JP3227718U - Molded saw wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double crimp molded saw wire which does not form a preferential cut surface during use.
A molded saw wire is made of a steel wire having two crimps in directions perpendicular to each other perpendicular to the axis of the molded saw wire. The waveforms applied are equal in both directions perpendicular to each other, only the phase introduced between both crimps differs. A feature of the forming wire is a projection that forms a convex trace with the corners connected by sides along the axis, with a number of corners of 3 or 4. That is, the sawwire is a quadrilateral or triangular spiral, which indicates a triangular or quadrilateral trace with a projection along the axis having three or four corners. Molded saw wires are inexpensive to make and have a spiral shape that does not give a preferred direction during cutting.
[Selection diagram] Fig. 1

Description

The present invention relates to a molded saw wire used for cutting hard and brittle materials such as silicon, sapphire, gallium arsenide and quartz.

Saw wires are used in saws for cutting hard and brittle materials. In saws, saw wires are spirally wound around a plurality of grooved winders to form a web. The saw wire is moved back and forth, and a viscous liquid containing abrasive particles called slurry is poured onto the web. Abrasive particles sandwiched between the workpiece and the saw wire wear the brittle material, thereby gradually cutting the workpiece.

Saw wire is a round and thin steel wire with high tensile strength. If the cutting length is long, for example, longer than 200 mm, there is a possibility that abrasive particles are not present at the outlet of the cutting portion and the cutting efficiency is locally reduced. This hinders the overall cutting speed of the manufacturing process. In order to overcome this, it has been proposed to provide a straight wire that is provided with a "local bend" and a straight segment connecting the bend between them, which is a "molded saw wire". The bent portion facilitates the slurry to be drawn into the cut portion, reducing the consumption of the abrasive toward the end of the cut portion.

Various proposals have been made to implement such a bent portion. First, a single zigzag crimp mounted on a steel wire was proposed (Japanese Unexamined Patent Publication No. 1988-0117836). However, in such a form, the zigzag plane does not match the cut portion, resulting in a non-linear cut. This issue was partially resolved by WO 2006/067062. Among them, a monofilament sawwire with two crimps is described, where each crimp has a pitch length and amplitude, and the crimps are arranged in at least two different planes. However, if one of the crimps predominates, the cutting will only be done by that crimp. In addition, the process is costly because two sets of crimp forming wheels are required to mount the crimp.

In order to provide a molded saw wire that does not have a preferred sewing plane and is efficient to manufacture, the inventor proposes:

An object of the present invention is to provide a double crimp saw wire that does not form a preferred cut surface during use.

This problem is solved by providing the molded saw wire according to claim 1. The molded saw wire comprises a steel wire. The steel wire has a small bend and has a substantially straight segment between the bends, thereby connecting the bends. The molded saw wire extends along the axis of the molded saw wire, for example, by keeping it taut under a small tension along the vertical. A center point can be defined for each orthogonal cross section of the steel wire. When these center points are connected, it becomes the center line of the steel wire.

The projection of the centerline on a plane orthogonal to the axis of the molded saw wire shows an angular convex trace. In other words, a trace is a curve in a plane orthogonal to the axis of the molded saw wire, formed by the intersection of that plane with a line parallel to the axis passing through any point on the centerline. A convex trace is a trace in which all points on the line connecting the pair of points on the trace remain inside the trace. The corners are connected on the sides. The curvature of the corners is larger than the curvature of the sides. Curvature is the reciprocal of the radius of curvature. The radius of curvature at any point on the trace is the radius of the osculating circle to the trace at that point. In the three-dimensional space, the plane of projection is the XY plane orthogonal to the Z axis, while the axis of the molded saw wire can be the Z axis.

In a preferred embodiment, the number of horns is 3 or 4. The most preferable is 4.

The steel wire is a round, long stretched, high-tensile, high-carbon steel wire having a diameter d of 40 to 300 μm. Most preferred is 100 to 120 μm, for example 115 μm. Finer gauge wires, such as 110, 100, and even 90-80 μm, are being used. Since the wire needs to be tensioned during cutting, the tensile strength needs to be increased accordingly. At present, a 120 μm wire generally has a tensile strength of more than 4000 N / mm ² .

Preferably, the molded saw wire has a diameter "D" of the circumscribed circle and the ratio D / d is 1.04 to 1.40. More preferably, the ratio D / d is 1.05 to 1.20, for example 1.10. The ratio D / d is a convenient measure to use as production control. The ratio of the optical diameter of the wire (corresponding to the diameter of the circumscribed cylinder) to the diameter of the steel wire. Larger D / d values greater than 2.0 are less preferred. In that case, the forming wire is stretched too much under a low load, which has an adverse effect on warpage formation at the time of cutting.

Preferably, the average distance along the axis of the molded saw wire between the bends is 5 to 50 times the diameter "d" of the saw wire itself. The average distance is the ratio of the measured length "L" along the axis of the molded saw wire to the number of bends in the three-dimensional space counted over that length "L". The measurement length "L" includes at least 10 bends.

If the average distance along the axis between the bent portions of the molded saw wire exceeds 50 times the diameter "d" of the steel wire, the recesses are too far apart and the abrasive is insufficiently drawn into the cut portion. Otherwise, if the average distance along the axis between the bends of the molded saw wire is less than 5 times the diameter "d" of the steel wire, there are too many bends per unit length and the wire will be in use. It grows too much. More preferably, the average distance along the axis of the molded saw wire between the bends is 15 to 25 times the diameter "d" of the saw wire itself, for example 20 times the diameter "d" of the saw wire. is there.

The centerline of the wire has a length "S" when measured over an axial length "L" along the axis of the molded saw wire, preferably (SL) / L is 0.006. From 0.6 percent. This (SL) / L is an "extra length" that is incorporated into the wire depending on the shape of the wire. When this "extra length" is less than 0.006%, the deformation of the wire for entraining the particles in the bent portion of the wire is insufficient, and the drawing of the abrasive material becomes insufficient. If this "extra length" exceeds 0.6%, the wire will stretch too much during use, causing the saw wire to loosen during the cutting process.

FIG. 1 displays the molded saw wire of the present invention in three dimensions and shows the axis of the saw wire. FIG. 2 is a first embodiment and shows a function of generating a molded saw wire. FIG. 3 is the second embodiment and shows the function of generating the molded saw wire.

Molded saw wires are produced by crimping. Crimping is the action of guiding a straight steel wire between a pair of toothed wheels that mesh with each other. The teeth of the toothed wheel are rounded to avoid damaging the wires. This is very similar to a pair of gears, but the gears are spaced to allow the steel wire to pass through. Since the tooth spacing of the toothed wheel is constant, the steel wire is deformed periodically.

This periodic deformation can be explained by the waveform "f (z)". Here, "z" is an independent variable of the function corresponding to the distance along the axis of the molded saw wire. The value of the function "f" corresponds, for example, to the deviation from the Z axis in the X direction. The value of f (z) varies between X = -a and X = + a, where "a" is the amplitude of the function. The waveform "f (z)" has the property of f (z + W) = f (z) for all independent variables "z" of the function. "W" is the wavelength of the waveform. Therefore, in the case of the value "z0" selected as the origin of the Z axis, "f (z)" needs to be zero. With that choice, f (0) must be zero and similarly f (W) must be zero. The waveform f (z) has one minimum value (f (w1) = −a) in “w1” and one maximum value (f (w2)) in “w2” within each range from 0 to W. = + A and w1 <w2). Therefore, another Z coordinate "w0" of f (w0) = 0 is required between 0 and W. In the case of w1 = W / 4 and w2 = W-w1, the waveforms are symmetric and "w0" is located at w0 = W / 2. When w1 is different from W / 4 and w2 = W-w1, the waveform is called "skewed". All other waveforms lead to non-convex projection traces.

The saw wire of the present invention is generated by one waveform f (z) and is first given a deformation in the X direction (that is, the steel wire acquires a crimp in the XZ plane). This single flat crimp then obtains a second crimp with exactly the same waveform f (z) in the Y direction orthogonal to the plane of the already crimped wire. However, the second crimp is shifted with respect to the first crimp when F is between W / 8 and 3W / 8, for example, due to the forward phase difference "F" of W / 4. Therefore, the waveform given in the Y direction is f (z + F).

The steel wire thus formed has a substantially spiral shape, and the projection of the center line of the steel wire on a plane orthogonal to the axis shows a convex trace with the corners connected by the sides. The curvature increases. The period of the helix corresponds to the wavelength of the crimper.

FIG. 1 is a perspective view of such a molded saw wire 100. The wire is composed of a steel wire that has acquired a spiral square deformation by first transforming the steel wire into a single crimp wire in the X direction according to a specific waveform f (z). The crimped wire is arranged in plane XZ. The wire is deformed in the Y direction with the same waveform, but is W / 4 shifted. In this way, a spiral space curve is obtained and its projection forms a square trace on the XY plane. The scales in the X and Y directions are the same, but these scales are different in the Z direction.

FIG. 2 shows three projections of the centerline of the steel wire. The generated deformation f (z) is a triangular function as shown in the upper right figure. The wavelength is 4 mm. The deformation amplitude "a" is 0.008 mm or 8 μm. The phase difference "F" between the two deformations is set to 0.78 mm or 0.19 × W. The diameter "d" of the wire itself is 120 μm. The circumscribed circle diameter D is 135 μm. Therefore, the ratio D / d is 1.125. The difference between the actual length of the center line "S" and the axial length "L" is 0.0061%, and this length is (SL) / L. On average, the distance between the bends is 1 mm or 9.2 times the diameter "d".

FIG. 3 shows a projection of the centerline of the steel wire of the molded saw wire according to another embodiment. Here, the deformation function f (z) is a distorted triangular waveform as shown in the lower left figure. The maximum value of the triangle does not reach at a quarter of 4 mm, that is, at a wavelength of 1 mm (but at 1.2 mm). The phase difference "F" was set to 1 mm, that is, W / 4. Again, the centerline is a projection on the XY plane that shows a convex quadrangle with different curvatures on the corners and sides. The diameter of the steel wire is 120 μm. The diameter of the circumscribed circle of the molded saw wire is 136 μm. Therefore, D / d is 1.13. The extra length (SL) / L is 0.0067%. The average distance between the bent portions is 9.2 × d.

The molded saw wire of the shape described has the advantage of providing a gap between the saw wire and the circumscribed cylinder where abrasive particles can be trapped. This improves the cutting efficiency. Due to the spiral shape, the saw wire does not initiate cutting in the preferred crimping direction. In addition, wires can be generated at high speed because only two phase-shifted crimps need to be created to obtain a helical structure.

Claims (6)

A molded saw wire comprising a steel wire having a bend with a segment in between, extending along the axis of the molded saw wire, the steel wire having a center line.
A projection of the centerline parallel to the axis of the molded saw wire on a plane orthogonal to the axis of the molded saw wire has a convex trace with corners connected by sides, the corners being said. A molded saw wire characterized by having a large curvature relative to the curvature of a side. The molded saw wire according to claim 1, wherein the number of corners is 3 or 4. The molded saw wire according to claim 1 or 2, wherein the steel wire has a diameter "d" and the diameter is 40 to 300 μm. The steel wire has a diameter "d", the molded saw wire has a circumscribed circle diameter "D", and the ratio D / d is 1.04 to 1.40.
The molded saw wire according to any one of claims 1 to 3. The steel wire has a diameter "d" and the average distance between the bent portions along the axis of the molded saw wire is 5 to 50 times the diameter "d".
The molded saw wire according to any one of claims 1 to 4. The length "S" of the center line when measured over the axial length "L" is 0.006% to 0.6% of the axial length "L" from the axial length "L". Also long, the axial length is measured along the axis of the molded saw wire.
The molded saw wire according to claim 1.

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