JPH09216154A - Driving device and method for grooved roller in wired cutting processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen the life of grooved rollers by driving the rotation of a plurality of grooved roller at the identical torque with respective separate motors. SOLUTION: In the feedback control system of a motor 21, deviation of the rotational speed of the motor 21 which is detected by a tachometer generator 33 from target rotational speed is detected by a subtraction circuit 34. A signal of indicating this deviation is given to a speed amplifier 31, and the output of the speed amplifier 31 is converted into driving current by a current amplifier 32, flowing to the motor 21. When a material to be cut is cut with wire, switches SW1a and SW2a turn ON and switches SW1b and SW2b turn OFF. A torque command generated at the feedback control system of the motor 21 is given to current amplifiers 42, 52. It is thus possible that the rotation of each of three grooved rollers is driven at identical torque by the motors 21, 22 and 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a groove roller driving device and method in a wire type cutting apparatus suitable for cutting a so-called brittle material such as a semiconductor material, a magnetic material or a ceramic into a wafer.

[0002]

2. Description of the Related Art A wire type cutting machine is also called a wire saw, and as shown in FIG. 5 or 6, three groove rollers 61, 62 arranged in parallel with each other at positions corresponding to the vertices of a triangle. And 63. Cutting wires 64 are stretched in parallel in the grooves of the groove rollers 61 to 63 at regular intervals. While the wire 64 is traveling in one direction and a machining liquid containing abrasive grains is sprayed from a nozzle (not shown), the workpiece 70 is pressed against the traveling wire 64 and the workpiece 70 is sliced.

Since the working fluid containing abrasive grains adheres to the wire 64, the grooves of the groove rollers 61 to 63 are also cut by the running of the wire 64. For this reason, it is necessary to periodically correct the groove rollers 61 to 63 and replace them as necessary. Of course, the wire 64 is also replaced if necessary.

Groove rollers 61 to drive the wire 64
One or several of the 63 are rotationally driven. The rotation driving method of the groove roller includes the following.

The drive system shown in FIG. 5 is a one-axis drive system or a two-axis driven system. One groove roller 61 is rotationally driven by the motor 60 via a speed reducer or another power transmission mechanism (not shown). The other two groove rollers 62, 63 are rotatably received by bearings. The rotational driving force of the groove roller 61 is transmitted to the other groove rollers 62 and 63 by the cutting wire 64 hung on the three rollers 61 to 63. The driven groove rollers 62 and 63 are driven by the frictional force with the wire 64.

In this driving method, the driving groove roller 61 is
Therefore, slippage is likely to occur between the groove roller 61 and the wire 64. When slippage occurs, the abrasion caused by the slippage causes the groove notch of the groove roller 61 to increase. Therefore, the life of the driving groove roller 61 is short. Further, the driven rollers 62 and 63 also slip due to the rotational resistance of the bearings, causing the same problem.

The drive system shown in FIG. 6 is a synchronous rotation system. Toothed wheel 65 on each of the shafts of the three groove rollers 61 to 63
Are fixed, and a toothed belt 66 is hung on these toothed wheels 65. One groove roller 61 is driven by the motor 60. The power of the motor 60 is transmitted to the other groove rollers 62 and 63 by the belt 66 and the wheel 65. Transmission of rotational power may be via pulleys and belts, gears and chains, etc.

In this drive system, the three groove rollers 61 to 63 are rotationally driven in synchronization at the same rotational speed. Therefore,
The wires 64 are also required to run synchronously at the same speed. This means that the peripheral speeds of the groove rollers 61 to 63 must be exactly the same, and the groove rollers 61 to 63 are required to have high processing accuracy. Diameter of groove rollers 61-63 (groove diameter)
If there is a slight error in the groove, or if the groove diameter is partially reduced for some reason, slippage will occur there. Sliding causes wear. Wear does not occur evenly. Concentrated wear occurs at the places where wear has occurred. An incision occurs in a groove roller or part of it,
It may be difficult to correct and even process the groove rollers for regeneration.

[0009]

DISCLOSURE OF THE INVENTION An object of the present invention is to reduce the slippage between a groove roller and a cutting wire as much as possible to prolong the service life of the groove roller or to modify the groove roller for easy use. To do.

According to the present invention, a cutting wire is hung on a plurality of groove rollers arranged in parallel, and at least one groove roller is rotationally driven to run the cutting wire, and a working fluid containing abrasive grains is supplied. In a wire-type cutting and processing device for cutting a material to be cut, a plurality of motors for respectively rotating a plurality of groove rollers are provided, and at least one motor is provided with feedback for matching the rotation speed of the motor to a target speed. A control system is provided, and another motor is controlled by the torque control signal generated by this feedback control system.

At least two groove rollers may be provided. Generally, three groove rollers will be provided. It goes without saying that the number of groove rollers may be four or more.

According to the present invention, the plurality of groove rollers are rotationally driven by the respective motors with the same torque.

In the conventional example shown in FIG. 5, one driven groove roller drives another driven groove roller via a wire, and therefore slippage is likely to occur due to the rotational resistance of the driven groove roller. According to the configuration of the present invention, all groove rollers are driven to rotate by separate motors, respectively, so that there is no rotation resistance and slippage hardly occurs. Wear caused by slippage is significantly reduced as compared with the conventional example. In addition, the wear of the plurality of groove rollers is almost equalized.

Further, compared with the conventional example shown in FIG. 6, slippage between the groove roller and the cutting wire can be extremely reduced. The plurality of groove rollers are rotationally driven with a constant torque. If the groove diameter of one groove roller becomes small for some reason, that groove roller is accelerated (torque is constant). As a result, the peripheral speeds of the wire and the groove roller are kept substantially equal, and there is almost no slippage between them.
That is, the circumferential length error of the plurality of groove rollers is allowed.

In this way, the wear between the cutting wire and the groove roller can be suppressed to reduce the degree of wear, and the wear of the groove roller can be equalized, so that the life of the groove roller can be extended. it can. In addition, since it is difficult for accelerated cuts to occur in a specific portion of the groove roller or in the specific groove roller, life management of the groove roller is facilitated, and the degree of recycling can be increased.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a groove roller and its driving device in a wire type cutting and processing apparatus.

Three groove rollers 11, 12 and 13 are arranged in parallel with each other at positions corresponding to the vertices of a triangle and are rotatably supported. Grooves are formed on the peripheral surfaces of the groove rollers 11 to 13 at regular intervals. The spacing of the grooves defines the thickness of the wafer formed by cutting.

A cutting wire 14 is used for these groove rollers 11 to 13
Are sequentially wound along those grooves, and are wound by the number of grooves in each groove roller. Two groove rollers 12 and 13
Material to be cut (semiconductor single crystal rod, etc.) 70
Are placed.

Motors 21, 22 and 23 are provided to rotate and drive the three groove rollers 11, 12 and 13, respectively. These motors 21 to 23 are drive-controlled so as to generate the same torque as described later. Groove roller
11 is rotationally driven by a motor 21 via an appropriate speed reducer or a rotary power transmission mechanism (not shown). Similarly,
The groove rollers 12 and 13 are rotationally driven by motors 22 and 23, respectively.

When the groove rollers 11 to 13 rotate in the same direction, the cutting wire 14 stretched around the groove rollers 11 to 13 runs in one direction. The material 70 to be cut is gradually moved upward, and the material 70 to be cut is pressed against the traveling wire 14,
In addition, a working liquid containing abrasive grains is supplied to a portion where the wire 14 and the material 70 to be cut are in contact with each other. As a result, the material 70 to be cut is cut into a large number of wafers having a constant width.

FIG. 2 shows a drive control circuit for the motors 21-23.

A feedback control system (feedback control circuit) for controlling the rotation speed of the three motors 21 to 23 to be constant.
Is provided. A common target rotation speed (speed target value) is given to these feedback control systems.

Explaining the feedback control system of the motor 21, a tachogenerator (rotation speed detector) 33 for detecting the rotation speed (rotation speed) of the motor 21 is provided.
The subtraction circuit 34 detects a deviation of the detected rotation speed from the target rotation speed, and a signal representing this deviation is sent to the speed amplifier 31.
Given to. The output of the speed amplifier 31 is converted into a drive current by the current amplifier 32, and is supplied to the motor 21. As a result, the motor 21 is controlled so that its rotation speed matches the set target rotation speed.

The feedback control system for the motors 22 and 23 has basically the same configuration as the feedback control system for the motor 21. Tachogenerators that detect the rotational speeds of motors 22 and 23, respectively, are shown at 43 and 53, respectively. Also, the subtraction circuits are shown at 44 and 54, the speed amplifiers at 41 and 51, and the current amplifiers at 42 and 52, respectively.

Further, the drive circuit includes a switching circuit 25 and
Includes 26. The switching circuit 25 is a switch provided between the output side of the speed amplifier 41 and the input side of the current amplifier 42.
It is composed of SW1b and a switch SW1a provided between the output side of the speed amplifier 31 and the input side of the current amplifier 42 (the input side of the switch SW1b). The switches SW1a and SW1b are interlocked, and when the switch SW1a is on, the switch SW1b is off, and when the switch SW1a is off, the switch SW1b is on.

The switching circuit 25 is provided in the feedback control system of the motor 22 and between this feedback control system and the feedback control system of the motor 21, while the switching circuit 26 is provided in the feedback control system of the motor 23. It is provided between the feedback control system and the feedback control system of the motor 22.

The switching circuit 26 includes two switches SW2a and SW2b which are interlocked with each other and turned on and off. The switch SW2a is connected between the input side of the current amplifier 42 and the input side of the current amplifier 52. Switch SW
2b is connected between the output side of the speed amplifier 51 and the input side of the current amplifier 52.

As shown in FIG. 3, the switching circuit 26 is connected to the motor 23.
It may be provided in the feedback control system and between the feedback control system and the feedback control system of the motor 21. That is, the switch SW2a of the switching circuit 26 is connected between the output side of the speed amplifier 31 and the input side of the current amplifier 52. Other configurations are the same as those shown in FIG.

These switches SW1a, SW1b, SW2a, SW2b
Is shown as a contact switch, but of course a semiconductor switch can be used.

When the material 70 to be cut is cut by the wire 14, the switches SW1a and SW2a are turned on and the switches SW1b and SW2b are turned off. This allows the motor
The feedback control system of 21 operates and the feedback control systems of the other motors 22 and 23 are opened. The motor 21 is controlled so that its rotation speed matches the target rotation speed. The torque command (output signal of the speed amplifier 31) generated in the feedback control system of the motor 21
23 is provided to current amplifiers 42 and 52 for driving 23 respectively. Therefore, the motors 22 and 23 are driven so as to generate the same torque as the motor 21.

The groove rollers 11, 12 and 13 are rotationally driven by the motors 21, 22 and 23 with the same torque. As compared with the conventional example shown in FIG. 5, since there is no rotation resistance, there is almost no slip between the groove rollers 11 to 13 and the wire 14. This significantly reduces the wear of the grooves of the groove rollers 11-13.
In addition, the degree of wear of the three groove rollers 11 to 13 can be equalized.

The three groove rollers 11 to 13 are driven with a constant torque. If the groove diameter of one groove roller becomes small for some reason, the groove roller is accelerated because the torque is constant. As a result, the circumferential speed of the groove and the running speed of the wire are kept approximately the same even if the groove diameter is reduced. Therefore, slippage is unlikely to occur. Therefore, compared with the conventional example shown in FIG. 6, the difference in the diameter of the groove roller can be tolerated, and the abrasion does not occur at an accelerated rate.

Both switches SW1a and SW2a are turned off,
When the switches SW1b and SW2b are turned on, the feedback control system of the motors 22 and 23 also operates. this is,
This is effective when the three motors 21, 22, and 23 are individually driven at the same target rotation speed. For example, wire 14
Is used to wind the three groove rollers 11 to 23, and to idle the motors 21 to 23 without wires.

FIG. 4 shows another embodiment. In this embodiment, the arrangement shown in FIG. 1 is turned upside down. The workpiece 70 is supported so as to gradually move downward from above. The same components as those shown in FIG. 1 are designated by the same reference numerals.

A device constituted by two groove rollers,
It goes without saying that the present invention can be applied to a device constituted by four or more groove rollers.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an arrangement of groove rollers and a driving device therefor according to an embodiment.

FIG. 2 is a circuit diagram showing a motor drive circuit.

FIG. 3 is a circuit diagram showing another example of a motor drive circuit.

FIG. 4 is a perspective view showing an arrangement of groove rollers and a driving device therefor according to another embodiment.

FIG. 5 is a perspective view showing an arrangement of groove rollers and a driving device thereof, showing a conventional example.

FIG. 6 is a perspective view showing an arrangement of groove rollers and a driving device therefor, showing a conventional example.

[Explanation of symbols]

 11, 12, 13 Groove roller 14 Cutting wire 21, 22, 23 Motor 25, 26 Switching circuit 31, 41, 51 Speed amplifier 32, 42, 52 Current amplifier 33, 43, 53 Tachogenerator 34, 44, 54 Subtraction circuit SW1a , SW1b, SW2a, SW2b switches

Claims (3)

[Claims] 1. A cutting wire is hung on a plurality of groove rollers arranged in parallel, and the cutting wire is run by rotating at least one groove roller to supply a working liquid containing abrasive grains. In a wire cutting machine for cutting a material to be cut, a feedback control system for providing a plurality of motors for respectively rotating a plurality of groove rollers, and for at least one motor, matching the rotation speed of the motor to a target speed The groove roller driving device is characterized in that the other motor is controlled by the torque control signal generated by the feedback control system. 2. A feedback control system for matching the rotation speed of the motor to a common target speed is provided for all the motors, and the feedback paths of other feedback control systems except one feedback control system are cut off, and The drive device according to claim 1, further comprising a switching circuit that applies a torque control signal generated by one feedback control system to another motor. 3. A cutting wire is hung on a plurality of groove rollers arranged in parallel, and the cutting wire is run by rotating at least one groove roller, and a working liquid containing abrasive grains is supplied. In a wire-type cutting and processing device that cuts the material to be cut, a plurality of groove rollers are driven to rotate by separate motors, and a torque control signal is generated by a feedback control system for matching the rotation speed of one motor with the target speed The groove roller driving method is characterized in that all the motors are controlled by this torque control signal.