Power supply plate position management method of wire electric discharge machine and wire electric discharge machine

Abstract

To provide a wire electric discharge machine which can save labor of position management of a power supply plate supplying power to a wire electrode, and a power supply plate position management method of the same.SOLUTION: A position management method of power supply plates 40 and 50 of a wire electric discharge machine 10 includes: fixing the power supply plates 40 and 50; relatively moving wire guide devices 20 and 24 and restraining devices 32 and 34 installed outside of the wire guide devices, restraining ends of rods 22 and 26 which are coupled to the power supply plates 40 and 50 and extend to the outside of the wire guide devices 20 and 24 by the restraining devices 32 and 34, and detecting a reference position signal; calculating coordinate positions of the power supply plates 40 and 50 on the basis of the coordinate positions of shaft feeding devices 44 and 54 acquired by an NC device 62 and relative positions of the power supply plates 40 and 50 to the shaft feeding devices 44 and 54 when detecting the reference position signal; releasing fixing of the power supply plates 40 and 50, and making the power supply plates movable; and moving the movable power supply plates 40 and 50 by a predetermined distance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for managing the position of a power feed plate in a wire electric discharge machine and a wire electric discharge machine. [Background technology]

[0002] The wire electrode of a wire electric discharge machine receives a voltage while sliding against a power feed plate, and the power feed plate is subject to wear due to the sliding of the wire electrode. For this reason, the power feed plate is made of a highly wear-resistant material, such as a cemented carbide alloy. Furthermore, it is common for the power feed plate to be used multiple times, moving it vertically relative to the wire electrode, i.e., shifting its position (for example, by 1 mm) each time it wears down to a desired amount. In this regard, Patent Document 1 discloses a wire electric discharge machine in which the contact position between the power feed plate and the wire electrode can be mechanically changed.

[0003] However, in a wire electric discharge machine such as that disclosed in Patent Document 1, the operator must manually record the number of times the power feed plate is used at the same contact position. Furthermore, because the time interval for shifting the power feed plate cannot be mechanically set, the operator must check it visually or using a checklist. Furthermore, because the lower wire guide device is typically located inside the machining tank, sludge may enter the power feed plate storage space. Pressing one side of the power feed plate with a pressure pin in this state could result in sludge galling between the other side of the power feed plate, away from the pressing point, and the wall of the storage space. Forcibly pushing such a power feed plate in could cause malfunction or damage to the wire guide device. To prevent this, the operator must regularly inspect the wire guide device to check for sludge buildup and remove it as necessary, resulting in increased work hours. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7162115 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above circumstances, an object of the present invention is to provide a method for managing the position of a power feeder plate in a wire electric discharge machine, and a wire electric discharge machine, which can reduce the labor required for managing the position of a power feeder plate that feeds power to a wire electrode. [Means for solving the problem]

[0006] According to one aspect of the present invention, a method for controlling the position of a power feed plate in a wire electric discharge machine is provided, which processes a workpiece into a desired shape by sliding a wire electrode running between two wire guide devices on a power feed plate movably arranged inside each wire guide device, applying a pulse voltage, and relatively moving the wire electrode and the workpiece using an axial feed device in accordance with a command from an NC device. The method includes fixing the power feed plate inside the wire guide device, relatively moving the wire guide device and a restraining device arranged outside the wire guide device, and restraining a workpiece with one end connected to the power feed plate and extending outside the wire guide device. a restraining device for restraining the other end of the rod to be moved, and detecting a reference position signal transmitted from the restraining device; calculating, when the reference position signal is detected, a coordinate position of the power feed plate based on the coordinate position of the axial feed device and the relative position of the power feed plate with respect to the axial feed device obtained from the NC device; releasing the fixation of the power feed plate with respect to the wire guide device, and making the power feed plate movable in a direction perpendicular to the traveling direction of the wire electrode and parallel to the sliding surface on which the wire electrode slides; and moving the movable power feed plate by a predetermined distance.

[0007] According to one aspect of the present invention, a wire electric discharge machine machines a workpiece into a desired shape by sliding a wire electrode running between two wire guide devices on a power supply plate movably arranged inside each wire guide device, applying a pulse voltage, and relatively moving the wire electrode and the workpiece using an axial feed device in accordance with commands from an NC device. The wire electric discharge machine includes a power supply plate arranged inside the wire guide device and capable of changing the position on which the wire electrode slides by moving in a direction perpendicular to the running direction of the wire electrode and parallel to the sliding surface on which the wire electrode slides; Provided is a wire electric discharge machine comprising: a fixing device that fixes a power feed plate that is movable inside the device; a rod that is connected at one end to the power feed plate and extends to the outside of a wire guide device in the direction of movement of the power feed plate; a restraining device that is arranged outside the wire guide device and moves the wire guide device and the restraining device relative to each other, restrains the other end of the rod, and emits a reference position signal when restrained; and a control device that receives the reference position signal and calculates the coordinate position of the power feed plate based on the coordinate position of the axial feed device obtained from the NC device and the relative position of the power feed plate with respect to the axial feed device. [Effects of the Invention]

[0008] According to one aspect of the present invention, a method for managing the position of a power feed plate in a wire electric discharge machine includes: fixing the power feed plate inside a wire guide device; moving the wire guide device relative to a constraint device disposed outside the wire guide device; and constraining the other end of the rod with the constraint device. Furthermore, by detecting a reference position signal transmitted from the constraint device, it is possible to detect when the constraint device has constrained the rod. Furthermore, upon detecting the reference position signal, it is possible to calculate the coordinate position of the power feed plate connected to the rod constrained by the constraint device from the coordinate position of the axial feed device and the relative position of the power feed plate with respect to the axial feed device obtained from the NC device. This allows the coordinate position of the power feed plate when the constraint device constrained the rod to be determined, and to determine how many times the wire electrode has been used at which position on the power feed plate. Furthermore, while the rod is constrained by the constraint device, the fixation of the power feed plate to the wire guide device can be released, and the power feed plate can be made movable in a direction perpendicular to the traveling direction of the wire electrode and parallel to the sliding surface on which the wire electrode slides, and the movable power feed plate can be moved a predetermined distance. Therefore, the sliding surface of the power supply plate that has worn due to the sliding of the wire electrode can be shifted to change the position of the wire electrode, which allows the position of the power supply plate to be grasped and changed mechanically, thereby reducing the labor required for position management of the power supply plate that supplies power to the wire electrode.

[0009] According to one aspect of the present invention, a wire electric discharge machine is configured such that, with a movable power feed plate inside a wire guide device fixed by a fixing device, the wire guide device and a constraint device installed outside the wire guide device are moved relative to each other, and the other end of the rod is constrained by the constraint device. The control device can detect when the constraint device constrains the rod by detecting a reference position signal transmitted from the constraint device. Furthermore, upon receiving the reference position signal, the control device can calculate and determine the coordinate position of the power feed plate connected to the rod constrained by the constraint device from the coordinate position of the axial feed device and the relative position of the power feed plate with respect to the axial feed device obtained from the NC device. Furthermore, with the rod constrained by the constraint device, the control device can release the power feed plate from its fixation with respect to the wire guide device, making the power feed plate movable in a direction perpendicular to the traveling direction of the wire electrode and parallel to the sliding surface on which the wire electrode slides, and move the movable power feed plate a predetermined distance. This allows the sliding surface of the power feed plate, which has worn due to sliding of the wire electrode, to be shifted, thereby changing the sliding position of the wire electrode. This allows the position of the power supply plate to be grasped and changed mechanically, thereby reducing the labor required for managing the position of the power supply plate that supplies power to the wire electrode. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows a front view of a wire electric discharge machine according to an embodiment. [Figure 2] FIG. 2 shows a block diagram of the wire electric discharge machine according to the embodiment. [Figure 3] Figure 3 shows a wire guide device, where Figure 3(a) is a front view looking in the longitudinal direction of the rod, Figure 3(b) is a side view looking in the axial direction of the rod, and Figure 3(c) is a rear view looking from the side where the fixation device is placed. [Figure 4] 4A and 4B show a restraining device, with FIG. 4A being a front view showing a state in which the restraining portion is pushed out, and FIG. 4B being a front view showing a state in which the restraining portion is retracted. [Figure 5]FIG. 5 shows the positional relationship of the current feeder plate with respect to the wire electrode, with FIG. 5(a) showing the positional relationship of the current feeder plate at the start of use and FIG. 5(b) showing the positional relationship of the current feeder plate at the end of use. [Figure 6] FIG. 6 shows a flowchart for managing the position of the feeder board. [Figure 7] 7(a) to 7(f) are diagrams illustrating a method for calculating the number of times a feed plate is used. [Figure 8] 8(a) to 8(g) are explanatory diagrams showing how the feed plate is moved. [Figure 9] FIG. 9 shows a front view of a pinch mechanism according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a wire electric discharge machine according to an embodiment will be described with reference to the accompanying drawings. Similar or corresponding elements are designated by the same reference numerals, and duplicated explanations will be omitted. For ease of understanding, the scale of the drawings may be changed.

[0012] Fig. 1 shows a schematic front view of a wire electric discharge machine 10 according to an embodiment. Fig. 2 shows a block diagram of wire guide devices 20, 24 and restraint devices 32, 34, which are essential parts of the wire electric discharge machine 10. Here, the wire electric discharge machine 10 includes a bed 12 fixed to the floor of the installation location (such as a factory), and a table 14 disposed on the upper surface of the bed 12 and having a work plate 14a on its upper surface for mounting a workpiece WK to be machined (a workpiece). The wire electric discharge machine 10 includes a wire electrode WE, an upper wire guide device 20 disposed above the workpiece WK, and a lower wire guide device 24 disposed below the workpiece WK.

[0013] The wire electrode WE is arranged so that it passes through the upper wire guide device 20 and the lower wire guide device 24, which are arranged so as to sandwich the workpiece WK vertically, and travels between them from top to bottom. The wire electrode WE arranged in this manner is configured to machine the workpiece WK by discharging electricity while forming a gap between it and the workpiece WK. The wire that makes up the wire electrode WE is mainly made of brass or tungsten, and the diameter of the wire is approximately 0.015 mm to 0.4 mm depending on the purpose of machining.

[0014] In the wire electric discharge machine 10 described here, the wire WE is described as running from the top to the bottom, but this is not limited to this, and the present invention is also applicable to wire electric discharge machines in which the wire runs in the left-right direction, i.e., parallel to the installation surface of the wire electric discharge machine.

[0015] The wire electric discharge machine 10 is equipped with a wire head 16, an upper wire guide device 20, a lower wire guide device 24, and a wire recovery mechanism 28, which are arranged along the travel path of the wire electrode WE, i.e., from top to bottom. The wire electric discharge machine 10 also includes a power supply device (not shown) for supplying power to the wire electrode WE via power supply plates 40, 50 (see FIG. 2).

[0016] The wire electric discharge machine 10 also includes axial feed devices 44 and 54 (see FIG. 2 ) that can move the wire head 16, the upper wire guide device 20, and the lower wire guide device 24 in the left-right direction (the X-axis direction in FIG. 1 ) and the front-back direction (the Y-axis direction in FIG. 1 ). Furthermore, an axial feed device (not shown) separate from the axial feed devices 44 and 54 can move the wire head 16 and the upper wire guide device 20 alone in the U-axis direction parallel to the X-axis, the V-axis direction parallel to the Y-axis, and the up-down direction (the Z-axis direction in FIG. 1 ). In normal machining, the upper wire guide device 20 and the lower wire guide device 24 are simultaneously moved in the X-axis and Y-axis directions to machine a vertical surface parallel to the Z-axis. In addition, in special machining, the upper wire guide device 20 alone can be moved in the X-axis, Y-axis, U-axis, and / or V-axis directions to machine a sloped or tapered surface that is inclined from the vertical. The upper wire guide device 20 can also be moved in the Z-axis direction to machine workpieces WK of various thicknesses. Furthermore, the X-axis and Y-axis feed devices may be provided on the table side, the upper wire guide device 20 may have only the U-axis, V-axis, and Z-axis, and the lower wire guide device 24 may be fixed to the bed. In this way, various configurations are included that allow the wire electrode WE and the workpiece WK to move relative to each other.

[0017] As will be described later, the wire electric discharge machine 10 also includes a first restraining device 32 and a second restraining device 34 as restraining devices for restraining the first rod 22 and the second rod 26 connected to the power feed plates 40, 50. The first restraining device 32 and the second restraining device 34 extend upward from the bed 12 and are attached to a restraining device guide 30 that also serves as the table 14.

[0018] The wire head 16 has a wire feeder 18 configured to continuously supply a wire electrode WE wound around a wire bobbin (not shown) while applying a predetermined tension to the wire electrode WE. The wire head 16 also has a wire cutter 36 (see FIG. 2) that cuts the wire electrode WE (wire) as needed, such as when measuring the positions of the power feed plates 40, 50, when processing is completed, or during automatic wire threading. The wire recovery mechanism 28, located downstream of the lower wire guide device 24, also has a wire winder 38 (see FIG. 2) that winds and recovers the wire electrode WE (wire).

[0019] As shown in FIGS. 2 and 3(a) to 3(c), the upper wire guide device 20 includes a plate-shaped first power supply plate 40 therein. The plate-shaped first power supply plate 40 is electrically connected to a power supply device and serves as a power supply plate for supplying power to the wire electrode WE. The first power supply plate 40 has a sliding surface 40a on which the wire electrode WE slides and is configured to be movable within the upper wire guide device 20. Specifically, the first power supply plate 40 is configured to be movable in the direction in which the wire electrode WE travels (here, perpendicular to the vertical direction) and in a direction parallel to the sliding surface 40a on which the wire electrode WE slides (the left-right direction in FIGS. 2 and 3). This allows the position of the wire electrode WE on the sliding surface 40a to be appropriately changed. One end of a rod-shaped first rod 22 is coupled to the first power supply plate 40, and the first rod 22 extends to the outside of the upper wire guide device 20. Therefore, the other end of the first rod 22 is exposed from the upper wire guide device 20, and the length of the first rod 22 exposed to the outside of the upper wire guide device 20 changes as the first power supply plate 40 to which the first rod 22 is connected moves inside the upper wire guide device 20. With this structure, the coordinate position of the first power supply plate 40 inside the upper wire guide device 20 relative to the axial feed device 44, which will be described later, can be calculated from the position (coordinate position) of the first rod 22.

[0020] Furthermore, the upper wire guide device 20 has a first fixing device 42 as a fixing device for fixing the first power feed plate 40 to the upper wire guide device 20 in order to feed power to the wire electrode WE. The first fixing device 42 has a first fixing portion 46 for pressing and fixing the first power feed plate 40 against the inner wall of the upper wire guide device 20, and a first locking mechanism 48 configured to lock the first fixing portion 46 that presses the first power feed plate 40. Therefore, it is possible to configure a fixed state in which the first power feed plate 40 is fixed within the upper wire guide device 20 by locking the first fixing portion 46 with the first locking mechanism 48, and a movable state in which the first power feed plate 40 is movable within the upper wire guide device 20 by releasing the lock by the first locking mechanism 48.

[0021] The lower wire guide device 24 also includes a second power supply plate 50, which is electrically connected to the power supply and serves as a power supply plate for supplying power to the wire electrode WE. The second power supply plate 50 has a sliding surface 50a on which the wire electrode WE slides, and is configured to be movable within the lower wire guide device 24. Specifically, the second power supply plate 50 is configured to be movable in the traveling direction of the wire electrode WE, which is, in this case, a direction perpendicular to the vertical direction and parallel to the wire electrode WE and the sliding surface 50a on which the wire electrode WE slides (the left-right direction in FIGS. 2 and 3 ). This allows the position of the wire electrode WE on the sliding surface 50a to be appropriately changed. One end of a rod-shaped second rod 26 is coupled to the second power supply plate 50, and the second rod 26 extends to the outside of the lower wire guide device 24. Therefore, the other end of the second rod 26 is exposed from the lower wire guide device 24, and the length of the second rod 26 exposed to the outside of the lower wire guide device 24 changes as the second power feed plate 50 to which the second rod 26 is connected moves inside the lower wire guide device 24. With this structure, the coordinate position of the second power feed plate 50 inside the lower wire guide device 24 relative to the axial feed device 54, which will be described later, can be calculated from the position (coordinate position) of the second rod 26.

[0022] Furthermore, the lower wire guide device 24 has a second fixing device 52 as a fixing device for fixing a second power feed plate 50 to the lower wire guide device 24 in order to supply power to the wire electrode WE. The second fixing device 52 has a plate-shaped second fixing portion 56 for pressing and fixing the second power feed plate 50 against the inner wall of the lower wire guide device 24, and a second locking mechanism 58 configured to lock the second fixing portion 56 that presses the second power feed plate 50. Therefore, a fixed state in which the second power feed plate 50 is fixed within the lower wire guide device 24 by locking the second fixing portion 56 with the second locking mechanism 58, and a movable state in which the second power feed plate 50 is movable within the lower wire guide device 24 by releasing the lock by the second locking mechanism 58 can be achieved. Note that, although the first rod 22 and the second rod 26 are described here as being arranged in the left-right direction of the paper, this is not limiting and they may be arranged in a direction perpendicular to the paper, for example. In this way, it may be oriented in any direction perpendicular to the wire electrode.

[0023] As shown in Fig. 2, the wire electric discharge machine 10 is equipped with a control device 60 having an NC device 62 for controlling the machining of the workpiece WK with the wire electrode WE. The control device 60 is configured to operate the first fixing device 42 and the second fixing device 52 as necessary (fixing device operation command in Fig. 2) to fix the first power feed plate 40 and the second power feed plate 50, and to make the first power feed plate 40 and the second power feed plate 50 movable when the positions of the first power feed plate 40 and the second power feed plate 50 are to be changed. The control device 60 is also configured to operate the axial feed devices 44, 54 (upper and lower guide feed command in Fig. 2) to move the upper wire guide device 20 and the lower wire guide device 24 in order to control the machining of the workpiece WK. Furthermore, when machining is completed, the control device 60 is configured to operate the wire cutter 36 to cut the wire electrode WE (wire) (wire cut command in FIG. 2), and to operate the wire winder 38 to wind up the cut wire electrode WE (wire) (wire wind command in FIG. 2). Furthermore, the control device 60 is provided with a display means 64 for displaying the number of uses and / or the remaining number of uses of the first power feed plate 40 and the second power feed plate 50 calculated by a method described below, and notifying the worker. The display means 64 is configured to allow the worker to recognize the number of uses by various known methods, such as displaying the remaining number of uses on a display or emitting sound or light according to the remaining number of uses.

[0024] The control device 60 is also configured to move the upper and lower wire guide devices 20 and 24 relative to the constraint device guide 30 so that they approach each other, and to constrain the first rod 22 with the first constraint device 32 and the second rod 26 with the second constraint device 34. The control device 60 is further configured to set the first and second power feed plates 40 and 50 to a movable state by releasing the first and second locking mechanisms 48 and 58, and to move the first and second constraint devices 32 and 34, which have constrained the first and second rods 22 and 26, relative to the upper and lower wire guide devices 20 and 24 so that they are separated from each other, thereby moving the first and second power feed plates 40 and 50 by a predetermined amount, for example, 1 mm, that can be changed by the control device 60. This allows the positions of the sliding surfaces 40 a, 50 a relative to the wire electrode WE to be changed. Here, the first and second power feed plates 40 and 50 are moved by pulling the first and second rods 22 and 26 out of the upper and lower wire guide devices 20 and 24. This reduces the risk of the first and second rods 22 and 26 choking on the sludge and hindering their movement or damaging the upper and lower wire guide devices 20 and 24, even if wear particles from the first and second power feed plates 40 and 50 or sludge produced by electrical discharge machining adhere to the inner walls of the upper and lower wire guide devices 20 and 24 of the first and second rods 22 and 26, compared to a configuration in which the first and second rods 22 and 26 are pushed into the upper and lower wire guide devices 20 and 24.

[0025] 4(a) and 4(b) are schematic front views of the first restraint device 32 and the second restraint device 34. The first restraint device 32 and the second restraint device 34 include cylindrical cylinders 32a, 34a, a piston head 70 configured to be slidable inside the cylinders 32a, 34a, a shaft 68 having one end connected to the piston head 70 and extending outside the cylinders 32a, 34a, and a restraining magnet 66 connected to the other end of the shaft 68. Furthermore, the cylinders 32a, 34a have air pressure ports 72a, 72b formed therethrough for connection to a compressor (not shown) for injecting air into the interiors or extracting air from the interiors. For this reason, as shown in FIG. 4(a), air is injected into the cylinders 32a, 34a through the air pressure port 72a on the side where the shaft 68 is not attached, pushing the piston head 70, and the shaft 68 and the restraining magnet 66 move to a restraining position where they are pushed out of the cylinders 32a, 34a. Also, as shown in FIG. 4(b), air is injected into the cylinders 32a, 34a through the air pressure port 72b on the side where the shaft 68 is attached, pushing the piston head 70 toward the side of the cylinders 32a, 34a where the shaft 68 is not attached. This causes the shaft 68 and the restraining magnet 66 to move to a retracted position where the shaft 68 is retracted into the cylinders 32a, 34a. Furthermore, cylinder sensors 74a, 74b, each having a reed switch, are attached to both longitudinal ends of the cylinders 32a, 34a to detect the passage of the moving piston head 70. This allows the cylinder sensors 74a, 74b to detect whether the piston head 70 is in the restraining position or the retracted position. The reed switch of the cylinder sensor 74b turns on or off with high repeatability, and as will be described later, it can transmit a reference position signal to the control device 60, which is required to calculate the coordinate positions of the power feed plates 40, 50.

[0026] 5(a) and 5(b) schematically show the positional relationship between the first and second restraint devices 32, 34 and the upper and lower wire guide devices 20, 24. Specifically, FIG. 5(a) shows the first and second power feed plates 40, 50 at the start of use, and FIG. 5(b) shows the first and second power feed plates 40, 50 at the end of use. That is, at the start of use, the first rod 22 and the second rod 26 are stored in the upper and lower wire guide devices 20, 24. As the first and second power feed plates 40, 50 are used, the position of the sliding surface 40a relative to the wire electrode WE is changed, i.e., shifted, so the first rod 22 and the second rod 26 are gradually pulled outward from the upper and lower wire guide devices 20, 24. When the first and second feed plates 40 and 50 are finished using, the first and second rods 22 and 26 are pulled out to their maximum extent from the upper and lower wire guide devices 20 and 24. The positions (coordinate positions) of the first and second feed plates 40 and 50 at the start and end of use are determined during machine design and are recorded in the control device 60. These values ​​may have accumulated errors due to component dimensions and assembly in individual machines. However, these values ​​can be corrected by performing calibration during manufacturing and recording the correction values ​​obtained in the control device 60. In principle, this calibration is performed only during manufacturing. However, if an overhaul is performed, such as disassembling or replacing the upper and lower wire guide devices 20 and 24, calibration can be performed again and new correction values ​​can be recorded in the control device 60. Furthermore, the total number of uses of the feed plates can be determined by dividing the distance between the positions of the first and second feed plates 40 and 50 at the start and end of use by a predetermined feed plate movement amount.

[0027] An encoder 76 is disposed on each of the axial feed devices 44, 54, each having a feed shaft 44a, 54a and a motor 44b, 54b. This allows the amount of displacement of the upper wire guide device 20 and the lower wire guide device 24 relative to the feed shaft 44a, 54a, respectively, to be detected. This allows the coordinate positions of the upper wire guide device 20 and the lower wire guide device 24 in the wire electric discharge machine 10 to be detected (calculated). The first rod 22 and the second rod 26 each have a magnetic material at least at their tip. The first restraining device 32 and the second restraining device 34 restrain the first rod 22 or the second rod 26 when the upper wire guide device 20 or the lower wire guide device 24 approaches the first restraining device 32 or the second restraining device 34 at a predetermined approach speed (moving speed) with the restraining magnet 66 in the restraining position. Furthermore, the first rod 22 or the second rod 26 pushes the shaft 68 of the first restraint device 32 or the second restraint device 34 into the cylinder 32a or the cylinder 34a at an approach speed. As a result, when the shaft 68 is pushed in by, for example, about 0.5 mm, the reed switch of the cylinder sensor 74b turns off and a reference position signal is sent to the control device 60. Here, the reference position signal is a signal that detects the relative position of the feeder plates 40, 50 with respect to the axial feed devices 44, 54 when the first rod 22 or the second rod 26 is restrained and pushed in (reference position), and notifies the control device 60 of the timing for calculating the coordinate position of the feeder plates 40, 50. Upon receiving the reference position signal, the control device 60 operates the axial feed device 44 or 54 and detects the relative position of the first feed plate 40 or the second feed plate 50 with respect to the axial feed device 44, 54 by reading values ​​from the encoders arranged thereon, and then calculates the coordinate position of the first feed plate 40 or the second feed plate 50. Note that the coordinate position of the first feed plate 40 of the upper wire guide device 20 and the coordinate position of the second feed plate 50 of the lower wire guide device 24 are calculated sequentially or at separate times. Therefore, only the piston head 70 of the restraining device 32, 34 corresponding to the feed plate 40, 50 whose coordinate position is to be measured is moved to the restraining position.

[0028] In the present embodiment, the first and second power feed plates 40 and 50 are both configured to be displaced in the X-axis direction. However, the second power feed plate may be configured to be displaced in the Y-axis direction. Furthermore, as long as the power feed plates are perpendicular to the wire electrode WE, they may be displaced not only in the X-axis direction and the Y-axis direction but also in a diagonal direction that combines the X-axis and Y-axis components. In this case, the restraining device is configured so that the direction of reciprocating movement of the piston head between the retracted position and the restraining position coincides with the direction of displacement of the power feed plates. Furthermore, to eliminate the need for reciprocating movement between the retracted position and the restraining position, the restraining device may have a device (e.g., a touch sensor) at the restraining position that constantly detects contact with the first rod 22 and the second rod 26, and the touch sensor detection device may emit a reference position signal. A configuration in which the touch sensor detection device is located within the stroke range in the X-axis and Y-axis directions may hinder machining or narrow the machining range. Therefore, a configuration in which the piston head reciprocates between the retracted position and the restraining position, as in this embodiment, is preferred. In addition, in this embodiment, it is described that magnets are placed on the restraint device 32, 34 side and that magnetic material is present at at least the tip of the rod 22, 26 side, but this is not limited to this, and the restraint device side may be made of magnetic material and the magnet may be placed at the tip of the rod side, or magnets may be placed on both the restraint device and the rod.

[0029] The operation and effect of the wire electric discharge machine 10 according to this embodiment will be described below through an explanation of the flowchart for managing the position of the power feed plates shown in Figure 6. Note that the first power feed plate 40 of the upper wire guide device 20 and the second power feed plate 50 of the lower wire guide device 24 are moved individually and their coordinate positions are detected, so for simplicity's sake, only the detection of the coordinate position of the first power feed plate 40 will be described. The coordinate position of the second power feed plate 50 is substantially the same as that of the first power feed plate 40, so its explanation will be omitted.

[0030] The control device 60 proceeds to step S10, where it pre-cuts the wire electrode WE using the wire cutter 36 and starts calculating the coordinate position of the first current feeder plate 40. Proceeding to step S20, it moves the upper wire guide device 20 and the restraining device guide 30 relative to each other. It moves the upper wire guide device 20 until the first rod 22 is restrained by the restraining magnet 66 (here, until it is connected by magnetic force) at the restraining position of the first restraining device 32 arranged in the restraining device guide 30. Once the first rod 22 is restrained by the restraining magnet 66, it proceeds to step S30, where it calculates the position of the first current feeder plate 40 from the coordinate position of the feeder 44. At this time, the restraining device 32 moves to the restraining position due to the pressure of air injected into the cylinder, and the upper wire guide device 20 moves due to the axial feeder 44. Therefore, these movements are not due to attraction by the magnetic force of the restraining magnet 66. In addition, after the restraint device 32 has completed moving to the restraint position, the pressure of the air injected into the cylinder can be reduced to reduce the force applied when the first rod 22 of the upper wire guide device 20 is restrained in step S30, which will be described later.

[0031] Once the coordinate position of the first power feed plate 40 has been calculated, the process proceeds to step S40, where the control device 60 calculates the number of uses and / or the remaining number of uses of the first power feed plate 40. Specific steps relating to the flow up to this point will be described with reference to the explanatory diagram of FIG. 7. As shown in FIG. 7(a) and described above, the control device 60 moves the upper wire guide device 20 and the first restraining device 32 relative to each other. Next, as shown in FIG. 7(b), the restraining magnet 66 of the first restraining device 32, which moves relatively, is moved to the restraining position. Furthermore, as shown in FIG. 7(c), the upper wire guide device 20 is moved closer until the first rod 22 is restrained by the restraining magnet 66 (step S20).

[0032] As shown in Figure 7(d), when the first rod 22 is restrained by the restraining magnet 66 and the first restraining device 32 transmits a reference position signal, the control device 60 receives this signal. The upper wire guide device 20 also transmits a reference position signal (feed position in Figure 7(d)) ​​to the axial feed device 44 informing that it has been restrained by the first restraining device 32, and the control device 60 receives this signal via the axial feed device 44 (step S30). This allows the control device 60 to determine the timing at which the upper wire guide device 20 was restrained by the first restraining device 32, and calculates the coordinate position of the first feeder plate 40 based on the coordinate position of the axial feeder 44 and the relative position of the first feeder plate 40 with respect to the axial feeder 44. The control device 60 compares the calculated coordinate position of the first power feed plate 40 with the pre-recorded position of the first power feed plate 40 at the start of use and divides the calculated coordinate position by a predetermined power feed plate movement amount (e.g., 1 mm) to calculate the number of uses of the first power feed plate 40 (the position of the sliding surface 40a and the total number of uses). Furthermore, the remaining number of uses can be calculated by subtracting the calculated number of uses from the total number of uses of the power feed plate 40, which is predetermined (step S40). Once the number of uses and the remaining number of uses are calculated, the upper wire guide device 20 is released from restraint, and the upper wire guide device 20 is moved away from the first restraining device 32, as shown in FIG. 7(e). Furthermore, the restraining magnet 66 is moved to the storage position, as shown in FIG. 7(f). The magnetic constraint between the first rod 22 and the constraining magnet 66 is sufficiently weak compared to the driving force of the axial feed device 44 and the fixing force of the first fixing device 42, and can be easily released by moving the first rod 22 and the constraining magnet 66 relative to each other. If necessary, the constraint may also be released by moving the first rod 22 and the constraining magnet 66 relative to each other in a direction perpendicular to the longitudinal direction of the first rod 22.

[0033] Once the number of uses and / or remaining number of uses of the first power feed plate 40 has been calculated, the process proceeds to step S50. The control device 60 checks whether the remaining number of uses is not zero. If the remaining number of uses is zero, the process proceeds to step S60, where the display means 64 displays that the remaining number of uses is zero, and the process proceeds to step S70, where the wire electric discharge machine 10 is stopped. If the remaining number of uses is not zero, the process proceeds to step S80, where the display means 64 displays the remaining number of uses. If the operator confirms that the remaining number of uses is zero, the operator either turns over the first power feed plate 40 and uses a new side, or replaces it with a new power feed plate.

[0034] Next, the process proceeds to step S90, where the position of the first current feeder plate 40 relative to the wire electrode WE is changed. Specific procedures will be described with reference to the explanatory diagram of FIG. 8. As shown in FIG. 8(a) and described above, the upper wire guide device 20 and the first constraining device 32 are moved relative to each other. Next, as shown in FIG. 8(b), the constraining magnet 66 of the relatively moving first constraining device 32 is moved to the constraining position. Furthermore, as shown in FIG. 8(c), the upper wire guide device 20 is moved closer until the first rod 22 is constrained by the constraining magnet 66. When the first rod 22 is constrained by the constraining magnet 66, the relative movement is stopped, and the first constraining device 32 transmits a reference position signal, which is received by the control device 60.

[0035] As shown in FIG. 8(d), upon receiving the reference position signal, the control device 60 activates the first fixing device 42 (feed plate unlock signal in FIG. 8(d)), thereby unlocking the first feed plate 40. Once the first feed plate 40 is unlocked, the process proceeds to step S100 (see FIG. 7), where the upper wire guide device 20 and the first restraining device 32 are moved relative to each other by a predetermined feed plate movement distance, as shown in FIG. 8(e). Here, the first restraining device 32 remains stationary, and only the upper wire guide device 20 moves. This causes the first rod 22 to be pulled out from the upper wire guide device 20 by the predetermined feed plate movement distance, allowing the position of the first feed plate 40 relative to the wire electrode WE to be changed.

[0036] Once the first rod 22 has been pulled out a predetermined distance, the process proceeds to step S110 (see FIG. 7). As shown in FIG. 8(f), the control device 60 activates the first fixing device 42 (feed plate lock signal in FIG. 8(f)) to fix the first feed plate 40. Once the first feed plate 40 has been fixed, the process proceeds to step S120 (see FIG. 7), where the coordinate position of the first feed plate 40 is recalculated using the same procedure as in step S30 described above. Once the coordinate position has been calculated, the upper wire guide device 20 is released from restraint, and the upper wire guide device 20 and the first restraining device 32 are moved relatively away from each other, as shown in FIG. 8(g), and the process proceeds to step S130 shown in FIG. 6. Because the first rod 22 is pulled out of the upper wire guide device 20, the possibility of galling can be reduced compared to the pressing method described in Patent Document 1. Even if an excessive pulling force acts on the first rod 22, when the force exceeds the restraining force of the magnet, the restraint between the first rod 22 and the first restraining device 32 is released, preventing damage to the upper wire guide device 20.

[0037] In step S130, the control device 60 checks whether the coordinate position of the first power feeder plate 40 is in the correct position, i.e., whether the first power feeder plate 40 is in a position moved by the desired power feeder plate movement distance from the coordinate position measured in step S30, i.e., whether the first power feeder plate 40 is in a position moved by one use count calculated in step S40. If the coordinate position of the first power feeder plate 40 is in the correct position, the control device 60 proceeds to step S150 and ends the process. If the control device 60 determines that the coordinate position of the first power feeder plate 40 is not in the correct position, the control device 60 proceeds to step S140, displays a message via the display means 64 indicating that the first power feeder plate 40 is not in the correct position, and then proceeds to step S150 and ends the process. By recalculating the coordinate position of the first power feeder plate 40 in this manner, it is possible to check whether the power feeder plate is being moved correctly, thereby preventing or suppressing problems such as malfunctions of the wire electric discharge machine 10.

[0038] The wire electric discharge machine 10 according to this embodiment is configured to move the upper and lower wire guide devices 20 and 24 relative to the first and second constraining devices 32 and 34 while the first and second power feed plates 40 and 50, which are movable within the upper and lower wire guide devices 20 and 24, are fixed by the first fixing device 42 and the second fixing device 52. Furthermore, the wire electric discharge machine 10 is configured to move these relative to each other and to constrain the first and second rods 22 and 26 by the constraining magnets 66. Furthermore, the control device 60 can detect when the first and second constraining devices 32 and 34 have constrained the first and second rods 22 and 26 by detecting reference position signals transmitted from the first and second constraining devices 32 and 34 when the first and second rods 22 and 26 are constrained. Furthermore, when the control device 60 receives the reference position signal, it can calculate the coordinate positions of the first and second feed plates 40 and 50 coupled to the constrained first and second rods 22 and 26 from the coordinate positions of the axial feed devices 44 and 54 acquired from the NC device 62 and the relative positions of the first and second feed plates 40 and 50 with respect to the axial feed devices 44 and 54. Therefore, it is possible to mechanically grasp the coordinate positions of the first and second feed plates 40 and 50 when the first and second constraint devices 32 and 34 constrain the first and second rods 22 and 26.

[0039] Furthermore, with the wire electric discharge machine 10 according to this embodiment, while the first rod 22 and the second rod 26 are restrained by the first restraining device 32 and the second restraining device 34, the first power feed plate 40 and the second power feed plate 50 can be released from the upper wire guide device 20 and the lower wire guide device 24, making them movable, and can be moved by a predetermined power feed plate movement amount that can be changed by the control device 60. This allows the sliding surfaces 40a, 50a of the first power feed plate 40 and the second power feed plate 50, which have worn due to sliding of the wire electrode WE, to be shifted, thereby changing the sliding position of the wire electrode WE. Here, the first and second power feed plates 40 and 50 can be moved in a direction perpendicular to the running direction of the wire electrode WE and parallel to the sliding surfaces 40a and 50a along which the wire electrode WE slides, thereby stabilizing the positions of the sliding surfaces 40a and 50a relative to the wire electrode WE. As a result, the positions of the first and second power feed plates 40 and 50 can be grasped and moved mechanically, thereby reducing the labor required for position management of the first and second power feed plates 40 and 50 that feed power to the wire electrode WE.

[0040] Furthermore, in the wire electric discharge machine 10 according to this embodiment, the control device 60 is configured to calculate the number of uses at each position of the sliding surfaces 40 a, 50 a of the first and second power feed plates 40 and 50, the number of uses for the sliding surfaces 40 a, 50 a as a whole, and / or the remaining number of uses. The wire electric discharge machine 10 also has display means 64 for displaying the calculated number of uses and / or the remaining number of uses. This allows the number of uses and the remaining number of uses of the sliding surfaces 40 a, 50 a of the first and second power feed plates 40 and 50 to be mechanically known without the operator, and further allows the operator to easily understand these numbers using the display means 64. This allows the operator to know when to replace the first and second power feed plates 40 and 50 without directly checking them visually or otherwise, thereby reducing the effort required for position management of the first and second power feed plates 40 and 50 that supply power to the wire electrode WE.

[0041] Furthermore, with the wire electrical discharge machine 10 according to this embodiment, the coordinate positions of the first and second power feed plates 40 and 50 can be changed by pulling out the first and second rods 22 and 26 from the upper and lower wire guide devices 20 and 24 while they are constrained by the constraining magnets 66 of the first and second constraining devices 32 and 34. This prevents or reduces the possibility of sludge eating away at the first and second power feed plates 40 and 50 and resulting damage to the upper and lower wire guide devices 20 and 24. This allows for safe position management of the first and second power feed plates 40 and 50, which supply power to the wire electrode WE.

[0042] Furthermore, in the wire electric discharge machine 10 according to this embodiment, the first constraining device 32 and the second constraining device 34 have constraining magnets 66 for constraining the first rod 22 and the second rod 26. This allows the first rod 22 and the second rod 26 to be stably constrained, and the first constraining device 32 and the second constraining device 34 to be configured compactly. This allows the positions of the first power feeder plate 40 and the second power feeder plate 50 to be changed mechanically in a stable manner, thereby reducing the labor required for position management of the first power feeder plate 40 and the second power feeder plate 50 that feed power to the wire electrode WE.

[0043] As described above, the method for managing the position of the power feeder plate of the wire electric discharge machine 10 and the wire electric discharge machine 10 according to this embodiment can reduce the labor required for managing the positions of the first power feeder plate 40 and the second power feeder plate 50 that supply power to the wire electrode WE. The timing for shifting the positions of the first power feeder plate 40 and the second power feeder plate 50 can be determined for each work site of the wire electric discharge machine. Examples of timing for shifting the positions of the first power feeder plate 40 and the second power feeder plate 50 include: at the end of a series of machining operations from automatic connection of the wire electrode WE to cutting the wire electrode WE with the wire cutter 36; when the wire electrode WE is cut by the wire cutter 36 immediately after the integrated value of the machining time from automatic connection of the wire electrode WE exceeds a predetermined time; when one workpiece WK or one process of the workpiece WK is completed; etc. As mentioned above, the width of the current feeder plate, which is made of a highly wear-resistant material such as cemented carbide, is 1 mm per shift, and if the maximum number of shifts is 15, the width of the sliding part with the wire electrode WE is 15 mm, and if there is a margin of, say, 5 mm on each side, the width becomes 25 mm. Furthermore, by being reversible, one current feeder plate can be used 30 times.

[0044] (First Modification) The following describes a first modified example of the wire electric discharge machine 10. Elements similar to or corresponding to those in this embodiment are given the same reference numerals, and redundant explanations will be omitted.

[0045] 9(a) and 9(b), the first restraining device 32 and the second restraining device 34 of the wire electric discharge machine 10 according to the first modified example have a pinch mechanism 80, instead of the restraining magnet 66, at the tip side for restraining the first rod 22 and the second rod 26. As shown in FIG. 9(a), the pinch mechanism 80 is configured such that, in a restraining state in which the first rod 22 and the second rod 26 are restrained, the pinch main bodies 82a and 82b are brought into close contact with each other by the spring force of a biasing spring 84, thereby restraining (gripping) the first rod 22 and the second rod 26. In addition, in a release state in which the first rod 22 and the second rod 26 are released, the pinch main bodies 82a and 82b are pushed apart by an actuator (not shown). Furthermore, the pinch mechanism 80 has stopper members 86a, 86b for locking the pinch bodies 82a, 82b to prevent the pinch bodies 82a, 82b from spreading excessively in the released state. This allows the first rod 22 and the second rod 26 to be stably restrained. This allows the positions of the first and second power feed plates 40, 50 to be changed mechanically and stably, reducing the labor required for position control of the first and second power feed plates 40, 50 that feed power to the wire electrode WE.

[0046] As described above, the method for managing the power feed plate position of the wire electric discharge machine 10 according to the first modified example and the wire electric discharge machine 10 can reduce the labor required for managing the first power feed plate 40 and the second power feed plate 50 that supply power to the wire electrode WE.

[0047] Although the method for managing the position of a power feed plate in the wire electric discharge machine 10 and the embodiment of the wire electric discharge machine 10 have been described above, the present invention is not limited to the above embodiment. In addition to the above, it is believed that a person skilled in the art would understand that various modifications of the above embodiment are possible. [Explanation of symbols]

[0048] 10. Wire Electrical Discharge Machine 20 Upper wire guide device (wire guide device) 22 First Rod (Rod) 24 Lower wire guide device (wire guide device) 26 Second Rod (Rod) 32 First restraint device (restraint device) 34 Secondary restraint device (restraint device) 40 First feed plate (feed plate) 40a sliding surface 42 First Fixation Device (Fixation Device) 44 Axial feeder 50 Second feeder plate (feeder plate) 50a sliding surface 52 Secondary Fixation Device (Fixation Device) 54 Axial feeder 60 Control device 62 NC device 64 Display means 66 Restraining magnet (magnet) 80 Pinch mechanism WE Wire Electrode WK Work

Claims

1. A method for managing the position of a power feed plate of a wire electric discharge machine that machines a workpiece into a desired shape by sliding a wire electrode traveling between two wire guide devices on a power feed plate movably arranged inside each of the wire guide devices, applying a pulse voltage, and relatively moving the wire electrode and a workpiece using an axial feed device in accordance with commands from an NC device, comprising: fixing the feed plate within the wire guide device; moving the wire guide device relative to a restraining device disposed outside the wire guide device, restraining one end of a rod connected to the power feed plate and extending outside the wire guide device with the restraining device, and detecting a reference position signal transmitted from the restraining device; When the reference position signal is detected, calculating a coordinate position of the power feed plate based on the coordinate position of the axial feed device and the relative position of the power feed plate with respect to the axial feed device, which are acquired from the NC device; releasing the current feed plate from the wire guide device and making the current feed plate movable in a direction perpendicular to the traveling direction of the wire electrode and parallel to a sliding surface on which the wire electrode slides; moving the movable feed plate by a predetermined distance; A method for managing the position of a power feed plate in a wire electric discharge machine, comprising:

2. 2. The method for managing the position of a power feeder plate in a wire electric discharge machine according to claim 1, further comprising calculating and notifying the number of times the power feeder plate has been used and / or the number of times it is still usable.

3. Moving the movable power feed plate by a predetermined distance includes: changing a coordinate position of the power feed plate by pulling out the rod from the wire guide device while the rod is restrained by the restraining device; Fixing the moved feed plate; 3. The method for managing the position of a power feeder plate in a wire electric discharge machine according to claim 1 or 2, further comprising:

4. A wire electric discharge machine that applies a pulse voltage to a wire electrode that travels between two wire guide devices by sliding the wire electrode on a power supply plate that is movably arranged inside each of the wire guide devices, and that uses an axial feed device to move the wire electrode and a workpiece relative to each other in accordance with commands from an NC device, thereby machining the workpiece into a desired shape, a current feeder plate disposed inside the wire guide device, the current feeder plate being capable of changing the sliding position of the wire electrode by moving in a direction perpendicular to the traveling direction of the wire electrode and parallel to the sliding surface on which the wire electrode slides; a fixing device disposed in the wire guide device and configured to fix the feed plate movable inside the wire guide device; a rod having one end connected to the power feed plate and extending outward from the wire guide device along the movement direction of the power feed plate; a restraining device disposed outside the wire guide device, which moves the wire guide device and the restraining device relative to each other to restrain the other end of the rod and transmits a reference position signal when the other end of the rod is restrained; a control device that receives the reference position signal and calculates a coordinate position of the power feed plate based on the coordinate position of the axial feed device and the relative position of the power feed plate with respect to the axial feed device, which are acquired from the NC device; A wire electric discharge machine comprising:

5. the two wire guide devices are an upper wire guide device located upstream of the workpiece in the traveling direction of the wire electrode, and a lower wire guide device located downstream of the workpiece; a first power feed plate as the power feed plate movably disposed inside the upper wire guide device; a first fixing device as the fixing device that fixes the first power supply plate; a first rod having one end coupled to the first power feed plate and extending to the outside of the upper wire guide device along the moving direction of the first power feed plate; a first restraining device as the restraining device that restrains the other end of the first rod and transmits a first reference position signal when restrained; a first control device as the control device that receives the first reference position signal and calculates a coordinate position of the first power feed plate based on the coordinate position of the axial feed device acquired from the NC device and the relative position of the first power feed plate with respect to the axial feed device; a second power feed plate as the power feed plate movably disposed inside the lower wire guide device; a second fixing device as the fixing device that fixes the second power supply plate; a second rod as the rod, one end of which is coupled to the second power feed plate and which extends to the outside of the lower wire guide device along the moving direction of the second power feed plate; a second restraining device as the restraining device that restrains the other end of the second rod and transmits a second reference position signal when restrained; a second control device as the control device that receives the second reference position signal and calculates a coordinate position of the second power feed plate based on the coordinate position of the axial feed device acquired from the NC device and the relative position of the second power feed plate with respect to the axial feed device; 5. The wire electric discharge machine according to claim 4, further comprising:

6. 5. The wire electric discharge machine according to claim 4, wherein the restraining device attracts and restrains the rod by magnetic force.

7. The wire electric discharge machine according to claim 4 , wherein the restraining device has a pinch mechanism that clamps the rod.

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