Wire saw, wire saw control method, and wire saw control program

Abstract

To provide a wire saw or the like that can prevent scattering of an object to be cut off (workpiece) at a point in completing cutting off of the workpiece.SOLUTION: A wire saw comprises: wire traveling means for allowing a wire to travel in a lengthwise direction in the state where the wire is stretched; tensile force adjusting means for adjusting the tensile force of the wire; workpiece (object to be cut off) feeding means for feeding a workpiece in a direction pushing against the wire; curved state detection means for detecting the curved state of the wire; tensile force control means for performing control of adjusting the tensile force of the wire for the tensile force adjusting means on the basis of the curved state of the wire; and feed speed control means for performing control of adjusting the feeding speed of the workpiece for the workpiece feeding means on the basis of the curved state of the wire.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wire saw and the like. [Background technology]

[0002] A wire saw uses a wire with abrasive grains attached. A wire saw is a device that cuts an object with this wire. When cutting, the wire is pressed against the object and the wire saw runs the wire in the direction of extension. For this reason, when cutting with a wire saw, it is important to properly control the tension applied to the wire and the running speed of the wire.

[0003] A technique for a wire saw device for high-speed cutting is disclosed in, for example, Patent Document 1. The wire saw device in Patent Document 1 is equipped with a tension adjusting means and a control device. The tension adjusting means adjusts the tension of the wire during reciprocating travel. The control device controls the wire tension and the wire travel speed. The control device sets a tension setting value so that the wire tension is 50% or more of the wire's breaking strength. The control device also controls the tension so that it is within ±2.5 N of the set value. Furthermore, when reversing the wire travel direction, the control device adjusts the wire acceleration / deceleration to 36,000 m / min. 2 Alternatively, the control device controls the time required for reversing the running direction to 3 seconds or less. This control allows for high-speed cutting processing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-105061 Summary of the Invention [Problem to be solved by the invention]

[0005] The wire saw device of Patent Document 1 is capable of performing high-speed cutting. However, when performing such high-speed cutting, there are cases where the workpiece is scattered when cutting is completed.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a wire saw or the like that can prevent the object to be cut from scattering when cutting of the object is completed. [Means for solving the problem]

[0007] In order to solve the above problems, the wire saw of the present invention comprises a wire running means for running the wire in a longitudinal direction while the wire is tensioned, a tension adjustment means for adjusting the tension of the wire, a workpiece feeding means for feeding the workpiece in a direction pressing it against the wire, a curved state detection means for detecting the curved state of the wire, a tension control means for controlling the tension adjustment means to adjust the tension of the wire based on the curved state of the wire, and a feed speed control means for controlling the workpiece feeding means to adjust the feed speed of the workpiece based on the curved state of the wire.

[0008] In addition, the wire saw control method of the present invention includes running the wire in a longitudinal direction while the wire is tensioned, adjusting the tension of the wire, feeding the workpiece in a direction pressing it against the wire, detecting the curvature of the wire, controlling the tension of the wire based on the curvature of the wire, and controlling the feed speed of the workpiece based on the curvature of the wire.

[0009] In addition, the control program for the wire saw of the present invention causes the wire saw to perform the following processes: running the wire in a longitudinal direction while the wire is tensioned; adjusting the tension of the wire; feeding the workpiece in a direction pressing it against the wire; detecting the curved state of the wire; controlling the tension of the wire based on the curved state of the wire; and controlling the feed speed of the workpiece based on the curved state of the wire. [Effects of the Invention]

[0010] The effect of the present invention is to provide a wire saw or the like that can prevent the object from scattering when cutting of the object is completed. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram showing a wire saw according to a first embodiment. [Figure 2] 4 is a flowchart showing the operation of the wire saw of the first embodiment. [Figure 3] FIG. 4 is a schematic diagram showing a wire saw according to a second embodiment. [Figure 4] FIG. 10 is a schematic diagram showing a first specific example of a bending state detection means according to the second embodiment. [Figure 5] FIG. 10 is a schematic diagram showing a second specific example of the bending state detection means of the second embodiment. [Figure 6] FIG. 10 is a schematic diagram showing a first state of an operation example of the wire saw according to the second embodiment. [Figure 7] FIG. 10 is a schematic diagram showing a second state of the operation example of the wire saw according to the second embodiment. [Figure 8] FIG. 10 is a schematic diagram showing a third state of the operation example of the wire saw according to the second embodiment. [Figure 9] FIG. 10 is a schematic diagram showing a fourth state of the operation example of the wire saw according to the second embodiment. [Figure 10] FIG. 10 is a schematic diagram showing a fifth state of the operation example of the wire saw according to the second embodiment. [Figure 11] FIG. 10 is a schematic diagram showing a sixth state of the operation example of the wire saw according to the second embodiment. [Figure 12] FIG. 10 is a schematic diagram showing a seventh state of the operation example of the wire saw according to the second embodiment. [Figure 13] FIG. 10 is a schematic diagram showing an eighth state of the operation example of the wire saw according to the second embodiment. [Figure 14] 10 is an example of a timing chart of the wire saw according to the second embodiment. [Figure 15]10 is another example of a timing chart of the wire saw according to the second embodiment. [Figure 16] 10 is a flowchart showing the operation of the wire saw of the second embodiment. [Figure 17] 10A and 10B are schematic diagrams showing specific examples of an object to be cut in the second embodiment. [Figure 18] FIG. 10 is a schematic diagram showing a modified example of the wire saw of the second embodiment. [Figure 19] FIG. 10 is a schematic diagram showing a first state of an operation example of a modified example of the second embodiment. [Figure 20] FIG. 10 is a schematic diagram showing a second state of the operation example of the modified example of the second embodiment. [Figure 21] FIG. 10 is a schematic diagram showing a third state of the operation example of the modified example of the second embodiment. [Figure 22] FIG. 10 is a schematic diagram showing a fourth state of the operation example of the modified example of the second embodiment. [Figure 23] 10 is a flowchart showing the operation of a modified example of the second embodiment. [Figure 24] 10 is a flowchart showing details of the operation of a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments described below are limited to technically preferable aspects for carrying out the present invention, but are not intended to limit the scope of the invention. Note that similar components in each drawing are given the same reference numerals, and their description may be omitted.

[0013] (First embodiment) 1 is a block diagram showing a wire saw according to a first embodiment. The wire saw 10 includes a wire traveling means 2, a tension adjusting means 3, a workpiece feeding means 4, a bending state detecting means 5, a tension control means 6, and a feed speed control means 7.

[0014] The wire running means 2 runs the wire 1 in the length direction while keeping the wire 1 tensioned.

[0015] The tension adjusting means 3 adjusts the tension of the wire 1 .

[0016] The object feeding means 4 feeds the object 900 in a direction in which it is pressed against the wire 1 .

[0017] The bent state detection means 5 detects the bent state of the wire 1. In this embodiment, the degree of bend at which the bend is detected is defined as a first threshold value.

[0018] The tension control means 6 controls the tension adjustment means 3 to adjust the tension of the wire 1 based on the bent state of the wire 1.

[0019] The feed speed control means 7 controls the workpiece feed means 4 to adjust the feed speed of the workpiece 900 based on the curved state of the wire 1.

[0020] FIG. 2 is a flowchart showing the operation of the wire saw 10 of the first embodiment. First, the wire traveling means 2 travels the wire 1 in the longitudinal direction while tensioning the wire 1 (S1). Next, the tension adjusting means 3 adjusts the tension of the wire 1 (S2). Next, the workpiece feeding means 4 feeds the workpiece 900 in a direction pressing the workpiece 900 against the wire 1 (S3). This operation progresses the cutting of the workpiece 900. Next, the bending state detecting means 5 detects the bending state of the wire 1 (S4). During cutting, the wire 1 is pressed against the workpiece 900. Meanwhile, a force acts on the wire 1, which tries to return it to its position when the workpiece 900 is not present. As a result, the wire 1 is bent so as to be convex in the direction in which the workpiece 900 is fed. The bending state detecting means 5 detects the degree of bending. Furthermore, after detecting the degree of bending, the tension control means 6 controls the tension adjusting means 3 based on the bending state. Through this control, the tension adjusting means 3 controls the tension of the wire 1 (S5). Next, the feed speed control means 7 controls the workpiece feeding means 4 based on the curvature state. Through this control, the workpiece feeding means 4 adjusts the feed speed (S6). In cutting the workpiece 900, the curvature state of the wire 1 changes as the cutting nears completion. In the wire saw 10, the tension of the wire 1 and the feed speed of the workpiece 900 are adjusted based on this change in the curvature state. Therefore, in the wire saw 10 of this embodiment, it is possible to control so as to prevent the workpiece from scattering when cutting is completed.

[0021] The wire saw 10 and the like according to the first embodiment have been described above.

[0022] The wire saw 10 comprises a wire traveling means 2, a tension adjusting means 3, an object feeding means 4, a curved state detecting means 5, a tension control means 6, and a feed speed control means 7. The wire traveling means 2 travels the wire 1 in the longitudinal direction while keeping the wire 1 tensioned. The tension adjusting means 3 adjusts the tension of the wire 1. The object feeding means 4 feeds the object 900 in a direction pressing it against the wire 1. The curved state detecting means 5 detects the curved state of the wire 1. The tension control means 6 controls the tension adjusting means 3 to adjust the tension of the wire 1 based on the curved state of the wire 1. The feed speed control means 7 controls the object feeding means 4 to adjust the feed speed of the object 900 based on the curved state of the wire 1.

[0023] In the above configuration, the tension of the wire 1 is controlled based on the curved state of the wire 1. Furthermore, the feed speed of the workpiece 900 is controlled based on the curved state of the wire 1. In this configuration, when cutting of the workpiece 900 is completed, the tension of the wire 1 and the feed speed of the workpiece are controlled based on the curved state. Therefore, in the wire saw 10, it is possible to perform control to prevent the workpiece from scattering when cutting is completed.

[0024] According to another aspect, in the wire saw 10, when the degree of curvature of the wire 1 in its curved state is equal to or greater than a first threshold, the curved state detection means 5 detects the curvature of the wire 1. By setting the first threshold for detecting the curvature, the timing of the control of the feed speed and the control of the tension before and after the cutting of the workpiece 900 is completed can be appropriately set.

[0025] According to another embodiment, the travel path of the wire 1 when the workpiece 900 is not in contact with the wire 1 is defined as a reference line. Then, a feed stop position is defined. The position in the direction in which the workpiece is fed a first distance from the reference line is the feed stop position. Then, when the workpiece 900 reaches the feed stop position at the end of cutting, the workpiece feeding means 4 is stopped. Therefore, when cutting of the workpiece 900 is completed, the wire saw 10 is controlled to prevent the workpiece 900 from scattering.

[0026] According to one embodiment, the tension of the wire 1 is reduced in the following cases: That is, when the position of the cutting end of the object 900 reaches the feed stop position and the degree of curvature of the wire 1 becomes within a first threshold value, the tension of the wire 1 is reduced. In this operation, the tension of the wire 1 is reduced when cutting of the object 900 is completed. Therefore, the wire saw 10 is controlled to prevent the object 900 from scattering when cutting of the object 900 is completed.

[0027] Furthermore, in the wire saw control method of this embodiment, the wire saw 10 runs the wire in the longitudinal direction while keeping the wire tensioned. The wire saw 10 also adjusts the tension of the wire 1. The wire saw 10 also feeds the workpiece 900 in a direction pressing it against the wire 1. The wire saw 10 also detects the curvature of the wire. The wire saw 10 also adjusts the tension of the wire 1 based on the curvature of the wire 1. The wire saw 10 also adjusts the feed speed of the workpiece 900 based on the curvature of the wire 1. Through these operations, in the wire saw control method of this embodiment, the wire saw 10 is controlled to prevent the workpiece 900 from scattering when cutting of the workpiece 900 is completed.

[0028] The control program for the wire saw of this embodiment also causes the wire saw 10 to execute the following processes. The processes include a process for running the wire 1. At this time, the longitudinal direction of the wire 1 in a tensioned state becomes the running direction. The processes also include a process for adjusting the tension of the wire 1. The processes also include a process for feeding the object 900 in a direction in which the object 900 is pressed against the wire 1. The processes also include a process for detecting the curved state of the wire 1. The processes also include a process for adjusting the tension of the wire 1 based on the curved state of the wire 1. The processes also include a process for adjusting the feed speed of the object 900 based on the curved state of the wire 1. With the above configuration, the control program for the wire saw controls the wire saw 10 to prevent the object 900 from scattering when cutting of the object 900 is completed.

[0029] (Second embodiment) In this embodiment, a specific configuration example of the wire saw 10 of the first embodiment will be described. Fig. 3 is a schematic diagram showing a wire saw 1000 of the second embodiment.

[0030] The wire saw 1000 includes the same wire 1 as in the first embodiment. Abrasive grains such as diamond are attached to the surface of the wire 1. The wire saw 1000 cuts the workpiece 900 by bringing the wire 1 into contact with the workpiece 900 and causing the wire 1 to travel.

[0031] The wire saw 1000 also includes a first reel 210, a second reel 220, a first guide pulley 230, a second guide pulley 240, and a third guide pulley 250 as specific examples of the wire traveling means 2 of the first embodiment.

[0032] The wire saw 1000 also includes a tension pulley 300, a rotary shaft 310, and an arm 320 as specific examples of the tension adjusting means 3 of the first embodiment.

[0033] The wire saw 1000 also includes a stage 400 as a specific example of the workpiece feeding means 4 of the first embodiment.

[0034] The wire saw 1000 also includes a bending state detection sensor 500 as a specific example of the bending state detection means 5 of the first embodiment.

[0035] The wire saw 1000 also includes a tension control unit 600 as a specific example of the tension control means 6 of the first embodiment.

[0036] The wire saw 1000 also includes a feed speed control unit 700 as a specific example of the feed speed control means 7 of the first embodiment.

[0037] The wire 1 is wound around the first reel 210 and the second reel 220. The wire 1 travels back and forth between them. At this time, one reel is the supply reel and the other is the recovery reel. In the following description, the first reel 210 is the supply reel and the second reel is the recovery reel. The wire 1 supplied from the first reel 210 travels through the third guide pulley 250, the tension pulley 300, the first guide pulley 230, and the second guide pulley 240. The wire 1 is then recovered by the second reel 220. The object 900 is pressed against the wire 1 between the first guide pulley 230 and the second guide pulley 240. As the wire 1 travels in this state, the object 900 is cut.

[0038] Tension pulley 300 is provided between third guide pulley 250 and first guide pulley 230. Tension pulley 300 adjusts the tension of wire 1. Tension pulley 300 is attached to arm 320 supported by rotary shaft 310. In the example of FIG. 3, when arm 320 rotates clockwise on the page, the tension increases. Conversely, when arm 320 rotates counterclockwise, the tension decreases. This tension adjustment operation is controlled by tension control unit 600.

[0039] The stage 400 holds the object 900. The object 900 is fixed to the stage 400 by, for example, suction or screwing. In this embodiment, the travel path of the wire 1 between the first guide pulley 230 and the second guide pulley 240 when the object 900 is not present is defined as a "reference line." The stage 400 can be moved in a direction perpendicular to this reference line by a movement mechanism (not shown). For example, a ball screw or a linear motor is used as the movement mechanism. The stage 400 then feeds the object 900 in a direction that presses the object 900 against the wire 1. Through this operation, the stage 400 adjusts the position of the object 900 and the feed speed in the direction of the wire 1. The feed speed is controlled by a feed speed control unit 700.

[0040] The bending state detection sensor 500 detects the degree of bending of the wire 1 relative to a reference line as the bending state. A specific example of the bending state detection sensor 500 will be described later.

[0041] The tension control unit 600 controls the tension based on the bending state. Specifically, the tension control unit 600 controls the tension by controlling the rotation of the arm 320.

[0042] The feed speed control unit 700 controls the feed speed of the workpiece 900 by controlling the feed speed of the stage 400. Specifically, the feed speed control unit 700 controls the feed speed by controlling the movement mechanism.

[0043] Next, a specific example of the bending state detection sensor will be described. FIG. 4 is a schematic diagram showing a first specific example of the bending state detection means of the second embodiment. The bending state detection sensor 500 of the first specific example includes an optical sensor 501. The optical sensor 501 optically detects the wire 1. The optical sensor 501 is disposed, for example, on the feed direction side of the workpiece 900 and a few millimeters away from the reference line. When the workpiece 900 is separated from the wire 1 as shown in the left side of FIG. 4, the wire 1 travels along the reference line. At this time, the wire 1 is not detected by the optical sensor 501. On the other hand, when the workpiece 900 is pressed against the wire 1 as shown in the right side of FIG. 4, the wire 1 is curved so as to be convex toward the feed direction side relative to the reference line. In this state, the wire 1 is detected by the optical sensor 501. In this way, the bending state detection sensor 500 detects the bending state of the wire 1. Furthermore, if the degree of curvature increases further as cutting progresses, the optical sensor 501 will no longer detect the wire 1. In this case, the tension control unit 600 will determine that "the curved state will be maintained until the optical sensor 501 detects the wire 1 again." The feed speed control unit 700 will also make a similar determination.

[0044] FIG. 5 is a schematic diagram showing a second specific example of the bending state detection means of the second embodiment. The bending state detection sensor 500 of the second specific example includes a roller 502a, an arm 502b, and a displacement sensor 502c. When the workpiece 900 is separated from the wire 1, as shown in the left diagram of FIG. 5, the wire 1 travels along the reference line. At this time, the roller 502a is in contact with the wire 1. However, almost no pressure is applied to the roller 502a, and the displacement sensor 502c does not detect any displacement. On the other hand, when the workpiece 900 is pressed against the wire 1, as shown in the right diagram of FIG. 5, the wire 1 is curved in a convex shape toward the feed direction from the reference line. In this state, the roller 502a is pressed by the wire 1, causing the arm 502b to rotate counterclockwise. As a result, the displacement sensor 502c detects the displacement of the arm 502b. In this way, the bending state detection sensor 500 detects the bending state of the wire 1. Specific displacement sensors that can be used include pressure-sensitive, optical, ultrasonic, and electrical (potentiometer) displacement sensors. The roller 502a is designed to have a high frictional force and be scratch-resistant at the contact point with the wire 1. Specifically, materials such as plastic, rubber, and hard sponge can be used.

[0045] (Example) Next, a specific example of cutting the object 900 by the wire saw 1000 will be described. In each state described below, the wire 1 travels in the length direction of the wire 1. The stage 400 also feeds the object 900 so as to press the object 900 against the wire 1. This causes the cutting to proceed.

[0046] 6 is a schematic diagram showing a first state of an example of the operation of the wire saw of the second embodiment. FIG. 6 shows the relationship between the workpiece 900 and the wire 1 before cutting. In this state, the workpiece 900 and the wire 1 are separated. Therefore, the wire 1 does not bend. The wire 1 runs along a reference line.

[0047] 7 is a schematic diagram showing a second state of the operation example of the wire saw of the second embodiment. Fig. 7 shows the state where the wire 1 touches the workpiece 900. This is the state where cutting has started. In this state, the wire 1 is not curved.

[0048] 8 is a schematic diagram showing a third state of an example of the operation of the wire saw of the second embodiment. FIG. 8 shows a state where cutting has started. As shown in the figure, the wire 1 is bent. However, at this stage, the bend state detection sensor 500 has not detected the bend. The threshold value of the bend for detecting the bend can be set arbitrarily by the user.

[0049] 9 is a schematic diagram showing a fourth state of an example of operation of the wire saw of the second embodiment. Fig. 9 shows a state in the middle of cutting. As shown in the figure, the wire 1 is curved. The curved state detection sensor 500 detects the curve.

[0050] Fig. 10 is a schematic diagram showing a fifth state of an example of operation of the wire saw of the second embodiment. Fig. 9 shows a state in the middle of cutting. As cutting progresses, the curvature of the wire 1 increases. At this time, if the curvature state detection sensor 500 is an optical type that optically detects the wire 1, the wire 1 will not be detected. On the other hand, if the curvature state detection sensor is a displacement sensor, an increase in curvature will be detected.

[0051] FIG. 11 is a schematic diagram showing a sixth state of an example of the operation of the wire saw of the second embodiment. FIG. 10 shows the state at the end of cutting. At this point, the curvature detection sensor 500 detects the curvature. In this example, this is because the curvature of the wire 1 becomes smaller at the end of cutting. Also, the end of the workpiece 900 has advanced further in the feed direction than the reference line. In this state, the feed speed control unit 700 ends the feed of the stage 400. In this embodiment, the position of the workpiece 900 at this time becomes the feed stop position. Also, the location of this feed stop position is arbitrary, but for example, the feed stop position is set several mm in the feed direction from the reference line.

[0052] 12 is a schematic diagram showing a seventh state of the operation example of the wire saw of the second embodiment. As the wire 1 continues to travel from the state shown in FIG. 10 in which the feeding of the workpiece 900 has stopped, the curvature of the wire 1 decreases. Then, at a certain point, the degree of curvature becomes less than the first threshold. When the degree of curvature becomes less than the first threshold, the tension control unit 600 performs control to reduce the tension.

[0053] Figure 13 is a schematic diagram showing an eighth state of the operation example of the wire saw of the second embodiment. Figure 13 shows the state in which cutting of the object 900 is completed. At this time, the path of the wire 1 has returned to the reference line. By reducing the tension from the state in Figure 12, scattering of the object 900 is prevented when cutting of the object 900 is completed.

[0054] Next, specific control timing will be described. FIG. 14 is an example of a timing chart for the wire saw of the second embodiment. FIG. 14 illustrates a case where the curvature detection sensor 500 is an optical sensor 501. First, at time t1, the wire 1 starts traveling at a predetermined tension and a predetermined traveling speed. Next, at time t2, the stage 400 starts feeding the workpiece 900. When cutting begins, the wire 1 bends. Then, at time t3, the degree of curvature exceeds a first threshold, and the curvature detection sensor 500 detects the curvature. As cutting progresses, the curvature increases, and at time t4, the wire 1 is no longer detected by the optical sensor. As cutting progresses further, at time t5, the end of the workpiece 900 reaches the feed stop position. At this point, feeding is stopped. As the wire 1 continues traveling, the curvature of the wire 1 decreases. Therefore, at time t6, the optical sensor 501 again detects the wire 1. At this point, the tension control unit 600 reduces the tension. As the cutting progresses further, the curvature of the wire 1 falls below the first threshold, and at time t7, the curvature is no longer detected. The wire 1 continues to travel until time t8, after a specified time has elapsed, whereby the cutting of the workpiece 900 is completed.

[0055] 15 is another example of a timing chart of the wire saw of the second embodiment. FIG. 15 shows an example in which the bending state detection sensor 500 is provided with a displacement sensor 502c. First, at time t 11 At time t, the wire 1 starts to travel at a predetermined tension and a predetermined traveling speed. 12 At time t 13 At time t, the degree of curvature exceeds the first threshold, and the curvature state detection sensor 500 detects the curvature. In this example, the intermediate degree of curvature is assumed to be constant. As the cutting progresses further, at time t 14 At this time, the end of the workpiece 900 reaches the feed stop position. At this point, the feed is stopped. As the wire 1 continues to travel, the curvature of the wire 1 decreases. Then, at time t 15 At time t 16 The tension control unit 600 reduces the tension until the specified time elapses, and the wire 1 continues to travel until time t17, whereby cutting of the workpiece 900 is completed.

[0056] FIG. 16 is a flowchart showing the operation of the wire saw 1000 of the second embodiment. First, the wire saw 1000 runs the wire 1 between the first guide pulley 230 and the second guide pulley 240 (S101). Next, the stage 400 feeds the workpiece 900 in a direction pressing it against the wire 1 (S102). This operation progresses the cutting of the workpiece 900. Next, the bend state detection sensor 500 detects the bend state of the wire 1 (S103). Next, the cutting of the workpiece 900 progresses, and the end of the workpiece 900 reaches a feed stop position (S104). When the end of the workpiece 900 reaches the feed stop position, the stage 400 stops the feed (S105). As the cutting progresses further, the degree of curvature gradually decreases. Then, the tension control unit 600 compares the degree of curvature with a first threshold value (S106). If the degree of curvature is less than the first threshold (S106_Yes), the tension control means 6 reduces the tension of the wire 1 (S107). Then, the wire saw 1000 continues running the wire 1 for a specified time (S108). This completes cutting of the workpiece 900. On the other hand, if the curvature is equal to or greater than the first threshold in S106 (106_No), the process returns to S106 after a predetermined time, and it is determined whether the curvature of the wire 1 has become less than the first threshold.

[0057] In the above operation, when cutting of the object 900 is completed, feeding of the object 900 is stopped. In parallel with this, the tension of the wire 1 is reduced. Due to these operations, the wire saw 1000 of this embodiment prevents the object 900 from scattering when cutting of the object 900 is completed.

[0058] FIG. 17 is a schematic diagram showing a specific example of the object to be cut in the second embodiment. In this specific example, the object to be cut 900 is a component. The object to be cut 900 is mounted on a circuit board 910. In addition, a component A_911, a component B_912, and a component C_913 are mounted on the circuit board 910. These components are adhered to the circuit board with a thermosetting resin or the like. For this reason, the object to be cut 900 cannot be removed without destroying the circuit board 910. Furthermore, each component is very expensive. Here, it is assumed that only the object to be cut 900 breaks down and needs to be replaced.

[0059] In such a case, the wire saw 1000 of this embodiment is used. That is, the wire saw 1000 is used to cut and remove only the object 900 parallel to the surface of the circuit board 910. At this time, with a normal wire saw, the object 900 may fly off and destroy other components. On the other hand, with the wire saw 1000 of this embodiment, the object 900 does not fly off during cutting. Therefore, with the wire saw 1000, other components are not destroyed when the object 900 is cut.

[0060] (Variation) Next, a modified example of the wire saw 1000 of the second embodiment will be described. Fig. 18 is a schematic diagram showing a modified example of the wire saw of the second embodiment. In addition to the configuration of the wire saw 1000, the modified wire saw 1001 includes an upper limit bend detection sensor 510 on the feed direction side of the bend state detection sensor 500. The other configuration is the same as that of the wire saw 1000.

[0061] The upper limit bend detection sensor 510 detects the upper limit of bend to prevent the wire 1 from being bent too much. The upper limit bend detection sensor 510 is provided a predetermined distance in the feed direction from the bent state detection sensor 500. The predetermined distance is, for example, several mm. The upper limit bend detection sensor 510 has the same structure as the bent state detection sensor 500. The upper limit bend detection sensor 510 detects the presence of the wire 1. The upper limit of the degree of bend is the second threshold value.

[0062] In this modification, the bending state detection sensor 500 functions as a sensor that detects the lower limit of bending. That is, it is a lower limit bending detection sensor. The lower limit bending degree is the first threshold value.

[0063] When cutting of the workpiece 900 is completed, the wire saw 1001 performs the same operation as the wire saw 1000 to prevent the workpiece 900 from scattering. However, there is a difference in the control of the feed rate in the middle of cutting.

[0064] The operation of the wire saw 1001 of the modified example will be described below using a specific example. Fig. 19 is a schematic diagram showing a first state of an operation example of the modified example of the second embodiment. In this state, the workpiece 900 and the wire 1 are separated. Therefore, the wire 1 is not bent and travels along the reference line. In this state, the bend state detection sensor 500 does not detect the wire 1. Furthermore, the upper limit bend detection sensor 510 does not detect the wire 1.

[0065] 20 is a schematic diagram showing a second state of an operation example of the modified example of the second embodiment. In this state, the wire 1 is bent further than the position of the bent state detection sensor 500. Also, the wire 1 is not bent further than the position of the upper limit bend detection sensor 510. In other words, the degree of bending of the wire 1 is maintained within an appropriate range.

[0066] 21 is a schematic diagram showing a third state of an operation example of a modified example of the second embodiment. In this state, the curvature of the wire 1 has reached the upper limit curvature detection sensor 510. In other words, in this state, the curvature of the wire 1 is too large. If the curvature is too large, the load on the wire 1 becomes too large, increasing the possibility of the wire being broken. For this reason, the wire saw 1001 performs control to reduce the curvature. This control is performed by the feed speed control unit 700 to reduce the feed speed of the stage 400.

[0067] 22 is a schematic diagram showing a fourth state of an operation example of a modified example of the second embodiment. In this state, the bent state detection sensor 500 does not detect the wire 1. Also, the upper limit bend detection sensor 510 does not detect the wire 1. In other words, the bend of the wire 1 is too small. In this state, the feed speed is too slow, resulting in poor cutting efficiency. Therefore, the feed speed control unit 700 controls the feed speed to increase.

[0068] Fig. 23 is a flowchart showing the operation of a modified example of the second embodiment. The flowchart in Fig. 23 is almost the same as the flowchart in Fig. 16 showing the operation of the wire saw 1000. However, in the wire saw 1000, the feed speed is controlled from when the curvature of the wire 1 is detected until the workpiece 900 reaches the feed stop position.

[0069] First, the wire saw 1001 runs the wire 1 between the first guide pulley 230 and the second guide pulley 240 (S201). Next, the stage 400 feeds the workpiece 900 in a direction pressing it against the wire 1 (S202). This operation progresses the cutting of the workpiece 900. Next, the bent state detection sensor 500 detects the bent state of the wire 1 (S203). Next, while the workpiece 900 is being cut, the feed speed is controlled based on the bent state (S204). This control will be described in detail later. Next, the cutting of the workpiece 900 progresses, and the end of the workpiece 900 reaches a feed stop position (S205). When the end of the workpiece 900 reaches the feed stop position, the stage 400 stops the feed (S206). As the cutting further progresses, the degree of curvature gradually decreases. Then, the tension control unit 600 compares the degree of curvature with a first threshold value (S207). If the degree of curvature is less than the first threshold value (S207_Yes), the tension control unit 600 reduces the tension of the wire 1 (S208). Then, the wire saw 1001 continues running the wire 1 for a specified time (S209). This completes cutting of the workpiece 900. On the other hand, if the curvature is equal to or greater than the first threshold value in S207 (S207_No), the process returns to S207 after a predetermined time has elapsed, and it is determined whether the curvature of the wire 1 has become less than the first threshold value.

[0070] FIG. 24 is a flowchart showing the details of the operation of a modified example of the second embodiment. The flowchart in FIG. 24 shows details of S204 in the flowchart in FIG. 23. First, it is determined whether the bending state detection sensor 500 has detected the wire 1. That is, the feed speed control unit 700 determines whether bending equal to or greater than the lower limit has been detected (S2041). If bending equal to or greater than the lower limit has not been detected, the feed speed control unit 700 controls to increase the feed speed (S2042). On the other hand, if bending equal to or greater than the lower limit has been detected (S2041_Yes), it is determined whether the bending has reached the upper limit (S2043). If the bending has not reached the upper limit (S2043_No), the feed speed is maintained (S2044) and the process ends. On the other hand, if the bending has reached the upper limit in S2043 (S2043_Yes), the feed speed control unit 700 stops the feeding (S2045). The stoppage is maintained for the specified time. Next, the feed speed control unit 700 determines whether the curvature is below the upper limit (S2046). If the curvature is below the upper limit (S2046_Yes), the feed speed control unit 700 reduces the feed speed and restarts feeding (S2047). Then, the process returns to S2041. On the other hand, if the curvature is above the upper limit (S2046_No) in S2046, the process returns to S3045, where the feed is again stopped for the specified time. Through the above operations, an appropriate feed speed can be set that does not place an excessive load on the wire 1 and that provides good cutting efficiency.

[0071] The wire saw 1000 and the like according to this embodiment have been described above.

[0072] The wire saw 1000 includes the same wire 1 as in the first embodiment. Abrasive grains such as diamond are attached to the surface of the wire 1. The wire saw 1000 cuts the workpiece 900 by bringing the wire 1 into contact with the workpiece 900 and running the wire 1. The wire saw 1000 also includes a first reel 210, a second reel 220, a first guide pulley 230, a second guide pulley 240, and a third guide pulley 250 as specific examples of the wire running means 2 of the first embodiment. The wire saw 1000 also includes a tension pulley 300, a rotation shaft 310, and an arm 320 as specific examples of the tension adjusting means 3 of the first embodiment. The wire saw 1000 also includes a stage 400 as a specific example of the workpiece feeding means 4 of the first embodiment. The wire saw 1000 also includes a bending state detection sensor 500 as a specific example of the bending state detection means 5 of the first embodiment. The wire saw 1000 also includes a tension control unit 600 as a specific example of the tension control means 6 of the first embodiment. The wire saw 1000 also includes a feed speed control unit 700 as a specific example of the feed speed control means 7 of the first embodiment.

[0073] In the above configuration, the tension of the wire 1 is controlled based on the curved state of the wire 1. Furthermore, the feed speed of the workpiece 900 is controlled based on the curved state of the wire 1. In this configuration, when cutting of the workpiece 900 is completed, the tension of the wire 1 and the feed speed of the workpiece are controlled based on the curved state. Therefore, in the wire saw 1000, it is possible to perform control to prevent the workpiece from scattering when cutting is completed.

[0074] According to another embodiment, when the degree of curvature in the curved state of the wire 1 is equal to or greater than a first threshold, the curved state detection means 5 detects the curvature of the wire 1. By setting the first threshold for detecting the curvature, the timing of control of the feed speed and the tension before and after cutting of the workpiece 900 is completed can be appropriately set.

[0075] According to another embodiment, the position of the wire 1 when the workpiece 900 is not in contact with the wire 1 is set as the reference line. A feed stop position is also set. The feed stop position is a position where the cutting end position of the workpiece 900 is separated from the reference line by a first distance in the direction in which the workpiece is fed. Then, when the cutting end feed stop position of the workpiece 900 is reached, the workpiece feeding means 4 is stopped. Therefore, when cutting of the workpiece 900 is completed, the wire saw 1000 is controlled to prevent the workpiece 900 from scattering.

[0076] According to one embodiment, the tension is reduced in the following cases: That is, when the position of the cutting end of the object 900 reaches the feed stop position and the degree of curvature of the wire 1 becomes within a first threshold, the tension of the wire 1 is reduced. In this operation, the tension of the wire 1 is reduced when cutting of the object 900 is completed. Therefore, the wire saw 1000 is controlled to prevent the object 900 from scattering when cutting of the object 900 is completed.

[0077] According to another embodiment, when the degree of curvature of the wire 1 reaches or exceeds a second threshold value that is greater than the first threshold value, the workpiece feeding means 4 is stopped for a specified time. This operation enables the wire saw 1000 to prevent excessive load from being applied to the wire 1.

[0078] According to one embodiment, when the degree of curvature of the wire 1 becomes less than the first threshold, the feed speed control unit 700 increases the feed speed. This operation increases the cutting speed of the wire saw 1000. As a result, the cutting efficiency improves.

[0079] According to one embodiment, the bending state detection means 5 of the wire saw 1000 includes an optical sensor 501 that optically detects the wire 1. The optical sensor 501 can optically detect the bending of the wire 1.

[0080] According to another embodiment, the bending state detection means 5 of the wire saw 1000 includes a displacement sensor 502c that detects the degree of bending of the wire 1 by displacement. The displacement sensor 502c can detect the bending of the wire 1 based on the displacement.

[0081] In the wire saw control method of this embodiment, the wire saw 1000 runs the wire in the longitudinal direction while keeping the wire tensioned. The wire saw 1000 also adjusts the tension of the wire 1. The wire saw 1000 also feeds the workpiece 900 in a direction pressing it against the wire 1. The wire saw 1000 also detects the curvature of the wire. The wire saw 1000 also adjusts the tension of the wire 1 based on the curvature of the wire 1. The wire saw 1000 also adjusts the feed speed of the workpiece 900 based on the curvature of the wire 1. Through these operations, in the wire saw control method of this embodiment, the wire saw 1000 is controlled to prevent the workpiece 900 from scattering when cutting of the workpiece 900 is completed.

[0082] The control program for the wire saw of this embodiment also causes the wire saw 1000 to execute the following processes. The processes include running the wire 1 in the longitudinal direction while keeping the wire 1 tensioned. The processes also include adjusting the tension of the wire 1. The processes also include feeding the object 900 in a direction pressing it against the wire 1. The processes also include detecting the curved state of the wire 1. The processes also include adjusting the tension of the wire 1 based on the curved state of the wire 1. The processes also include adjusting the feed speed of the object 900 based on the curved state of the wire 1. With the above configuration, the control program for the wire saw controls the wire saw 1000 to prevent the object 900 from scattering when cutting of the object 900 is completed.

[0083] The scope of the present invention also includes a program for causing a computer to execute the processing of the first or second embodiment described above, and a recording medium storing the program. Examples of recording media that can be used include a magnetic disk, a magnetic tape, an optical disk, a magneto-optical disk, and a semiconductor memory.

[0084] The present invention has been described above using the first and second embodiments as exemplary examples. However, the present invention is not limited to the above embodiments. In other words, the present invention can be applied in various aspects that are understandable to those skilled in the art within the scope of the present invention. [Explanation of symbols]

[0085] 1 wire 2. Wire running means 3 Tension adjustment means 4. Material feeding means 5. Curvature detection means 6 Tension control means 7 Feed rate control means 10, 1000, 1001 wire saw 210 First Reel 220 Second Reel 230 First guide pulley 240 Second guide pulley 250 Third guide pulley 300 tension pulley 310 Rotational Axis 320 Arm 400 stages 500 Curvature detection sensor 600 Tension control section 700 Feed speed control unit 900 Object to be cut

Claims

1. a wire running means for running the wire in a longitudinal direction while the wire is tensioned; a tension adjusting means for adjusting the tension of the wire; a workpiece feeding means for feeding the workpiece in a direction pressing the workpiece against the wire; a bending state detection means for detecting a bending state of the wire; a tension control means for controlling the tension adjusting means to adjust the tension of the wire based on the bent state of the wire; a feed speed control means for controlling the workpiece feeding means to adjust the feed speed of the workpiece based on the bent state of the wire; Equipped with When the degree of bending in the bent state is equal to or greater than a first threshold, the bent state detection means detects the bending of the wire, a travel path of the wire when the wire is not in contact with the workpiece is defined as a reference line; When the position of the cutting end of the workpiece reaches a feed stop position in the direction in which the workpiece is fed by a first distance from the reference line, the feed speed control means stops the workpiece feeding means, the tension control means reduces the tension when the cutting end of the workpiece is at a feed stop position and the degree of curvature of the wire falls within the first threshold value; A wire saw characterized by:

2. When the degree of bending of the wire becomes equal to or greater than a second threshold value that is greater than the first threshold value, the feed speed control means stops the workpiece feeding means for a specified time. The wire saw according to claim 1 .

3. The feed speed control means increases the feed speed when the degree of curvature of the wire becomes less than the first threshold value until the position of the end of cutting of the workpiece reaches the feed stop position.

3. The wire saw according to claim 2.

4. The bending state detection means an optical sensor for optically detecting the wire; 4. The wire saw according to claim 1, wherein the cutting edge is a slit.

5. The bending state detection means A displacement sensor is provided to detect the degree of bending of the wire by displacement.

4. The wire saw according to claim 1, wherein the cutting edge is a slit.

6. The wire is run in the longitudinal direction while being tensioned, adjusting the tension of the wire; The object to be cut is fed in a direction in which it is pressed against the wire. Detecting a bent state of the wire when the degree of bending of the wire is equal to or greater than a first threshold; controlling a feed speed of the workpiece based on the bending state of the wire; a travel path of the wire when the wire is not in contact with the workpiece is defined as a reference line; In the control of the feed speed, when a cutting end position of the object to be cut reaches a feed stop position in a direction in which the object to be cut is fed by a first distance from the reference line, feeding of the object to be cut is stopped; reducing the tension when the cutting end of the workpiece is at a feed stop position and the degree of bending of the wire is within the first threshold value; A method for controlling a wire saw.

7. a process of running the wire in a longitudinal direction while the wire is tensioned; adjusting the tension of the wire; a process of feeding the workpiece in a direction in which the workpiece is pressed against the wire; a process of detecting a bent state of the wire when the degree of bending of the wire is equal to or greater than a first threshold; a process of controlling the tension of the wire based on the bending state of the wire; a process of controlling a feed speed of the workpiece based on a curved state of the wire; The wire saw is then caused to execute the above. A travel path of the wire when the wire is not in contact with the workpiece is used as a reference line; In the process of controlling the feed speed, when a cutting end position of the object to be cut reaches a feed stop position in a direction in which the object to be cut is fed by a first distance from the reference line, feeding of the object to be cut is stopped; In the process of controlling the tension, the tension is reduced when the cutting end of the workpiece is at a feed stop position and the degree of curvature of the wire is within the first threshold value. A wire saw control program comprising:

Images