Wire saw state monitoring system, wire saw, and wire saw state monitoring method

Abstract

This wire saw state monitoring system comprises: a first processing roller and a second processing roller; a wire bridging between the first processing roller and the second processing roller; and a moving member that moves so as to press a workpiece against the wire between the first processing roller and the second processing roller while the wire is traveling. The wire saw state monitoring system comprises: a detection data acquisition unit that acquires detected data from a first wire sensor that detects the amount of wire fed to the first processing roller and detected data from a second wire sensor that detects the amount of wire delivered from the second processing roller; an estimation unit that estimates the state of the wire on the basis of the fed amount and the delivered amount; and an output unit that outputs the estimated result from the estimation unit.

Description

Wire saw condition monitoring system, wire saw, and wire saw condition monitoring method

[0001] The present disclosure relates to a wire saw condition monitoring system, a wire saw, and a wire saw condition monitoring method.

[0002] In the technical field related to wire saws, a wire curvature monitoring system such as that disclosed in Patent Document 1 is known.

[0003] JP 2014-060397 A

[0004] Wire saws cut workpieces by pressing them against a traveling wire. If a workpiece is cut with a wire that is in poor condition, the quality of the cut workpiece may be reduced and the productivity of the wire saw may decrease.

[0005] The present disclosure is directed to monitoring the condition of wires.

[0006] According to the present disclosure, there is provided a wire saw condition monitoring system comprising a first processing roller and a second processing roller, a wire hung between the first processing roller and the second processing roller, and a moving member that moves to press a workpiece against the wire between the first processing roller and the second processing roller while the wire is running, the wire saw condition monitoring system comprising: a detection data acquisition unit that acquires detection data from a first wire sensor that detects the amount of wire fed into the first processing roller and detection data from a second wire sensor that detects the amount of wire fed out from the second processing roller; an estimation unit that estimates the state of the wire based on the feed amount and the feed amount; and an output unit that outputs the estimation result by the estimation unit.

[0007] According to the present disclosure, the condition of the wire can be monitored.

[0008] FIG. 1 is a diagram schematically showing a wire saw according to an embodiment. FIG. 2 is a block diagram showing the wire saw according to an embodiment. FIG. 3 is a block diagram showing a state monitoring system for a wire saw according to an embodiment. FIG. 4 is a diagram for explaining the operation of a wire saw according to an embodiment. FIG. 5 is a diagram for explaining the relationship between the state of a wire and the amount of deflection according to an embodiment. FIG. 6 is a diagram for explaining the relationship between the state of a wire and the amount of deflection according to an embodiment. FIG. 7 is a diagram for explaining the difference between the amount of wire feed-in and the amount of wire feed-out according to an embodiment. FIG. 8 is a flowchart showing a state monitoring method for a wire saw according to an embodiment. FIG. 9 is a block diagram showing a computer system according to an embodiment. FIG. 10 is a diagram schematically showing a portion of a wire saw according to another embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0010] [Wire Saw] Fig. 1 is a diagram schematically showing a wire saw 1 according to an embodiment. Fig. 2 is a block diagram showing the wire saw 1 according to an embodiment. The wire saw 1 cuts a workpiece W. The wire saw 1 slices the workpiece W. Examples of the workpiece W include a silicon ingot, synthetic quartz, crystal, and a magnet.

[0011] As shown in Figures 1 and 2, the wire saw 1 includes a processing roller 2, a roller motor 3, a wire 4, a moving member 5, a bobbin 6, a reel motor 7, a traverser 8, a dancer roller 9, a dancer motor 10, a guide roller 11, a wire sensor 12, and a controller 13.

[0012] The processing roller 2 rotates while supporting the wire 4. A plurality of grooves parallel to one another are provided on the surface of the processing roller 2. At least a portion of the wire 4 is disposed inside the grooves.

[0013] At least two processing rollers 2 are provided. In the embodiment, two processing rollers 2 are provided. The processing rollers 2 include a processing roller 2A and a processing roller 2B. It is to be noted that three or four processing rollers 2 may be provided.

[0014] The roller motor 3 generates a rotational force that rotates the processing roller 2. The roller motor 3 is connected to the processing roller 2. The processing roller 2 is rotated in both a forward direction and a reverse direction by the roller motor 3. In this embodiment, the roller motor 3 includes a roller motor 3A connected to the processing roller 2A and a roller motor 3B connected to the processing roller 2B. The processing rollers 2A and 2B rotate synchronously in the forward direction or the reverse direction.

[0015] The wire 4 is stretched across the processing roller 2A and the processing roller 2B. At least a portion of the wire 4 is disposed between the processing roller 2A and the processing roller 2B. When the processing roller 2 rotates in the forward direction, the wire 4 between the top of the processing roller 2A and the top of the processing roller 2B runs in one direction, from the processing roller 2A toward the processing roller 2B. When the processing roller 2 rotates in the reverse direction, the wire 4 between the top of the processing roller 2A and the top of the processing roller 2B runs in the other direction, from the processing roller 2B toward the processing roller 2A.

[0016] The wire 4 cuts the workpiece W. In the embodiment, the wire saw 1 slices the workpiece W using a fixed abrasive grain method. The fixed abrasive grain method refers to a method of cutting the workpiece W using a wire 4 that includes a core wire and abrasive grains fixed to the surface of the core wire. The core wire of the wire 4 is made of carbon steel, for example. Diamond abrasive grains are exemplified as the abrasive grains. Note that the wire saw 1 may also be a loose abrasive method in which the workpiece W is cut by the wire 4 while slurry is supplied to the traveling wire 4.

[0017] The moving member 5 moves so as to press the workpiece W against the wire 4 between the processing rollers 2A and 2B while the wire 4 is running. In this embodiment, the moving member 5 is positioned above the wire 4 between the processing rollers 2A and 2B. The moving member 5 moves up and down while holding the workpiece W. The workpiece W is fixed to the underside of the moving member 5. As the moving member 5 moves downward, the workpiece W held by the moving member 5 is pressed against the wire 4 running between the top of the processing roller 2A and the top of the processing roller 2B. As the workpiece W is pressed against the running wire 4, the workpiece W is cut by the wire 4.

[0018] The bobbins 6 unwind and wind the wire 4. The wire 4 is wound around the bobbins 6. Two bobbins 6 are provided. The bobbins 6 include a bobbin 6A and a bobbin 6B. One end of the wire 4 is connected to the bobbin 6A. The other end of the wire 4 is connected to the bobbin 6B.

[0019] The reel motor 7 generates a rotational force that rotates the bobbin 6. The reel motor 7 is connected to the bobbin 6. In this embodiment, the reel motor 7 includes a reel motor 7A connected to the bobbin 6A and a reel motor 7B connected to the bobbin 6B. The reel motors 7A and 7B rotate synchronously alternately in the forward direction and the reverse direction.

[0020] When the processing roller 2 rotates in the forward direction, the bobbin 6A rotates to pay out the wire 4, and the bobbin 6B rotates to take up the wire 4. The wire 4 paid out from the bobbin 6A is fed to the processing roller 2A. The wire 4 paid out from the processing roller 2B is taken up onto the bobbin 6B.

[0021] When the processing roller 2 rotates in the reverse direction, the bobbin 6B rotates to unwind the wire 4, and the bobbin 6A rotates to wind up the wire 4. The wire 4 unwound from the bobbin 6B is fed to the processing roller 2B. The wire 4 unwound from the processing roller 2A is wound onto the bobbin 6A.

[0022] The traverser 8 adjusts the position of the wire 4 wound onto the bobbin 6. Two traversers 8 are provided. The traverser 8 includes a traverser 8A that adjusts the position of the wire 4 wound onto the bobbin 6A, and a traverser 8B that adjusts the position of the wire 4 wound onto the bobbin 6B. The traverser 8 has a traverse roller 14 that is movable in the axial direction of the bobbin 6 at a position opposite the bobbin 6. The traverse roller 14 moves in the axial direction of the bobbin 6 by a driving force generated by a traverse actuator (not shown).

[0023] The traverse rollers 14 move in the axial direction of the bobbin 6 to adjust the position of the wire 4 in the axial direction of the bobbin 6. The traverse rollers 14 are arranged between the processing roller 2 and the bobbin 6. Two traverse rollers 14 are provided. The traverse rollers 14 include a traverse roller 14A provided on the traverser 8A and a traverse roller 14B provided on the traverser 8B. The traverse roller 14A is arranged between the processing roller 2A and the bobbin 6A. The traverse roller 14B is arranged between the processing roller 2B and the bobbin 6B. The wire 4 comes into contact with the traverse rollers 14. The traverse rollers 14 are driven rollers that rotate as the wire 4 travels.

[0024] The dancer rollers 9 adjust the tension of the wire 4 by swinging. The dancer rollers 9 are rotatably supported at the tip of the dancer arm 15. The dancer rollers 9 are arranged between the processing roller 2 and the bobbin 6. The dancer rollers 9 are arranged between the processing roller 2 and the traverse roller 14. Two dancer rollers 9 are provided. The dancer rollers 9 include a dancer roller 9A arranged between the processing roller 2A and the bobbin 6A, and a dancer roller 9B arranged between the processing roller 2B and the bobbin 6B. The dancer roller 9A is arranged between the processing roller 2A and the traverse roller 14A. The dancer roller 9B is arranged between the processing roller 2B and the traverse roller 14B. The wire 4 comes into contact with the dancer rollers 9. The dancer rollers 9 are driven rollers that rotate as the wire 4 travels.

[0025] The dancer motor 10 generates a driving force for oscillating the dancer rollers 9 via the dancer arm 15. The dancer motor 10 is connected to the dancer arm 15. In this embodiment, the dancer motor 10 includes a dancer motor 10A for oscillating the dancer roller 9A and a dancer motor 10B for oscillating the dancer roller 9B. The dancer rollers 9 are oscillated by the driving force of the dancer motor 10, thereby adjusting the tension of the wire 4.

[0026] The guide rollers 11 guide the wire 4. The guide rollers 11 are arranged between the processing roller 2 and the bobbin 6. The guide rollers 11 are arranged between the processing roller 2 and the dancer roller 9. At least two guide rollers 11 are provided. In this embodiment, the guide rollers 11 include a guide roller 11A arranged between the processing roller 2A and the bobbin 6A, and a guide roller 11B arranged between the processing roller 2B and the bobbin 6B. The guide roller 11A is arranged between the processing roller 2A and the dancer roller 9A. The guide roller 11B is arranged between the processing roller 2B and the dancer roller 9B. The wire 4 comes into contact with the guide rollers 11. The guide rollers 11 are driven rollers that rotate as the wire 4 travels.

[0027] Note that any number of two or more guide rollers 11 may be provided. For example, four or six guide rollers 11 may be provided. Two or more guide rollers 11 may be disposed between the processing roller 2A and the dancer roller 9A. Two or more guide rollers 11 may be disposed between the processing roller 2B and the dancer roller 9B.

[0028] The wire sensor 12 detects the amount of movement of the wire 4. Two wire sensors 12 are provided. The wire sensors 12 include a wire sensor 12A that detects the amount of movement of the wire 4 relative to the processing roller 2A, and a wire sensor 12B that detects the amount of movement of the wire 4 relative to the processing roller 2B.

[0029] When the processing roller 2 moves in the forward direction, the wire sensor 12A detects the amount of wire 4 fed into the processing roller 2A. When the processing roller 2 moves in the forward direction, the wire sensor 12B detects the amount of wire 4 fed out from the processing roller 2B.

[0030] When the processing roller 2 moves in the reverse direction, the wire sensor 12B detects the amount of wire 4 fed into the processing roller 2B. When the processing roller 2 moves in the reverse direction, the wire sensor 12A detects the amount of wire 4 fed out from the processing roller 2A.

[0031] The amount of wire 4 fed into the processing roller 2 refers to the amount of wire 4 moving into the rotating processing roller 2. The amount of wire 4 fed out from the processing roller 2 refers to the amount of wire 4 moving out of the rotating processing roller 2. The amount of wire 4 moving may be the amount of wire 4 moving per unit time. The amount of wire 4 moving may be the amount of wire 4 moving in a third state, which will be described later.

[0032] In the embodiment, the wire sensor 12 includes a rotary encoder capable of detecting the number of rotations of the guide roller 11. As described above, the guide roller 11 is a driven roller that rotates as the wire 4 travels. There is a one-to-one correspondence between the amount of movement of the wire 4 and the number of rotations of the guide roller 11. The higher the number of rotations of the guide roller 11, the greater the amount of movement of the wire 4, and the lower the number of rotations of the guide roller 11, the smaller the amount of movement of the wire 4. The wire sensor 12 detects the amount of movement of the wire 4 by detecting the number of rotations of the guide roller 11. The number of rotations of the guide roller 11 may be the number of rotations per unit time. The number of rotations of the guide roller 11 may also be the number of rotations of the guide roller 11 in a third state, which will be described later.

[0033] The wire sensor 12 may be a magnetic encoder or an optical encoder. When the wire sensor 12 is a magnetic encoder, a permanent magnet is provided on the guide roller 11. The wire sensor 12 detects the number of rotations of the guide roller 11 by detecting a magnetic field that changes with the rotation of the guide roller 11.

[0034] When the processing roller 2 moves in the forward direction, the wire sensor 12A detects the number of rotations of the guide roller 11A as the amount of wire 4 fed into the processing roller 2A. When the processing roller 2 moves in the forward direction, the wire sensor 12B detects the number of rotations of the guide roller 11B as the amount of wire 4 paid out from the processing roller 2B.

[0035] When the processing roller 2 moves in the reverse direction, the wire sensor 12B detects the number of rotations of the guide roller 11B as the amount of wire 4 fed into the processing roller 2B. When the processing roller 2 moves in the reverse direction, the wire sensor 12A detects the number of rotations of the guide roller 11A as the amount of wire 4 paid out from the processing roller 2A.

[0036] The controller 13 controls the wire saw 1. The controller 13 includes a computer system having at least one processor.

[0037] 3 is a block diagram showing a condition monitoring system 20 for the wire saw 1 according to the embodiment. The condition monitoring system 20 monitors at least the condition of the wire 4. The condition monitoring system 20 estimates the condition of the wire 4 based on detection data from the wire sensor 12. The condition of the wire 4 includes the amount of deflection of the wire 4 between the processing roller 2A and the processing roller 2B.

[0038] The condition monitoring system 20 has a wire sensor 12, a processing device 21, and an output device 22. The processing device 21 performs calculation processing. The processing device 21 includes a computer system having at least one processor. The output device 22 outputs the calculation results by the processing device 21. The output device 22 includes an output device capable of outputting display data. The output device 22 may also include an audio output device capable of outputting audio data. The output device 22 may also output a control signal for controlling the wire saw 1 based on the calculation results by the processing device 21.

[0039] The processing device 21 includes a detection data acquisition unit 23 , an estimation unit 24 , and an output unit 25 .

[0040] The detection data acquisition unit 23 acquires detection data from the wire sensor 12A and detection data from the wire sensor 12B. When the processing roller 2 rotates in the forward direction, the detection data from the wire sensor 12A indicates the amount of wire 4 fed into the processing roller 2A, and the detection data from the wire sensor 12B indicates the amount of wire 4 fed out from the processing roller 2B. When the processing roller 2 rotates in the reverse direction, the detection data from the wire sensor 12B indicates the amount of wire 4 fed into the processing roller 2B, and the detection data from the wire sensor 12A indicates the amount of wire 4 fed out from the processing roller 2A.

[0041] The estimation unit 24 estimates the state of the wire 4 based on the feed-in amount of the wire 4 and the pay-out amount of the wire 4. In the embodiment, the estimation unit 24 estimates the state of the wire 4 based on the difference between the feed-in amount of the wire 4 and the pay-out amount of the wire 4. The estimation unit 24 estimates the amount of deflection of the wire 4 between the processing roller 2A and the processing roller 2B as the state of the wire 4. The estimation unit 24 estimates the state of the wire 4 while the workpiece W is being processed.

[0042] The output unit 25 outputs the estimation result by the estimation unit 24. The output unit 25 outputs the deflection amount of the wire 4 estimated by the estimation unit 24. The output unit 25 causes the output device 22 to output the estimation result by the estimation unit 24. The output unit 25 may output a control signal for controlling the wire saw 1 based on the deflection amount of the wire 4 estimated by the estimation unit 24.

[0043] [Estimation of Wire State] Next, a method for estimating the state of the wire 4 according to the embodiment will be described. In the following description, it is assumed that the processing roller 2 rotates in the forward direction.

[0044] 4 is a diagram for explaining the operation of the wire saw 1 according to the embodiment. When cutting the workpiece W with the wire 4, the controller 13 drives the roller motor 3 and the reel motor 7 so that the wire 4 travels. While the wire 4 is traveling, the controller 13 controls the moving member 5 so that the workpiece W changes from a first state to a second state and then to a third state. The moving member 5 moves downward at a predetermined speed. The moving member 5 may move downward at a constant speed, or may move downward while changing its speed in stages.

[0045] The first state is a state in which the workpiece W is separated from the wire 4. In the first state, the workpiece W held by the moving member 5 is positioned above the wire 4 between the processing roller 2A and the processing roller 2B. In the first state, the wire 4 between the processing roller 2A and the processing roller 2B is not bent.

[0046] The second state is the state at the moment when the workpiece W, which has moved closer to the wire 4, comes into contact with the wire 4. As the moving member 5 holding the workpiece W moves downward closer to the wire 4, the workpiece W changes from the first state to the second state. In the second state, the workpiece W comes into contact with the wire 4 between the upper part of the processing roller 2A and the upper part of the processing roller 2B. In the second state, the wire 4 between the processing roller 2A and the processing roller 2B is not bent.

[0047] The third state is a state in which the workpiece W, in contact with the wire 4, moves in a manner that causes the wire 4 to bend. After the workpiece W comes into contact with the wire 4, the moving member 5 moves further downward, causing the workpiece W to change from the second state to the third state. In the third state, the wire 4 between the upper part of the processing roller 2A and the upper part of the processing roller 2B bends downward. In the third state, the wire 4 between the processing roller 2A and the processing roller 2B gradually bends as the workpiece W moves downward. In the third state, the amount of bending of the wire 4 gradually increases as the workpiece W moves downward.

[0048] After the deflection of the wire 4 gradually increases, the pressing force of the workpiece W against the wire 4 reaches a certain value, and cutting of the workpiece W begins, at which point the change in the deflection of the wire 4 decreases. In other words, when cutting of the workpiece W begins, the deflection of the wire 4 changes from a non-steady state to a steady state.

[0049] In the first and second states, the amount of wire 4 fed into the processing roller 2A is equal to the amount of wire 4 fed out from the processing roller 2B.

[0050] In the third state, the amount of deflection of the wire 4 between the processing roller 2A and the processing roller 2B changes, so the amount of wire 4 paid out from the processing roller 2B becomes smaller than the amount of wire 4 fed into the processing roller 2A. After the workpiece W comes into contact with the wire 4, during the period in which the amount of deflection of the wire 4 gradually increases due to the movement of the workpiece W, the amount of wire 4 paid out from the processing roller 2B becomes smaller than the amount fed into the processing roller 2A. Because the amount of wire 4 paid out from the processing roller 2B becomes smaller than the amount fed into the processing roller 2A, the rotation speed of the guide roller 11B decreases.

[0051] When the pressing force of the workpiece W against the wire 4 reaches a certain value and cutting of the workpiece W begins, the amount of wire 4 fed out from the processing roller 2B approaches the amount of wire 4 fed into the processing roller 2A. In other words, when the deflection of the wire 4 reaches a steady state, the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 fed out from the processing roller 2B become substantially equal.

[0052] That is, in the third state where the deflection of the wire 4 is unsteady, a change in the deflection causes a difference between the feed-in amount and the pay-out amount of the wire 4. The greater the deflection of the wire 4 when the deflection changes from the unsteady state to the steady state, the greater the difference between the feed-in amount and the pay-out amount, and the smaller the deflection, the smaller the difference between the feed-in amount and the pay-out amount.

[0053] 5 and 6 are diagrams for explaining the relationship between the state of the wire 4 and the amount of deflection according to the embodiment. Fig. 5 shows the amount of deflection of the wire 4 when the state of the wire 4 is good. Fig. 6 shows the amount of deflection of the wire 4 when the state of the wire 4 is poor.

[0054] The good condition of the wire 4 means that the wire 4 is in a state in which it is easy to cut the workpiece W. For example, when the wire 4 is in a new condition or when abrasive grains are sufficiently attached to the surface of the core wire of the wire 4, the wire 4 is easy to cut the workpiece W.

[0055] The poor condition of the wire 4 means that the wire 4 is in a state in which it is difficult for the wire 4 to cut the workpiece W. For example, if the wire 4 is in a state in which it has deteriorated due to use, or if abrasive grains are not sufficiently attached to the surface of the core wire of the wire 4, the wire will have difficulty cutting the workpiece W.

[0056] As shown in Fig. 5, when the wire 4 is in good condition, cutting of the workpiece W begins even when the pressing force of the workpiece W against the wire 4 is small in the third state. In other words, because a wire 4 that breaks easily is used, cutting of the workpiece W begins simply by lightly pressing the workpiece W against the wire 4. Therefore, as shown in Fig. 5, when the wire 4 is in good condition, the amount of deflection of the wire 4 when the workpiece W is cut by the wire 4 is small.

[0057] As shown in Fig. 6, when the condition of the wire 4 is poor, in order to cut the workpiece W in the third state, it is necessary to increase the pressing force of the workpiece W against the wire 4. In other words, because a wire 4 that is difficult to break is used, in order to start cutting the workpiece W, it is necessary to press the workpiece W strongly against the wire 4. Therefore, as shown in Fig. 6, when the condition of the wire 4 is poor, the amount of deflection of the wire 4 when the workpiece W is cut by the wire 4 is large.

[0058] As described above, in the third state, the greater the deflection of the wire 4, the greater the difference between the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 paid out from the processing roller 2B; and the smaller the deflection of the wire 4, the smaller the difference between the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 paid out from the processing roller 2B. Therefore, the estimation unit 24 can estimate the condition of the wire 4 based on the difference between the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 paid out from the processing roller 2B detected by the wire sensor 12 in the third state. If the difference between the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 paid out is large, the estimation unit 24 can estimate that the condition of the wire 4 is poor. If the difference between the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 paid out is small, the estimation unit 24 can estimate that the condition of the wire 4 is good.

[0059] 7 is a diagram for explaining the difference between the feed-in amount and the pay-out amount of the wire 4 according to the embodiment. In the graph shown in FIG. 7, the horizontal axis represents the elapsed time from the start of slicing the workpiece W. The vertical axis represents the difference between the feed-in amount and the pay-out amount of the wire 4. The feed-in amount of the wire 4 is detected by the wire sensor 12A, and the pay-out amount of the wire 4 is detected by the wire sensor 12B. The start of slicing is when the workpiece W is in the first state.

[0060] 7, line La shows the relationship between the difference between the amount of wire 4 fed in and the amount of wire 4 fed out and the elapsed time when slicing is performed using a wire 4 in good condition, while line Lb shows the relationship between the difference between the amount of wire 4 fed in and the amount of wire 4 fed out and the elapsed time when slicing is performed using a wire 4 in poor condition.

[0061] As shown in Figure 7, when the workpiece W is in the first state, the amount of wire 4 fed into the processing roller 2A is equal to the amount of wire 4 fed out from the processing roller 2B, so the difference between the amount of wire 4 fed in and the amount of wire 4 fed out is zero.

[0062] 7, time t1 is the time when the workpiece W changes from the first state to the second state. After the workpiece W changes from the first state to the second state, the workpiece W moves downward so as to bend the wire 4, and as a result, after time t1 has passed, the difference between the feed-in amount and the feed-out amount of the wire 4 gradually increases.

[0063] The maximum difference between the amount of wire 4 fed in and the amount of wire 4 fed out when the condition of the wire 4 is good is value Da. The maximum difference between the amount of wire 4 fed in and the amount of wire 4 fed out when the condition of the wire 4 is poor is value Db. Value Db is greater than value Da. In other words, when the condition of the wire 4 is good, the difference between the amount of wire 4 fed in and the amount of wire 4 fed out in the third state is small. When the condition of the wire 4 is poor, the difference between the amount of wire 4 fed in and the amount of wire 4 fed out in the third state is large.

[0064] The difference between the amount of wire 4 fed in and the amount of wire 4 paid out corresponds one-to-one to the amount of deflection of the wire 4. The detection data acquisition unit 23 acquires, at least in the third state, detection data from the wire sensor 12A that detects the amount of wire 4 fed into the processing roller 2A and detection data from the wire sensor 12B that detects the amount of wire 4 paid out from the processing roller 2B. The estimation unit 24 can estimate the condition of the wire 4 based on the difference between the amount of wire 4 fed in and the amount of wire 4 paid out acquired by the detection data acquisition unit 23 in the third state. If the difference between the amount of wire 4 fed in and the amount of wire 4 paid out in the third state is small, the estimation unit 24 can estimate that the condition of the wire 4 is good. If the difference between the amount of wire 4 fed in and the amount of wire 4 paid out in the third state is large, the estimation unit 24 can estimate that the condition of the wire 4 is poor.

[0065] The amount of deflection of the wire 4 may vary depending on the machining conditions of the workpiece W. For example, if the lowering speed of the movable member 5 is increased in order to slice the workpiece W in a short time, the amount of deflection of the wire 4 in the third state will increase even if the condition of the wire 4 is good. When estimating the condition of the wire 4 based on the maximum value of the difference between the feed-in amount and the feed-out amount of the wire 4, the machining conditions of the workpiece W (the lowering speed of the movable member 5) when estimating the condition of the wire 4 must be the same.

[0066] 8 is a flowchart showing a state monitoring method of the wire saw 1 according to the embodiment. When cutting the workpiece W with the wire 4, the controller 13 drives the roller motor 3 and the reel motor 7 so as to move the wire 4. While the wire 4 is moving, the controller 13 controls the moving member 5 so as to change the state of the workpiece W from a first state to a second state and then to a third state.

[0067] The wire sensor 12A detects the number of rotations of the guide roller 11 A. The wire sensor 12B detects the number of rotations of the guide roller 11 B. The detection data acquisition unit 23 acquires the detection data of the wire sensors 12A and 12B (step S1).

[0068] Based on the detection data acquired in step S1, the estimation unit 24 calculates the difference between the rotation speed of the guide roller 11A and the rotation speed of the guide roller 11B. By calculating the difference between the rotation speed of the guide roller 11A and the rotation speed of the guide roller 11B, the difference between the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 paid out from the processing roller 2B is calculated (step S2).

[0069] The estimation unit 24 estimates the amount of deflection of the wire 4 between the processing roller 2A and the processing roller 2B based on the difference between the feed-in amount and the feed-out amount of the wire 4 calculated in step S2 (step S3).

[0070] The output unit 25 causes the output device 22 to output the estimated deflection amount, which is the estimated value of the deflection amount estimated in step S3 (step S4).

[0071] The operator or manager of the wire saw 1 can recognize the condition of the wire 4 by checking the estimated deflection amount output to the output device 22. If the estimated deflection amount is small, the operator or manager of the wire saw 1 can recognize that the condition of the wire 4 is good. If the estimated deflection amount is large, the operator or manager of the wire saw 1 can recognize that the condition of the wire 4 is poor. For example, if the estimated deflection amount is smaller than a predetermined deflection amount, the operator or manager of the wire saw 1 recognizes that the condition of the wire 4 is good. For example, if the estimated deflection amount is larger than the predetermined deflection amount, the operator or manager of the wire saw 1 recognizes that the condition of the wire 4 is poor.

[0072] In step S4, the output unit 25 may output a control signal for controlling the wire saw 1 based on the estimated deflection amount. For example, if the condition of the wire 4 is poor, the output unit 25 may output a control signal for changing the processing conditions for the wire saw 1 or for stopping the operation of the wire saw 1. For example, if the estimated deflection amount is larger than a predetermined deflection amount, the output unit 25 may output a control signal for decreasing the descent speed of the moving member 5 or for stopping the movement of the moving member 5. If the estimated deflection amount is smaller than the predetermined deflection amount, the output unit 25 may output a control signal for increasing the descent speed of the moving member 5.

[0073] [Computer System] FIG. 9 is a block diagram showing a computer system 1000 according to an embodiment. The controller 13 and processing device 21 described above each comprise a computer system 1000. The computer system 1000 includes a processor 1001 such as a central processing unit (CPU), a main memory 1002 including a nonvolatile memory such as a read-only memory (ROM) and a volatile memory such as a random access memory (RAM), a storage 1003, and an interface 1004 including an input / output circuit. The functions of the controller 13 and processing device 21 described above are stored in the storage 1003 as computer programs. The processor 1001 reads the computer programs from the storage 1003, loads them into the main memory 1002, and executes the above-described processing in accordance with the programs. The computer programs may be distributed to the computer system 1000 via a network.

[0074] In accordance with the above-described embodiment, the computer program or computer system 1000 can detect the amount of wire 4 fed into the processing roller 2A using the wire sensor 12A, detect the amount of wire 4 fed out from the processing roller 2B using the wire sensor 12B, estimate the state of the wire 4 based on the difference between the amount fed in detected by the wire sensor 12A and the amount fed out detected by the wire sensor 12B, and output the estimated result.

[0075] [Effects] As described above, according to the embodiment, the condition monitoring system 20 can monitor the condition of the wire 4 based on the difference between the amount of wire 4 fed into the processing roller 2A and the amount of wire 4 fed out from the processing roller 2B. If it is determined that the condition of the wire 4 is poor, measures such as replacing the wire 4 can be taken, thereby preventing a decrease in the quality of the workpiece W after cutting and a decrease in the productivity of the wire saw 1.

[0076] The state of the wire 4 includes the amount of deflection of the wire 4. For example, when detecting the amount of deflection of the wire 4 using a displacement sensor, it may be difficult to install the displacement sensor in a position facing the wire 4 between the processing rollers 2A and 2B, or it may take time to install the displacement sensor. In the embodiment, the wire sensor 12 can be easily installed in a position away from the processing rollers 2A and 2B.

[0077] [Another embodiment] In the above-described embodiment, the wire sensor 12 detects the number of rotations of the guide roller 11. The wire sensor 12 may detect the number of rotations of the dancer rollers 9 or the number of rotations of the traverse rollers 14.

[0078] FIG. 10 is a schematic diagram illustrating a portion of a wire saw 1 according to another embodiment. In the above-described embodiment, the wire sensor 12 detects the rotation speed of a driven roller such as the guide roller 11. As shown in FIG. 10 , the wire sensor 16 may include a detection device capable of detecting the traveling speed of the wire 4. The detection device may be a laser device. In the example shown in FIG. 10 , when the processing roller 2 rotates in the forward direction, the wire sensor 16 includes a wire sensor 16A that detects the traveling speed of the wire 4 entering the processing roller 2A and a wire sensor 16B that detects the traveling speed of the wire 4 exiting the processing roller 2B. The wire sensor 16A is disposed between the guide roller 11A and the processing roller 2A and detects the traveling speed of the wire 4 traveling from the guide roller 11A to the processing roller 2A. The wire sensor 16B is disposed between the processing roller 2B and the guide roller 11B and detects the traveling speed of the wire 4 traveling from the processing roller 2B to the guide roller 11B. The estimation unit 24 can estimate the state of the wire 4 based on the difference between the running speed of the wire 4 entering the processing roller 2A and the running speed of the wire 4 discharged from the processing roller 2B. Furthermore, the estimation unit 24 can estimate the feed amount of the wire 4 entering the processing roller 2A and the payout amount of the wire 4 discharged from the processing roller 2B based on the running speed of the wire 4.

[0079] In the above-described embodiment, the wire saw 1 may be provided with the condition monitoring system 20. The controller 13 and the processing device 21 may be configured as a single piece of hardware. The condition monitoring system 20 may include a network connected to the wire saw 1 or the controller 13.

[0080] DESCRIPTION OF SYMBOLS 1...wire saw, 2...processing roller, 2A...processing roller, 2B...processing roller, 3...roller motor, 3A...roller motor, 3B...roller motor, 4...wire, 5...moving member, 6...bobbin, 6A...bobbin, 6B...bobbin, 7...reel motor, 7A...reel motor, 7B...reel motor, 8...traverser, 8A...traverser, 8B...traverser, 9...dancer roller, 9A...dancer roller, 9B...dancer roller, 10...dancer motor, 10A...dancer motor, 10B...dancer motor, 11...guide roller, 11A...guide roller, 11B...guide roller , 12...wire sensor, 12A...wire sensor, 12B...wire sensor, 13...controller, 14...traverse roller, 14A...traverse roller, 14B...traverse roller, 15...dancer arm, 16...wire sensor, 16A...wire sensor, 16B...wire sensor, 20...condition monitoring system, 21...processing device, 22...output device, 23...detection data acquisition unit, 24...estimation unit, 25...output unit, 1000...computer system, 1001...processor, 1002...main memory, 1003...storage, 1004...interface, W...work.

Claims

1. A wire saw condition monitoring system comprising a first processing roller and a second processing roller, a wire hung between the first processing roller and the second processing roller, and a moving member that moves to press a workpiece against the wire between the first processing roller and the second processing roller while the wire is running, the wire saw condition monitoring system comprising: a detection data acquisition unit that acquires detection data from a first wire sensor that detects the amount of wire fed into the first processing roller and detection data from a second wire sensor that detects the amount of wire fed out from the second processing roller; an estimation unit that estimates the condition of the wire based on the feed amount and the feed amount; and an output unit that outputs the estimation result by the estimation unit.

2. The wire saw condition monitoring system according to claim 1, wherein the estimation unit estimates the condition of the wire based on the difference between the feed amount and the feed amount.

3. The wire saw condition monitoring system according to claim 1, wherein the condition of the wire includes an amount of deflection of the wire between the first processing roller and the second processing roller.

4. The wire saw condition monitoring system according to claim 1, wherein the estimation unit estimates the condition of the wire while a workpiece is being machined.

5. A wire saw condition monitoring system as described in claim 4, wherein the movable member is controlled to change from a first state in which the workpiece is separated from the wire, through a second state in which the workpiece is in contact with the wire, to a third state in which the workpiece moves so as to bend the wire, and the estimation unit estimates the condition of the wire based on the feed amount and the payout amount obtained in the third state.

6. The wire saw comprises a first bobbin that pays out the wire to be fed to the first processing roller, a second bobbin that winds up the wire paid out from the second processing roller, a first driven roller that is disposed between the first processing roller and the first bobbin and rotates as the wire travels, and a second driven roller that is disposed between the second processing roller and the second bobbin and rotates as the wire travels, wherein the first wire sensor detects the number of rotations of the first driven roller as the feed amount, and the second wire sensor detects the number of rotations of the second driven roller as the feed amount. A condition monitoring system for a wire saw as described in claim 1.

7. The wire saw condition monitoring system according to claim 6, wherein each of the first driven roller and the second driven roller is a guide roller that guides the wire.

8. The wire saw condition monitoring system according to claim 6, wherein each of the first wire sensor and the second wire sensor includes a rotary encoder.

9. The wire saw condition monitoring system according to claim 1, wherein each of the first wire sensor and the second wire sensor includes a detection device capable of detecting the traveling speed of the wire.

10. A wire saw comprising the wire saw condition monitoring system according to claim 1.

11. A method for monitoring the condition of a wire saw comprising a first processing roller and a second processing roller, a wire hung between the first processing roller and the second processing roller, and a movable member that moves to press a workpiece against the wire between the first processing roller and the second processing roller while the wire is running, comprising: detecting an amount of the wire fed into the first processing roller with a first wire sensor; detecting an amount of the wire fed out from the second processing roller with a second wire sensor; estimating a condition of the wire based on a difference between the amount of the wire fed in detected by the first wire sensor and the amount of the wire fed out detected by the second wire sensor; and outputting the estimation result.

Images