JP2015100814A - Manufacturing method and manufacturing apparatus of saw wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method which enables a saw wire 28 having proper habits to easily be obtained.SOLUTION: A manufacturing apparatus 2 of a saw wire 28 has a wire drawing machine 4, a take-off device 6, a measuring roller 8, a corrector 10, a tension loading device 14, a dancer 16, and a take up reel 18. An element wire 24 passes through a die of the wire drawing machine 4. A final wire drawing is applied on the element wire 24 by this passage. The element wire 24 passes through the corrector 10. This corrector 10 has many correction rollers. The element wire 24 causes repetitive plastic deformation on contact with these correction rollers. A saw wire 28 is obtained by this plastic deformation. The saw wire 28 having left the corrector 10 proceeds to the tension loading device 14. Tension is loaded on the element wire 24 passing through the corrector 10 by this tension loading device 14.

Description

  The present invention relates to a saw wire used for manufacturing a silicone wafer or the like. Specifically, the present invention relates to an improvement in a saw wire manufacturing method and manufacturing apparatus.

  Silicon wafers are obtained from silicon ingots. A saw machine is used to manufacture the wafer. The saw machine includes a pair of main rollers and a saw wire. Each main roller has a number of grooves. This groove extends in the circumferential direction. A wire is passed through this groove. The wire advances by the rotation of the main roller. The ingot is sliced by this wire to obtain a wafer.

  In the manufacture of saw wire, patenting and wire drawing are repeatedly performed on the wire. As a result, the wire becomes thinner. This strand is subjected to final patenting and final drawing to obtain a saw wire.

  In the final wire drawing, the strand is passed through the die while the lubricating liquid is supplied to the die. This die is slightly inclined with respect to the pass line of the strand. Due to this inclination, the strands are addicted. By this curling, a saw wire having a free coil diameter of about 200 mm to 800 mm is obtained. A saw wire with an appropriate free coil diameter maintains a straight running posture in a saw machine. With this saw wire, a wafer having excellent slice surface accuracy can be obtained.

  The free coil diameter largely depends on the inclination angle of the die. In order to obtain a saw wire with an appropriate free coil diameter, the inclination of the die needs to be set to an appropriate angle. This setting is made depending on the skill of the worker. Setting an appropriate angle is not easy. Setting an appropriate angle requires time and effort.

  In the final wire drawing, the inner peripheral surface of the die gradually wears. Due to this wear, the free coil diameter of the saw wire changes. The free coil diameter may vary due to fluctuations in the state of the wire. Furthermore, the free coil diameter may vary depending on the state of the lubricating liquid. Wafers obtained from saw wires with large variations in free coil diameter have poor slice surface accuracy. The total length of the saw wire is extremely long. For example, there is a saw wire having a length of 500 km. It is necessary that the variation of the free coil diameter is small over the entire length of the saw wire.

  Japanese Patent No. 2957571 describes a saw wire manufacturing method including a heat treatment after the final wire drawing. By this heat treatment, the internal stress of the saw wire is reduced. The variation in the free coil diameter of the saw wire is small. However, this heat treatment is performed on a line different from the final drawing line. This heat treatment takes time. The manufacturing cost of this saw wire is high.

  Japanese Patent Application Laid-Open No. 2006-342375 describes a saw wire manufacturing method including a straightening process after final drawing. A number of straightening rollers are used in the straightening process. The habit of the saw wire can be optimized by the correction process.

Japanese Patent No. 2957571 JP 2006-342375 A

  In the manufacturing method described in Japanese Patent Application Laid-Open No. 2006-342375, optimization of habit is not sufficient. An object of the present invention is to provide a manufacturing method and a manufacturing apparatus in which a saw wire having an appropriate habit can be easily obtained.

The method for manufacturing a saw wire according to the present invention includes:
(1) A process of drawing a wire and setting the wire. (2) Applying tension to the wire with a tension applying device, and abutting on the wire and plasticizing the wire. It includes a step of straightening this strand of wire with a straightener having a number of straightening rollers that cause deformation.

  Preferably, the diameter of each straightening roller is not less than 60 times and not more than 100 times the diameter of the wire contacting the straightening roller.

  Preferably, the ratio of the tension applied to the strand when the strand passes through the straightener to the breaking load of the strand is not less than 30% and not more than 60%.

  Preferably, the ratio of the surface hardness of each straightening roller to the hardness of the wire is 90% or more and 150% or less.

  In the straightener, a large number of straightening rollers can be arranged in a staggered manner. Preferably, the number of these correction rollers is 11 or more.

The saw wire manufacturing apparatus according to the present invention includes:
(1) A wire drawing machine for drawing a wire and setting the wire.
(2) A straightener having a number of straightening rollers that abut against the strands and cause plastic deformation of the strands, and is located downstream of the wire drawing machine;
And (3) a tension applying device that is located downstream of the straightener and applies tension to the strands of the straightener.

  By the manufacturing method according to the present invention, a saw wire having an appropriate habit can be easily obtained.

FIG. 1 is a schematic view showing equipment used in a manufacturing method according to an embodiment of the present invention. FIG. 2 is an enlarged view showing the straightener of the facility of FIG. FIG. 3 is a graph showing changes in the free coil diameter due to correction. FIG. 4 is a graph showing the results of Experiment I. FIG. 5 is a graph showing the results of Experiment II. FIG. 6 is a graph showing the results of Experiment III.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  1 includes a wire drawing machine 4, a take-up device 6, a measuring roller 8, a straightening device 10, a reversing roller 12, a tension load device 14, a dancer 16, and a take-up reel 18. . The tension load device 14 includes a first roller 20 and a second roller 22.

  The strand 24 passes through a die (not shown) of the wire drawing machine 4. By this passage, the final wire is applied to the strand 24. In the final wire drawing, the die is slightly inclined with respect to the pass line of the strand 24. Due to this inclination, the wire 24 is addicted.

  The wire 24 advances to the take-up device 6 and further advances to the measuring roller 8. The strand 24 is wound a plurality of times between the take-up device 6 and the measuring roller 8. By this winding, the slip between the measuring roller 8 and the wire 24 is suppressed. In the measuring roller 8, the length of the strand 24 is measured.

  The strand 24 passes through the corrector 10. FIG. 2 shows the straightener 10. The straightener 10 has a number of straightening rollers 26. The strand 24 contacts a part of the outer peripheral surface of each correction roller 26. In the present embodiment, the number of correction rollers 26 is fifteen. These correction rollers 26 are arranged in a staggered manner. With this arrangement, the 15 straightening rollers 26 are divided into 8 first row rollers 26a and 7 second row rollers 26b. The strands 24 abut on the first row roller 26a and the second row roller 26b alternately. Due to these contact, the wire 24 repeatedly undergoes plastic deformation. The saw wire 28 is obtained by this plastic deformation.

  The saw wire 28 exiting the corrector 10 proceeds to the first roller 20 and further proceeds to the second roller 22. The saw wire 28 is wound a plurality of times between the first roller 20 and the second roller 22. By this winding, slip of the strand 24 in the tension load device 14 is suppressed.

  The peripheral speed of the first roller 20 is slightly larger than the traveling speed of the wire 24 in the straightener 10. Due to this speed difference, tension is applied to the strand 24 of the straightener 10. By passing through the corrector 10 in a tensioned state, the habit of the saw wire 28 is optimized as will be described in detail later.

  The saw wire 28 exiting the tension load device 14 passes through the dancer 16 and is taken up by the take-up reel 18.

  The free coil diameter of the strand 24 before entering the straightener 10 is indicated by D1. The free coil diameter of the saw wire 28 after passing through the corrector 10 is indicated by D2. The free coil diameter means the diameter of an arc drawn by the strand 24 (or saw wire 28) when placed on a smooth plate without load. The free coil diameter is also referred to as a free circle diameter.

  Since the peculiarity is corrected by the corrector 10, the free coil diameter D <b> 2 of the saw wire 28 is generally larger than the free coil diameter D <b> 1 of the strand 24. In this specification, the ratio D2 / D1 is referred to as a correction rate. In the manufacturing method according to the present invention, the tension is applied while the strand 24 is being tensioned by the tension load device 14. Therefore, the correction rate D2 / D1 is large.

  The free coil diameter before and after correction when the saw wire 28 is obtained by the manufacturing apparatus 2 shown in FIGS. 1 and 2 is shown in Table 1 below.

  The free coil diameter before and after correction when the saw wire 28 is obtained by the manufacturing apparatus 2 that does not have the tension load device 14 is shown in Table 2 below.

  The graph of FIG. 3 shows the change in the free coil diameter due to correction. In this graph, a round point represents the free coil diameter when the saw wire 28 is obtained by the manufacturing apparatus 2 shown in FIGS. In this graph, the square point represents the free coil diameter when the saw wire is obtained by a manufacturing apparatus having the straightener 10 but not the tension load device 14.

  As is apparent from FIG. 3, when the wire 24 having a small free coil diameter D1 is corrected by the manufacturing apparatus 2 shown in FIGS. 1 and 2, the correction rate D2 / D1 is extremely large. On the other hand, when the strand 24 having a large free coil diameter D1 is corrected by the manufacturing apparatus 2 shown in FIG. 1, the correction rate D2 / D1 is not so large. In the manufacturing method according to the present invention, the dependence of the free coil diameter D2 of the saw wire 28 on the free coil diameter D1 of the strand 24 is small. Therefore, even if the variation of the free coil diameter D1 of the strand 24 is large, the variation of the free coil diameter D2 of the saw wire 28 is small. By this manufacturing method, the saw wire 28 having an appropriate habit can be obtained.

  In this manufacturing method, some variation in the free coil diameter D1 of the strand 24 after the final wire drawing is allowed. This manufacturing method does not require delicate adjustment of the die angle. By this manufacturing method, a high-quality saw wire 28 can be obtained at a low cost.

  The free coil diameter D2 can be appropriately set according to the use, material, diameter, and the like of the saw wire 28. A typical free coil diameter D2 is 300 mm to 500 mm. The general correction rate D2 / D1 is 1.01 to 3.00.

  The ratio of the tension applied to the strand 24 when the strand 24 passes through the straightener 10 to the breaking load of the strand 24 is preferably 30% to 60%. By the manufacturing method in which this ratio is 30% or more, the saw wire 28 with a small variation in the free coil diameter D2 can be obtained. In this respect, the ratio is more preferably equal to or greater than 40%. In the manufacturing method in which this ratio is 60% or less, disconnection is unlikely to occur. In this respect, the ratio is more preferably equal to or less than 55%.

  The ratio of the surface hardness H1 of the correction roller 26 to the hardness H2 of the wire 24 is preferably 90% or more and 150% or less. The correction roller 26 having this ratio of 90% or more is not easily worn. Accordingly, the replacement frequency of the correction roller 26 is small. From this viewpoint, the ratio is more preferably 100% or more. The correction roller 26 having this ratio of 150% or less is difficult to scratch the surface of the wire 24. A saw wire 28 having an excellent appearance can be obtained by the correction roller 26 having this ratio of 150% or less. In this respect, the ratio is more preferably equal to or less than 130%.

  The surface hardness H1 of the correction roller 26 is measured by a Vickers hardness test. An indenter is pushed into the outer peripheral surface of the correction roller 26.

  The hardness H2 of the strand 24 is measured by a Vickers hardness test. A test specimen for measurement is embedded in a resin block. An indenter is pushed into a cross section perpendicular to the length direction of the wire 24. The indenter is pushed into the position of 20 μm from the surface toward the center of the cross section.

  The diameter of the correction roller 26 is preferably 60 times or more and 100 times or less the diameter of the wire 24. The straightening roller 26 provides a saw wire 28 with a small variation in the free coil diameter D2. From this viewpoint, the diameter of the correction roller 26 is more preferably 70 times or more and 90 times or less than the diameter of the wire 24.

  The number of the correction rollers 26 in the correction device 10 is preferably 11 or more. With this corrector 10, a saw wire 28 with a small variation in the free coil diameter D2 is obtained. From this viewpoint, the number is more preferably 17 or more. From the viewpoint of efficiency, this number is preferably 30 or less.

[Experiment I]
[Example 1]
A saw wire was manufactured using the manufacturing apparatus shown in FIGS. The total length of this saw wire is 500 km. The manufacturing conditions are as follows.
Saw wire diameter: 0.13 mm
Straightening roller diameter: 10mm
Number of straightening rollers: 30
Straightening roller surface hardness H1 (Hv): 800
Wire hardness H2 (Hv): 800
Wire tension in straightener: 26N
Breaking load of wire: 48N

[Comparative Example 1]
A saw wire was manufactured in the same manner as in Example 1 except that no tension load device was provided. The tension | tensile_strength of the strand in an orthodontic device was 8N.

[Comparative Example 2]
A saw wire was manufactured in the same manner as in Example 1 except that the straightener and the tension load device were not provided.

[Evaluation]
At a position where the distance from the front end of the saw wire is shown in Table 3 below, a test piece having a length of 2.5 m was cut and the free coil diameter was measured. The results are shown in Table 3 below and FIG.

  As shown in FIG. 4, in the saw wire obtained by the manufacturing method according to Example 1, the variation in the free coil diameter is small.

[Experiment II]
[Example 2]
Ten saw wires were continuously manufactured using the manufacturing apparatus shown in FIGS. The total length of each saw wire is 500 km. The total length of the ten saw wires is 5000 km. The manufacturing conditions are the same as in Example 1.

[Comparative Example 3]
Ten saw wires were manufactured in the same manner as in Example 2 except that no tension load device was provided. The tension | tensile_strength of the strand in an orthodontic device was 12N.

[Comparative Example 4]
Ten saw wires were manufactured in the same manner as in Example 2 except that the straightener and the tension load device were not provided.

[Evaluation]
A test piece having a length of 2.5 m was cut from the vicinity of the rear end of each saw wire, and the free coil diameter was measured. The results are shown in Table 4 below and FIG.

  As shown in FIG. 5, in the manufacturing method according to Example 2, the variation in the free coil diameter among the ten saw wires is small.

[Experiment III]
[Example 3-6]
A saw wire was produced in the same manner as in Example 1 except that the surface hardness H1 of the straightening roller was as shown in Table 5 below.

[Evaluation]
The appearance of the saw wire was observed with a microscope, and an evaluation point was assigned. The results are shown in Table 5 below and FIG. The larger the value, the better the appearance.

  From Table 5 and FIG. 6, it can be seen that the preferred range of the ratio of the hardness H1 of the straightening roller to the hardness H2 of the strand is 150% or less.

  The saw wire obtained by the production method according to the present invention is suitable not only for cutting silicon ingots but also for cutting artificial quartz, cemented carbide, ceramics and the like. A saw wire having abrasive grains on its surface can also be produced by the production method according to the present invention.

DESCRIPTION OF SYMBOLS 4 ... Wire drawing machine 6 ... Taking-up device 8 ... Measuring roller 10 ... Straightener 14 ... Tension load device 24 ... Elementary wire 26 ... Straightening roller 28 ... Saw wire

Claims (6)

A process of drawing the wire and setting the wire, and applying a tension to the wire with a tension applying device, and abutting the wire to cause plastic deformation of the wire A method for manufacturing a saw wire, which includes a step of correcting a characteristic of a strand with a straightener having a straightening roller.   The manufacturing method according to claim 1, wherein the diameter of each straightening roller is 60 times or more and 100 times or less than the diameter of the wire in contact with the straightening roller.   The manufacturing method according to claim 1 or 2, wherein a ratio of a tension applied to the strand when the strand passes through the straightener to a breaking load of the strand is 30% or more and 60% or less. .   The method according to any one of claims 1 to 3, wherein the ratio of the surface hardness of each straightening roller to the hardness of the wire is 90% or more and 150% or less.   The manufacturing method according to any one of claims 1 to 4, wherein a number of correction rollers are arranged in a staggered manner in the correction device, and the number of these correction rollers is 11 or more. (1) A wire drawing machine for drawing a wire and setting the wire.
(2) A straightener having a number of straightening rollers that abut against the strands and cause plastic deformation of the strands, and is located downstream of the wire drawing machine;
And (3) A saw wire manufacturing apparatus provided with a tension applying device that is located downstream of the straightening device and applies tension to the strands of the straightening device.

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