Wire saw traverse device

Abstract

To provide a traverse device which has a low component replacement frequency, is not susceptible to the influence of disturbance like scatter of slurry and vibration, and has high detection accuracy.SOLUTION: A traverse device comprises: traverse pulleys 20 which are provided respectively between two bobbins 5A, 5B and a wire guide 4 and guide a wire 3; position displacement detection sensors 21, 22 which are provided between the bobbins 5A, 5B and the traverse pulleys 20 and can detect the position displacement in an axis X direction of the bobbin of the wire in a non-contact manner; a traverse unit 23 which reciprocally moves the traverse pulley and the position displacement detection sensors in substantially-parallel to the axis X direction of the bobbin; and a traverse control unit 11 which controls a traverse motor 24 of the traverse unit when the position displacement detection sensor detects the position displacement of the wire with respect to the position displacement detection sensor to change the position or the reciprocal movement speed of the traverse pulley and locate the wire within a prescribed range from the position displacement detection sensor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a traverse device for a wire saw. [Background technology]

[0002] Conventionally, a wire saw is known that slices a workpiece such as a semiconductor ingot by pressing it against a wire traveling at high speed. The wire is unwound from one bobbin, passes through one traverse device, is wound around a wire guide, and cuts the workpiece between the wire guides. After cutting the workpiece, the wire passes through the other traverse device and is wound onto the other bobbin.

[0003] The traverse device includes a traverse pulley provided near one bobbin and another bobbin for guiding the wire. The traverse device is configured to move the traverse pulley back and forth in the axial direction of the bobbin, thereby allowing the traverse pulley to follow changes in the position where the wire is unwound from the bobbin or the position where the wire is wound onto the bobbin, and to maintain the angle of the wire between the bobbin and the traverse pulley in a direction approximately perpendicular to the axial direction of the bobbin.

[0004] However, due to various factors, there may be a misalignment between the position where the wire is unwound from the bobbin or the position where the wire is wound onto the bobbin and the position of the traverse pulley. If such a misalignment occurs and the angle of the wire between the bobbin and the traverse pulley changes from a substantially perpendicular state, friction occurs between the wires, causing problems such as damage to the wire.

[0005] To prevent the above-mentioned problems by maintaining the angle of the wire between the bobbin and the traverse pulley at a substantially right angle, a traverse device has been proposed that detects a reference resultant force of the wire at the position of the tension roller and detects a fluctuating resultant force based on the displacement of the wire from a target position at the position of the traverse roller, thereby controlling the speed of the traverse roller, as in Patent Document 1. Also, a traverse device has been proposed that detects contact between the touch roller and the wire by detecting the contact load between the touch roller and the wire, and corrects the moving speed of the slider, as in Patent Document 2. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5177701 [Patent Document 2] Patent No. 5612367 Summary of the Invention [Problem to be solved by the invention]

[0007] When detecting wire displacement indirectly from the position of the traverse roller rather than directly detecting the wire, as in Patent Document 1, there is a risk that the detection accuracy of the wire position will decrease due to the influence of vibrations caused by the running wire. When detecting wire contact, as in Patent Document 2, if the detection part or the wire wears due to contact between the detection member and the wire, the frequency of part replacement will increase. Furthermore, the wire detection part in these conventional traverse devices has a complex shape, and if slurry used in processing the workpiece splashes and adheres to it, this could reduce detection accuracy or impair the detection function itself.

[0008] The present invention has been made in consideration of these points, and its purpose is to provide a traverse device with excellent detection accuracy that detects the wire itself non-contact, thereby requiring less frequent part replacement and being less susceptible to external disturbances such as slurry splashing and vibration. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention is adapted to detect the wire itself in a non-contact manner.

[0010] Specifically, the first invention is directed to a traverse device provided in a wire saw having a wire for processing a workpiece, a plurality of wire guides for winding the wire, a bobbin on one side for feeding the wire to the wire guide, and a bobbin on the other side for winding the wire from the wire guide, a traverse pulley provided between each of the two bobbins and the wire guide, for guiding the wire; a position displacement detection sensor provided between the bobbin and the traverse pulley, capable of detecting a position displacement of the wire in the axial direction of the bobbin in a non-contact manner; a traverse unit that reciprocates the traverse pulley and the position displacement detection sensor substantially parallel to the axial direction of the bobbin; and a traverse control unit that, when the position displacement detection sensor detects a position displacement of the wire relative to the position displacement detection sensor, controls the drive unit of the traverse unit to change the position or reciprocating movement speed of the traverse pulley, thereby positioning the wire within a predetermined range from the position displacement detection sensor.

[0011] According to the above configuration, the positional displacement detection sensor provided between the bobbin and the traverse pulley can grasp the positional displacement of the wire in the axial direction of the bobbin by detecting the wire itself. Since the wire itself is detected, the detection accuracy is excellent. Furthermore, since the wire and the positional displacement detection sensor do not come into contact with each other, the frequency of part replacement is low and the system is less susceptible to disturbances such as slurry splashes and vibrations.

[0012] In the second invention, in the first invention, the traverse pulley has a rotation axis extending in a direction substantially perpendicular to the axial direction of the bobbin, and is configured to be swingable about a swing axis extending in a direction substantially parallel to the axial direction of the bobbin, The swing shaft is characterized by having a locking mechanism that restricts the swing of the traverse pulley while the wire is running.

[0013] When the diameter of the wire wound on the bobbin changes, the position of the start point of the wire being unwound from the bobbin or the start point of the wire being wound onto the bobbin shifts. However, with the above configuration, the traverse pulley can swing about the swing axis so that the contact end between the wire and the traverse pulley points toward the start point of the wire being unwound from the bobbin or the start point of the wire being wound onto the bobbin in response to changes in the diameter of the bobbin. By restricting the swing of the traverse pulley with a locking mechanism while the wire is running, it is possible to prevent vibrations caused by the swing of the traverse pulley from affecting the wire detection accuracy of the position displacement detection sensor. It is also possible to prevent uneven wear of the traverse pulley due to the swing.

[0014] In the third invention, in the first invention, the traverse pulley has a rotation axis extending in a direction substantially perpendicular to the axial direction of the bobbin, and is configured to be swingable about a swing axis extending in a direction substantially parallel to the axial direction of the bobbin, The oscillating shaft is provided with a locking mechanism that restricts the oscillation of the traverse pulley, and the locking mechanism is characterized in that it releases the restriction on the oscillation of the traverse pulley when the running speed of the wire is in a low speed range.

[0015] According to the above configuration, the traverse pulley can swing about the swing axis in response to changes in the bobbin winding diameter so that the contact end between the wire and the traverse pulley faces the start point of the wire being unwound from the bobbin or the start point of the wire being wound onto the bobbin. Furthermore, the locking mechanism releases the restriction on the swing of the traverse pulley when the wire is traveling at a low speed, preventing vibrations caused by the swing of the traverse pulley from affecting the wire detection accuracy of the position displacement detection sensor. This also prevents uneven wear of the traverse pulley due to the swing.

[0016] In a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, a power source that applies a direct current, an alternating current, or a pulsed current to the wire; The position displacement detection sensor is a magnetic sensor that can detect the position displacement of the wire relative to the position displacement detection sensor by utilizing a magnetic field that is generated in the current-carrying wire at a constant or specific period.

[0017] According to the above configuration, the wire itself can be detected by the magnetic sensor, resulting in high detection accuracy. Furthermore, since the magnetic field of the wire is detected, the detection is less susceptible to disturbances such as scattering of slurry and vibration.

[0018] In the fifth invention, in the fourth invention, The position displacement detection sensors are arranged on both axial sides of the bobbin, sandwiching the wire therebetween.

[0019] According to the above configuration, the positional displacement detection sensors arranged on both sides of the wire make it possible to detect the positional displacement of the wire with higher accuracy.

[0020] In a sixth aspect of the present invention, in the fourth or fifth aspect of the present invention, The position displacement detection sensor is characterized in that it is covered with a non-magnetic material.

[0021] According to the above configuration, the position displacement detection sensor can be protected without affecting detection accuracy by being covered with a non-magnetic material.

[0022] In a seventh aspect of the present invention, in any one of the fourth to sixth aspects of the present invention, The present invention is characterized in that the strength of the current passing through the wire can be adjusted according to at least one of the diameter, running speed, and type of the wire, or the sensitivity of the position displacement detection sensor can be adjusted or corrected by output value calculation processing.

[0023] According to the above configuration, the present invention can be applied regardless of the diameter, traveling speed, and type of wire, making it highly versatile and easy to maintain the detection accuracy of the position displacement detection sensor. [Effects of the Invention]

[0024] As described above, according to the present invention, by detecting the wire itself non-contact using a position displacement detection sensor, it is possible to provide a traverse device with excellent detection accuracy, which requires less frequent part replacement and is less susceptible to external disturbances such as slurry splashing and vibration. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic diagram of a wire saw including a traverse device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of a traverse device according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view of a main part of the traverse device according to the embodiment of the present invention. [Figure 4] FIG. 3 is an enlarged view of a main part of FIG. 2. [Figure 5] FIG. 2 is a side view of a main part of the traverse device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] (Wire saw configuration) 1 shows the configuration of a wire saw 1 including traverse devices 2A and 2B according to an embodiment of the present invention. The wire saw 1 has a wire 3 for machining a workpiece W, multiple wire guides 4 around which the wire 3 travels, a bobbin 5A on one side that pays out the wire 3 to the wire guide 4, and a bobbin 5B on the other side that winds up the wire 3 from the wire guide 4.

[0028] The wire guides 4, 4 have rotation axes that extend substantially parallel to each other and are rotatably supported at a distance from each other. The wire guide 4 is rotationally driven by a wire guide drive motor 41, which is controlled by a wire speed control unit 30. A wire 3 is wound around the wire guides 4, 4 and can travel at high speed in a direction substantially perpendicular to the rotation axis of the wire guide 4. A table 6 is arranged above the wire guides 4, 4 so that it can be raised and lowered. A workpiece W, such as a semiconductor ingot, is detachably attached to the underside of the table 6.

[0029] A machining fluid supply unit (not shown) may be provided above the wire guides 4, 4 to supply a slurry containing abrasive grains to the wire 3. By lowering the table 6 while running the wire 3 with abrasive grains at high speed, the workpiece W is pressed against the wire 3 between the wire guides 4, 4 and cut.

[0030] The bobbins 5A and 5B are spaced apart from each other at positions away from the wire guides 4 and are supported so as to be rotatable in both forward and reverse directions. The bobbins 5A and 5B are driven to rotate in both forward and reverse directions by a bobbin drive motor 51 controlled by a bobbin control unit 50. The bobbins 5A and 5B rotate around an axis X, which is the rotation axis, to pay out the wire 3 onto the wire guide 4 and take up the wire 3 from the wire guide 4.

[0031] Traverse devices 2A and 2B for guiding the wire 3 are provided between the bobbin 5A on one side and the wire guide 4, and between the bobbin 5B on the other side and the wire guide 4, respectively. For example, the traverse device 2A on one side guides the wire 3 so that it is unwound from the bobbin 5A in a direction substantially perpendicular to the axial X direction of the bobbin 5A. The traverse device 2B on the other side guides the wire 3 so that it extends from the wire guide 4 to the bobbin 5B in a direction substantially perpendicular to the axial X direction of the bobbin 5B and is then wound up. Note that, because the bobbins 5A and 5B are each capable of rotating forward and backward, the unwound and wound directions of the wire 3 are not limited to the above.

[0032] Between the traverse devices 2A, 2B and the wire guide 4, there is provided a guide pulley 7 having a function of adjusting the tension of the wire 3, and the guide pulley 7 detects and adjusts the tension of the wire 3. Specifically, the guide pulley 7 is equipped with a wire tension detection unit 70 that detects the tension of the wire 3. The wire tension detection unit 70 detects the tension of the wire 3 wound around the guide pulley 7, and based on the detection signal, a wire tension control unit 71 inputs control signals to a bobbin control unit 50 and a traverse control unit 11, which will be described later. The bobbin control unit 50 and the traverse control unit 11 then control a bobbin drive motor 51 that drives the bobbins 5A, 5B and a traverse motor 24 that drives the traverse devices 2A, 2B, thereby applying an appropriate tension to the wire 3. The bobbin control unit 50 and the traverse control unit 11 are NC control units.

[0033] (Traverse device configuration) Next, the traverse device will be described. Since the traverse devices 2A and 2B basically have the same configuration, the following description will focus on the configuration of the traverse device 2A on one side.

[0034] The traverse device 2A includes a traverse pulley 20 provided between the bobbin 5A and the wire guide 4, position displacement detection sensors 21 and 22 provided between the bobbin 5A and the traverse pulley 20 and capable of contactlessly detecting the position displacement of the bobbin 5A of the wire 3 in the axial X direction, and a traverse unit 23 that moves the traverse pulley 20 and the position displacement detection sensors 21 and 22 back and forth approximately parallel to the axial X direction of the bobbin 5A.

[0035] 2 and 3, the traverse pulley 20 is disposed near the bobbin 5A and is provided in the traverse unit 23 via a first base member 25 and a second base member 26. The wire 3 unwound from the bobbin 5A extends substantially perpendicular to the axial direction X of the bobbin 5A and is then wound around the traverse pulley 20. The wire 3 wound around the traverse pulley 20 then extends from the traverse pulley 20 to the wire guide 4.

[0036] The traverse pulley 20 has a rotation axis that extends in a direction substantially perpendicular to the axis X of the bobbin 5A, and is rotatably supported by a first base member 25. The first base member 25 has a pulley support surface 25a that rotatably supports the traverse pulley 20, and a sensor support surface 25b that stands upright from the end of the pulley support surface 25a. The angle formed by the pulley support surface 25a and the sensor support surface 25b is substantially a right angle.

[0037] The first base member 25 is connected to the adjacent second base member 26 at a sensor support surface 25b. The sensor support surface 25b includes a sensor support portion 25c on the bobbin 5A side of the rotation axis of the traverse pulley 20. The sensor support portion 25c protrudes from the sensor support surface 25b toward the traverse pulley 20, and includes position displacement detection sensors 21 and 22 between the bobbin 5A and the traverse pulley 20 that can detect position displacement of the bobbin 5A of the wire 3 in the direction of the axis X in a non-contact manner.

[0038] The traverse pulley 20 is configured to be swingable about a swing axis Y extending in a direction substantially parallel to the axial X direction of the bobbin 5A. Specifically, the second base member 26 has the swing axis Y extending in a direction substantially parallel to the axial X direction of the bobbin 5A. The first base member 25 is swingably connected to the second base member 26 via the swing axis Y. Therefore, by driving the swing axis Y, the traverse pulley 20 and the position displacement detection sensors 21 and 22 can swing together with the first base member 25.

[0039] The second base member 26 is attached to the traverse unit 23 and is capable of reciprocating along a guide rail (not shown) provided on the traverse unit 23. When the traverse unit 23 is driven by the traverse motor 24, the second base member 26 and the first base member 25 reciprocate substantially parallel to the axial X direction of the bobbin 5A, and the traverse pulley 20 and the position displacement detection sensors 21 and 22 reciprocate together with the first base member 25.

[0040] -Configuration of position displacement detection sensor- 4, the position displacement detection sensors 21, 22 are provided between the bobbin 5A and the traverse pulley 20 and are capable of contactlessly detecting the position displacement of the wire 3 in the axial direction of the bobbin 5A. Specifically, the position displacement detection sensors 21, 22 are attached to the lower surface of the sensor support portion 25c and positioned above the wire 3. The number and positions of the position displacement detection sensors 21, 22 are not limited as long as they are capable of contactlessly detecting the wire 3 itself. However, as in this embodiment, if at least two position displacement detection sensors 21, 22 are arranged on both sides of the bobbin 5A in the axial direction of the wire 3, it is possible to detect the position displacement of the wire 3 with higher accuracy.

[0041] The position displacement detection sensors 21, 22 are, for example, magnetic sensors that can detect the position displacement of the wire 3 relative to the position displacement detection sensors 21, 22 by utilizing a magnetic field that is generated in the current-carrying wire 3 at a constant or specific cycle. When magnetic sensors are used as the position displacement detection sensors 21, 22 as in this embodiment, it is necessary to provide a power supply 8 for supplying a direct current, an alternating current, or a pulse current to the wire 3. Two electrodes extending from the power supply 8 are connected to the bobbins 5A, 5B, respectively, so that the wire 3 is electrified between the bobbins 5A, 5B.

[0042] Generally, a wire saw is energized to detect a wire breakage and stop the cutting operation. The position displacement detection sensors 21 and 22 of this embodiment utilize this function to energize the wire 3 and detect the magnetic field generated in the wire 3 at a constant or specific cycle.

[0043] When magnetic sensors are used as the position displacement detection sensors 21 and 22, they are less susceptible to disturbances such as vibrations, slurry, and coolant. The position displacement detection sensors 21 and 22 may be covered with a non-magnetic material. For example, by covering the surfaces of the position displacement detection sensors 21 and 22 with a resin about 2 mm thick, the position displacement detection sensors 21 and 22 can be protected without affecting detection accuracy and can be prevented from being damaged.

[0044] Wire saws used to precisely cut semiconductor ingots and the like use very thin wires with diameters of, for example, approximately 0.05 mm to 0.2 mm. If too much current is passed through such thin wires, the wires may be damaged. Therefore, the position displacement detection sensors 21 and 22 must be capable of measuring magnetic fields generated by weak currents of, for example, 1 mA to 100 mA, and in this regard, magnetic sensors are considered to be ideal.

[0045] The magnetic sensor may be of any type, provided that it can detect magnetic components in one or more dimensions. For example, a magnetic impedance element, a Hall element, or the like can be used as the magnetic sensor. A small sensor with excellent sensitivity and accuracy is preferable as the magnetic sensor. In this embodiment, a small magnetic sensor capable of detecting a minute magnetic force of ±2 μT or less is used as the position displacement detection sensors 21 and 22.

[0046] This small magnetic sensor utilizes the characteristics of an element in which the impedance of a magnetically sensitive body through which a high frequency current flows changes in response to the surrounding magnetic field, and the surrounding magnetic field is measured by detecting the change in impedance.

[0047] The sensitivity of this small magnetic sensor can be adjusted or corrected by adjusting the strength of the DC current, AC current or pulse current passed through the wire depending on at least one of the diameter, running speed and type of the wire, or by output value calculation processing in the traverse control unit 11.

[0048] In this embodiment, experiments were conducted to determine the optimum conditions for detecting the wire using small magnetic sensors as the position displacement detection sensors 21 and 22. Experiments 1 to 4 are the results of experiments conducted using a model that is assumed to be mounted on a wire saw.

[0049] In this experiment, pulse and AC currents that generate a specific periodic magnetic field (frequency 10 Hz to 1000 Hz) were used to pass current through the wire 3. Some types of magnetic sensors are suitable for detecting a certain magnetic field, but since the wire saw itself can generate magnetic noise, giving the magnetic field emitted from the wire a specific period makes it easier to distinguish it from surrounding magnetic noise.

[0050] Experiment 1: Evaluation of voltage characteristics with changes in frequency The current applied to the wire 3 was fixed at 4 mA, the distance from the wire to the miniature magnetic sensor was fixed at 5 mm, and the frequency was changed in the range of 10 Hz to 1000 Hz for both square waves and sine waves to confirm the voltage characteristics. In the range of 10 Hz to 300 Hz, greater noise was observed than in the range of 300 Hz to 1000 Hz. From these results, it can be said that either a square wave or a sine wave can be used as the current applied to the wire, and that the frequency is not particularly limited, but is preferably 300 Hz to 1000 Hz.

[0051] Experiment 2: Evaluation of voltage characteristics by changing current The frequency applied to wire 3 was fixed at 500 Hz, the distance from the wire to the small magnetic sensor was fixed at 5 mm, and the current was varied in the range of 1 mA to 100 mA to check the voltage characteristics. Within the range of 1 mA to 100 mA, a voltage was detected that was proportional to the magnitude of the current. From these results, it can be said that even a weak current of 1 mA to 100 mA can be detected with high accuracy, and depending on the detection capability of the position displacement detection sensor and the distance from the wire to the sensor, it may be possible to detect with a current of 1 mA or less.

[0052] Experiment 3: Evaluation of voltage characteristics depending on the distance between the wire and the small magnetic sensor The frequency applied to the wire was fixed at 500 Hz, the current at 10 mA, and the distance from the wire to the miniature magnetic sensor was varied in the range of 1 mm to 10 mm to confirm the voltage characteristics. The detected voltage was slightly inversely proportional to the distance from the wire, with the voltage decreasing as the distance increased. The distance from the wire to the position displacement detection sensor is not particularly limited, as it can be shortened by increasing the current, but in this embodiment, assuming that a weak current of about 1 to 5 mA is applied to the wire, it is considered preferable that the distance from the wire to the miniature magnetic sensor be about 5 mm.

[0053] Experiment 4: Voltage characteristics evaluation with changes in wire type and frequency We measured the voltage characteristics of standard wires without abrasive grains, with diameters of 0.1 mm and 0.12 mm, and diamond wires with diamond grains attached, with diameters of 0.12-0.18 mm, 0.16-0.22 mm, and 0.18-0.24 mm. The distance from the wire to the miniature magnetic sensor was 5 mm, the applied current was fixed at 4 mA, and the frequency applied to each wire was varied from 10 Hz to 1000 Hz. The detected voltage did not vary significantly with wire diameter or type between 10 Hz and 500 Hz, but at 1000 Hz, the voltage varied depending on the wire diameter and type. From these results, we concluded that, although the wire diameter and type are not particularly limited, it is preferable to apply a voltage of 1000 Hz or less. This range allows for easy adjustment of the sensor sensitivity depending on the wire diameter, running speed, and type.

[0054] Experiment 5: Confirmation of noise in the actual device A small magnetic sensor was installed on a wire saw (Toyo Advanced Technologies, T-8331A) to check the noise and its magnitude detected when the wire stopped running. Noticeable noise of 0.04 V near 60 Hz and 0.02 V near 180 Hz was detected. Slight noise was also detected at 300 Hz. To prevent this type of noise from affecting the detection of the wire's magnetic field, it is thought that a frequency of 300 Hz or higher is preferable for the frequency applied to the wire.

[0055] When the position displacement detection sensors 21, 22 detect a position displacement of the wire 3 in the direction of the axis X of the bobbin 5A relative to the position displacement detection sensors 21, 22, a detection signal is input from the sensor output detection unit 10 to the traverse control unit 11, as shown in Fig. 1. The traverse control unit 11 controls the traverse motor 24, which is the drive unit of the traverse unit 23, to change the position or reciprocating movement speed of the traverse pulley 20, and position the wire 3 within a predetermined range from the position displacement detection sensors 21, 22. For example, if either of the position displacement detection sensors 21, 22 detects a large signal that exceeds a preset signal range, the traverse position (reversal position of reciprocation) or reciprocating movement speed of the traverse pulley 20 is changed according to the magnitude of the signal.

[0056] Specifically, this occurs when a difference occurs in the magnitude of the signals detected by the left and right position displacement detection sensors 21, 22, and the difference exceeds a preset signal range and a large signal is detected. For example, if the signal from the right position displacement detection sensor 22 is larger than that from the left position displacement detection sensor 21, the wire 3 is biased toward the right position displacement detection sensor 21 of the left and right position displacement detection sensors 21, 22. The bias of the wire 3 toward either of the position displacement detection sensors 21, 22 means that the perpendicular state between the running direction of the wire 3 and the axial X direction of the bobbin 5A is lost between the bobbin 5A and the traverse pulley 20. In such a case, the traverse control unit 11 changes the reciprocating speed from a preset speed or changes the preset traverse position (reversal position of the reciprocating movement) of the traverse pulley 20 to restore the perpendicular state between the running direction of the wire 3 and the axial X direction of the bobbin 5A.

[0057] By detecting the bias of the wire 3 based on the difference between the signals detected from the left and right position displacement detection sensors 21, 22, it is possible to prevent the detection accuracy of the wire 3 from being affected even when the distance between the position displacement detection sensors 21, 22 and the wire 3 fluctuates due to disturbances such as unevenness in the wire winding shape of the bobbin.

[0058] -Traverse pulley swing lock mechanism- 3 and 5, the traverse pulley 20 can swing about a swing axis Y in response to changes in the winding diameter of the bobbin 5A so that a contact end 20a between the wire 3 on the bobbin 5A side and the traverse pulley 20 faces the wire payout start points 31 and 32 from the bobbin. This change in the angle of the traverse pulley 20 caused by the swing axis Y allows for more accurate payout and winding of the wire 3 from the bobbins 5A and 5B, preventing damage to the wire 3.

[0059] However, if the traverse pulley 20 is always in a state where it can swing, the swinging of the traverse pulley 20 while the wire 3 is running will cause vibrations, and there is a risk that the position displacement detection sensors 21, 22 will not be able to accurately detect the position displacement of the wire 3.

[0060] Therefore, it is preferable that the oscillation shaft Y be provided with a locking mechanism 27 that restricts the oscillation of the traverse pulley 20 while the wire 3 is running. Specifically, the drive of the oscillation shaft Y is controlled by the locking mechanism 27, such as a clamp, provided on the second base member 26. By restricting the oscillation of the traverse pulley 20 by the locking mechanism 27 while the wire 3 is running, it is possible to prevent vibrations caused by the oscillation of the traverse pulley 20 from affecting the detection accuracy of the wire 3 by the position displacement detection sensors 21, 22. It is also possible to prevent uneven wear of the traverse pulley 20 due to the oscillation.

[0061] Furthermore, the locking mechanism 27 may be configured to release the restriction on the swinging of the traverse pulley 20 when the running speed of the wire 3 is in a low-speed range, for example, 100 m / min or less. When the running speed of the wire 3 is in a high-speed range, there is a risk that the vibration caused by the swinging of the traverse pulley 20 will be large, but in the low-speed range, the vibration caused by the swinging of the traverse pulley 20 will be small, so even if the swing restriction is released and the traverse pulley 20 is allowed to swing and the angle is changed, the detection accuracy of the position displacement detection sensors 21, 22 is unlikely to be affected.

[0062] As described above, according to the present invention, the positional displacement of the wire 3 in the direction of the bobbin axis X can be grasped by detecting the wire 3 itself using the positional displacement detection sensors 21, 22 provided between the bobbins 5A, 5B and the traverse pulley 20. Since the wire 3 itself is detected, detection accuracy is excellent, and since the wire 3 and the positional displacement detection sensors 21, 22 do not come into contact with each other, part replacement frequency is low and the system is less susceptible to disturbances such as slurry scattering and vibration.

[0063] It should be noted that the above-described embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of symbols]

[0064] 1 wire saw 2A Traverse Device 2B Traverse Device 3 wire 4 Wire Guide 5A bobbin 5B bobbin 6 tables 7 Guide pulley 8 Power supply 10 Sensor output detection section 11 Traverse control section 20 Traverse pulley 21 Position displacement detection sensor 22 Position displacement detection sensor 23 Traverse Unit 24 Traverse motor (traverse unit drive unit) 25 First base member 26 Second base member 27 Locking mechanism X bobbin rotation axis Y swing axis

Claims

1. A traverse device provided in a wire saw having a wire for processing a workpiece, a plurality of wire guides for winding the wire, a bobbin on one side for feeding the wire to the wire guide, and a bobbin on the other side for winding the wire from the wire guide, a traverse pulley provided between each of the two bobbins and the wire guide, the traverse pulley having a rotation axis extending in a direction substantially perpendicular to the axial direction of the bobbin, and guiding the wire; a position displacement detection sensor provided between the bobbin and the traverse pulley, capable of detecting a position displacement of the wire in the axial direction of the bobbin in a non-contact manner; a base member that supports the traverse pulley and the position displacement detection sensor and is configured to be swingable about a swing axis that extends in a direction substantially parallel to the axial direction of the bobbin; a traverse unit that reciprocates the base member substantially parallel to the axial direction of the bobbin; a traverse control unit that controls a drive unit of the traverse unit to change the position or reciprocating speed of the traverse pulley when the position displacement detection sensor detects a position displacement of the wire relative to the position displacement detection sensor, and positions the wire within a predetermined range from the position displacement detection sensor so that the running direction of the wire is perpendicular to the axial direction of the bobbin, the traverse pulley is capable of swinging together with the base member and the position displacement sensor by driving the swing shaft in accordance with a change in the winding diameter of the bobbin, The oscillating shaft is provided with a locking mechanism that restricts the oscillation of the traverse pulley, and when the wire running speed is 100 m / min or less, the locking mechanism releases the restriction on the oscillation of the traverse pulley, ensuring that vibrations caused by the oscillation of the traverse pulley do not affect the detection accuracy of the position displacement detection sensor.

2. a power source that applies a direct current, an alternating current, or a pulsed current to the wire; The wire saw traverse device according to claim 1, characterized in that the position displacement detection sensor is a magnetic sensor capable of detecting the position displacement of the wire relative to the position displacement detection sensor by utilizing a magnetic field generated in the energized wire at a constant or specific period.

3. 3. The traverse device for a wire saw according to claim 2, wherein the position displacement detection sensors are arranged on both axial sides of the bobbin with the wire sandwiched therebetween.

4. 4. The traverse device for a wire saw according to claim 2, wherein the position displacement detection sensor is covered with a non-magnetic material.

5. A wire saw traverse device as described in any one of claims 2 to 4, characterized in that it is configured to adjust the strength of the current passed through the wire according to at least one of the diameter, running speed and type of the wire, or to adjust or correct the sensitivity of the position displacement detection sensor by output value calculation processing.

Images