresponding to the first angle and the relative position.

[0005] A second aspect of the present disclosure is a pivot position calculation device for calculating the pivot position of a wire electrode in two wire guides of a wire electrical discharge machining machine, the pivot position calculation device comprising: a relative position acquisition unit that acquires the relative position from a storage unit that stores the relative position of the pivot position corresponding to a first angle, which is the angle of inclination of the wire electrode with respect to a reference line, and the pivot position corresponding to each of a plurality of angles different from the first angle; a pivot position measurement unit that inclins the wire electrode to the first angle with respect to the reference line and measures the pivot position corresponding to the first angle; and a pivot position calculation unit that calculates the pivot position corresponding to each angle based on the measured pivot position corresponding to the first angle and the relative position. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a schematic diagram of a wire electrical discharge machining (EDM) machine. [Figure 2] Figure 2 is a schematic diagram showing the wire electrode in a tilted position. [Figure 3] Figure 3A is a schematic diagram illustrating the upper fulcrum, which changes depending on the angle of inclination of the wire electrode. Figure 3B is a schematic diagram illustrating the lower fulcrum, which changes depending on the angle of inclination of the wire electrode. [Figure 4] Figure 4 is a table showing examples of upper and lower support point positions corresponding to the angle of inclination of the wire electrode. [Figure 5] Figure 5 is a table showing examples of the relative positions of the upper and lower support points. [Figure 6] Figure 6 is a table showing examples of upper and lower support point positions determined from relative positions. [Figure 7] Figure 7 is a flowchart showing the pivot point position calculation process performed in the control device. [Modes for carrying out the invention]

[0007] To tilt the wire electrode to a precise angle, it is necessary to accurately determine the distance between the support points. This distance is determined from the support point positions of the wire electrode in each of the two wire guides. Since the support point positions change depending on the angle of tilt of the wire electrode, it is necessary to obtain the support point positions corresponding to each of multiple angles through prior measurement.

[0008] When wire guides are replaced or otherwise modified, their position may change. When the wire guide position changes, the pivot point positions corresponding to each angle of the wire electrode's inclination also change. Therefore, conventionally, each time a wire guide was replaced or modified, the pivot point positions corresponding to each of the multiple angles were obtained through measurement. However, this method of obtaining the pivot point positions corresponding to each of the multiple angles through measurement is time-consuming and problematic.

[0009] This disclosure aims to reduce the time required to obtain the pivot point position corresponding to each of multiple angles.

[0010] [First Embodiment] [Wire EDM Machine Configuration] Figure 1 is a schematic diagram of a wire electrical discharge machining (EDM) machine 10. The wire electrical discharge machining machine 10 has a machine body 12 and a control device 14.

[0011] The machining center body 12 applies a voltage between the wire electrode 18 and the workpiece 16 to generate a discharge. As a result, the workpiece 16 is subjected to electrical discharge machining.

[0012] The control device 14 controls the machine body 12. The control device 14 controls the table drive mechanism 20 to move the table 22. As a result, the wire electrode 18 moves relative to the workpiece 16 placed on the table 22 in the X-axis and Y-axis directions.

[0013] The control device 14 controls the upper nozzle drive mechanism 24 to move the upper nozzle 26a. As a result, the upper nozzle 26a moves in the U-axis direction, V-axis direction, and Z-axis direction. The U-axis direction is parallel to the X-axis direction. The V-axis direction is parallel to the Y-axis direction. The Z-axis direction is perpendicular to the U-axis direction and the V-axis direction.

[0014] The control device 14 has a calculation unit 30 and a storage unit 32. The calculation unit 30 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The calculation unit 30 has a pivot point position measurement unit 34, a relative position acquisition unit 36, a pivot point position calculation unit 38, and an angle control unit 40. The pivot point position measurement unit 34, the relative position acquisition unit 36, the pivot point position calculation unit 38, and the angle control unit 40 are realized by the calculation unit 30 executing a program stored in the storage unit 32. At least a part of the pivot point position measurement unit 34, the relative position acquisition unit 36, the pivot point position calculation unit 38, and the angle control unit 40 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). At least a part of the pivot point position measurement unit 34, the relative position acquisition unit 36, the pivot point position calculation unit 38, and the angle control unit 40 may be realized by an electronic circuit including discrete devices.

[0015] The storage unit 32 is composed of a computer-readable storage medium, which includes a volatile memory (not shown) and a non-volatile memory (not shown). The volatile memory is, for example, RAM (Random Access Memory). The non-volatile memory is, for example, ROM (Read Only Memory) or flash memory. Data is stored, for example, in the volatile memory. Programs, tables, maps, etc., are stored, for example, in the non-volatile memory. At least a part of the storage unit 32 may be provided in the processor, integrated circuit, etc., as described above. At least a part of the storage unit 32 may be mounted on equipment connected to the wire electrical discharge machining machine 10 by a network.

[0016] The processes performed in the pivot position measurement unit 34, relative position acquisition unit 36, pivot position calculation unit 38, and angle control unit 40 of the control device 14 will be described in detail later. The control device 14 corresponds to the pivot position calculation device of the present invention.

[0017] [Regarding the tilt of the wire electrodes] Figure 2 is a schematic diagram showing the wire electrode 18 in an inclined position. The upper nozzle 26a has an upper wire guide 42a that supports the wire electrode 18. The lower nozzle 26b has a lower wire guide 42b that supports the wire electrode 18. Hereafter, when the upper wire guide 42a and the lower wire guide 42b are not distinguished, they may be referred to as wire guide 42.

[0018] Hereinafter, the point supporting the wire electrode 18 in the upper wire guide 42a may be referred to as the upper fulcrum P1. The point supporting the wire electrode 18 in the lower wire guide 42b may be referred to as the lower fulcrum P2. When the upper fulcrum P1 and the lower fulcrum P2 are not distinguished, they may be referred to as fulcrum P. In addition, the Z-axis coordinate value of the upper fulcrum P1 may be referred to as the upper fulcrum position z1. The Z-axis coordinate value of the lower fulcrum P2 may be referred to as the lower fulcrum position z2.

[0019] When tapering is performed on the workpiece 16, or when machining the workpiece 16 to create different shapes on the top and bottom, the machining center body 12 performs machining on the workpiece 16 with the wire electrode 18 tilted relative to the reference line 44. The reference line 44 is a line that passes through the lower pivot point P2 and is parallel to the Z-axis direction. When the wire electrode 18 is not tilted relative to the reference line 44, the wire electrode 18 is located on the reference line 44.

[0020] The upper fulcrum P1 moves together with the upper nozzle 26a in the U-axis direction or the V-axis direction. By moving the upper fulcrum P1 in the U-axis direction or the V-axis direction, the wire electrode 18 is tilted with respect to the reference line 44. The amount of movement of the upper fulcrum P1 is set according to the angle of inclination of the wire electrode 18 with respect to the reference line 44. Hereafter, when referred to as "angle," it refers to the angle of inclination of the wire electrode 18 with respect to the reference line 44.

[0021] For example, in order to tilt the wire electrode 18 to an angle α, the upper fulcrum point P1 is moved in the U-axis direction from the reference line 44. Let the moving distance be M. Let the distance in the Z-axis direction between the upper fulcrum point P1 and the lower fulcrum point P2 be the distance H between the fulcrum points. The moving distance M is obtained by the following formula (1) based on the distance H between the fulcrum points and the angle α.

[0022] (Equation 1) M = H × tan α…(1)

[0023] That is, if the distance H between the fulcrum points is known, the moving distance M of the upper nozzle 26a necessary to tilt the wire electrode 18 to the angle α can be obtained. This distance H between the fulcrum points is obtained by the following formula (2) based on the upper fulcrum point position z1 and the lower fulcrum point position z2.

[0024] (Equation 2) H = z1 - z2…(2)

[0025] The upper fulcrum point position zA and the lower fulcrum point position z2 change according to the angle of inclination of the wire electrode 18. That is, the distance H between the fulcrum points changes according to the angle of inclination of the wire electrode 18.

[0026] Fig. 3A is a schematic diagram for explaining the upper fulcrum point P1 that changes according to the angle of inclination of the wire electrode 18. Fig. 3B is a schematic diagram for explaining the lower fulcrum point P2 that changes according to the angle of inclination of the wire electrode 18. As shown in Fig. 3A, as the angle of inclination of the wire electrode 18 increases, the upper fulcrum point P1 moves in the negative Z-axis direction. As shown in Fig. 3B, as the angle of inclination of the wire electrode 18 increases, the lower fulcrum point P2 moves in the positive Z-axis direction.

[0027] Fig. 4 is a table showing examples of the upper fulcrum point position z1 and the lower fulcrum point position z2 corresponding to the angle of inclination of the wire electrode 18. The upper fulcrum point position z1 in Fig. 4 shows a value based on the Z-axis coordinate value of the reference point Q (Fig. 2) of the upper nozzle 26a. The Z-axis coordinate value of the lower fulcrum point position z2 in Fig. 4 shows a value based on the origin (Z = 0).

[0028] By obtaining the upper and lower support point positions z1 and z2 corresponding to each of the multiple angles of the wire electrode 18 through prior measurements, it is possible to accurately determine the distance H between the support points according to each angle.

[0029] [Regarding changes in the upper and lower support positions due to wire guide replacement, etc.] The wire guide 42 may be removed and reinstalled by the user, for example, by replacing the wire guide 42.

[0030] If the wire guide 42 is replaced or otherwise modified, the position of the wire guide 42 in the Z-axis direction may change. When the position of the wire guide 42 in the Z-axis direction changes, the upper and lower pivot positions z1 and z2 corresponding to each angle of inclination of the wire electrode 18 also change. However, even if the upper and lower pivot positions z1 and z2 corresponding to each angle of inclination of the wire electrode 18 change, the relative positions of the upper and lower pivot positions z1 and z2 corresponding to each angle remain constant.

[0031] Figure 5 is a table showing examples of the relative positions of the upper and lower support points z1 and z2. Figure 5 shows the relative positions of the upper and lower support points z1 and z2 corresponding to angles 15° and 20°, with the upper and lower support points z1 and z2 corresponding to angles 10° as the reference.

[0032] If the upper and lower support positions z1 and z2 corresponding to an angle of 10° are obtained through prior measurements, the upper and lower support positions z1 and z2 corresponding to angles of 15° and 20° can be calculated using the relative positions shown in Figure 5.

[0033] Figure 6 is a table showing examples of upper and lower support positions z1 and z2 determined from relative positions. The upper and lower support positions z1 and z2 corresponding to angles 15° and 20° in Figure 6 are calculated based on the upper and lower support positions z1 and z2 corresponding to angle 10°, which were measured in advance, and the relative positions.

[0034] [Regarding processing in the control unit] As described above, the control device 14 includes a pivot position measurement unit 34, a relative position acquisition unit 36, a pivot position calculation unit 38, and an angle control unit 40.

[0035] Figure 7 is a flowchart showing the pivot point position calculation process performed in the control device 14.

[0036] The relative angles corresponding to each angle are determined before the pivot position calculation process is performed. The relative angles corresponding to each angle are determined by the pivot position measurement unit 34.

[0037] The pivot position measuring unit 34 measures the upper pivot position z1 and the lower pivot position z2 for each of several angles, including an angle of 10°, in which case the inclination of the wire electrode 18 is. The method for measuring the upper pivot position z1 and the lower pivot position z2 is known, so its explanation is omitted.

[0038] The pivot position measurement unit 34 calculates the relative positions of the upper pivot position z1 and lower pivot position z2 corresponding to each angle, using the upper pivot position z1 and lower pivot position z2 corresponding to an angle of 10° as a reference. The pivot position measurement unit 34 stores the relative positions in the storage unit 32, associating them with each angle.

[0039] The process of determining the relative position only needs to be performed once in the wire EDM machine 10. Alternatively, the process of determining the relative position may be performed for each type of upper wire guide 42a and lower wire guide 42b. The relative position corresponding to each angle may be stored in the memory unit 32 when the wire EDM machine 10 is shipped from the factory.

[0040] If the wire guide 42 is replaced or otherwise modified, the control device 14 performs pivot point position calculation processing according to the flowchart shown in Figure 7.

[0041] In step S1, the relative position acquisition unit 36 ​​acquires the relative positions of the upper pivot position z1 and lower pivot position z2 corresponding to each angle from the storage unit 32. Then, the process proceeds to step S2.

[0042] In step S2, the pivot position measuring unit 34 measures the upper pivot position z1 and the lower pivot position z2 when the wire electrode 18 is tilted at an angle of 10°. Then, the process proceeds to step S3.

[0043] In step S3, the pivot position calculation unit 38 calculates the upper pivot position z1 and lower pivot position z2 corresponding to each angle. After that, the pivot position calculation process ends. The upper pivot position z1 and lower pivot position z2 corresponding to each angle are calculated based on the upper pivot position z1 and lower pivot position z2 corresponding to an angle of 10° and the relative position corresponding to each angle. The calculated upper pivot position z1 and lower pivot position z2 may be associated with each angle and stored in the storage unit 32.

[0044] The angle control unit 40 calculates the distance between the support points H using equation (2) above, based on the upper support point position z1 and the lower support point position z2, which correspond to the angle α of the wire electrode 18 tilt specified during machining. The angle control unit 40 calculates the travel distance M of the upper nozzle 26a using equation (1) above, based on the specified angle α and the distance between the support points H. The angle control unit 40 controls the upper nozzle drive mechanism 24 to move the upper nozzle 26a by a travel distance M from the reference line 44. As a result, the tilt of the wire electrode 18 becomes the specified angle α.

[0045] In the above, the pivot position measurement unit 34 calculates the relative positions of the upper pivot position z1 and lower pivot position z2 corresponding to each angle, using the upper pivot position z1 and lower pivot position z2 corresponding to the inclination angle of 10° of the wire electrode 18 as a reference. Alternatively, the pivot position measurement unit 34 may calculate the relative positions of the upper pivot position z1 and lower pivot position z2 corresponding to each angle, using the upper pivot position z1 and lower pivot position z2 corresponding to angles other than 10° as a reference for the inclination of the wire electrode 18. In this case, in step S2 above, the pivot position measurement unit 34 needs to measure the upper pivot position z1 and lower pivot position z2 corresponding to the angle that serves as the reference for the relative position.

[0046] [Effects and Effects] In order to tilt the wire electrode 18 to a precise angle, it is necessary to accurately determine the distance H between the support points. The distance H between the support points is determined from the upper support position z1 and the lower support position z2. Since the upper support position z1 and the lower support position z2 change according to the angle of tilt of the wire electrode 18, it is necessary to obtain the upper support position z1 and the lower support position z2 corresponding to each of several angles through prior measurement.

[0047] When the wire guide 42 is replaced or otherwise modified, its position in the Z-axis direction may change. When the position of the wire guide 42 in the Z-axis direction changes, the upper and lower pivot positions z1 and z2 corresponding to each angle of inclination of the wire electrode 18 also change. Therefore, conventionally, each time the wire guide 42 was replaced or otherwise modified, the upper and lower pivot positions z1 and z2 corresponding to each of the multiple angles were obtained by measurement. However, there is a problem in that it takes a long time to obtain the upper and lower pivot positions z1 and z2 corresponding to each of the multiple angles by measurement.

[0048] The inventors have focused on the fact that even when the upper and lower pivot positions z1 and z2 corresponding to each angle of inclination of the wire electrode 18 change, the relative positions of the upper and lower pivot positions z1 and z2 corresponding to each angle remain constant.

[0049] This embodiment discloses a pivot position calculation method for calculating the upper pivot position z1 and lower pivot position z2 of a wire electrical discharge machining machine 10. In this pivot position calculation method, relative positions corresponding to each of a plurality of angles, including a first angle (for example, an angle of 10°), are obtained from the storage unit 32. The wire electrode 18 is tilted to the first angle, and the upper pivot position z1 and lower pivot position z2 corresponding to the first angle are measured. Based on the upper pivot position z1 and lower pivot position z2 corresponding to the first angle and the relative positions corresponding to each angle, the pivot position corresponding to each angle is calculated.

[0050] Furthermore, in this embodiment, a control device 14 is disclosed as a pivot position calculation device for calculating the upper pivot position z1 and lower pivot position z2 of the wire electrical discharge machining machine 10. In the control device 14, a relative position acquisition unit 36 ​​acquires relative positions corresponding to each of a plurality of angles, including a first angle (for example, an angle of 10°), from a storage unit 32. A pivot position measurement unit 34 tilts the wire electrode 18 to a first angle and measures the upper pivot position z1 and lower pivot position z2 corresponding to the first angle. A pivot position calculation unit 38 calculates the pivot position corresponding to each angle based on the upper pivot position z1 and lower pivot position z2 corresponding to the first angle and the relative positions corresponding to each angle.

[0051] As a result, if the wire guide 42 is replaced or otherwise modified, and the upper and lower support positions z1 and z2 corresponding to the first angle can be obtained by measurement, the upper and lower support positions z1 and z2 corresponding to each of the multiple angles can be obtained by calculation. Consequently, the time required to obtain the upper and lower support positions z1 and z2 corresponding to each of the multiple angles after the wire guide 42 has been replaced or otherwise modified can be reduced.

[0052] The following additional information is disclosed regarding the above embodiment.

[0053] (Note 1) A pivot position calculation method for calculating the pivot position of a wire electrode (18) in two wire guides (42) of a wire electrical discharge machining machine (10), comprising: a relative position acquisition step of acquiring the relative position from a storage unit (32) that stores the relative position of the pivot position corresponding to a first angle, which is the angle of inclination of the wire electrode with respect to a reference line (44), and the pivot position corresponding to each of a plurality of angles different from the first angle; a pivot position measurement step of inclining the wire electrode to the first angle with respect to the reference line and measuring the pivot position corresponding to the first angle; and a pivot position calculation step of calculating the pivot position corresponding to each angle based on the measured pivot position corresponding to the first angle and the relative position. This reduces the time required to obtain the pivot position corresponding to each of the plurality of angles.

[0054] (Note 2) In the pivot position calculation method described in Appendix 1, the pivot position calculation method includes a storage step in which, before the wire electrode is removed, the wire electrode is tilted to a plurality of angles including the first angle with respect to the reference line, the pivot position corresponding to each angle is measured, and the relative position calculated based on the measured pivot position corresponding to each angle is stored in the storage unit. The pivot position measurement step may be performed after the wire electrode has been removed and installed. This reduces the time required to obtain the pivot position corresponding to each of the plurality of angles.

[0055] (Note 3) A pivot position calculation device (14) for calculating the pivot position of a wire electrode in two wire guides of a wire electrical discharge machining machine, the pivot position calculation device includes: a relative position acquisition unit (36) that acquires the relative position from a storage unit that stores the relative position of the pivot position corresponding to a first angle, which is the angle of inclination of the wire electrode with respect to a reference line, and the pivot position corresponding to each of a plurality of angles different from the first angle; a pivot position measurement unit (34) that inclins the wire electrode to the first angle with respect to the reference line and measures the pivot position corresponding to the first angle; and a pivot position calculation unit (38) that calculates the pivot position corresponding to each angle based on the measured pivot position corresponding to the first angle and the relative position. This reduces the time required to obtain the pivot position corresponding to each of the plurality of angles.

[0056] While embodiments of this disclosure have been described in detail, this disclosure is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the spirit of the invention or the idea and spirit of the invention derived from the claims and their equivalents. For example, the order of operations and processes in the embodiments described above are shown as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above. [Explanation of symbols]

[0057] 10…Wire electrical discharge machining machine 14…Fulfillment position calculation device (control device) 18...Wire electrodes 32...Memory unit 34...Fulfillment point position measurement unit 36...Relative position acquisition unit 38...Fulfillment point position calculation unit 42...Wire guide 44…Reference line

Claims

1. A method for calculating the pivot position of the wire electrode (18) in two wire guides (42) of a wire electrical discharge machining machine (10), A relative position acquisition step involves acquiring the relative position from a storage unit (32) that stores the relative positions of the pivot point position corresponding to a first angle, which is the angle of inclination of the wire electrode with respect to a reference line (44), and the pivot point position corresponding to each of a plurality of angles different from the first angle. A pivot position measurement step in which the wire electrode is tilted at a first angle with respect to the reference line and the pivot position corresponding to the first angle is measured, A pivot position calculation step of calculating the pivot position corresponding to each angle based on the pivot position corresponding to the measured first angle and the relative position, A method for calculating the position of a pivot point, comprising the following characteristics.

2. In the method for calculating the pivot point position according to claim 1, Before the wire electrode is removed, the wire electrode is tilted to a plurality of angles, including the first angle, with respect to the reference line, the pivot point position corresponding to each angle is measured, and the relative position calculated based on the measured pivot point position corresponding to each angle is stored in the storage unit. The aforementioned pivot point position measurement step is a pivot point position calculation method performed after the wire electrode has been removed and installed.

3. A pivot position calculation device (14) for calculating the pivot position of the wire electrode in two wire guides of a wire electrical discharge machining machine, A relative position acquisition unit (36) acquires the relative position from a storage unit that stores the relative positions of the pivot point position corresponding to a first angle, which is the angle of inclination of the wire electrode with respect to a reference line, and the pivot point position corresponding to each of a plurality of angles different from the first angle, A pivot position measuring unit (34) tilts the wire electrode at a first angle with respect to the reference line and measures the pivot position corresponding to the first angle, A pivot position calculation unit (38) calculates the pivot position corresponding to each angle based on the pivot position corresponding to the measured first angle and the relative position, A pivot point position calculation device having the following features.

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