JP2010105061A - Wire saw apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wire saw apparatus capable of preventing a wire from breaking, even if a fixed abrasive grain wire is used, and surely achieving high working efficiency and high-speed cutting inherent to a fixed abrasive grain method. <P>SOLUTION: The wire saw apparatus 1 includes a wire 2 capable of reciprocating for cutting a workpiece 11 which is pushed, wherein abrasive grains are fixed to the wire 2 in advance. The apparatus includes a tension adjusting means 6 for adjusting the tension of the wire 2 while the wire 2 reciprocates, and a controller 12 for controlling the tension of the wire 2 via the means 6 and also controlling the traveling speed of the wire 2. The controller 12 controls the acceleration/deceleration of the wire 2 to be 36,000 m/min<SP>2</SP>or higher when the wire 2 is reversed in running from normal running in one direction to normal running in the other direction while controlling the tension of the wire 2 to be within ±2.5N with respect to a set value which is 50% or higher of the breaking strength of the wire 2 or controls the time required for the reverse in running to be 3 seconds or shorter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wire saw device for cutting a workpiece into a thin plate shape by reciprocating a wire to which abrasive grains are fixed.

  As a means for producing a wafer-like thin plate from a semiconductor crystal material such as silicon or a hard and brittle material such as quartz, a loose abrasive method is known (see, for example, Patent Document 1). In this machining method, a grooved roller around which a wire is wound at a predetermined pitch is rotated to run the wire back and forth, and the workpiece is run while supplying and adhering slurry to the running wire. Cutting is performed by pressing against the wire. The slurry is formed by mixing an abrasive with an oily or aqueous dispersion medium.

  On the other hand, in recent years, for the purpose of improving productivity by high-speed cutting, improving the working environment, and reducing waste, a processing method of a fixed abrasive method using a fixed abrasive wire in which an abrasive is fixed to the wire. Has attracted attention (see, for example, Patent Document 2). In this processing method, only the processing liquid that does not disperse the abrasive is supplied for cooling, and the workpiece is cut. As a method for fixing the abrasive to the wire, there are fixing by electrodeposition and fixing by a resin.

The fixed abrasive wire has a feature that it has a high processing capability against free abrasive grains because the abrasive grains serving as cutting edges are fixed to the wire, but is weak against radial twist.
In order to prevent this, when using a fixed abrasive wire in a conventional wire saw device, the acceleration / deceleration time of the wire has been lengthened so as not to give a fluctuation in tension to the wire. Alternatively, it is generally used in a low cycle in which the stroke of the reciprocating wire is increased to several kilometers to several tens of kilometers so that the twist of the wire does not accumulate.

  However, although the fixed abrasive method using a fixed abrasive wire has a high processing capability and is characterized by high-speed cutting, if the wire acceleration / deceleration time is lengthened as described above, the speed decreases. The cutting time is low and the cutting capacity during acceleration / deceleration time is low. Further, since it is necessary to reduce the feed rate of the workpiece in accordance with the decrease in the wire speed, the cutting ability in the acceleration / deceleration time is further deteriorated.

In addition, when the reciprocating cycle number required for cutting the workpiece is reduced by increasing the stroke of the reciprocating wire as described above, the surface state of the cut wafer differs depending on the traveling direction of the wire, and the stripes A pattern (saw mark) occurs. These saw marks not only look but also make the surface roughness of each wafer different and cause minute undulations and irregularities on the surface, thereby deteriorating the quality of the wafer.
JP 2006-297847 A JP 2001-54850 A

  The present invention has been made in view of the above points, and even when a fixed abrasive wire is used, the wire is prevented from being broken, and the original processing capability of the fixed abrasive method and high-speed cutting processing are prevented. It aims at providing the wire saw apparatus which can implement | achieve reliably.

In order to achieve the above object, according to the first aspect of the present invention, in a wire saw apparatus having a reciprocating wire for cutting a pressed workpiece, the abrasive grains being fixed to the wire in advance. A tension adjusting means for adjusting the tension of the wire during the reciprocating movement of the wire, and a control device for controlling the traveling speed of the wire while controlling the tension of the wire through the tension adjusting means; The control device shifts from steady running in one direction to steady running in the other direction while controlling the tension of the wire to plus or minus 2.5 N or less with respect to a set value that is 50% or more of the breaking strength of the wire. in practicing the running reversing of the wire, and characterized by controlling the acceleration and deceleration of the wire or controlled 36000m / min ² or more, or, the time required for the running reversing below 3 seconds To provide that the wire saw apparatus.

According to a second aspect of the present invention, in the wire saw device according to the first aspect, the control device reciprocates the wire at least 3 reciprocations and at most 20 reciprocations per minute, and the travel length of the wire per reciprocation. The length is controlled to 300 m or less.
According to a third aspect of the present invention, in the wire saw device according to the first or second aspect, the control device controls the maximum speed during steady running of the wire to 400 m / min or more and 950 m / min or less. It is characterized by.

  According to a fourth aspect of the present invention, in the wire saw device according to any one of the first to third aspects, the control device reduces a difference between a traveling length of the wire in the forward movement direction and a traveling length of the wire in the backward movement direction to 4 m or less. It is characterized by control.

In the first aspect of the invention, the tension of the wire is set to 50% or more of the breaking strength of the wire through the tension adjusting means by the control device, and the wire is subjected to a tension fluctuation of ± 2.5 N or less with respect to the set value. By reciprocating the wire, the acceleration / deceleration at the time of acceleration / deceleration of the wire when reciprocating is increased to 36000 m / min ² or more, or the wire decelerates from the maximum speed when reciprocating and reverses the traveling direction and accelerates. Thus, the time from the start of deceleration to the end of acceleration when the maximum speed is reached again can be reduced to 3 seconds or less. Accordingly, the wire can be stretched with the highest possible tension, and the wire can be reciprocated while suppressing fluctuations in tension, and as a result, the wire can be run at high speed. For this reason, the original high-speed cutting process of a fixed abrasive grain system is reliably realizable. In addition, as the wire speed increases and the acceleration / deceleration during wire reciprocation increases, even if the wire stroke is shortened and the number of reciprocation cycles is increased, the surface roughness of the workpiece is made uniform and minute waviness is achieved. And unevenness can be suppressed, and the saw mark can be made inconspicuous. Thereby, the cutting accuracy of the workpiece can be further stabilized or improved.

  In the second aspect of the invention, the control device can reciprocate the wire at 3 to 20 reciprocations per minute and control the length of the wire per reciprocation to 300 m or less. It becomes possible to reciprocate at high speed by shortening the stroke length. Thereby, the original high-speed cutting process of a fixed abrasive grain system is realizable reliably. In addition, as the wire speed increases and the acceleration / deceleration during wire reciprocation increases, even if the wire stroke is shortened and the number of reciprocation cycles is increased, the surface roughness of the workpiece is made uniform and minute waviness is achieved. And unevenness can be suppressed, and the saw mark can be made inconspicuous. Thereby, the cutting accuracy of the workpiece can be further stabilized or improved.

In the invention of claim 3, since the maximum speed of the wire can be controlled to 400 m / min or more and 950 m / min or less by the control device, the reciprocating operation is performed at a speed capable of exhibiting the high processing ability of the fixed abrasive wire. Can be made.
In the invention of claim 4, the control device can control the difference between the wire travel length in the forward movement direction and the wire travel length in the backward movement direction during the reciprocating travel to 4 m or less. The amount of fixed abrasive wire used can be reduced, the running cost can be reduced, and the cost can be reduced.

1 and 2 schematically show a wire saw device according to the present invention.
As shown in the figure, a wire saw device 1 according to the present invention includes a wire 2, a pair of bobbin portions 3 around which the wire 2 is wound, and a plurality of wires (two in the drawing) for winding the wire 2 in a spiral shape. ) And a plurality of guide rollers 5 for guiding the wire between the groove roller portion 4 and the bobbin portion 3. The groove rollers 4a and 4b are spaced apart in the horizontal direction and arranged in parallel to each other.

  The wire 2 is a fixed abrasive wire having a diameter of 0.13 mm or less, and an abrasive is electrodeposited and fixed on the surface thereof in advance. The pair of bobbin portions 3 includes a feeding bobbin 3a and a receiving bobbin 3b. The wire 2 fed out from the feeding bobbin 3a is repeatedly wound in a spiral between the groove rollers 4a and 4b to form a processed part wire row 2a, and then wound around the receiving bobbin 3b.

  In addition to the guide roller 5 described above, a tension adjusting roller 6 is provided between the feeding bobbin 3a and the groove roller 4a and between the groove roller 4b and the receiving bobbin 3b. These tension adjusting rollers 6 can adjust the tension of the wire 2. Specifically, the tension adjusting roller 6 is attached to the distal end of an arm 13 that can be rotated around its base end, and this arm 13 generates a predetermined tension on the wire in advance according to its rotational angle. It is energized. An angle detector 7 is provided at the base end of the arm 13, and the angle detector 7 outputs a signal indicating the rotation angle position of the arm 13, that is, the tension of the wire 2.

  On the other hand, a bobbin motor 8 and a groove roller motor 9 are attached to at least one (4a in the drawing) of the feeding bobbin 3a, the receiving bobbin 3b, and the plurality of groove rollers. By driving these motors 8 and 9 in the same positive direction, the wire 2 is fed out from the feeding bobbin 3a, circulates around the groove rollers 4a and 4b repeatedly, and is wound around the receiving bobbin 3b. On the other hand, when the motors 8 and 9 are driven in the opposite directions, the wire 2 fed out from the receiving bobbin 3b is wound around the feeding bobbin 3a through the groove rollers 4a and 4b.

  Therefore, by driving the three motors 8 and 9 in synchronization, the wire 2 can be accurately reciprocated. In practice, the motors 8 and 9 are rotated forward and backward at predetermined time intervals. At this time, the feeding length of the wire 2 on the forward side traveling from the feeding bobbin 3a toward the receiving bobbin 3b is received from the receiving bobbin 3b. By making the wire 2 longer than the delivery length of the wire 2 on the backward movement side that travels toward the feeding bobbin 3a, the wire 2 is gradually sent out from the feeding bobbin 3a while repeating reciprocation, and gradually. The used wire 2 is wound around the receiving bobbin 3b.

  A workpiece lifting / lowering device 10 is provided above the processing portion wire row 2a (downward in the case of a round-up type), and the workpiece 11 can be supported on the workpiece lifting / lowering device 10. The workpiece lifting / lowering device 10 can be moved up and down, reciprocating the wire 2 and lowering the workpiece lifting / lowering device 10 (up in the rounding type) to press the workpiece 11 against the machining part wire row 2a. The workpiece 11 is cut by the processed part wire row 2a.

  The wire saw device 1 further includes a control device 12. The control device 12 includes an angle detector 7 and a feed for the tension adjusting roller 6 provided between the feed bobbin 3a and the groove roller unit 4 and between the groove roller unit 4 and the receiving bobbin 3b. The bobbin motor 8a, 8b of each of the bobbin 3a and the receiving bobbin 3b and the groove roller motor 9 are electrically connected. Therefore, based on the detection signal from the angle detector 7, the control device 12 controls the bobbin motors 8 a and 8 b of the feeding bobbin 3 a and the receiving bobbin 3 b so that the rotational angle position of the arm 13 is constant. Correct the speed. As a result, the tension of the wire 2 can be adjusted with high responsiveness, and fluctuations in the tension of the wire 2 can be minimized. Reference numeral 14 denotes a traverser.

FIG. 3 is a graph showing the relationship between wire speed and time in the wire saw device 1 according to the present invention.
As shown in the figure, at the acceleration time ta, for example, the wire 2 is accelerated and sent out on the forward movement side, and the area a on the graph is the sending length of the wire 2 at the time of acceleration. In the next constant speed time tb, the wire 2 is traveling at the maximum speed (steady traveling), and the area b on the graph is the wire 2 feed length at the constant speed. At the next deceleration time tc, the wire 2 is traveling at a reduced speed, and the area c on the graph is the feed length of the wire 2 at the time of deceleration.

  When the deceleration is finished and the wire speed becomes zero, the traveling direction of the wire 2 is reversed, and at the next acceleration time td, the wire 2 is accelerated and traveling on the backward side, The area d is the delivery length of the wire 2 during acceleration. In the next constant speed time te, the wire 2 is traveling at the maximum speed (steady traveling), and the area e on the graph is the feed length of the wire 2 at the constant speed. At the next deceleration time tf, the wire 2 is traveling at a reduced speed, and the area f on the graph is the feed length of the wire 2 at the time of deceleration. This is one reciprocating cycle of the wire 2, and when the reciprocating cycle, that is, when the reciprocating travel of the wire 2 is repeated, the feed length (a + b + c) of the wire 2 on the forward side is set as described above. By making the wire 2 longer than the feed length (d + e + f), it is possible to supply a new wire 2 from the feed bobbin 3a toward the workpiece 11 while gradually winding the wire 2 around the receiving bobbin 3b. It becomes.

As a means for supplying the new wire 2 gradually as described above, the maximum speeds of the wire 2 on the forward side and the backward side are the same, and the constant speed time tb in the forward movement is set to the constant speed time in the backward movement. There are a method in which the speed is longer than te and a method in which the constant speed times of the wire 2 on the forward movement side and the backward movement side are the same, and the maximum speed in the forward movement is faster than the maximum speed in the backward movement.
As described above, the wire 2 is reciprocated and the workpiece 11 is pressed against the wire 2 for cutting. During this processing, the control device 12, based on the detection signal from the angle detector 7, the bobbin motors 8 a, the bobbin motors 8 a, the feed bobbin 3 a and the receiving bobbin 3 b so that the rotational angle position of the arm 13 is constant. By correcting the speed of 8b, the tension of the wire 2 is controlled within a range of plus or minus 2.5N with respect to the set tension of 50% or more of the breaking strength of the wire (wire bus bar) 2.

On the other hand, the control device 12 controls the driving of the motors 8 and 9 while suppressing the fluctuation of the tension of the wire 2 as described above, and thereby, the acceleration / deceleration speed of the wire 2 when traveling reciprocally is 36000 m / min ² or more. Alternatively, the wire 2 decelerates from the maximum speed during reciprocating travel, accelerates by reversing the traveling direction, and reaches the maximum speed again, that is, the time from the start of deceleration to the end of acceleration (see FIG. 2). tc + td) is set to 3 seconds or less.

Therefore, the control device 12 stretches the wire 2 with the highest possible tension, and further suppresses fluctuations in tension, and when the traveling direction of the wire 2 is reversed between the forward movement and the backward movement, returns to its maximum speed. Since the time required for reversing the running time is greatly shortened, the original high-speed cutting process of the fixed abrasive method can be sufficiently exhibited.
More specifically, the control device 12 controls the traveling length of the wire 2 per one reciprocating stroke to be 300 m or less while causing the wire 2 to reciprocate within a period of 3 to 20 reciprocating strokes per minute. For this reason, since the reciprocating stroke length of the wire 2 is short, the number of reciprocating cycles of the wire 2 required to cut the workpiece 11 can be increased. Therefore, the surface roughness of the workpiece 11 can be made uniform, the occurrence of minute undulations and irregularities can be suppressed, and the saw mark can be made inconspicuous. Thereby, the cutting accuracy of the workpiece 11 can be further stabilized or increased in accuracy.

  Furthermore, the control device 12 has a maximum speed of the wire 2 (speed at tb and te in FIG. 2) of 400 m / min or more as a speed range of the wire 2 that can exhibit the high processing ability of the fixed abrasive wire, and is 950 m. / Min or less. In the range where the maximum speed of the wire 2 is lower than 400 m / min, the high processing capability of the fixed abrasive wire is not exhibited. Conversely, in the range higher than 950 m / min, the abrasive grains fixed to the wire 2 are processed. The phenomenon of up-slip that slides on the workpiece 11 before biting into the workpiece 11 is likely to occur, and efficient machining cannot be performed.

Furthermore, the control device 12 controls the difference between the wire travel length in the forward movement direction and the wire travel length in the backward movement direction during the reciprocating travel to 4 m or less. The newly supplied wire 2 can be reduced, the amount of fixed abrasive wire used can be reduced, running cost can be reduced, and cost can be reduced.
FIG. 4 is a schematic side view of another wire saw device according to the present invention.

  As shown in the figure, the groove roller portion 4 is composed of three groove rollers 4a, 4b, and 4c. These groove rollers 4a, 4b, and 4c form a triangular apex in a side view, and the lower wire 2 serves as a processed portion wire row 2a. A groove roller motor 9 is attached to the upper groove roller 4a. Therefore, the example of this figure is the round-up type mentioned above, and the to-be-processed object 11 is located below the process part wire row 2a. Even in such a configuration, the workpiece 11 is lifted by the workpiece lifting / lowering device 10, and the workpiece 11 is pressed against the machining portion wire row 2a, whereby the workpiece 11 is cut by the machining portion wire row 2a. Can be processed. Other configurations, operations, and effects are the same as those shown in FIGS.

1 is a schematic side view of a wire saw device according to the present invention. It is a schematic plan view of the wire saw apparatus of FIG. It is a graph which shows the relationship between the wire speed and time in the wire saw apparatus which concerns on this invention. It is a schematic side view of another wire saw apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wire saw apparatus 2 Wire 3 Bobbin part 3a Feeding bobbin 3b Receiving bobbin 4 Groove roller part 4a Groove roller 4b Groove roller 4c Groove roller 5 Guide roller 6 Tension adjusting roller 7 Angle detector 8 Bobbin motor 9 Groove roller motor DESCRIPTION OF SYMBOLS 10 Support stand 11 Work piece 12 Control apparatus 13 Arm 14 Traverser

Claims (4)

Having a reciprocating wire for cutting the pressed workpiece,
In a wire saw device in which abrasive grains are fixed to the wire in advance,
Tension adjusting means for adjusting the tension of the wire during the reciprocating travel of the wire;
A control device for controlling the traveling speed of the wire while controlling the tension of the wire via the tension adjusting means;
The control device shifts from steady running in one direction to steady running in the other direction while controlling the tension of the wire to plus or minus 2.5 N or less with respect to a set value that is 50% or more of the breaking strength of the wire. A wire saw device characterized in that, when the traveling reversal of the wire is performed, the acceleration / deceleration speed of the wire is controlled to 36000 m / min ² or more, or the time required for the traveling reversal is controlled to 3 seconds or less.   2. The control device according to claim 1, wherein the control device causes the wire to reciprocate between 3 and 20 reciprocations per minute and controls the travel length of the wire per reciprocation to 300 m or less. Wire saw device.   The wire saw device according to claim 1 or 2, wherein the control device controls the maximum speed of the wire during steady running to 400 m / min or more and 950 m / min or less.   The wire saw according to any one of claims 1 to 3, wherein the control device controls the difference between the traveling length of the wire in the forward movement direction and the traveling length of the wire in the backward movement direction to 4 m or less. apparatus.

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