JPH04129661A - Control method for cutting speed of wire type cutter and device thereof - Google Patents

Abstract

PURPOSE:To prevent the deflection of a wire at the fluctuation time of a cut length, by detecting a cutting resistance with the increase and decrease of the load current of a roller driving motor for traveling a wire, controlling the rotation number of a lift motor which lifts the member to be cut in case of exceeding the specified value, regulating the lift speed of the member to be cut and making the cutting resistance at a preset value. CONSTITUTION:A member W to be cut is cut in a wafer shape with its pressing to a wire S row while traveling at high speed the wire S row spread at the specified intervals by plural support rollers 2a-2c. In this case, the cutting resistance value received to the wire S at cutting time from the load current value of the driving motor M1 of the support roller 2A is detected by a detector 21. Then, a control signal is imparted to the control mechanism 24 of the lift motor M2 for pushing up the member W to be cut, when exceeding an allowable range with this detected current value being compared with the set current value sent from a set current generator 22 by a comparing circuit 23. The pushup speed of the member W to be cut is thus regulated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a wire-type cutting method for cutting highly hard and brittle materials such as semiconductor materials and ceramics (hereinafter referred to as parts to be cut) while supplying machining fluid to a wire running at high speed. The present invention relates to a cutting speed control method of a cutting device and its device.

[Conventional technology]

The wire-type cutting device cuts the workpiece by a so-called lapping action, and usually uses a plurality of support rollers 50, for example three, as shown in FIG. 3(a).
a, 50b, 50c, wires S are wound spirally at predetermined intervals, and a lifting platform 5 on which a member to be cut W is placed.
1 is gradually pushed up, a machining fluid containing abrasive grains is supplied from a machining fluid supply pipe 52 to the cutting portion of the wire S, and the workpiece W to be cut is cut into wafer shapes. However, depending on the material of the member to be cut, the shape of the surface to be cut, the sharpness of the abrasive grains contained in the machining fluid, etc., the wire S is bent upward as shown in FIG. 3(b). Therefore, the wire S has problems such as deflection in the lateral direction, which causes variations in the thickness of the wafer to be cut, and the variation in thickness, which deteriorates the cutting precision.

Therefore, as a means for reducing the above-mentioned deflection angle, for example, there is a method in which changes in cutting length, that is, changes in cutting resistance, are stored in advance during cutting, and the lifting speed of the workpiece to be cut is regulated accordingly. 26467), or a method of detecting the contact load with the wire using a strain gauge or the like when pushing up the mounting table of the member to be cut, and regulating the lifting of the mounting table (for example, Japanese Patent Laid-Open No. 62-68267); Other methods include directly measuring the amount of deflection .alpha. shown in FIG. 3(b) and regulating the speed at which the member to be cut is pushed up (for example, Japanese Utility Model Application No. 63-97449).

[Problem to be solved by the invention] However, when performing the above-mentioned cutting, it is difficult to cut with a constant sharpness due to changes in the sharpness of the abrasive grains, and even if changes in the contact load or variation in the amount of deflection are detected. , which is based on the results caused by cutting, and it is difficult to detect minute changes.

In consideration of this, the present invention focuses on the fact that fluctuations in cutting resistance can be captured as fluctuations in the load of the motor that drives the wire, and quickly responds to even minute fluctuations in cutting resistance to speed up the cutting process. That is, the purpose is to control the pushing up speed of the member to be cut.

[Means for Solving the Problem] The cutting speed fl+IJi1 method of the wire-type cutting device of the present invention to achieve the above object is based on the current value of the power supply ti of the drive motor of the support roller that stretches the wire, which is applied to the wire during cutting. The cutting resistance value is detected and the speed at which the member to be cut is pushed up is regulated.

Further, the cutting speed control device for implementing the above method includes a current detector provided in the load circuit of the drive motor of the support roller, a current value at a preset cutting load, a detected current value, and a set current value. The comparison circuit is configured to apply a control signal to the control mechanism of the lifting motor for pushing up the member to be cut when the detected current value exceeds the allowable range with respect to the set current value.

[For production]

As the contact load of the member to be cut on the wire, that is, the cutting resistance changes, the current value applied to the support roller drive motor that drives the wire to travel changes. This fluctuation is detected and a control signal is given to the control mechanism of the motor for pushing up the member to be cut, thereby regulating the pushing up speed. Thereby, the cutting resistance applied to the wire can be regulated within an allowable range.

〔Example〕

1 and 2 show an embodiment of the invention.

FIG. 1 shows an overall schematic diagram of a wire-type cutting device 1 to which the present invention is applied, in which 2a, 2b, and 2c are supporting rollers having a large number of grooves on the circumferential surface, and a cutting wire S is connected to the supporting rollers. Wrap it in a spiral along the edge. The upper support roller 2a among these support rollers is used as a drive roller, and a roller drive motor M1 is connected to this drive roller 2a. In addition, wire S is wound on a reel at both ends,
One side is used as a take-up reel, and the wire S is fed out from the other reel and wound around one take-up reel in synchronization with the running of the wire S by the roller drive motor M1, so that the wire S runs in one direction at high speed. This is well known and the explanation will be omitted.

Reference numeral 10 indicates a lifting mechanism for lifting the workpiece W, in which a lifting table 13 is fitted into a vertical guide 12 erected on a base 11 so as to be slidable in the vertical direction. Place it. Also, this lifting platform 13 has a screw I which is screwed into the screw shaft ]5! 114 is attached, the screw shaft 15 is rotatably supported at the lower part by a bearing 16, and a lifting servo motor (hereinafter simply referred to as lifting motor) M2 and a pulley 17. Connected via 18 and 19. As a result, the lifting table 13 is pushed up by the rotation of the lifting motor, and the member W to be cut is pressed against the wire S and cut.

In the above configuration, the present invention regulates the lifting speed (cutting speed) of the workpiece W by the lifting motor M2 according to the cutting resistance, and the cutting speed control device 20 includes the support roller drive motor M1 and the current detector 21. , a current (hereinafter referred to as set current) generator 22 that is applied to the drive motor M1 at the time of a preset cutting load, and a comparison circuit 23 for comparing the measured current value and the set current value. This comparison circuit 23
The output signal from the lift motor M2 is applied to the control mechanism 24 of the lift motor M2 to regulate the rotational speed of the lift motor M2. The procedure will be explained below based on FIG. 2.

The roller drive motor M1 is outputted with a predetermined number of cycles of alternating current by the speed setting device 30, and is driven by the control mechanism 31. PG indicates a pulse generator, which feeds back the motor rotation speed to the control mechanism 31. The load current for this drive motor M1 is detected by a power supply detector 21.

The lifting motor M2 outputs a predetermined number of cycles of alternating current by the push-up speed setting device 33, and is driven by the controller W424 according to this number of cycles.

In the above configuration, the current value for the roller drive motor M1 is detected by the current detector 21, and the detected value and the set current value from the set current generator 22 are compared by the comparator circuit 23, and the detected value is within the allowable range. If so, turn switch 34 OFF
Let it be F. Therefore, the lift motor M2 is operated by the push-up speed setting device 33.
is driven based on the number of output cycles. PG is a pulse generator that feeds back the rotation speed of the motor M2 to the control mechanism 24.

Next, when the current value detected by the current detector 22 is smaller than the set current value, that is, when the load is light, the switch 34 is turned on.
and applies a positive signal to the control mechanism 24. As a result, the control mechanism 24 drives the lifting motor M2 at a speed higher than the speed set by the push-up speed setting device 33, and
Increases the rate of rise.

As the cutting progresses and the load increases, when the detected current value increases within the above-mentioned allowable range, the switch 34 is turned OFF and the lifting motor M2 is operated at the above-mentioned set speed.

Then, when the cutting resistance increases further, that is, the current value detected by the current detector 21 based on this increases to the set current generator 22.
When the value becomes larger than the set value, turn the switch 34 to OFF again.
N, a minus signal is given to the control mechanism 24, and the rotational speed of the lifting motor M2 is decreased from the set value of the push-up speed setting device 33. The amount of reduction is controlled according to the ratio between the detected value and the set value in the comparator circuit 23, as in the case of speed increase described above.

Along with this, the rising speed of the lifting platform 13 decreases.

As a result, the cutting resistance also decreases, and when the detected value of the current detector 21 decreases again within the above-mentioned allowable range, the switch 34 turns OFF.
F is given.

Repeat the above. As a result, the cutting resistance value can be kept constant, the deflection α shown in FIG. 3(b) can be reduced, and the wire S between the support rollers 2b and 2c on both sides of the lower part can be held in a substantially straight line.

The switch 34 is provided with a circuit that is turned on when the workpiece W is within the processing range to be cut. This control mechanism uses the signal from the load current detector to control the speed of the lifting motor by QN-OFF in order to enter the set load tolerance range, and the speed of the lifting motor is proportionally controlled according to the value of the load current. It can also be applied to PIA control by taking into account the load current and the speed change of the lifting motor.

〔Effect of the invention〕

According to the present invention, the cutting resistance is detected by the increase/decrease in the load current of the roller drive motor for running the wire, and when the cutting resistance exceeds a predetermined value, the rotation speed of the lifting motor that raises the workpiece to be cut is controlled, and the Since the rising speed is regulated and the cutting resistance is set to a preset value, the wire is prevented from bending even when the cutting length changes or the sharpness of the abrasive grains in the processing fluid changes, and the thickness of the cut wafer is reduced. It is possible to prevent variations in the cutting edge and improve cutting accuracy.

[Brief explanation of the drawing]

1 and 2 relate to embodiments of the present invention; FIG. 1 is an overall schematic diagram of a cutting speed control device for a wire-type cutting device;
First of all, this is an overall circuit diagram of the cutting speed control device, and FIG. 3 is an explanatory diagram of the cutting procedure in the wire type cutting device. 1 is a wire type cutting device, 2a, 2b, 2c are support rollers, 20 is a cutting speed controller, 21 is a current detector, 22 is a setting current generator, 23 is a comparison circuit, 24 is a lifting motor controller 41L, M1 is a support roller drive motor, M2 is a lifting motor, S is a wire, and W is a member to be cut. Patent applicant Nippon Spindle Manufacturing Co., Ltd. Figure 1 Ml: Support Ti rope skill a journey = 7 W: New τηM wire material

Claims (2)

[Claims] (1) In a wire-type cutting device that cuts a member to be cut into wafers by pressing a member to be cut against a wire row stretched at a predetermined interval by a plurality of support rollers while traveling at high speed, the support roller A cutting speed control method for a wire-type cutting device, characterized in that a cutting resistance value applied to a wire during cutting is detected from a load current value of a drive motor, and a pushing-up speed of a member to be cut is regulated. (2) In a wire-type cutting device that cuts a member to be cut into wafers by pressing a member to be cut against a wire row stretched at a predetermined interval by a plurality of support rollers while traveling at high speed, the support roller A current detector installed in the drive circuit of the drive motor, a current value at a preset cutting load, and a comparison circuit for comparing the detected current value and the set current value, and the comparison circuit is configured to compare the detected current value with the set current value. A cutting speed control device for a wire-type cutting device, characterized in that when the permissible range is exceeded, a control signal is given to a control mechanism of a lifting motor for pushing up a member to be cut.