JP3898655B2 - Wire saw and wire tension control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wire saw that uses a wire to perform a work such as cutting on a work made of a hard and brittle material such as a semiconductor material, a magnetic material, and ceramic, and a wire tension control method in the wire saw.
[0002]
[Prior art]
Generally, in this type of wire saw, both ends of one wire are wound around a take-up reel, and the wire is spirally wound at a predetermined pitch between a plurality of processing rollers. Then, as the processing roller and the take-up reel rotate, the slurry including loose abrasive grains is supplied onto the wire while the wire travels between the processing rollers. In this state, the workpiece is pressed against and contacted with the wire, and the workpiece is cut.
[0003]
[Problems to be solved by the invention]
In general, in a wire saw, a tension adjusting device is provided between the processing roller and both take-up reels, and adjustment control is performed so that the wire tension is the same on the wire feeding side and the feeding side with respect to the processing roller. It had been.
[0004]
As described above, when the tension of the wire is adjusted, as shown in FIG. 3, the contact pressure of the workpiece with respect to the wire becomes non-uniform at different processing positions in the axial direction of the processing roller. That is, when the wire is fed from one end of the processing roller and the wire is fed from the other end, the processing position shifts from the wire feeding side to the feeding side along the axial direction of the processing roller. Along with this, the contact pressure of the workpiece with respect to the wire gradually decreased. For this reason, there existed a problem that the workpiece | work could not be processed with the same precision over the whole region of the processing position in the axial direction of the processing roller.
[0005]
The present invention has been made paying attention to such problems existing in the prior art. The purpose of the wire saw is to make the contact pressure of the workpiece to the wire uniform at each machining position in the machining roller axial direction, and to machine the workpiece with high precision over the entire machining position, and its To provide a wire tension control method in a wire saw.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, while a wire wound between a plurality of processing rollers is run, a workpiece is brought into contact with the wire to perform a cutting process. In the wire saw as described above, tension adjusting means are provided on the wire feeding side and the feeding side with respect to the processing roller, so that the contact pressure of the workpiece to the wire is uniform at each processing position in the axial direction of the processing roller. Control means for separately controlling the tension adjusting means is provided.
[0007]
Therefore, according to the first aspect of the present invention, the contact pressure of the workpiece with respect to the wire can be made uniform at each processing position in the axial direction of the processing roller. Therefore, the workpiece can be machined with high accuracy over the entire machining position in the length direction of the machining roller.
[0008]
According to a second aspect of the present invention, in the first aspect of the invention, each of the tension adjusting means adjusts the tension of the wire based on the detection means for detecting the tension of the wire and the detection result of the detection means. It is characterized by comprising tension adjusting means including a torque motor.
[0009]
Therefore, according to the second aspect of the present invention, during the processing of the workpiece, a delay occurs based on the detection result while detecting the wire tension on the wire feeding side and the feeding side with respect to the processing roller. The tension can be adjusted without any change.
[0010]
According to a third aspect of the present invention, in the first or second aspect of the present invention, there is provided a storage means for preliminarily storing the tension on the feeding side and the feeding side of the wire.
[0011]
Therefore, according to the third aspect of the present invention, the tension on the wire feeding side and the feeding side of the wire is set in advance, and tension adjustment can be easily performed based on the set value.
[0012]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects of the present invention, the control means includes a wire feeding side and a workpiece feeding side as the workpiece is processed. It is characterized by changing and controlling the tension on the delivery side.
[0013]
Therefore, according to the fourth aspect of the present invention, it is possible to suppress a decrease in machining accuracy, particularly at the start and end of machining of the workpiece, and the workpiece can be accurately processed from the start to the end of machining. Can be processed.
[0014]
According to the fifth aspect of the present invention, the wire tension control of the wire saw is configured such that the wire wound between the plurality of processing rollers travels while the workpiece is brought into contact with the wire to perform cutting processing. In the method, the tension on the feeding side and the feeding side of the wire with respect to the processing roller is separately adjusted and controlled so that the contact pressure of the workpiece with respect to the wire becomes uniform at each processing position between the processing rollers. Is.
[0015]
Therefore, according to the fifth aspect of the present invention, the same action as that of the first aspect can be obtained.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, in this wire saw, three processing rollers 11, 12, 13 are arranged in parallel, and a large number of annular grooves (not shown) formed at a predetermined pitch on the outer periphery thereof have 1. A wire 14 is wound. Then, when these processing rollers 11 to 13 are rotated by the roller rotation motor 15, the wire 14 travels between the processing rollers 11 to 13. The traveling of the wire 14 is advanced stepwise as a whole by repeating a certain amount of forward movement and a certain amount of backward movement.
[0017]
A pair of take-up reels 16A and 16B are disposed so as to correspond to both ends of the processing rollers 11 to 13, and both ends of the wire 14 are wound around the take-up reels 16A and 16B. The take-up reels 16A and 16B are rotated by the reel rotation motors 17A and 17B, so that any one of the take-up reels 16A and 16B is passed through the plurality of guide rollers 29 to the processing rollers 11 to 11. A wire 14 is fed onto 13. At the same time, the wire 14 is fed from the processing rollers 11 to 13 to the other take-up reels 16B and 16A.
[0018]
A pair of slurry supply pipes 18 is disposed above the wire 14 between the processing rollers 11 to 13. Then, the slurry supply pump 19 is rotated by the pump motor 20 so that slurry containing loose abrasive grains is supplied from the slurry supply pipe 18 to the wire 14 between the processing rollers 11 to 13. It has become.
[0019]
A work 21 made of a hard and brittle material is disposed above the wire 14 between the processing rollers 11 to 13 so as to be movable up and down via a work support mechanism (not shown). As the wire 14 travels and the slurry is supplied onto the wire 14 from the slurry supply pipe 18, the workpiece 21 is moved downward by the workpiece feed moving motor 22 shown in FIG. 2. Thereby, the work 21 is pressed against the wire 14 and cut into slices.
[0020]
As shown in FIG. 1, a pair of tension adjusting devices 23A and 23B as tension adjusting means are disposed between the processing rollers 11 to 13 and the take-up reels 16A and 16B. Each tension adjusting device 23A, 23B includes detection sensors 24A, 24B as detection means for detecting the tension of the wire 14, and tension adjustment means for adjusting the tension of the wire 14 based on the detection results of the detection sensors 24A, 24B. And tension adjusting mechanisms 25A and 25B. The detection sensors 24A and 24B detect a tension load acting on one guide roller 29 between the tension adjusting mechanisms 25A and 25B and the processing rollers 11 to 13, and are made of, for example, a load cell.
[0021]
Each of the tension adjusting mechanisms 25A and 25B is composed of dancer arms 27A and 27B rotated by torque motors 26A and 26B, and dancer rollers 28A and 28B rotatably supported at the tips of the dancer arms 27A and 27B. Yes. Between the processing rollers 11 to 13 and the reels 16A and 16B, the wire 14 is hung on the dancer rollers 28A and 28B of the tension adjusting mechanisms 25A and 25B. In this state, the dancer arms 27A and 27B are rotationally displaced by constant torque control of the torque motors 26A and 26B in accordance with the tension fluctuation of the wire 14 caused by the fluctuation of the machining load and the like. The dancer rollers 28A and 28B are moved up and down by the rotational displacement of the dancer arms 27A and 27B, whereby a predetermined tension is applied to the wire 14. And the tension | tensile_strength of the sending side of the wire 14 and the sending side is adjusted by changing each setting torque value of torque motor 26A, 26B.
[0022]
Next, the control configuration of the wire saw configured as described above will be described.
As shown in FIG. 2, the control device 31 as a control unit controls the operation of the entire wire saw based on a program and various data stored in a memory 32 as a storage unit. Further, when the tension on the feeding side and the feeding side of the wire 14 with respect to the processing rollers 11 to 13 is input and set in advance from the input device 33 prior to the processing of the workpiece 21, the control device 31 sets the tension values. Is stored in the memory 32.
[0023]
In this case, the tension on the feeding side and the feeding side of the wire 14 is set so that, for example, the feeding side is more than the feeding side so that the contact pressure of the work 21 against the wire 14 is uniform at each machining position in the axial direction of the processing rollers 11 to 13. Is set to be higher. Further, the tension on the feeding side and the feeding side of the wire 14 is changed in three stages so that it becomes higher at the start of machining and at the end of machining of the workpiece 21 as the machining of the workpiece 21 progresses. Input setting.
[0024]
Further, as the machining operation of the workpiece 21 proceeds, the control device 31 sequentially reads the tension setting values on the feeding side and the feeding side of the wire 14 at the start of machining, during the machining, and at the end of machining, stored in the memory 32. Based on these tension setting values, the tension adjusting devices 23A and 23B on the feeding side and the feeding side of the wire 14 are controlled separately. In this case, in each tension adjusting device 23A, 23B, the tension of the wire 14 is detected by the detection sensors 24A, 24B, and the set torque values of the torque motors 26A, 26B are set so that the detection result matches the tension set value. The tension of the wire 14 is adjusted by changing the tension.
[0025]
Next, the operation of the wire saw configured as described above will be described with reference to the flowchart of FIG.
When the machining operation for the workpiece 21 is started with this wire saw, the tension setting values on the feeding side and the feeding side of the wire 14 at the time of machining start are read from the memory 32 (step S1), and the set values are obtained. Based on this, the tension adjusting devices 23A and 23B are controlled. That is, in each of the tension adjusting devices 23A and 23B, the tension of the wire 14 is detected by the detection sensors 24A and 24B, and it is determined whether or not the detected value matches the tension setting value (step S2).
[0026]
In this determination, when the detected value and the set value do not match, the set torque values of the torque motors 26A and 26B are changed. As a result, the dancer arms 27A and 27B are rotationally displaced and the dancer rollers 28A and 28B are moved up and down to adjust the tension of the wire 14 (step S3). Thereafter, it is determined whether or not the workpiece 21 has been processed to a predetermined position (predetermined cutting depth) through the processing start position (step S4). While being processed to the predetermined position, the process returns to step S2 and returns to step S2. The operation of .about.S4 is repeated.
[0027]
At the start of machining of the workpiece 21, the tension on the feeding side and the feeding side of the wire 14 is set to a higher value than the tension during the machining, and the contact pressure of the workpiece 21 with respect to the wire 14 is higher than that during the machining. Touched with. For this reason, as shown in FIG. 4, the possibility that the groove width of the cutting start portion of the workpiece 21 becomes wide can be suppressed and high-precision machining can be achieved. Incidentally, when the contact pressure of the workpiece 21 with respect to the wire 14 is low at the start of machining, the wire 14 is shaken and the groove width of the cut portion of the workpiece 21 is widened.
[0028]
In the case of machining the workpiece 21, the tension on the delivery side of the wire 14 is set to a higher value than the tension on the delivery side. For this reason, as shown in FIG. 3, the contact pressure of the workpiece 21 with respect to the wire 14 gradually decreases as the processing position shifts to the delivery side of the wire 14 along the axial direction of the processing rollers 11 to 13. The conventional phenomenon is corrected, and the contact pressure can be made uniform. In addition, the traveling direction of the wire 14 is switched at regular time intervals, and the feeding side and the feeding side are reversed. At each reversal, the level of the wire tension is also switched.
[0029]
Furthermore, when the tension of the wire 14 is set to be higher than that in the middle of machining at the start of machining of the workpiece 21, the pump motor 20 of the slurry supply pump 19 is activated according to the set value of the tension. The rotation is controlled, and the amount of slurry supplied from the slurry supply pipe 18 is reduced. For this reason, the possibility that the workpiece 21 is excessively processed can be suppressed.
[0030]
Next, when the workpiece 21 is machined to a predetermined position in the discrimination in step S4, lower tension setting values on the feeding side and the feeding side of the wire 14 during the machining are read from the memory 32 (step S5). Based on these set values, the tension adjusting devices 23A and 23B are controlled. Also in this case, in the tension adjusting devices 23A and 23B, the tension of the wire 14 is detected by the detection sensors 24A and 24B, and it is determined whether or not the detected value matches the tension setting value (step S6).
[0031]
In this determination, when the detected value and the set value do not match, the set torque values of the torque motors 26A and 26B are changed. As a result, the dancer arms 27A and 27B are rotationally displaced and the positions of the dancer rollers 28A and 28B are moved up and down to adjust the tension of the wire 14 (step S7). Thereafter, it is determined whether or not the workpiece 21 has been processed to a position immediately before the end of processing (step S8). While being processed to that position, the process returns to step S6 and the operations of steps S6 to S8 are repeated.
[0032]
Even during the processing of the workpiece 21, the tension on the delivery side of the wire 14 is set to a higher value than the tension on the delivery side. For this reason, as shown in FIG. 3, the contact pressure of the workpiece | work 21 with respect to the wire 14 can be made uniform in each processing position in the axial direction of the processing rollers 11-13, and the workpiece | work 21 is processed with high precision. be able to.
[0033]
Subsequently, in the determination in step S8, when the workpiece 21 is machined to a position just before the machining end, higher tension setting values on the feeding side and the feeding side of the wire 14 at the time of machining are read from the memory 32 (step S8). S9) The tension adjusting devices 23A and 23B are controlled based on the set values. Also in this case, in each of the tension adjusting devices 23A and 23B, the tension of the wire 14 is detected by the detection sensors 24A and 24B, and it is determined whether or not the detected value matches the tension setting value (step S10).
[0034]
In this determination, if the detected value and the set value do not match, the set torque value of the torque motors 26A and 26B is changed to adjust the tension of the wire 14 (step S11). Thereafter, it is determined whether or not the machining of the workpiece 21 is completed (step S12), and until the machining is completed, the process returns to step S10 and the operations of steps S10 to S12 are repeated. When the machining of the workpiece 21 is completed, the operation of the wire saw is stopped.
[0035]
Also, at the end of the machining of the workpiece 21, the tension on the feeding side and the feeding side of the wire 14 is set to the above-mentioned higher value than the tension during the machining, similarly to the time when the machining is started. The workpiece 21 is brought into contact with a higher contact pressure than during the machining. For this reason, as shown in FIG. 5, when the processing length L of the workpiece 21 by the wire 14 is shortened in the vicinity of the processing end position, it is possible to suppress the perturbation such as the shake of the wire 14. That is, when the contact pressure of the workpiece 21 against the wire 14 is low, the wire 14 may be shaken near the processing end position.
[0036]
Furthermore, since the tension of the wire 14 is set to be higher than that in the middle of machining at the end of machining of the workpiece 21 as in the above-described machining start, the pump motor 20 is set according to the set value of the tension. As a result of this rotation control, the amount of slurry supplied from the slurry supply pipe 18 is reduced. Therefore, the possibility that the workpiece 21 is excessively processed can be suppressed.
[0037]
Therefore, according to this embodiment, the following effects can be obtained.
(1) In this wire saw, tension adjusting devices 23A and 23B are provided on the feeding side and the feeding side of the wire 14 with respect to the processing rollers 11, 12, and 13. A control device 31 for separately controlling the tension adjusting devices 23A and 23B is provided so that the contact pressure of the workpiece 21 with respect to the wire 14 becomes uniform at each processing position in the axial direction of the processing rollers 11 to 13. Yes.
[0038]
Therefore, the workpiece 21 can be processed with uniform accuracy over the entire area of each processing position in the axial direction of the processing rollers 11 to 13, and as a result, the workpiece 21 can be processed with high accuracy. it can.
[0039]
(2) In this wire saw, each of the tension adjusting devices 23A and 23B detects the sensors 24A and 24B for detecting the tension of the wire 14, and the torque for adjusting the tension of the wire 14 based on the detection results of the sensors 24A and 24B. It comprises tension adjusting mechanisms 25A and 25B including a motor. For this reason, while processing the workpiece 21, while detecting the tension of the wire 14 on the feeding side and the feeding side of the wire 14 with respect to the processing rollers 11 to 13, there is no time delay based on the detection result. The tension can be adjusted effectively.
[0040]
(3) In this wire saw, the tension on the feeding side and the feeding side of the wire 14 is automatically changed and controlled by the control device 31 as the workpiece 21 is processed. For this reason, for example, it is possible to suppress a reduction in machining accuracy at the start and end of machining of the workpiece 21, and the workpiece 21 can be machined with high accuracy from the machining start to the end.
[0041]
(4) In this wire saw, when the tension of the wire 14 is changed and controlled by the control device 31 as the workpiece 21 is processed, the amount of slurry supplied to the wire 14 according to the change of the tension. Is adjusted and controlled. For this reason, when the tension | tensile_strength of the wire 14 is changed at the time of the process start of the workpiece | work 21 and the completion | finish of a process, the supply amount of slurry is reduced and the workpiece | work 21 is suppressed from being excessively processed. be able to. On the other hand, it is possible to solve the lack of cutting when the tension of the wire 14 is low.
[0042]
(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
In the embodiment, the configuration of the tension adjusting devices 23A and 23B is arbitrarily changed. For example, a linear actuator such as a solenoid is connected to the dancer arms 27A and 27B, and the wire tension is adjusted by the operation of the actuator.
[0043]
In the above-described embodiment, the present invention is applied to a wire saw in which the wire 14 moves stepwise, but the present invention is embodied in a wire saw in which the wire 14 continuously moves in one direction. In the wire saw in which the wire 14 is continuously moved in one direction, when the substantially entire length of the wire 14 is wound around one of the reels 16A and 16B, the traveling direction of the wire 14 is reversed.
[0044]
【The invention's effect】
As described above, as exemplified in the embodiment, in the present invention, the contact pressure of the workpiece with respect to the wire can be made uniform at each processing position in the axial direction of the processing roller. Therefore, the workpiece can be machined with high accuracy over the entire machining position in the length direction of the machining roller.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a wire saw according to an embodiment.
FIG. 2 is a block diagram showing a control configuration of the wire saw in FIG. 1;
FIG. 3 is an explanatory view showing a tension state of a wire at a processing position.
FIG. 4 is a partial cross-sectional view showing a state at the start of machining a workpiece with a wire.
FIG. 5 is a cross-sectional view showing a state at the end of machining a workpiece with a wire.
FIG. 6 is a flowchart showing the operation of the wire saw of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11, 12, 13 ... Processing roller, 14 ... Wire, 15 ... Roller rotation motor, 16A, 16B ... Winding reel, 21 ... Workpiece, 23A, 23B ... Tension adjusting device as tension adjusting means, 24A, 24B ... Detection sensor as detection means, 25A, 25B ... tension adjusting mechanism as tension adjusting means, 26A, 26B ... torque motor, 27A, 27B ... dancer arm, 28A, 28B ... dancer roller, 31 ... control device as control means, 32 ... Memory as storage means.

Claims (5)

In a wire saw in which a wire wound between a plurality of processing rollers is run while a workpiece is brought into contact with the wire so that the workpiece is cut.
Tension adjusting means are provided on the wire feeding side and the sending side with respect to the processing roller, and each tension adjusting means is separately provided so that the contact pressure of the workpiece to the wire is uniform at each processing position in the axial direction of the processing roller. A wire saw provided with a control means for controlling. 2. The tension adjusting means includes a detecting means for detecting the tension of the wire, and a tension adjusting means including a torque motor for adjusting the tension of the wire based on a detection result of the detecting means. Wire saw as described in The wire saw according to claim 1 or 2, further comprising storage means for preliminarily storing tensions on the feeding side and the feeding side of the wire. The said control means changes and controls the tension | tensile_strength of the sending side of a wire, and a sending side as a workpiece | work of a work progresses, The control method as described in any one of Claims 1-3 characterized by the above-mentioned. Wire saw. In a wire saw in which a wire wound between a plurality of processing rollers is run while a workpiece is brought into contact with the wire to perform a cutting process.
The wire is characterized by separately adjusting and controlling the tension on the feeding side and the feeding side of the wire with respect to the processing roller so that the contact pressure of the workpiece with respect to the wire becomes uniform at each processing position in the axial direction of the processing roller. Tension control method.

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