JPH1110515A - Main roller of wire saw taking deformation by tension into account - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the cutting accuracy of a workpiece from being reduced even if a main roller is curved by the tension of a wire saw wrapped around the main roller. SOLUTION: A main roller 22 comprises a hollow core bar 221 and a covering member 222 which is made of a urethane resin and is fixed concentrically to the outside surface of the core bar 221. The core bar 221 is shaped convexly such that it is bulged outward slightly in the radial direction at the center in the axial direction compared with both ends in the axial direction. Since the uniformly thick covering member 222 is fixed to the outer surface of the convex core bar 221, the cross section of the main roller 22 is shaped convexly in the axial direction and hence the outer surface thereof can be held flat in the axial direction even if the wire tension is applied thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire saw for cutting into thin slices (wafers) by supplying a slurry containing abrasive grains to a wire traveling on a hard and brittle material such as a semiconductor material and a magnetic material. Belongs to the technical field.

[0002]

2. Description of the Related Art FIG. 4 is a side view of a conventional wire saw including a work processing section 10 and a control section 100 for controlling the traveling of the wire and the entire apparatus, without a cover. A column 60 is erected on the base 50 of the wire saw.
The workpiece processing unit 10 and the workpiece support mechanism 70 are attached to one side of the workpiece 0. Work processing part 10 of this wire saw
Includes a wire row 16 formed by winding one wire 14 between, for example, three main rollers 12, 12, 12 arranged so as to be parallel to each other, and the wire row 16 containing abrasive grains. Slurry nozzles 18, 18 for supplying aqueous or oily slurry.

[0003] The particle size of the abrasive grains contained in the slurry is usually on the order of several tens of microns.
Is carried to the cut surface of the work W.

FIG. 5 is a sectional view in the axial direction of a conventional main roller 12, 12, 12 constituting the work processing section 10. As shown in FIG.
The main rollers 12, 12, 12 are cylindrical mandrel 1
A coating member 122 made of urethane resin or the like having a uniform thickness is fixed to the outer surface of the core 21 so as to be concentric with the mandrel 121. Annular grooves are formed on the outer surface of the covering member 122 at a predetermined pitch, and guided by the annular grooves formed on the main rollers 12, 12, 12, respectively.
One wire is wound multiple times between the main rollers 12, 12, 12.

When the reel 101 unwinds and winds up the wire 14, the wire row 14 travels at a predetermined speed in accordance with the rotation direction of the reel 101, and at the same time, the wire row 16 of the work processing section 10 also travels. I do. Reel 10
1 is controlled by a reel rotation motor. The unwound wire 14 is traversed up and down by the traverse mechanism 104, and is further guided by the tension applying mechanism 106 to the workpiece processing unit 10. Therefore, a predetermined tension is always applied to the wire row 16 of the work processing unit 10.

The work holding mechanism 70 attached to the column 60 can move up and down with respect to the wire row 16.
A work W made of a hard and brittle material is held. The work W held by the work holding mechanism 70 descends and is pressed against and contacts the traveling wire row 16. At this time, a slurry containing abrasive grains is supplied from the slurry nozzle 18 to the wire row 16. The slurry containing the abrasive grains is brought into the cut surface of the work W, and the work W is cut by the lapping action for a relatively long time.

A reel 101 is driven by a reel rotating motor.
By reversing the rotation direction, the traveling direction of the wire row of the work processing portion can be reversed.

[0008]

The wire array 1
The wire 14 constituting the wire 6 must be wound between the main rollers 12, 12, 12 with a tension t necessary for cutting the work W.

As shown in FIG. 6, the tensions t, t exerted on the main roller 12 by one turn of the wire 14 uniformly act on the tangential direction of the main roller 12 around which the wire 14 is wound, and its magnitude is large. Is set to about 2.5 kg, for example. The resultant force T of the tensions t, t
2, 12, 12 work in the direction of drawing to the center of the work cutting part 10, and its size is about 4.4 kg. Since the wire row 16 is composed of several hundred wires in the axial direction, when the resultant force T is viewed over the entire wire row 16, the size becomes several to several tens tons.

That is, the central attraction T applied to the main roller 12 is generated for each of the wires 14 forming the wire row 16, and therefore, one main roller 12
Is increased in proportion to the number of turns of the wire 14. Therefore, as the length of the main roller 12 increases in the axial direction, the total amount of the central attraction T applied to the main roller 12 increases. The central attraction T applied to the main roller 12 is maximum at the axial center of the main roller 12. Therefore, as shown by the imaginary line in FIG. 5, the main roller 12 during the cutting operation has a concave portion at the axial center as a whole (upper side in FIG. 5) in contact with the wire row 16 as shown by the imaginary line in FIG. Deforms into a curved shape. Note that, in practice, the amount of deformation of the main roller 12 due to the central direction attractive force T is very small, and is about several tens of microns even in the axial center where the amount of deformation is the largest, but for convenience of explanation, FIG. The degree of deformation is exaggerated. Also, the side opposite to the side in contact with the wire row 16 (lower side in FIG. 5) is deformed in accordance with the deformation on the side in contact with the wire row 16 (upper side in FIG. 5). Since there is no relationship, it is not shown in FIG.

Such a curved deformation of the main roller 12 is caused by the wire train 16 that is guided by the main roller 12 and travels.
Therefore, there is a problem that the cutting precision of the sliced piece (wafer) differs depending on the position in the axial direction.

[0012]

SUMMARY OF THE INVENTION According to the present invention, a wire array formed by wires wound at a predetermined pitch is reciprocated between a plurality of main rollers to supply a slurry containing abrasive grains on the wires. A main roller of a wire saw for performing a cutting process by pressing a workpiece against the wire row, wherein the main roller has a hollow cylindrical mandrel and a groove fixed to an outer surface of the mandrel. The above problem is solved by a main roller of a wire saw, wherein the main roller has a shape in which the central portion in the axial direction projects radially outward from both ends in the axial direction.

According to an embodiment of the present invention, as in claim 2, the shape of the mandrel is formed in a middle-high shape in which the central portion in the axial direction projects outward from both ends in the axial direction. The thickness of the axially central portion of the covering member fixed to the mandrel is formed thicker than the axially opposite end portions, and
As in the fourth aspect, it is conceivable that the thickness of the central portion in the axial direction of the mandrel is formed thicker than the both ends in the axial direction. It should be noted that these embodiments can be implemented in combination.

[0014]

According to the present invention, the main roller has a shape in which the central portion in the axial direction projects radially outward from both ends in the axial direction. Even if is curved and deformed,
As a whole, the outer surface of the main roller can be flat when viewed in the axial direction.

[0015]

1 to 3, an embodiment of a main roller of a wire saw according to the present invention will be described. In addition, the overall structure of the wire saw, the running method of the wire 14,
The control unit 100 for controlling the entire apparatus and the method of cutting the work W by this apparatus are the same as those of the conventional apparatus shown in FIG.

FIG. 1 is an axial sectional view of a main roller 22 of a wire saw according to a first embodiment of the present invention. This main roller 22 is provided on the outer surface of a hollow mandrel 221.
A covering member 222 made of urethane resin or the like is fixed and formed so as to be concentric with the mandrel 221. Mandrel 22
1 has a uniform thickness, a central portion in the axial direction is curved so as to slightly protrude outward from both ends in the axial direction, and has a middle-high shape. The mandrel 221 is made of metal, and
Since 2 is made of a synthetic resin, the former is usually higher in rigidity. As described above, since the covering member 222 having a substantially uniform thickness is fixed to the outer surface of the mandrel 221 having a middle and high shape,
The outer shape of the main roller 22 is a middle-high shape as a whole. The illustration of the grooves formed on the surface of the covering member 222 is omitted.

As described above, since the main roller 22 having a middle and high shape is used, the main roller
Even if a force due to the tension of the wire 14 and a work pressing force are applied to the central portion in the axial direction of 2, the concave portion due to the deformation of the middle and high portions of the main roller 22 cancel each other out, and the outer surface of the main roller 22 as a whole is in the axial direction. Flatten.

Next, FIG. 2 shows an axial sectional view of a second embodiment of the present invention. The main roller 32 has a hollow cylindrical mandrel 321 formed in a cylindrical shape having the same outer diameter as the conventional roller, and an outer surface of the mandrel 321 so as to be concentric with the mandrel 321. It is formed by fixing a covering member 322 made of urethane resin or the like. Coating member 32
The thickness of 2 changes so as to be slightly convex at the axial center portion as compared with the axial end portion. Accordingly, the outer diameter of the main roller 32 has a middle-thick shape in which the central portion has a larger diameter than the end portion as a whole.

Next, FIG. 3 shows an axial sectional view of a third embodiment of the present invention. The main roller 42 is formed by fixing a hollow mandrel 421 and a covering member 422 made of urethane resin or the like having a uniform thickness and concentric with the mandrel 421 on the outer surface of the mandrel 421. The thickness of the mandrel 421 changes so that the central portion in the axial direction slightly projects outward in the radial direction as compared with both end portions in the axial direction. As described above, since the coating member 422 having a uniform thickness is fixed to the outer surface of the mandrel 421 having the middle thickness in the axial direction, the axial cross section of the main roller 42 has a middle thickness as a whole. I have.

In FIGS. 1 to 3, for convenience of explanation, the central portions of the main rollers 22, 32, 42 in the axial direction are drawn to be considerably higher or thicker than the both ends in the axial direction. However, since the amount of curving deformation of the main rollers 22, 32, and 42 due to the actually generated center direction attractive force T is very small, the main roller is actually flat as a whole, offsetting the amount of curving deformation. Middle and high, or
What is necessary is just to make it into a bold shape.

[0021]

According to the present invention, the wire wound around the main roller exerts a force in the direction of pulling the main roller toward the center of the workpiece cutting portion, and even if the main roller is bent and deformed, the radial direction of the main roller is reduced. The original shape that protrudes outward cancels out the curved deformation, and as a whole, there is an effect that the main roller is maintained in a flat shape in the axial direction.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a first embodiment of a main roller of a wire saw of the present invention.

FIG. 2 is an axial sectional view of a second embodiment of the main roller of the wire saw of the present invention.

FIG. 3 is an axial sectional view of a third embodiment of the main roller of the wire saw according to the present invention.

FIG. 4 is a side view of the structure of a conventional wire saw, excluding a cover.

FIG. 5 is an axial sectional view of a main roller of a conventional wire saw.

FIG. 6 is an explanatory diagram of wire tension applied to a main roller.

[Explanation of symbols]

22, 32, 42: Main rollers 221, 32
1,421: mandrel 222,322,422: coating member 16: wire row 18: slurry nozzle W: work

Claims (4)

[Claims] 1. A wire array formed by wires wound at a predetermined pitch is reciprocated between a plurality of main rollers, a slurry containing abrasive grains is supplied on the wires, and a work is applied to the wire array. A main roller of a wire saw that performs cutting by pressing, wherein the main roller includes a hollow cylindrical mandrel, and a coating member having a groove formed and fixed to an outer surface of the mandrel. A main roller for a wire saw, wherein the roller has a shape in which a central portion in the axial direction projects radially outward from both ends in the axial direction. 2. The main roller of the wire saw according to claim 1, wherein the mandrel is formed in a middle and high shape in which a central portion in the axial direction projects radially outward from both ends in the axial direction. 3. The main roller of the wire saw according to claim 1, wherein the thickness of the coating member fixed to the mandrel at the central portion in the axial direction is thicker than the thickness at both ends in the axial direction. 4. The main roller of the wire saw according to claim 1, wherein a thickness of the central portion of the mandrel in the axial direction is formed larger than thicknesses of both ends in the axial direction.