JP7824036B2 - Wire saw traverse device - Google Patents

Description

The present invention relates to a traverse device for a wire saw.

Conventionally, wire saws are known that cut a workpiece such as a semiconductor ingot into slices by pressing it against a wire traveling at high speed. The wire is unwound from a bobbin on one side, passes through a traverse device on one side, and is wound around a wire guide, cutting the workpiece between the wire guides. After cutting the workpiece, the wire passes through a traverse device on the other side and is wound onto a bobbin on the other side.

The traverse device is equipped with a traverse pulley that is provided near the bobbin on one side and the bobbin on the other side and guides the wire. The traverse device is configured to move the traverse pulley back and forth in the axial direction of the bobbin, causing 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.

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 this misalignment occurs and the angle of the wire between the bobbin and the traverse pulley changes from a nearly perpendicular state, friction will occur between the wires, causing damage to the wire and other problems.

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

Patent No. 5177701 Patent No. 5612367

When detecting wire displacement indirectly from the position of the traverse roller rather than directly, as in Patent Document 1, there is a risk that the detection accuracy of the wire position will decrease due to the effects of vibrations caused by the wire traveling. 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 part will need to be replaced more frequently. 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 even impair the detection function itself.

The present invention was made in light of these issues, and its purpose is to provide a traverse device with excellent detection accuracy that detects the wire itself without contact, requires less frequent part replacement, and is less susceptible to external disturbances such as slurry splashes and vibrations.

To achieve the above objective, this invention is designed to detect the wire itself without contact.

Specifically, the first invention is directed to a traverse device provided in a wire saw having a wire for machining 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.

With the above configuration, the positional displacement detection sensor installed 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. Because the wire itself is detected, detection accuracy is excellent. Furthermore, because the wire and the positional displacement detection sensor do not come into contact, part replacement is less frequent and the system is less susceptible to disturbances such as slurry splashes and vibrations.

In a second aspect of the present invention, in the first aspect of the present 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.

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 winding the wire 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 winding the wire onto the bobbin in response to changes in the bobbin diameter. By restricting the swing of the traverse pulley using a locking mechanism while the wire is running, vibrations caused by the swing of the traverse pulley can be prevented from affecting the accuracy of wire detection by the position displacement detection sensor. It also prevents uneven wear of the traverse pulley due to the swing.

In a third aspect of the present invention, in the first aspect of the present 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 releases the restriction on the oscillation of the traverse pulley when the running speed of the wire is in a low speed range.

With the above configuration, the traverse pulley can swing around 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 restrictions on the swinging of the traverse pulley when the wire is traveling at a low speed, preventing vibrations caused by the swinging of the traverse pulley from affecting the wire detection accuracy of the position displacement detection sensor. It also prevents uneven wear of the traverse pulley due to the swinging.

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.

With the above configuration, the wire itself can be detected using a magnetic sensor, resulting in high detection accuracy. Furthermore, because the magnetic field of the wire is detected, it is less susceptible to disturbances such as slurry scattering and vibrations.

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

With the above configuration, the positional displacement detection sensors located on both sides of the wire make it possible to detect the positional displacement of the wire with greater accuracy.

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.

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

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.

The above configuration makes the present invention applicable regardless of the diameter, running speed, or type of wire, making it highly versatile and making it easier to maintain the detection accuracy of the position displacement detection sensor.

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 splashes and vibrations.

1 is a schematic diagram of a wire saw including a traverse device according to an embodiment of the present invention. FIG. 2 is a plan view of a traverse device according to an embodiment of the present invention. FIG. 2 is a perspective view of a main part of the traverse device according to the embodiment of the present invention. FIG. 3 is an enlarged view of a main part of FIG. 2. FIG. 2 is a side view of a main part of the traverse device according to the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

(Configuration of wire saw)
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 is wound, 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.

The wire guides 4, 4 have rotation axes that extend approximately parallel to each other and are rotatably supported at a distance. The wire guide 4 is driven to rotate 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 approximately perpendicular to the rotation axis of the wire guide 4. A table 6 is positioned above the wire guides 4, 4 and can be raised and lowered. A workpiece W, such as a semiconductor ingot, is removably attached to the underside of the table 6.

A machining fluid supply unit (not shown) may also 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 attached at high speed, the workpiece W is pressed against the wire 3 between the wire guides 4, 4 and cut.

The bobbins 5A and 5B are spaced apart from each other at positions away from the wire guides 4 and are supported so that they can rotate forward and backward. The bobbins 5A and 5B are driven to rotate forward and backward by a bobbin drive motor 51 controlled by a bobbin control unit 50. The bobbins 5A and 5B rotate around axis X, which is the rotation axis, and pay out the wire 3 onto the wire guide 4 and wind up the wire 3 from the wire guide 4.

Traverse devices 2A and 2B that guide 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 approximately 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 approximately perpendicular to the axial X direction of the bobbin 5B and is then wound up. Note that because the bobbins 5A and 5B can each rotate forward and backward, the unwound and wound directions of the wire 3 are not limited to these.

A guide pulley 7, capable of adjusting the tension of the wire 3, is provided between each of the traverse devices 2A and 2B and the wire guide 4. 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, the wire tension control unit 71 inputs control signals to the bobbin control unit 50 and traverse control unit 11 (described below). The bobbin control unit 50 and traverse control unit 11 then control the bobbin drive motor 51 that drives the bobbins 5A and 5B and the traverse motor 24 that drives the traverse devices 2A and 2B, thereby applying appropriate tension to the wire 3. The bobbin control unit 50 and traverse control unit 11 are NC controlled devices.

(Configuration of traverse device)
Next, the traverse devices 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.

The traverse device 2A includes a traverse pulley 20 disposed between the bobbin 5A and the wire guide 4, position displacement detection sensors 21 and 22 disposed between the bobbin 5A and the traverse pulley 20 and capable of non-contact detection of the position displacement of the wire 3 in the axial direction of the bobbin 5A, and a traverse unit 23 that moves the traverse pulley 20 and the position displacement detection sensors 21 and 22 back and forth substantially parallel to the axial direction of the bobbin 5A.

As shown in Figures 2 and 3, the traverse pulley 20 is positioned near the bobbin 5A and is attached to 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 approximately 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.

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 the 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.

The first base member 25 is connected to the adjacent second base member 26 at the sensor support surface 25b. The sensor support surface 25b has 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 is equipped with position displacement detection sensors 21 and 22 between the bobbin 5A and traverse pulley 20 that can detect position displacement of the wire 3 in the axial X direction of the bobbin 5A without contact.

The traverse pulley 20 is configured to be swingable about a swing axis Y that extends in a direction substantially parallel to the axial X direction of the bobbin 5A. Specifically, the second base member 26 has a swing axis Y that extends 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.

The second base member 26 is attached to the traverse unit 23 and is capable of reciprocating movement 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 direction X of the bobbin 5A, and the traverse pulley 20 and position displacement detection sensors 21 and 22 reciprocate together with the first base member 25.

-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 are 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.

The position displacement detection sensors 21, 22 are magnetic sensors that can detect the position displacement of the wire 3 relative to the position displacement detection sensors 21, 22, for example, by utilizing a magnetic field generated at a constant or specific cycle in the current-carrying wire 3. When using magnetic sensors as the position displacement detection sensors 21, 22, as in this embodiment, it is necessary to provide a power supply 8 for passing DC, AC, or pulsed current through 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 energized between the bobbins 5A, 5B.

Generally, wire saws are energized to detect 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.

When magnetic sensors are used as the position displacement detection sensors 21, 22, they are less susceptible to disturbances such as vibrations, slurry, and coolant. The position displacement detection sensors 21, 22 may also be coated with a non-magnetic material. For example, by coating the surfaces of the position displacement detection sensors 21, 22 with a resin approximately 2 mm thick, it is possible to protect the position displacement detection sensors 21, 22 without affecting detection accuracy and prevent damage.

Wire saws used to precisely cut semiconductor ingots and other materials use very thin wires, with diameters of approximately 0.05 mm to 0.2 mm, for example. If too much current is passed through such thin wires, there is a risk that the wires may be damaged. Therefore, position displacement detection sensors 21 and 22 must be able to measure the magnetic field generated by a weak current of, for example, 1 mA to 100 mA, and in this regard, magnetic sensors are ideal.

There are no restrictions on the type of magnetic sensor, as long as it can detect magnetic components in one or more dimensions. For example, magnetic impedance elements, Hall elements, etc. can be used as magnetic sensors. Small sensors with excellent sensitivity and accuracy are preferred. In this embodiment, small magnetic sensors capable of detecting minute magnetic forces of ±2 μT or less are used as the position displacement detection sensors 21 and 22.

This small magnetic sensor utilizes the element's characteristic that the impedance of a magnetically sensitive element through which a high-frequency current flows changes in response to the surrounding magnetic field, and measures the surrounding magnetic field by detecting changes in that impedance.

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

In this embodiment, small magnetic sensors were used as the position displacement detection sensors 21 and 22, and experiments were conducted to determine the optimal detection conditions for the wire. Note that Experiments 1 to 4 are the results of experiments conducted using a model designed to be mounted on a wire saw.

In this experiment, the wire 3 was energized using pulsed and alternating current, which generates a specific periodic magnetic field (frequency 10 Hz to 1000 Hz). Some types of magnetic sensors are suitable for detecting a certain magnetic field, but since the wire saw itself can emit magnetic noise, giving the magnetic field emitted from the wire a specific period makes it easier to distinguish it from surrounding magnetic noise.

Experiment 1: Evaluation of voltage characteristics with frequency change The current applied to 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 between 10 Hz and 1000 Hz for both square waves and sine waves to confirm the voltage characteristics. In the 10 Hz to 300 Hz range, greater noise was observed than in the 300 Hz to 1000 Hz range. 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, although there are no particular restrictions on the frequency, a frequency between 300 Hz and 1000 Hz is preferable.

Experiment 2: Evaluation of voltage characteristics due to changes in current The frequency applied to the 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 changed in the range of 1 mA to 100 mA to confirm 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 weak currents of 1 mA to 100 mA can be detected with high accuracy, and depending on the detection capabilities 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.

Experiment 3: Evaluation of voltage characteristics depending on the distance between the wire and the small magnetic sensor The frequency and current applied to the wire were fixed at 500 Hz and 10 mA, respectively, and the distance between the wire and the small magnetic sensor was varied between 1 mm and 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 between the wire and the position displacement detection sensor is not particularly limited, as it can be shortened by increasing the current. However, in this embodiment, assuming that a weak current of approximately 1 to 5 mA is applied to the wire, it is considered preferable that the distance between the wire and the small magnetic sensor be approximately 5 mm.

Experiment 4: Evaluation of voltage characteristics depending on wire type and frequency For ordinary wires with no abrasive grains attached, with wire diameters of 0.1 mm and 0.12 mm, and diamond wires with diamond abrasive grains attached, with wire 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 small magnetic sensor was fixed at 5 mm, the applied current was fixed at 4 mA, and the frequency applied to each wire was changed from 10 Hz to 1000 Hz to confirm the voltage characteristics. At 10 Hz to 500 Hz, the detected voltage did not change significantly depending on the wire diameter or type, but at 1000 Hz, the voltage varied depending on the wire diameter and type. From these results, although there are no particular limitations on the wire diameter or type, it is preferable that the applied voltage be 1000 Hz or less, and within this range, it is considered easy to correct the sensor sensitivity according to the wire diameter, running speed, and type.

Experiment 5: Confirmation of noise on actual machine A small magnetic sensor was installed on a wire saw (T-8331A, manufactured by Toyo Advanced Technologies Co., Ltd.) to confirm 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 confirmed. Slight noise was also confirmed at 300 Hz. To prevent such noise from affecting the detection of the wire's magnetic field, it is considered preferable that the frequency applied to the wire be 300 Hz or higher.

When the position displacement detection sensors 21, 22 detect a position displacement of the wire 3 in the axial X direction 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 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 reciprocating movement) or reciprocating speed of the traverse pulley 20 is changed depending on the magnitude of the signal.

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. 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. The bias of the wire 3 toward either of the position displacement detection sensors 21, 22 means that the perpendicularity between the running direction of the wire 3 and the axial X direction of the bobbin 5A between the bobbin 5A and the traverse pulley 20 has been lost. 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 perpendicularity between the running direction of the wire 3 and the axial X direction of the bobbin 5A.

By detecting the misalignment of the wire 3 based on the difference in signals detected by the left and right position displacement detection sensors 21, 22, the detection accuracy of the wire 3 can be prevented 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 irregularities in the wire winding shape of the bobbin.

- Traverse pulley swing lock mechanism -
3 and 5, the traverse pulley 20 can swing about the swing axis Y in response to changes in the winding diameter of the bobbin 5A so that the contact end 20a between the wire 3 on the bobbin 5A side and the traverse pulley 20 is directed toward 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.

However, if the traverse pulley 20 is always in a swingable state, the swinging of the traverse pulley 20 while the wire 3 is running will cause vibrations, which may prevent the position displacement detection sensors 21, 22 from accurately detecting the position displacement of the wire 3.

It is therefore preferable that the oscillating shaft Y be equipped 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 oscillating shaft Y is controlled by a 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.

The locking mechanism 27 may also 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. However, in the low-speed range, the vibration caused by the swinging of the traverse pulley 20 will be small. Therefore, even if the swing restriction is released and the traverse pulley 20 is allowed to swing, changing the angle, the detection accuracy of the position displacement detection sensors 21, 22 is unlikely to be affected.

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 determined 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. Because the wire 3 itself is detected, detection accuracy is excellent, and because the wire 3 and the positional displacement detection sensors 21, 22 do not come into contact, part replacement is less frequent and the system is less susceptible to disturbances such as slurry splashing and vibration.

Note that the above embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses.

REFERENCE SIGNS LIST 1 Wire saw 2A Traverse device 2B Traverse device 3 Wire 4 Wire guide 5A Bobbin 5B Bobbin 6 Table 7 Guide pulley 8 Power supply 10 Sensor output detection unit 11 Traverse control unit 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 Rotation axis of bobbin Y Swing axis

Claims (5)

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 . 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. A wire saw traverse device as described in claim 2, characterized in that the position displacement detection sensors are arranged on both axial sides of the bobbin, sandwiching the wire. A wire saw traverse device according to claim 2 or 3, characterized in that the position displacement detection sensor is coated with a non-magnetic material. A wire saw traverse device as described in any one of claims 2 to 4, characterized in that the strength of the current passed through the wire can be adjusted, or the sensitivity of the position displacement detection sensor can be adjusted or corrected by output value calculation processing, depending on at least one of the diameter, traveling speed, and type of the wire.