WO2017073843A1

WO2017073843A1 - Crimped saw wire with a flat shape

Info

Publication number: WO2017073843A1
Application number: PCT/KR2016/000688
Authority: WO
Inventors: Byung Ho Lee; Gwang Weon YU
Original assignee: Hongduk Industrial Co., Ltd.
Priority date: 2015-10-29
Filing date: 2016-01-22
Publication date: 2017-05-04
Also published as: KR20170050068A

Abstract

A crimped saw wire with a flat shape includes, when a section of the crimped saw wire, which is cut in a direction perpendicular to a length direction of the crimped saw wire, is seen from the length direction of the crimped saw wire: a major axis portion, facing surfaces of which are in parallel to each other, when a circular section is pressurized at both sides thereof; and a minor axis portion protruding in a round shape from both ends of the major axis portion.

Description

CRIMPED SAW WIRE WITH A FLAT SHAPE

One or more exemplary embodiments relate to a crimped saw wire with a flat shape, and more particularly, to a crimped saw wire with a flat shape, wherein a major axis portion and a minor axis portion are formed by pressurizing the saw wire of a circular section at both sides thereof, in order to increase an efficiency of supplying and discharging abrasive particles and to reduce a quality deviation of an object.

Generally, saw wires used in a saw machine cut an object by contacting and driving through the object with an appropriate pressure, together with a cutting material that is a mixture of an abrasive material, such as silicon carbide powder, diamond powder, etc., with an oil, etc.

A method of cutting a hard material, for example, a silicon block, by using the saw wires is as follows. The saw wires are wound around a plurality of rollers having a plurality of grooves, and the saw wires are driven through the silicon block, which is the object to cut, to press the object by a constant force. Here, a cutting material is spilled between the saw wires and the object to cut the silicon block by a cutting operation of abrasive particles. This type of cutting method is referred to as a grain-type method.

In addition to the cutting method that cuts an object by spilling a cutting material between the saw wires and the object, there is a method of cutting a silicon block, according to which an abrasive material is proactively fixed onto the saw wires by a resin or plating to cut the silicon block. This type of cutting method is referred to as a fixed-type method. Both the grain-type and the fixed-type method have the same cutting principle, that is, interposing an abrasive material between the saw wires and the object.

According to the cutting method using the saw wires, cutting dust is generated, and the cutting dust is discharged to the outside by the saw wires. However, when the cutting dust is not sufficiently discharged and remains in the saw machine, the cutting performance may deteriorate. To solve this, a continuous crimp is formed in the saw wires to improve supply power of a cutting material and to rapidly discharge the cutting dust generated during the cutting process, and thus, the cutting process is performed at a high speed without deteriorating a surface quality of an object.

A saw wire 10 according to the conventional art, in which a continuous crimp is formed, will be described by referring to FIGS. 1 and 2.

The saw wire 10 according to the conventional art, in which the continuous crimp is formed, has a circular section, which is cut in a direction perpendicular to a length direction of the saw wire 10. An abrasive material 20 is interposed between the saw wire 10 and an object 30, so as to cut the object 30.

The crimp of the saw wire 10 according to the conventional art has a wave shape that is curved in a direction that is perpendicular to the length direction of the saw wire 10, and the crimp is formed also in a direction that is perpendicular both to the direction that is perpendicular to the length direction of the saw wire 10 and to the length direction of the saw wire 10. Thus, when the cut surface of the saw wire 10, which is cut in the direction perpendicular to the length direction of the saw wire 10, is seen from the length direction of the saw wire 10, the circular section is formed as illustrated in FIG. 2 and the crimp is formed in upper and lower and right and left portions of the circular section.

However, the saw wire 10 according to conventional art may have the following problems.

First, when the saw wire 10 is continually used, the saw wire 10 having the circular section is worn out by the shape of the circular section. Referring to FIG. 2, in general, the saw wire 10 is used until about 10% of the saw wire 10 is worn out. However, since the saw wire 10 is worn out by the shape of the circular section, a thickness deviation of the object 30 that is about 10% occurs between an initial cutting process and a last cutting process, together with quality deterioration. That is, a thickness of the object 30 that is cut in the initial cutting is different from a thickness of the object 30 that is cut in the last cutting.

Also, in the initial cutting, the abrasive material 20 may be applied to the saw wire 10 by a higher degree of content, due to a soft plating layer which exists on a surface of the saw wire 10. However, the abrasive material 20 becomes less applied to the saw wire in the last cutting, because the plating layer is removed together with the object 30, when the object 30 is cut. Also, the cutting material may be contaminated due to the plating element.

Japanese Patent No. 2011-189444 discloses a method of improving an ability of supplying an abrasive material by etching a wire surface by electrolytic separation to form grooves in the wire surface, which are apart from each other by a predetermined distance, and facilitating an application of the abrasive material onto the grooves. However, although in an initial stage of cutting, this method has an effect of containing the abrasive material, i.e., the effect does not continue since the wire surface itself is worn out.

One or more exemplary embodiments include a crimped saw wire with a flat shape, wherein a major axis portion and a minor axis portion are formed by pressurizing the saw wire of a circular section at both sides thereof so as to increase an efficiency of supplying and discharging abrasive particles, and wherein a crimp is formed to have a constant cycle in a length direction of the saw wire and to have a wave shape that is curved in a length direction of the major axis portion so as to decrease a deviation of a thickness and a quality of an object, when the object is cut.

According to one or more exemplary embodiments, a crimped saw wire with a flat shape includes, when a section of the crimped saw wire, which is cut in a direction perpendicular to a length direction of the crimped saw wire, is seen from the length direction of the crimped saw wire: a major axis portion, facing surfaces of which are in parallel to each other, when a circular section is pressurized at both sides thereof; and a minor axis portion protruding in a round shape from both ends of the major axis portion, wherein a distance between the facing surfaces of the major axis portion is referred to as a minor axis, and a sum of a length of the major axis portion, a protrusion height in which the minor axis portion protrudes from an end of the major axis portion, and a protrusion height in which the minor axis portion protrudes from the other end of the major axis portion is referred to as a major axis, and a length of the major axis is greater than a length of the minor axis.

A continuous crimp may be formed in the crimped saw wire. The length direction of the crimped saw wire may be perpendicular to a length direction of the major axis portion. The continuous crimp may have a constant cycle in the length direction of the crimped saw wire, and may have a wave shape that is curved in the length direction of the major axis portion.

An aspect ratio indicating a ratio of the length of the major axis to the length of the minor axis may be about 1.01 to about 5.00. The length of the major axis may be about 0.05 mm to about 0.750 mm, and the length of the minor axis may be about 0.025 mm to about 0.500 mm.

A cycle of the continuous crimp may be referred to as a unit crimp, and an average pitch of the unit crimp may be about five times to about fifty times the length of the major axis. A cycle of the continuous crimp may be referred to as a unit crimp, and an average wave height of the unit crimp may be about one point one times to about three times the length of the major axis.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to the one or more of the above exemplary embodiments, the saw wire of the circular section is pressurized at both sides thereof to form the major axis portion and the minor axis portion, and thus, an efficiency of supplying and discharging abrasive particles is increased.

Also, the crimp has a constant cycle in the length direction of the saw wire, and has a wave shape that is curved in the length direction of the major axis portion. Thus, the abrasion of the saw wire mainly occurs in the minor axis portion. Accordingly, the life span of the saw wire is increased, a thickness and quality deviation of an object is reduced, and a cutting efficiency and a maximum cutting speed are increased with an increased cutting surface pressure.

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic plan view of a crimped saw wire according to a conventional art;

FIG. 2 is a cross-sectional view of a crimped saw wire according to a conventional art;

FIG. 3 is a schematic plan view of a crimped saw wire with a flat shape according to an exemplary embodiment;

FIG. 4 is a cross-sectional view of a crimped saw wire with a flat shape according to an exemplary embodiment; and

FIG. 5 is a schematic plan view of a crimped saw wire with a flat shape according to another exemplary embodiment.

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the exemplary embodiments are merely described below, by referring to the figures, to explain aspects of the present description.

One or more exemplary embodiments relate to a saw wire used in a wire saw machine, the saw wire being used to cut or slice a hard material, such as a semiconductor, ceramic, and a cemented carbide.

Hereinafter, exemplary embodiments will be described in detail by referring to the accompanying drawings.

One or more exemplary embodiments relate to a crimped saw wire 100 with a flat shape, and more particularly, to the crimped saw wire 100 in which a major axis portion 120 and a minor axis portion 130 are provided by pressurizing the saw wire of a circular section at both sides thereof.

Referring to FIGS. 3 and 4, the crimped saw wire 100 with a flat shape is manufactured by cold-rolling a strand having a circular section, on which a drawing process is performed. In detail, when a section of the saw wire 100, which is cut in a direction perpendicular to a length direction of the saw wire 100, is seen from the length direction of the saw wire 100, the saw wire 100 includes a major axis portion 120, facing surfaces of which are parallel to each other when the circular section is pressurized at both sides thereof, and a minor axis portion 130 protruding in a round shape from both ends of the major axis portion 120.

That is, the major axis portion 120 includes a pair of parallel flat surfaces, and the minor axis portion 130 is formed as curved surfaces at both ends of the major axis portion 120. Referring to FIG. 4, with respect to the section of the saw wire 100, a pair of straight lines of the major axis portion 120 extend in parallel to each other in an up and down direction, in a central portion of the section, and the minor axis portion 130 protrudes as round shapes in upper and lower positions of the major axis portion 120. Here, a distance between the pair of straight lines of the major axis portion 120 is indicated as a minor axis b, and a sum of a length of the major axis portion 120, and a protrusion height in which the minor axis portion 130 protrudes from an end of the major axis portion 120 and a protrusion height in which the minor axis portion 130 protrudes from the other end of the major axis portion 120 is indicated as a major axis a. The major axis a is longer than the minor axis b.

With respect to the section of the saw wire 100, it is desirable that the minor axis portion 130 have a semicircular shape having a constant curvature. However, the minor axis portion 130 may have an arc shape, or a semielliptical shape having an inconstant curvature. It is desirable that the major axis portion 120 include a pair of parallel straight lines. However, the major axis portion 120 is not limited thereto. The major axis portion 120 may have an inclined shape. Also, the major axis portion 120 may have an irregular shape, for example, of a hacksaw, rather than a straight line, thereby reducing a contact area between the major axis portion 120 and an object 140, and minimizing friction between the major axis portion 120 and a cutting surface of the object 140.

The crimped saw wire 100 with a flat shape may not have a crimp or may have a continuous crimp. The continuous crimp may have a constant cycle in the length direction of the saw wire 100 and may have a wave shape that is curved in a length direction of the major axis portion 120. Here, the length direction of the major axis portion 120 and the length direction of the saw wire 100 are perpendicular to each other.

Referring to FIG. 3, the continuous crimp has a constant cycle, and one cycle of the continuous crimp is referred to as a unit crimp 110. A length of the cycle of the unit crimp 110 is referred to as a pitch P, and a height between a highest point and a lowest point of the unit crimp 110 is referred to as a wave height H.

According to an exemplary embodiment of manufacturing the crimp, a pretilt wire rod of 5.5 mm that has a carbon content of 0.70% to 1.3% is prepared. After a drawing process is performed twice on the wire rod, a heat treatment is performed on the wire rod for the wire rod to have a diameter of 0.155 mm. Next, the wire rod is rolled by using a rolling device, and then, a crimp having a wave shape that is curved in the length direction of the major axis portion 120, which is perpendicular to the length direction of the saw wire 100, is formed via a crimp generating device. Here, the rolling process and the crimp generating process may be performed in the opposite order.

A method of cutting the object 140 by using the crimp of the saw wire 100 is as follows. The crimp is formed to have a wave shape that is curved in the length direction of the major axis portion 120, which is perpendicular to the length direction of the saw wire 100. Thus, when the object 140 is cut or sliced by using the saw wire 100, the object 140 is put in the direction that is perpendicular to the length direction of the major axis portion 120. In this case, the minor axis portion 130 protruding in a round shape at an end of the major axis portion 120 contacts the object 140. Then, with an appropriate pressure, the saw wire 100 is driven over the object 140.

When the object 140 is cut by the saw wire 100 by this method, a cutting groove 141 having a width of the minor axis b is formed in the object 140, as illustrated in FIG. 4.

When the cutting process continues, an abrasion of the saw wire 100 mainly occurs in the minor axis portion 130, since the minor axis portion 130 contacts the object 140 by receiving the pressure. However, the major axis portion 120 including the flat surfaces contacts both side surfaces of the cutting groove 141, in the cutting process. Thus, the major axis portion 120 receives less pressure than the minor axis portion 130 formed as curved surfaces, and is relatively less worn out than the minor axis portion 130. (Generally, a curved surface contacting the object 140 is worn out more than a flat surface contacting the object 140, because abrasion occurs when the curved surface is sharpened). The major axis portion 120 tends not to be worn out so that a thickness of the cutting groove 141 of the object 140 is maintained constant.

An aspect ratio a/b indicating a ratio of a length of the major axis a to a length of the minor axis b may be 1.01 to 10.00. It is desirable that the aspect ratio be 1.01 to 5.00, by taking into account a manufacturing condition of the saw wire 100. For example, when the aspect ratio is equal to or higher than 5.00, the length of the major axis a is much greater than the length of the minor axis b, and thus, it is difficult to roll the saw wire 100.

It is desirable that the length of the minor axis b of the saw wire 100 be within a range of 0.025 mm to 0.500 mm. When the object 140 is cut and sliced by the saw wire 100, it is desirable that a width of the cutting groove 141 formed in the object 140 be minimized. When the object 140 is cut and sliced by the saw wire 100, the minor axis portion 130 contacts the object 140 to cut and slice the object 140, and thus, the width of the cutting groove 141 formed in the object 140 has the minor axis b.

Accordingly, it is desirable that the length of the minor axis b be small. That is, it is desirable that the length of the minor axis b be within 0.500 mm. If the length of the minor axis b is too small, a cutting strength is decreased, due to thinning. Thus, it is desirable that the length of the minor axis b be equal to or greater than 0.025 mm. It is desirable that the length of the major axis a be 0.05 mm to 0.750 mm, by taking into account the manufacturing condition of the saw wire 100, which includes the aspect ratio a/b and the length of the minor axis b.

When the length of the minor axis b is 0.025 mm, and the length of the major axis a is 0.05 mm, the aspect ratio a/b is 2. Also, when the length of the minor axis b is 0.500 mm, and the length of the major axis a is 0.750 mm, the aspect ratio a/b is 1.5. The aspect ratio a/b may vary by selecting the length of the minor axis b between 0.025 mm to 0.500 mm and selecting the length of the major axis a between 0.05 mm and 0.750 mm. By taking into account the manufacturing condition, it is desirable that the aspect ratio a/b be 1.01 to 5.00.

It is desirable that a diameter of the circular section before pressurizing the saw wire 100 at both sides thereof be 0.05 mm to 0.50 mm, by taking into account the manufacturing condition of the saw wire 100, which includes the aspect ratio a/b, the length of the minor axis b, and the length of the major axis a.

It is desirable that an average pitch P of the unit crimp 110 be five times to fifty times the length of the major axis a. If the length of the unit crimp 110 is too great, an efficiency of supplying and discharging an abrasive material 150 due to the continuous crimp may be decreased. Also, if the length of the unit crimp 110 is too small, it may be difficult to form the crimp. Thus, it is desirable that the average pitch P of the unit crimp 110 be five times to fifty times the length of the major axis a.

It is desirable that an average wave height H of the unit crimp 110 be one point one times to three times the length of the major axis a. If the average wave height H is too small, the effect of the continuous crimp may not be generated. If the average wave height H is too great, the efficiency of supplying and discharging the abrasive material 150 may be decreased, and it may be difficult to form the crimp. Thus, it is desirable that the average wave height H of the unit crimp 110 be one point one times to three times the length of the major axis a.

The unit crimp 110 may have an asymmetrical or a symmetrical shape. Referring to FIG. 3, the unit crimp 110 has a symmetrical shape, and referring to FIG. 5, a unit crimp 210 has an asymmetrical shape. The asymmetrical crimp may include a short crimp area 211, and a long crimp area 212. The asymmetrical crimp may improve a retaining force of a cutting material, thereby increasing a cutting speed, and may make it possible to smoothly discharge cutting dust, thereby preventing a quality deterioration of a cutting surface of the object 140. To this end, it is desirable that a ratio of the short crimp area 211 to the long crimp area 212 be 1:1.2 to 1:1.4.

According to an exemplary embodiment, the saw wire 100 with a flat shape may have a carbon content of 0.7 to 1.32 wt%, a tensile strength of 300 to 700 kgf/mm², and an elongation of 0.1 to 2.0 % in a section of 5 to 10% of a cutting strength, and an elongation to break of 1.5 to 3.5 %.

The saw wire 100 with a flat shape described above has the following effects.

First, according to the conventional art, a section of the saw wire 10 has a circular shape, and thus, when the object 30 is cut by the saw wire 10, the saw wire 10 is worn out by the shape of the circular section. However, according to the exemplary embodiments, the saw wire 100 includes the minor axis portion 130 including curved surfaces and the major axis portion 120 including flat surfaces, and thus, the abrasion mainly occurs in the minor axis portion 130. Thus, the saw wire 100, in which the minor axis portion 130 is mainly worn out, is worn out less than the saw wire 10 according to the conventional art, which is worn out by the shape of the circular section. Thus, the saw wire 100 has a longer life span than the saw wire 10.

Also, the saw wire 10 according to the conventional art, which is worn out by the shape of the circular section, is used until about 10% of the thickness thereof is worn out. Thus, between an initial cutting process and a last cutting process, there is a decrease in a thickness and a quality of the object 30. However, in the saw wire 100 according to the exemplary embodiments, in which the minor axis portion 130 is mainly worn out, there is no decrease in a thickness and a quality of the object 140. That is, since the major axis portion 120 is not usually worn out, a distance between the flat surfaces of the major axis portion 120 may be maintained so that the thickness of the object 140 may not be reduced.

The saw wire 10 according to the conventional art, which is worn out by the shape of the circular section, is used until about 10% of the thickness thereof is worn out. However, the saw wire 100 according to the exemplary embodiments does not generate a decrease in the thickness of the object 140, and thus, the saw wire 100 may be continually used as the ratio of the major axis portion 120 is increased, based on the aspect ratio a/b. Thus, the life span of the saw wire 100 is increased.

Next, the saw wire 100 according to the exemplary embodiments may be thinned, since the saw wire 100 includes the major axis portion 120 and the minor axis portion 130 formed by pressurizing the circular section at both sides thereof. When the object 140 is cut by the saw wire 100, it is desirable that a width of the cutting groove 141 of the object 140 be minimized, in order to reduce a loss rate of the object 140. Since the circular section of the saw wire 100 according to the exemplary embodiments is pressurized at both sides thereof, the saw wire 100 may be thinned and a width d2 of the object 140, which is formed by saw wire 100 of FIG. 4 may be smaller than a width d1 of the object 30, which is formed by the saw wire 10 of FIG. 2. Accordingly, when the object 140 is cut by the saw wire 100, the width of the cutting groove 141 of the object 140 may be reduced, and the loss rate of the object 140 may be decreased.

The saw wire 100 according to the exemplary embodiments is thinned by pressurizing the circular section of the saw wire 100 at both sides thereof to form the major axis portion 120 and the minor axis portion 130. Accordingly, compared with the saw wire 10 according to the conventional art, a contact surface contacting the object 140 is reduced and a cutting surface pressure is increased. Therefore, a cutting efficiency and a maximum cutting speed may be increased. Also, according to the increase in the cutting efficiency, cutting material contamination due to a plating element of the saw wire 100 may be reduced. Also, according to the increase in the cutting surface pressure, an efficiency of supplying the abrasive material 150 may be increased and an efficiency of discharging cutting dust generated by the cutting process may be increased.

Next, when a polycrystalline silicon ingot having a size of 650 mm x 650 mm x 250 mm is cut into sixteen silicon blocks having a size of 156 mm x 156 mm, characteristics of exterior appearances of silicon bricks, which are cut by four types of wires having the above-described structure, are comparatively shown.

Here, the working condition includes a wire supply speed of 12 m/sec and a silicon ingot cutting speed of 800 μm/min, and a cutting speed when the saw wire which penetrates the silicon ingot in the final cutting of the silicon ingot is bent by 15 mm, is measured as a maximum cutting speed, in order to compare the cutting performance. The measurements are shown in the following table.

Division	Major axis a(μm)	Minor axis b(μm)	a:b	Pitch (mm)	Brick Cutting Result
Division	Major axis a(μm)	Minor axis b(μm)	a:b	Pitch (mm)	Maximum Cutting Speed(μm/min)	Numberof cut bricks	Defects	Success rate	Kerfloss
1^st exemplary embodiment	120.1	110.5	1:1.09	3.2	1329	240	7	81.9%	95
2^nd exemplary embodiment	129.2	99.1	1:1.30	3.2	1507	240	5	84.1%	93
3^rd exemplary embodiment	132.6	89.5	1:1.48	3.2	1628	240	4	85.3%	90
1^st comparative embodiment	115.7	115.9	1:1.00	3.2	1305	240	12	81.6%	100

As shown in Table 1, when the silicon ingot is cut, a defect occurrence rate of bricks is significantly lower in the case of the first through third exemplary embodiments than the 1^st comparative embodiment.

The success rate shown in Table 1 is determined based on a quality deviation according to a difference of thicknesses of the object between an initial cutting and a last cutting. According to the firstthrough third exemplary embodiments, the thickness of the object is changed less and the quality deviation is smaller between the initial cutting and the last cutting, compared with the first comparative embodiment. Accordingly, the success rate is higher in the case of the first through third exemplary embodiments than the first comparative embodiment.

Also, the maximum cutting speed is higher in the case of the first through third exemplary embodiments than the first comparative embodiment, since abrasion efficiency is increased due to a relative increase in an abrasion surface pressure for the pressurized surface.

The kerfloss indicates a width of the cutting groove 141, which is formed when the saw wire 100 penetrates the object 140, and the kerfloss is related to a loss rate of the object 140. As the kerfloss decreases, the loss rate of the object 140 decreases. When it is assumed that the kerfloss of the first comparative embodiment is 100, the kerfloss according to the first through third exemplary embodiments is 90 to 95, and thus, it is understood that the loss rate of the object 140 is lower in the case of the first through third exemplary embodiments than the first comparative embodiment.

As shown above, when the circular section of the saw wire 100 is pressurized at both sides thereof to include the major axis portion 120 and the minor axis portion 130, the maximum cutting speed may be increased and the defect rate may be decreased. Also, the success rate may be increased and the loss rate of the object 140 may be decreased. Therefore, the quality of the object 140 may be improved.

As described above, according to the one or more of the above exemplary embodiments, the saw wire of the circular section is pressurized at both sides thereof to form the major axis portion and the minor axis portion, and thus, an efficiency of supplying and discharging abrasive particles is increased.

It should be understood that exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each exemplary embodiment should typically be considered as available for other similar features or aspects in other exemplary embodiments.

While one or more exemplary embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.

Claims

A crimped saw wire with a flat shape, the crimped saw wire comprising, when a section of the crimped saw wire, which is cut in a direction perpendicular to a length direction of the crimped saw wire, is seen from the length direction of the crimped saw wire:

a major axis portion, facing surfaces of which are in parallel to each other, when a circular section is pressurized at both sides thereof; and

a minor axis portion protruding in a round shape from both ends of the major axis portion,

wherein a distance between the facing surfaces of the major axis portion is referred to as a minor axis, and a sum of a length of the major axis portion, a protrusion height in which the minor axis portion protrudes from an end of the major axis portion, and a protrusion height in which the minor axis portion protrudes from the other end of the major axis portion is referred to as a major axis, and

a length of the major axis is greater than a length of the minor axis.
The crimped saw wire of claim 1, wherein a continuous crimp is formed in the crimped saw wire,

the length direction of the crimped saw wire is perpendicular to a length direction of the major axis portion, and

the continuous crimp has a constant cycle in the length direction of the crimped saw wire, and has a wave shape that is curved in the length direction of the major axis portion.
The crimped saw wire of claim 1 or 2, an aspect ratio indicating a ratio of the length of the major axis to the length of the minor axis is about 1.01 to about 5.00.
The crimped saw wire of claim 1 or 2, wherein the length of the major axis is about 0.05 mm to about 0.750 mm, and the length of the minor axis is about 0.025 mm to about 0.500 mm.
The crimped saw wire of claim 1 or 2, wherein a diameter of the circular section, before the crimped saw wire is pressurized at both sides thereof, is about 0.05 mm to about 0.50 mm.
The crimped saw wire of claim 2, wherein a cycle of the continuous crimp is referred to as a unit crimp, and

an average pitch of the unit crimp is about five times to about fifty times the length of the major axis.
The crimped saw wire of claim 2, wherein a cycle of the continuous crimp is referred to as a unit crimp, and

an average wave height of the unit crimp is about one point one times to about three times the length of the major axis.
The crimped saw wire of claim 2, wherein a cycle of the continuous crimp is referred to as a unit crimp, and the unit crimp has an asymmetrical or a symmetrical shape.