Method for managing feeder plate position in wire electric discharge machine and wire electric discharge machine

Abstract

A wire electric discharge machine capable of reducing the labor required for managing the position of a power supply plate that supplies power to a wire electrode, and a method for managing the position of the power supply plate. [Solution] A method for managing the position of the power feed plates 40, 50 of the wire electric discharge machine 10 includes fixing the power feed plates 40, 50, moving the wire guide devices 20, 24 and the restraining devices 32, 34 installed outside them relatively, restraining the ends of the rods 22, 26 connected to the power feed plates 40, 50 and extending outside the wire guide devices 20, 24 with the restraining devices 32, 34, detecting a reference position signal, calculating the coordinate position of the power feed plates 40, 50 based on the coordinate positions of the axial feed devices 44, 54 obtained from the NC device 62 and the relative positions of the power feed plates 40, 50 with respect to the axial feed devices 44, 54, releasing the fixation of the power feed plates 40, 50 to make them movable, and moving the movable power feed plates 40, 50 a predetermined distance.

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 supply plate, and the power supply plate is worn down by the sliding of the wire electrode. For this reason, the power supply plate is made of a highly wear-resistant material such as cemented carbide. Also, it is common to use the power supply plate multiple times by 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 supply plate and the wire electrode can be mechanically changed.

[0003] However, in the wire electric discharge machine disclosed in Patent Document 1, the number of times the feed plate is used at the same contact position must be recorded by the operator himself. In addition, since the time interval for shifting the feed plate cannot be mechanically set, the operator must check it visually or using a checklist. Furthermore, since the lower wire guide device is usually arranged inside the processing tank, sludge may enter the storage space of the feed plate. If one side of the feed plate is pressed by the pressing pin in this state, galling by sludge may occur between the other side of the feed plate away from the pressing point and the wall surface of the storage space. And, if such a feed plate is forcibly pressed in, it may cause malfunction or damage of the wire guide device. To prevent this, the operator must check the wire guide device from time to time to check for adhesion of sludge and remove it as necessary, which results in an increase in the number of work steps. [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 supply plate in a wire electric discharge machine, which can reduce the labor required for managing the position of a power supply plate that supplies power to a wire electrode, and a wire electric discharge machine. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a method for controlling the position of a power feed plate of a wire electric discharge machine in which a wire electrode running between two wire guide devices is slid against a power feed plate movably arranged inside each wire guide device, a pulse voltage is applied, and the wire electrode and the workpiece are moved relatively using an axial feed device in accordance with a command from an NC device, thereby machining the workpiece into a desired shape. 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 the wire electrode and the workpiece so that one end of the power feed plate is connected to the power feed plate and extends outside the wire guide device. the other end of the rod is restrained by a restraining device, and a reference position signal transmitted from the restraining device is detected; when the reference position signal is detected, a coordinate position of the feed plate is calculated based on the coordinate position of the axial feed device and the relative position of the feed plate with respect to the axial feed device obtained from the NC device; releasing the fixation of the feed plate to the wire guide device, and rendering the 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 feed plate a predetermined distance.

[0007] According to one aspect of the present invention, there is provided a wire electric discharge machine which machines a workpiece into a desired shape by sliding a wire electrode running between two wire guide devices against a current feed plate movably arranged inside each wire guide device, and relatively moving the wire electrode and the workpiece using an axial feed device in accordance with a command from an NC device. The wire electric discharge machine comprises a current feed plate which is arranged inside the wire guide device and can change the position against 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 against which the wire electrode slides, and a wire guide plate which is arranged in the wire guide device and can change the position against which the wire electrode slides. The present invention provides a wire electric discharge machine comprising: a fixing device for fixing a feeder plate that is movable inside the device; a rod having one end connected to the feeder plate and extending to the outside of the wire guide device along the movement direction of the feeder plate; a restraining device arranged outside the wire guide device, which 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 feeder plate based on the coordinate position of the axial feed device obtained from the NC device and the relative position of the feeder plate with respect to the axial feed device. Effect of the Invention

[0008] According to a method for managing the position of a feeder plate of a wire electric discharge machine according to one aspect of the present invention, the wire guide device and a constraint device arranged outside the wire guide device are moved relative to each other while the feeder plate is fixed inside the wire guide device, and the other end of the rod is constrained by the constraint device. In addition, 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, when the reference position signal is detected, it is possible to calculate the coordinate position of the feeder plate coupled to the rod constrained by the constraint device from the coordinate position of the axial feed device acquired from the NC device and the relative position of the feeder plate with respect to the axial feed device. Therefore, it is possible to grasp the coordinate position of the feeder plate when the constraint device constrains the rod, and to grasp how many times the wire electrode has been used at which position of the feeder plate. In addition, it is possible to release the fixation of the feeder plate to the wire guide device while the rod is constrained by the constraint device, and to make the feeder plate movable in a direction perpendicular to the running direction of the wire electrode and parallel to the sliding surface on which the wire electrode slides, and to move the movable feeder plate by a predetermined distance. Therefore, the sliding surface of the current feeder plate that has become worn due to the sliding of the wire electrode can be shifted to change the position where the wire electrode slides. This makes it possible to mechanically grasp and change the position of the current feeder plate, thereby reducing the labor required for position management of the current feeder plate that feeds power to the wire electrode.

[0009] According to one aspect of the present invention, the wire electric discharge machine is configured to move the wire guide device and the restraining device installed outside the wire guide device relative to each other while the feed plate movable inside the wire guide device is fixed by the fixing device, and the other end of the rod is restrained by the restraining device. The control device can detect when the restraining device restrains the rod by detecting a reference position signal transmitted from the restraining device. Furthermore, when the control device receives the reference position signal, the control device can calculate and grasp the coordinate position of the feed plate coupled to the rod restrained by the restraining device from the coordinate position of the axial feed device acquired from the NC device and the relative position of the feed plate with respect to the axial feed device. Furthermore, the control device can release the fixation of the feed plate to the wire guide device while the rod is restrained by the restraining device, and can move the feed plate in a movable state 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 feed plate by a predetermined distance. Therefore, the sliding surface of the feed plate worn by the sliding of the wire electrode can be shifted to change the position on which the wire electrode slides. This makes it possible to mechanically grasp and change the position of the current feeder plate, thereby reducing the labor required for managing the position of the current feeder plate that feeds current to the wire electrode. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 shows a front view of a wire electric discharge machine according to an embodiment. [Diagram 2] FIG. 2 shows a block diagram of the wire electric discharge machine according to the embodiment. [Diagram 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 fixing device is positioned. [Figure 4] FIG. 4 shows a restraining device, in which FIG. 4(a) is a front view showing a state in which the restraining portion is pushed out, and FIG. 4(b) is a front view showing a state in which the restraining portion is retracted. [Diagram 5]FIG. 5 shows the positional relationship of the current feeder plate 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 flow chart for controlling the position of the feeder plate. [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 diagrams illustrating a method for moving the feed plate. [Figure 9] FIG. 9 shows a front view of a pinch mechanism according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 given the same reference numerals, and duplicated explanations will be omitted. In order to facilitate 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 restraining devices 32, 34 which are essential parts of the wire electric discharge machine 10. The wire electric discharge machine 10 here comprises a bed 12 fixed to the floor surface of an installation location (such as a factory), and a table 14 arranged on the upper surface of the bed 12 and having a work plate 14a on whose upper surface a workpiece WK to be processed (a workpiece) is attached. The wire electric discharge machine 10 comprises a wire electrode WE, an upper wire guide device 20 arranged above the workpiece WK as a wire guide device, and a lower wire guide device 24 arranged below the workpiece WK as a wire guide device.

[0013] The wire electrode WE is disposed so as to pass through the interior of the upper wire guide device 20 and the lower wire guide device 24, which are disposed so as to sandwich the workpiece WK in the vertical direction, and to run between them from above to below. The wire electrode WE disposed 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 constitutes the wire electrode WE is mainly made of brass or tungsten, and the diameter of the wire is set to a size of about 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 above to below, 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, along the travel path of the wire electrode WE, i.e., from the top to the bottom, a wire head 16, an upper wire guide device 20, a lower wire guide device 24, and a wire recovery mechanism 28. 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, 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 (X-axis direction in FIG. 1) and the front-rear direction (Y-axis direction in FIG. 1). Furthermore, an axial feed device (not shown) other than the axial feed devices 44, 54 can move only the wire head 16 and the upper wire guide device 20 in the U-axis direction parallel to the X-axis, the V-axis direction parallel to the Y-axis, and the up-down direction (Z-axis direction in FIG. 1). In normal machining, the upper wire guide device 20 and the lower wire guide device 24 are moved simultaneously in the X-axis and Y-axis directions to machine a vertical surface parallel to the Z-axis. In addition, in special machining, only the upper wire guide device 20 can be moved in the X-axis, Y-axis, U-axis, and / or V-axis directions to machine a sloped surface or a tapered surface inclined from the vertical. The upper wire guide device 20 can 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 a U-axis, a V-axis, and a 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] Furthermore, as described below, wire electric discharge machine 10 is provided with first restraining device 32 and second restraining device 34 as restraining devices for restraining first rod 22 and second rod 26 connected to power feed plates 40, 50. First restraining device 32 and second restraining device 34 extend upward from bed 12 and are attached to restraining device guide 30 which also serves as table 14.

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

[0019] As shown in Fig. 2 and Fig. 3(a) to Fig. 3(c), the upper wire guide device 20 has therein a plate-shaped first power supply plate 40 that 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 inside the upper wire guide device 20. Specifically, the first power supply plate 40 is configured to be movable in the running direction of the wire electrode WE, which is perpendicular to the vertical direction here, and in a direction in which the wire electrode WE and the sliding surface 40a on which the wire electrode WE slides are parallel (the left-right direction in Fig. 2 and Fig. 3). Therefore, the position on the sliding surface 40a on which the wire electrode WE slides can 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 side 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 described below 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 be able to lock the first fixing portion 46 pressing the first power feed plate 40. For this reason, 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 can be configured.

[0021] The lower wire guide device 24 also includes a second power supply plate 50, which is electrically connected to the power supply device 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 inside the lower wire guide device 24. Specifically, the second power supply plate 50 is configured to be movable in the running direction of the wire electrode WE, which is perpendicular to the vertical direction here, and in a direction in which the wire electrode WE and the sliding surface 50a on which the wire electrode WE slides are parallel (the left-right direction in Figs. 2 and 3). Therefore, the position on the sliding surface 50a on which the wire electrode WE slides can 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. For this reason, the other end side 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 described below 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 the second power feed plate 50 to the lower wire guide device 24 in order to feed 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 be able to lock the second fixing portion 56 pressing the second power feed plate 50. Therefore, a fixed state in which the second power feed plate 50 is fixed in 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 in the lower wire guide device 24 by releasing the lock by the second locking mechanism 58 can be configured. Note that, in this embodiment, the first rod 22 and the second rod 26 are described as being arranged in the left-right direction of the paper, but are not limited thereto, and may be arranged in a direction perpendicular to the paper, for example. Thus, it may be oriented in any direction perpendicular to the wire electrode.

[0023] As shown in Fig. 2, the wire electric discharge machine 10 includes a control device 60 having an NC device 62 for controlling machining of the workpiece WK by 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 machining of the workpiece WK. Furthermore, 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) when machining is completed. Furthermore, the control device 60 includes 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 to be described later, and for notifying the worker. The display means 64 is configured so that the worker can recognize it by various known methods, such as a configuration for displaying the remaining number of uses on a display or the like, or a configuration for emitting sound, light, or the like according to the remaining number of uses.

[0024] The control device 60 is configured to relatively move the upper wire guide device 20 and the lower wire guide device 24 and the restraining device guide 30 so as to approach each other, and to restrain the first rod 22 by the first restraining device 32 and the second rod 26 by the second restraining device 34. The control device 60 is further configured to set the first power feed plate 40 and the second power feed plate 50 to a movable state by releasing the first locking mechanism 48 and the second locking mechanism 58, and to relatively move the first restraining device 32 and the second restraining device 34, which have restrained the first rod 22 and the second rod 26, away from the upper wire guide device 20 and the lower wire guide device 24, so as to move the first power feed plate 40 and the second power feed plate 50 by a predetermined movement amount that can be changed by the control device 60, for example, 1 mm at a time. This makes it possible to change the position of the sliding surfaces 40a, 50a relative to the wire electrode WE. Here, the first and second power feed plates 40 and 50 are moved by pulling out the first and second rods 22 and 26 from the upper and lower wire guide devices 20 and 24. As a result, even if wear powder of the first and second power feed plates 40 and 50 or sludge generated by electric discharge machining adheres to the inner walls of the upper and lower wire guide devices 20 and 24 of the first and second rods 22 and 26, the risk of their movement being hindered or the upper and lower wire guide devices 20 and 24 being damaged due to the first and second power feed plates 40 and 50 biting into the sludge can be reduced 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 have cylindrical cylinders 32a and 34a, a piston head 70 configured to be slidable inside the cylinders 32a and 34a, a shaft 68 having one end connected to the piston head 70 and extending outside the cylinders 32a and 34a, and a restraining magnet 66 as a magnet connected to the other end of the shaft 68. Furthermore, the cylinders 32a and 34a have air pressure ports 72a and 72b formed therethrough to connect to a compressor (not shown) for injecting air into the cylinders 32a and 34a or for drawing air out of the cylinders 32a and 34a. For this reason, as shown in FIG. 4(a), air is injected into the cylinders 32a and 34a from the air pressure port 72a on the side where the shaft 68 is not attached, and the piston head 70 is pushed, so that the shaft 68 and the restraining magnet 66 move to a restraining position pushed out from the cylinders 32a and 34a. Also, as shown in FIG. 4(b), air is injected into the cylinders 32a and 34a from the air pressure port 72b on the side where the shaft 68 is attached, so that the piston head 70 is pushed to the side of the cylinders 32a and 34a where the shaft 68 is not attached. As a result, the shaft 68 and the restraining magnet 66 move to a storage position where the shaft 68 is stored in the cylinders 32a and 34a. Furthermore, cylinder sensors 74a and 74b having reed switches for detecting the passage of the moving piston head 70 are attached to both ends of the longitudinal direction of the cylinders 32a and 34a. 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 has high repeatability in terms of the timing at which it turns on or off, and can transmit a reference position signal to the control device 60, which is required to calculate the coordinate positions of the feed plates 40, 50, as described below.

[0026] 5(a) and 5(b) are schematic diagrams showing the positional relationship between the first and second restraining 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 and second rods 22, 26 are stored in the upper and lower wire guide devices 20, 24. In order to change, i.e., to shift, the position of the sliding surface 40a with respect to the wire electrode WE as the first and second power feed plates 40, 50 are used, the first and second rods 22, 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 the 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 information (values) determined at the time of designing the machine and are recorded in the control device 60. Furthermore, these values ​​may have accumulated errors due to the part dimensions and assembly in each individual machine, but they can be corrected by recording the correction value obtained by performing calibration at the time of manufacture in the control device 60. In principle, this calibration is performed only at the time of manufacture, but when 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 a new correction value 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 provided on the axial feed devices 44, 54 having the feed shafts 44a, 54a and the motors 44b, 54b. Therefore, the displacement amounts of the upper wire guide device 20 and the lower wire guide device 24 relative to the feed shafts 44a, 54a can be detected. This makes it possible to detect (calculate) the coordinate positions of the upper wire guide device 20 and the lower wire guide device 24 in the wire electric discharge machine 10. The first rod 22 and the second rod 26 each have a magnetic body at least at the 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 shaft 68 of the first restraining device 32 or the second restraining device 34 is pushed into the cylinder 32a or the cylinder 34a at an approach speed by the first rod 22 or the second rod 26. 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 transmits a reference position signal to the control device 60. Here, the reference position signal is a signal that detects the relative position of the power feed plates 40, 50 with respect to the axial feed devices 44, 54 at the position (reference position) where the first rod 22 or the second rod 26 is restrained and pushed in, and notifies the control device 60 of the timing for calculating the coordinate position of the power feed plates 40, 50. When the control device 60 receives the reference position signal, it 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 ​​using the encoders arranged thereon, and further calculates the coordinate position of the first feed plate 40 or the second feed plate 50. 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 described as being shifted in the X-axis direction, but the second power feed plate may be shifted in the Y-axis direction. Furthermore, the power feed plate may be shifted in an oblique direction obtained by combining the X-axis and Y-axis components, not limited to the X-axis and Y-axis directions, as long as it is perpendicular to the wire electrode WE. In this case, the restraining device is configured so that the direction of reciprocating movement of the piston head between the storage position and the restraining position coincides with the direction in which the power feed plate is shifted. In addition, the restraining device may have a device (e.g., a touch sensor or the like) that constantly detects contact with the first rod 22 and the second rod 26 at the restraining position so that it is not necessary to reciprocate between the storage position and the restraining position, and the touch sensor detection device may be configured to emit a reference position signal. Here, a configuration in which the touch sensor detection device is disposed within the stroke range in the X-axis and Y-axis directions may cause an obstacle to machining or narrow the machining range, so that a configuration in which the reciprocating movement between the storage position and the restraining position as in this embodiment is preferable. In addition, in this embodiment, a magnet is arranged on the restraint device 32, 34 side, and a magnetic material is provided at at least the tip of the rod 22, 26 side. However, this is not limited to this, and the restraint device side may be made of a magnetic material and a magnet may be arranged at the tip of the rod side, or magnets may be arranged 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 plate shown in Fig. 6. Note that since 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, for simplicity's sake, only the detection of the coordinate position of the first power feed plate 40 will be explained. The coordinate position of the second power feed plate 50 is substantially the same as that of the first power feed plate 40, and therefore its explanation will be omitted.

[0030] The control device 60 proceeds to step S10, cuts the wire electrode WE in advance by the wire cutter 36, and starts calculating the coordinate position of the first current feeder plate 40. When proceeding to step S20, the upper wire guide device 20 and the restraining device guide 30 are moved relative to each other. The upper wire guide device 20 is moved until the first rod 22 is restrained by the restraining magnet 66 at the restraining position of the first restraining device 32 arranged in the restraining device guide 30 (here, until it is connected by magnetic force). When the first rod 22 is restrained by the restraining magnet 66, the control device 60 proceeds to step S30, and calculates the position of the first current feeder plate 40 from the coordinate position of the feed device 44. At this time, the restraining device 32 moves to the restraining position by the pressure of the air injected into the cylinder, and the upper wire guide device 20 moves by the axial feed device 44. For this reason, these movements are not caused by attraction by the magnetic force of the restraining magnet 66. In addition, by reducing the pressure of the air injected into the cylinder after the restraint device 32 has completed moving to the restraint position, the force applied when the first rod 22 of the upper wire guide device 20 is restrained can be reduced in step S30 described below.

[0031] After calculating the coordinate position of the first power feed plate 40, 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 relatively. 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 Fig. 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 it. Further, the upper wire guide device 20 transmits a reference position signal (feed position in Fig. 7(d)) indicating that it has been restrained by the first restraining device 32 to the axial feed device 44, and the control device 60 receives this via the axial feed device 44 (step S30). Thereby, the control device 60 grasps the timing when the upper wire guide device 20 is restrained by the first restraining device 32, and calculates the coordinate position of the first power supply plate 40 based on the coordinate position of the axial feed device 44 and the relative position of the first power supply plate 40 with respect to the axial feed device 44. The control device 60 compares the calculated coordinate position of the first power supply plate 40 with the position at the start of use of the first power supply plate 40 recorded in advance, and divides by a predetermined power supply plate movement amount (for example, 1 mm) to calculate the number of times the first power supply plate 40 has been used (the position of the sliding surface 40a and the total number of times of use). Also, the remaining available number of times can be calculated by subtracting the calculated number of times of use from the total available number of times of the power supply plate 40 determined in advance (step S40). When these number of times of use and the remaining available number of times are calculated, as shown in Fig. 7(e), the restraint of the upper wire guide device 20 is released and they are moved so as to be separated from the first restraining device 32. Further, as shown in Fig. 7(f), the restraining magnet 66 is moved to the storage position. The magnetic restraint between the first rod 22 and the restraining 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, etc., and can be easily released by the relative movement of the first rod 22 and the restraining magnet 66. If necessary, the restraint may be released by relatively moving the first rod 22 and the restraining magnet 66 in a direction perpendicular to the longitudinal direction of the first rod 22.

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

[0034] Then, the process proceeds to step S90, where the position of the first current feeder plate 40 relative to the wire electrode WE is changed. A specific procedure 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 constraint device 32 are moved relative to each other. Next, as shown in FIG. 8(b), the constraint magnet 66 of the first constraint device 32, which moves relatively, is moved to the constraint 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 constraint magnet 66. When the first rod 22 is constrained by the constraining magnet 66, the relative movement is stopped, and the first constraint device 32 transmits a reference position signal, which is received by the control device 60.

[0035] As shown in FIG. 8(d), when the control device 60 receives the reference position signal, it activates the first fixing device 42 (feed plate unlock signal in FIG. 8(d)) to release the lock of the first feed plate 40 caused by these devices. When the lock of the first feed plate 40 is released, the process proceeds to step S100 (see FIG. 7), and as shown in FIG. 8(e), the upper wire guide device 20 and the first restraining device 32 are moved relatively by a predetermined feed plate movement amount. Here, the first restraining device 32 is stopped, 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 amount, making it possible to change the position of the first feed plate 40 relative to the wire electrode WE.

[0036] When the first rod 22 is pulled out by a predetermined feeder plate movement amount, the process proceeds to step S110 (see FIG. 7). As shown in FIG. 8(f), the control device 60 operates the first fixing device 42 (feeder plate lock signal in FIG. 8(f)) to fix the first feeder plate 40. When the first feeder plate 40 is fixed, the process proceeds to step S120 (see FIG. 7), and the coordinate position of the first feeder plate 40 is calculated again in the same procedure as in step S30 described above. When the coordinate position is calculated, the restraint of the upper wire guide device 20 is released as shown in FIG. 8(g), and the upper wire guide device 20 and the first restraint device 32 are moved relatively away from each other, and the process proceeds to step S130 shown in FIG. 6. Since the first rod 22 is pulled out from the upper wire guide device 20, the possibility of gnawing 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] When the process proceeds to step S130, the control device 60 checks whether the coordinate position of the first power feed plate 40 is in the normal position, i.e., whether the first power feed plate 40 is in a position moved by the desired power feed plate movement amount from the coordinate position measured in step S30, i.e., whether the first power feed plate 40 is in a position moved by one use count calculated in step S40. If the coordinate position of the first power feed plate 40 is in the normal position, the process proceeds to step S150 and ends. If it is determined that the coordinate position of the first power feed plate 40 is not in the normal position, the process proceeds to step S140, and after displaying that the first power feed plate 40 is not in the normal position via the display means 64, the process proceeds to step S150 and ends. By recalculating the coordinate position of the first power feed plate 40 in this way, it is possible to check whether the power feed plate is being moved correctly, and to prevent or suppress problems such as malfunction of the wire electric discharge machine 10.

[0038] According to the wire electric discharge machine 10 of this embodiment, the upper wire guide device 20 and the lower wire guide device 24 are moved relatively to the first constraining device 32 and the second constraining device 34 in a state where the first and second power supply plates 40 and 50 movable inside 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 relatively and constrain the first rod 22 and the second rod 26 by the constraining magnet 66. Moreover, the control device 60 can detect when the first and second constraining devices 32 and 34 have constrained the first rod 22 and the second rod 26 by detecting the reference position signal 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, 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, 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 restraining devices 32 and 34 restrain 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 and second power feed plates 40 and 50 can be released from their fixed position relative to the upper and lower wire guide devices 20 and 24, respectively, and moved in a movable state by a predetermined power feed plate movement amount that can be changed by the control device 60. This makes it possible to shift the sliding surfaces 40a, 50a of the first and second power feed plates 40 and 50 that have become worn due to the sliding of the wire electrode WE, thereby changing the position at which the wire electrode WE slides. Here, the first current feeder plate 40 and the second current feeder plate 50 can be moved in a direction perpendicular to the running direction of the wire electrode WE and parallel to the sliding surfaces 40a, 50a along which the wire electrode WE slides, thereby stabilizing the positions of the sliding surfaces 40a, 50a relative to the wire electrode WE. As described above, the positions of the first current feeder plate 40 and the second current feeder plate 50 can be grasped and moved mechanically, and the labor required for position management of the first current feeder plate 40 and the second current feeder plate 50 that feed power to the wire electrode WE can be reduced.

[0040] Furthermore, according to the wire electric discharge machine 10 of this embodiment, the control device 60 is configured to calculate the number of uses at each position of the sliding surfaces 40a, 50a of the first power feed plate 40 and the second power feed plate 50, the number of uses of the sliding surfaces 40a, 50a as a whole, and / or the remaining number of uses. The wire electric discharge machine 10 also has a display means 64 for displaying the calculated number of uses and / or the remaining number of uses. Therefore, the number of uses and the remaining number of uses of the sliding surfaces 40a, 50a of the first power feed plate 40 and the second power feed plate 50 can be mechanically known without the operator, and further, the operator can easily know these numbers using the display means 64. This allows the operator to know the time to replace the first power feed plate 40 and the second power feed plate 50 without directly checking with the naked eye, etc., and reduces the labor required for position management of the first power feed plate 40 and the second power feed plate 50 that feed power to the wire electrode WE.

[0041] Furthermore, according to the wire electric discharge machine 10 of 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 restrained by the restraining magnets 66 of the first and second restraining devices 32 and 34. This makes it possible to prevent or suppress the possibility of sludge gnawing into 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 the positions of the first and second power feed plates 40 and 50, which supply power to the wire electrode WE, to be safely managed.

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

[0043] As described above, the method for managing the position of the power feed plate of the wire electric discharge machine 10 and the wire electric discharge machine 10 according to the present embodiment can reduce the labor required for managing the positions of the first power feed plate 40 and the second power feed plate 50 that feed power to the wire electrode WE. The timing for shifting the positions of the first power feed plate 40 and the second power feed plate 50 can be determined for each work site of the wire electric discharge machine. Examples of such timings include the end of a series of machining steps from automatic connection of the wire electrode WE to cutting the wire electrode WE by the wire cutter 36, the cutting of the wire electrode WE 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, the end of one workpiece WK or one process of the workpiece WK, etc. As described above, the width of the current feeder plate made of a highly wear-resistant material such as cemented carbide is, for example, 1 mm per shift, and the maximum number of shifts is 15, so the width of the sliding part with the wire electrode WE is 15 mm, and if there is a margin of, for example, 5 mm on each side, the width becomes 25 mm. Furthermore, by making it possible to use the current feeder plate upside down, 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 duplicated descriptions will be omitted.

[0045] As shown in Figures 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 modification have a pinch mechanism 80, instead of the restraining magnet 66, on the tip side for restraining the first rod 22 and the second rod 26. As shown in Figure 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 (holding) the first rod 22 and the second rod 26. 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 so that the pinch bodies 82a, 82b do not spread 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 feeder plate 40 and the second feeder plate 50 to be changed mechanically and stably, and reduces the effort required for position management of the first feeder plate 40 and the second feeder plate 50 that feed power to the wire electrode WE.

[0046] As described above, the power feed plate position management method for the wire electric discharge machine 10 and the wire electric discharge machine 10 according to the first modified example 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 embodiment of the method for managing the position of the power feed plate of the wire electric discharge machine 10 and 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 considered that a person skilled in the art would understand that various modifications of the above embodiment are possible. [Explanation of symbols]

[0048] 10. Wire Electric 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 fixing device (fixing device) 44 Axis feed device 50 Second feed plate (feed plate) 50a sliding surface 52 Secondary Fixation Device (Fixation Device) 54 Axial feed device 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 in which a wire electrode running between two wire guide devices is caused to slide against a power feed plate movably arranged inside each of the wire guide devices, a pulse voltage is applied, and the wire electrode and a workpiece are moved relatively using an axial feed device in accordance with a command from an NC device, thereby machining the workpiece into a desired shape, 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 a rod having one end connected to the power feed plate and the other end extending outside the wire guide device with the restraining device, and detecting a reference position signal transmitted from the restraining device; calculating a coordinate position of the power feed plate based on a coordinate position of the axial feed device and a relative position of the power feed plate with respect to the axial feed device, the coordinate position being acquired from the NC device when the reference position signal is detected; 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 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 feed plate by a predetermined distance includes: changing a coordinate position of the 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 feed plate in a wire electric discharge machine according to claim 1 or 2, further comprising:

4. A wire electric discharge machine which applies a pulse voltage to a wire electrode running between two wire guide devices by sliding the wire electrode against a power supply plate movably arranged inside each of the wire guide devices, and which machines the workpiece into a desired shape by relatively moving the wire electrode and the workpiece using an axial feed device in accordance with a command from an NC device, a current supply plate disposed inside the wire guide device, the current supply plate being capable of changing a position along which the wire electrode slides by moving in a direction perpendicular to a traveling direction of the wire electrode and parallel to a sliding surface along which the wire electrode slides; a fixing device disposed in the wire guide device and configured to fix the current feed plate movable inside the wire guide device; a rod having one end connected to the current feed plate and extending outside the wire guide device along a moving direction of the current feed plate; a restraining device disposed outside the wire guide device, the restraining device moving the wire guide device and the restraining device relative to each other to restrain the other end of the rod and to generate a reference position signal when 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 acquired from the NC device and the relative position of the power feed plate with respect to the axial feed device; A wire electric discharge machine comprising:

5. the two wire guide devices being an upper wire guide device located upstream of the workpiece in a traveling direction of the wire electrode and a lower wire guide device located downstream of the workpiece; a first power supply plate as the power supply plate movably disposed inside the upper wire guide device; a first fixing device as the fixing device for fixing the first power supply plate; a first rod having one end coupled to the first current feed plate and extending to the outside of the upper wire guide device along a moving direction of the first current 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 supply plate based on the coordinate position of the axial feed device acquired from the NC device and the relative position of the first power supply 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 for fixing the second power supply plate; a second rod having one end coupled to the second current feed plate and extending to the outside of the lower wire guide device along a moving direction of the second current 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 supply plate based on the coordinate position of the axial feed device acquired from the NC device and the relative position of the second power supply 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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