Wire saw

Abstract

To provide a wire saw that is configured so as to make force acting on a work-piece feeding mechanism constant even if cutting resistance at the time of cutting a work-piece varies.SOLUTION: A wire saw 1 comprises: a wire 54 that cuts a work-piece W; a plurality of rollers 52 for processing around which the wire 54 is wound; a work-piece feeding mechanism 7 that feeds the work-piece W in a cutting direction in which the work-piece is cut with respect to the wire 54; and a balancer 8 that holds the work-piece feeding mechanism 7. The balancer 8 applies, to the work-piece feeding mechanism 7, force in a direction in which reaction force generated when the wire 54 cuts the work-piece W, own weight of a movable part of the work-piece feeding mechanism 7 and own weight of the work-piece W are offset.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wire saw equipped with a work feeding mechanism.

Background Art

[0002] Generally, a wire saw that cuts a work such as a semiconductor material or a magnetic material with a wire cuts the work by feeding the work in a cutting direction by a work feeding device while supplying a processing liquid to the wire.

[0003] Generally, the work feeding mechanism of a wire saw includes a guide rail, a nut member provided on a work feeding table, a rod screw screwed into the nut member, and a drive motor that rotationally drives the rod screw to raise and lower the work feeding table (see, for example, Patent Document 1).

[0004] The work formed by cutting becomes a thin semiconductor wafer, and thus is required to be cut with high precision. The shape of the semiconductor wafer is determined by the relative displacement between the work and the wire. For this reason, since the straightness of the work feeding mechanism is transferred to the wafer, high precision and high rigidity are required.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the wire saw described in Patent Document 1 and in general wire saws, due to the cutting resistance during processing, a reaction force is generated on the work feed mechanism, causing the machine to deform. This reaction force always changes depending on the size of the work, the size of the cross-sectional area, and the change in machining cuttability. For this reason, in a wire saw, it has been desired to have a work feed mechanism that does not deform due to the cutting resistance even when the cutting resistance changes.

[0007] Therefore, an object of the present invention is to provide a wire saw that can keep the force applied to the work feed mechanism constant even when the cutting resistance during the cutting process of the work changes.

Means for Solving the Problems

[0008] To solve the above problems, a wire saw according to the present invention includes a wire for cutting a work, a plurality of processing rollers around which the wire is wound, a work feed mechanism for feeding the work in the cutting direction for cutting the work with respect to the wire, and a balancer for holding the work feed mechanism. The cylinder device constituting the balancer, a control valve for varying the pressure of the fluid supplied to the cylinder device, and a controller capable of arbitrarily setting a command value for the control valve of the pressure of the fluid supplied to the cylinder device according to the cutting position of the workpiece The balancer applies a force in a direction that cancels out the reaction force generated when cutting the work with the wire, the weight of the movable part of the work feed mechanism, and the weight of the work, to the work feed mechanism. and, when cutting the workpiece with the wire, the controller controls the force in a direction that cancels out the reaction force generated when cutting the workpiece, the self-weight of the movable part of the workpiece feeding mechanism, and the self-weight of the workpiece, by varying the command value for the control valve of the pressure of the fluid supplied to the cylinder device It is characterized by this.

Effects of the Invention

[0009] According to the present invention, it is possible to provide a wire saw that can keep the force applied to the work feed mechanism constant even when the cutting resistance during the cutting process of the work changes.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] The wire saw according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In the present embodiment, with respect to the work feed table 61 of the clamp device 6 shown in FIG. 1, the direction in which the work feed table 61 faces forward, the rear direction of the work feed table 61 is rear, the vertically upward side is up, the vertically downward side is down, the left direction in FIG. 2 is left, and the right direction in FIG. 2 is right, and the description will be made as appropriate.

[0012] First, before describing the wire saw 1, the work W used for the wire saw 1 will be described. Further, as shown in FIG. 3, since the main part of the wire saw 1 is formed substantially symmetrically about the left and right, one of them will be described as appropriate and the description of the other will be omitted.

[0013] <Work> As shown in FIG. 1, the work W is made of a brittle material such as a semiconductor material, a magnetic material, or a ceramic. The work W is attached to the work holding portion 63 of the clamp device 6 and is cut and severed by being pressed against the wire 54 of the processing device 5 arranged on the wire saw 1.

[0014] <Wire saw> The wire saw 1 is a cutting device that cuts the work W by the wire 54 of the processing device 5. As shown in FIG. 1, the wire saw 1 mainly includes a base (not shown), a column 3, a saddle 4, a processing device 5, a clamp device 6, a work feed mechanism 7, a control valve 90, and a controller 10.

[0015] <Base> The base (not shown) is a base that holds the column 3 and the processing device 5 from below. The base (not shown) is arranged over the entire lower end portion of the wire saw 1.

[0016] <Column> Column 3 is a columnar member that stands on a base (not shown) and constitutes the machine body of the wire saw 1. Inside column 3, a saddle 4, a work feed mechanism 7, and a balancer 8 are provided.

[0017] <Saddle> As shown in FIG. 1, saddle 4 is a vertical feed base arranged to be movable in the vertical direction with respect to column 3. On the front surface of saddle 4, a clamping device 6 for clamping work W is supported. Saddle 4 is provided with a work feed mechanism 7 for feeding work W in the cutting direction for cutting work W with respect to wire 54, and a balancer 8 that holds work feed mechanism 7.

[0018] <Processing device> Processing device 5 is a cutting mechanism for processing unprocessed work W clamped in the work holding portion 63 of clamping device 6. Processing device 5 includes a pair of processing rollers 51, 52 arranged to face each other in the horizontal direction at appropriate intervals, a wire 54 for cutting work W wound around processing roller 51 and processing roller 52, a drive motor (not shown) for rotationally driving processing rollers 51, 52, and a bracket 55. Processing device 5 is installed on a base (not shown) via bracket 55 in the vicinity of column 3.

[0019] Work W is composed of a plurality of pieces arranged side by side along the axial direction of processing rollers 51, 52 (in the attached drawings, it is omitted and only one is shown). During the operation of wire saw 1, wire 54 runs between processing rollers 51, 52, and work W held by clamping device 6 is lowered toward processing device 5 by work feed mechanism 7 and pressed against wire 54 to be cut.

[0020] The processing rollers 51 and 52 are configured to run the wire 54 only between the processing rollers 51 and 52 that are rotated by a drive motor (not shown) and driven via a transmission mechanism (not shown) including a pulley and a belt. The processing rollers 51 and 52 may be at least a pair, and may be three or more as long as they are arranged in parallel with a space therebetween.

[0021] The wire 54 is, for example, a processing wire formed of a single wire rod. The wire 54 is driven by the processing rollers 51 and 52 to repeatedly move forward and backward by a certain amount, and thus move forward step by step as a whole or continuously move forward in one direction.

[0022] <Clamping device> As shown in FIG. 1, the clamping device 6 is a holding mechanism for clamping the workpiece W when the workpiece W is processed by the processing device 5. The clamping device 6 holds the workpiece W until it clamps the unprocessed workpiece W, presses the workpiece W against the wire 54 of the processing device 5 for processing, and then unclamps the workpiece W after the processing is completed. The clamping device 6 includes a workpiece holding portion 63 that holds the workpiece W, a clamping portion 62 that clamps the workpiece holding portion 63, and a workpiece feed table 61 that moves the workpiece holding portion 63 and the clamping portion 62 up and down by a workpiece feed mechanism 7.

[0023] <Workpiece feed mechanism> The workpiece feed mechanism 7 is a transfer device for moving the workpiece W between a processing position where the workpiece W is cut by the wire 54 and a workpiece exchange position where the processed workpiece W and the unprocessed workpiece W are exchanged. Further, the workpiece feed mechanism 7 also functions as a lifting device for lifting and lowering the workpiece W when the workpiece W is processed. The workpiece feed mechanism 7 is composed of a linear motor 70.

[0024] <Linear motor> As shown in FIG. 1, the linear motor 70 is a drive source for moving the saddle 4 in the vertical direction. The linear motor 70 mainly includes a base 75, a stator 74 fixed to the base 75 and having a permanent magnet 73, and a mover 72 provided so as to be relatively movable with respect to the stator 74 and having an armature winding 71. The linear motor 70 is configured such that the mover 72 is driven when an alternating current is supplied from a power supply device (not shown) to the armature winding 71. At this time, since the armature winding 71 generates heat, a cooling device (not shown) for cooling the heat is disposed in contact with the armature winding 71. The stator 74 is fixed to the base 75, and the mover 72 is disposed on the saddle 4. The base 75 is connected to the column 3. The linear motor 70 is electrically connected to a power supply (not shown) via the controller 10.

[0025] <Balancer> As shown in FIG. 1, the balancer 8 is a device that applies a force in a direction that cancels out the weight of the saddle 4, the weight of the movable part of the work feed mechanism 7, and the reaction force (processing resistance) generated when the work W is cut with the wire 54, and controls and supports the saddle 4 at an appropriate position. The balancer 8 mainly includes a cylinder device 80. Further, as a specific example, the balancer 8 includes a cylinder device 80, a control valve 90, a controller 10, and a cylinder pump P1 of a cylinder hydraulic unit (not shown). The balancer 8 is controlled by the controller 10 so as to move in synchronization with the linear motor 70.

[0026] <Cylinder device> As shown in FIGS. 1 and 3, the cylinder device 80 is a device that supports the weight of the work feed mechanism 7 and the like that move in the vertical direction and cancels it out. The cylinder device 80 includes a cylinder 81, a piston rod 83, and a saddle connecting member 84. The cylinder device 80 supports the saddle 4 by operating a piston (not shown) with oil sent from a cylinder hydraulic unit (not shown) via the control valve 90.

[0027] Inside the cylinder 81, a piston (not shown) and a piston rod 83, and oil supplied from a cylinder hydraulic unit (not shown) via a control valve 90 are accommodated. The cylinder 81 is attached to a saddle 4 that supports a clamp device 6 for holding the work W. The cylinder 81 is connected to a cylinder pump P1 of a cylinder hydraulic unit (not shown) via the control valve 90. The pressure of the oil supplied to the cylinder 81 can be arbitrarily set by the controller 10 according to the self-weight of the saddle 4, the self-weight of the mover 72 of the linear motor 70, and the machining resistance when machining the work W (see FIG. 1).

[0028] The piston rod 83 has its lower end integrally fixed to a piston (not shown), and a saddle connecting member 84 is connected to its upper end.

[0029] The saddle connecting member 84 is a member that connects the upper end of the piston rod 83 and the upper end of the saddle 4 to enable the saddle 4 to move up and down by the cylinder device 80. The cylinder device 80 supports the saddle 4 by raising and lowering the cylinder 81 with the hydraulic pressure of the oil.

[0030] The control valve 90 is a control valve for driving a piston 82 that varies the pressure of the oil supplied to the cylinder 81 of the balancer 8. The control valve 90 is connected between the cylinder pump P1 of the cylinder hydraulic unit and the cylinder 81. The cylinder pump P1 of the cylinder hydraulic unit is a pump that generates hydraulic pressure for driving the cylinder 81 forward and backward and discharges oil into the cylinder 81. The control valve 90 and the cylinder pump P1 have a function of varying the pressure of the oil supplied to the cylinder 81 according to the self-weight of the saddle 4, the self-weight of the mover 72 of the linear motor 70, and the machining resistance when machining the work W (see FIG. 1). The control valve 90 consists of a proportional electromagnetic pressure reducing valve and is driven by the controller 10.

[0031] <Controller> The controller 10 is a control device having a function of arbitrarily setting a command value to the control valve 90 for the pressure of the oil supplied to the cylinder 81 of the balancer 8 according to the cutting position of the work W. Further, as described above, the controller 10 also has a function of driving the control valve 90 and the cylinder pump P1 according to the dead weight of the saddle 4, the dead weight of the mover 72 of the linear motor 70, and the machining resistance when machining the work W (see FIG. 1). That is, when cutting the work W with the wire 54, the controller 10 changes the command value to the control valve 90 for the pressure of the fluid supplied to the cylinder device 80, thereby controlling the force in the direction that cancels the reaction force generated during the cutting process of the work W and the dead weight of the movable part of the work feeding mechanism 7, and keeping the deformation amount of the machine constant.

[0032] Note that the reaction force generated during cutting always changes depending on the size, material, cutting area of the work W, and the sharpness of the wire 54 used.

[0033] [Operation] Next, the operation of the wire saw 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3.

[0034] As shown in FIG. 1, first, the work W is attached to the work holding part 63. By driving the linear motor 70 to lower the work W, it is pressed against the wire 54 of the processing device 5 to cut the work W.

[0035] The balancer 8 can cancel the dead weight of the saddle 4, the dead weight of the movable part of the work feeding mechanism 7, and the machining resistance when machining the work W, and support it in a stable state. Therefore, the balancer 8 can reduce the load lifted by the linear motor 70, so that the linear motor 70 can be miniaturized.

[0036] As described above, as shown in FIG. 1, the wire saw 1 according to the embodiment of the present invention includes a wire 54 for cutting a workpiece W, a plurality of processing rollers 52 around which the wire 54 is wound, a workpiece feed mechanism 7 for feeding the workpiece W in the cutting direction for cutting the workpiece W with the wire 54, and a balancer 8 for holding the workpiece feed mechanism 7. The balancer 8 applies a force in a direction that cancels out the reaction force generated when cutting the workpiece W with the wire 54, the weight of the movable part of the workpiece feed mechanism 7, and the weight of the workpiece W, to the workpiece feed mechanism 7.

[0037] According to such a configuration, since the balancer 8 applies a force in a direction that cancels out the reaction force generated when cutting the workpiece W with the wire 54, the weight of the movable part of the workpiece feed mechanism 7, and the weight of the workpiece W, to the workpiece feed mechanism 7, even if the cutting resistance during the cutting process of the workpiece W changes, the force applied to the workpiece feed mechanism 7 can be made constant. Therefore, the present invention can provide a wire saw 1 having a workpiece feed mechanism 7 that does not deform due to cutting resistance even when the cutting resistance changes due to the size of the workpiece W, the size of the cross-sectional area of the workpiece W, or changes in machining cuttability during machining. Thus, the wire saw 1 can keep the force applied to the workpiece feed mechanism 7 constant, and can further machine the workpiece W with high precision.

[0038] Also, as shown in FIG. 1, the wire saw 1 includes a cylinder device 80 that constitutes the balancer 8, a control valve 90 for varying the pressure of the fluid supplied to the cylinder device 80, and a controller 10 capable of arbitrarily setting a command value for the control valve 90 for the pressure of the fluid supplied to the cylinder device 80 according to the cutting position of the workpiece W. The controller 10 controls a force in a direction that cancels out the reaction force generated when cutting the workpiece W with the wire 54, the weight of the movable part of the workpiece feed mechanism 7, and the weight of the workpiece W, by varying the command value for the control valve 90 for the pressure of the fluid supplied to the cylinder device 80 when cutting the workpiece W with the wire 54.

[0039] According to such a configuration, when the controller 10 cuts the workpiece W with the wire 54, it controls the force in a direction that cancels out the reaction force generated during the cutting process of the workpiece W, the weight of the movable part of the workpiece feeding mechanism 7, and the weight of the workpiece W by varying the command value to the control valve 90 for the pressure of the fluid supplied to the cylinder device 80. Therefore, the balancer 8 can reduce the load lifted by the workpiece feeding mechanism 7, so that the workpiece feeding mechanism 7 can be miniaturized, and the entire column 3 can be miniaturized and the cost can be reduced.

[0040] [Modification Example] Note that the present invention is not limited to the above-described embodiment, and various modifications and changes are possible within the scope of its technical idea. Naturally, the present invention also extends to these modified and changed inventions. Hereinafter, the configurations already described will be denoted by the same reference numerals and their descriptions will be omitted. FIG. 4 is a schematic longitudinal sectional view of a main part showing a modification example of the wire saw according to an embodiment of the present invention. FIG. 5 is an enlarged view of the main part of FIG. 4.

[0041] In the above embodiment, as shown in FIG. 1, the wire saw 1 provided with the linear motor 70 as the workpiece feeding mechanism 7 for moving the workpiece W in the vertical direction has been described as an example, but the present invention is not limited thereto.

[0042] As shown in FIG. 1 or FIG. 4, the workpiece feeding mechanisms 7, 7A may include a linear motor 70 for moving the workpiece W in the vertical direction or a ball screw mechanism 71A for moving the workpiece W in the vertical direction and a motor 70A for driving the ball screw mechanism 71A.

[0043] In this case, as shown in FIG. 4 or FIG. 5, the workpiece feeding mechanism 7A includes a ball screw mechanism 71A composed of a nut portion 72A and a screw shaft portion 73A, a motor 70A, a sensor S1, a saddle 4A for connecting the nut portion 72A to the workpiece feeding table 61 via the sensor S1, and a controller 10 for driving the motor 70A.

[0044] The sensor S1 is a strain sensor that detects a resistance value that changes when the saddle 4A interposed between the nut portion 72A and the work feed table 61 expands and contracts, or a load cell that detects the force (mass, torque) applied to the saddle 4A and converts it into an electrical signal. Therefore, the sensor S1 can detect the load applied to the work feed table 61 and the self-weights of all the movable components in the vertical direction, such as the balancer 8, the work feed mechanism 7A, and the saddle 4A. The sensor S1 is electrically connected to the controller 10.

[0045] The controller 10 can control the balancer 8 according to the reaction force during machining detected by the sensor S1, keep the deformation amount of the machine constant, and maintain the posture of the machine constant. Therefore, even when the cutting resistance during the cutting process of the wire saw 1A changes, the controller 10 can control the value of the sensor S1 to be constant, so that the force applied to the work feed mechanism 7A can be made constant. Thus, the wire saw 1A can further improve the cutting accuracy of the work W.

[0046] The reaction force during machining can also be known from the load factor (motor current value) of the linear motor 70 or the motor 70A that drives the ball screw. The motor 70A controls the position of the clamp device 6. If the machining load is constant, the load factor of the motor 70A will be constant regardless of the position of the clamp device 6. If the load on the motor 70A changes depending on the position of the clamp device 6, the machining load also changes. Therefore, if the balancer 8 is controlled so that the load factor of the motor 70A becomes constant, the force applied to the work feed mechanism 7A will become constant.

[0047] According to such a configuration, as shown in FIG. 1, the work feed mechanism 7 is composed of a linear motor 70, so that the moving permanent magnet 73 moves relative to the stationary armature winding 71 in a non-contact state. Therefore, the linear motor 70 does not wear and deteriorate, so that the movement during cutting can be made smooth. In addition, the wire saw 1 can eliminate the work of maintaining the components of the linear motor 70, and can improve the maintainability. In addition, since the work feed mechanism 7A includes a ball screw mechanism 71A and a motor 70A, the frictional resistance of the ball screw mechanism 71A is low, so the movement during cutting can be made smooth.

Explanation of Signs

[0048] 1, 1A Wire saw 5 Processing device 7, 7A Work feed mechanism 8 Balancer 10 Controller 52 Processing roller 54 Wire 70 Linear motor 70A Motor 71A Ball screw mechanism 80 Cylinder device 90 Control valve W Workpiece

Claims

1. A wire for cutting a workpiece, A plurality of processing rollers around which the wire is wound, A workpiece feeding mechanism for feeding the workpiece in a cutting direction for cutting the workpiece with respect to the wire, A balancer for holding the workpiece feeding mechanism, A cylinder device constituting the balancer, A control valve for varying the pressure of the fluid supplied to the cylinder device, A controller capable of arbitrarily setting a command value to the control valve for the pressure of the fluid supplied to the cylinder device according to the cutting position of the workpiece, comprising: The balancer applies a force in a direction that cancels out a reaction force generated when cutting the workpiece with the wire, the weight of the movable part of the workpiece feeding mechanism, and the weight of the workpiece, to the workpiece feeding mechanism. When cutting the workpiece with the wire, the controller controls the force in a direction that cancels out a reaction force generated when cutting the workpiece, the weight of the movable part of the workpiece feeding mechanism, and the weight of the workpiece, by varying a command value to the control valve for the pressure of the fluid supplied to the cylinder device. A wire saw characterized by the above.

2. The workpiece feeding mechanism includes a linear motor for moving the workpiece in the vertical direction, or a ball screw mechanism for moving the workpiece in the vertical direction and a motor for driving the ball screw mechanism. The wire saw according to claim 1, characterized by the above.

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