JP2013244552A - Fixed abrasive grain type saw wire and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixed abrasive grain type saw wire whose production cost is suppressed low and which has a long life and high productivity while maintaining a high holding force of abrasive grains with respect to an abrasive grain fixing method by electrodeposition.SOLUTION: Abrasive grains 14 are temporarily fitted to an outer circumferential surface of a wire 11 applied with a brass plating 12 together with temporary nickel plating 13. The abrasive grains are increased in fixing strength by subjecting the nickel plating to resistance heating by a power supply roller. It is preferred that the nickel plating is fused through the resistance heating and hardened again to form a wide-based substrate 15. Furthermore, a fixed nickel plating 16 is provided thereupon and fixed to cover the abrasive grains.

Description

The present invention relates to a saw wire that slices and cuts hard and brittle materials such as silicon ingot, crystal, sapphire, and ceramic, which are wafer materials for semiconductors and solar cells, and in particular, a fixed abrasive saw wire having hard abrasive grains fixed to the wire surface and It relates to the manufacturing method.

The saw wire is a wire for slicing and cutting a hard and brittle material such as a silicon ingot, crystal, sapphire, or ceramic, and there are two types of saw wires, a free abrasive type and a fixed abrasive type.

The free-abrasive saw wire is a method of cutting while spraying slurry (liquid containing abrasive grains), and the fixed-abrasive saw wire is a method of cutting with a wire in which abrasive grains are fixed to the wire surface in advance. It is.

Since the free-abrasive saw wire uses slurry, the cutting speed is slow because the abrasive grains move and rotate during cutting. In addition, since a large amount of a mixture of slurry and swarf is generated during cutting, the object to be cut is contaminated and needs to be cleaned, resulting in high production costs.
On the other hand, since the abrasive grains are fixed to the wire in advance in the fixed-abrasive type saw wire, the abrasive grains do not move or rotate during cutting, and the abrasive grains efficiently cut the workpiece by running the wire. Continue grinding. Therefore, the cutting speed is more than several times that of the loose abrasive type, and since there is little mixture of slurry and swarf, the cleaning time is short and it is environmentally friendly. Is becoming mainstream.

A saw machine 40 is known as an apparatus for slicing a hard and brittle material. FIG. 5 is a schematic view of a saw machine. In the saw machine 40, the fixed abrasive saw wire 41 is supplied from the supply reel 42, and several tens to several hundreds of wires are stretched around the main roller 43. Then, it is taken up on the take-up reel 44.
The object to be cut 45 is pressed from above onto a saw wire that travels at a high speed, whereby the object to be cut 45 is ground and thinly sliced by abrasive grains fixed to the surface of the saw wire.

As a method for fixing the abrasive grains of the fixed abrasive saw wire, there is a method by electrodeposition.
The method by electrodeposition is a method of fixing abrasive grains by metal plating. Since it is fixed by metal plating, its adhesion is high and its life is long. However, in order to increase the adhesive strength of abrasive grains, there are only a method of increasing the plating hardness by temporarily adding and fixing the abrasive grains and a method of increasing the plating hardness by adding an additive (brightening agent, etc.). It became large and the plating solution management became very difficult. (Japanese Patent Laid-Open No. 2011-230258)
In addition, when the abrasive grains are temporarily attached and the wire passes through the rollers, there is a problem that the abrasive grains fall off due to a load that rotates the rollers.

JP 2011-230258 A JP 2006-55952 A

The present invention is an improvement of the above-described method for fixing abrasive grains by electrodeposition, and is to provide a fixed abrasive saw wire that has a low production cost, a long life, and high productivity.

In order to solve the above-mentioned problems, the inventors have intensively researched, embedded the lower part of the abrasive grains in the nickel plating layer, and further provided a base part having a flared shape, thereby providing a temporary nickel plating tank and a fixed nickel plating tank. Shortened and made it possible to increase productivity.

That is, the fixed abrasive saw wire of the present invention is
With abrasive grains fixed in the longitudinal direction of the wire,
Abrasive grains are temporarily attached with a temporary nickel plating layer, and the lower part of the abrasive grains is buried in the nickel plating layer by melting of the nickel plating, and fixed nickel plating is applied to the outer peripheral portion thereof.
The thickness of the temporary nickel plating is 0.1 to 2.0 μm,
The thickness of the fixed nickel plating is 0.1 to 0.8 times the average abrasive grain size,
The tensile strength is 3500 MPa or more.

The temporary nickel plating layer has a base portion that spreads out from the bottom.

Moreover, it is preferable that the average abrasive grain diameter of the said abrasive grain is 5-60 micrometers.

Moreover, it is preferable that 20 to 70% of the average abrasive grain size is covered with a base portion.

Furthermore, it is preferable that an angle θ formed by the base portion and the abrasive grains is 0 ° or more and less than 5 °.

The method for producing the fixed abrasive saw wire of the present invention is as follows:
The surface of the wire is temporarily nickel-plated with abrasive grains along with the abrasive grains,
Applying resistance heating to the temporary nickel plating part to melt the nickel plating and bury the lower part of the abrasive grains in the nickel plating layer, and further fix the abrasive grains by providing a base part that spreads out at the bottom,
The outer peripheral part is fixed nickel-plated so as to cover the abrasive grains.

According to the present invention, the lower part of the abrasive grains is buried in the nickel plating layer by melting the nickel plating, and further, the fixing force is increased by having the base part having a flared shape, and the temporary nickel plating tank and the fixed nickel plating tank are provided. In addition to shortening the current density, it is possible to reduce the current density and increase the linear velocity of the wire, so that it is possible to obtain a fixed-abrasive saw wire with a long life and high productivity, while keeping the production cost low.

FIG. 1 is a schematic view showing a cross section perpendicular to the central axis of the fixed abrasive saw wire of the present invention. FIG. 2 is a view for explaining the angle of the base portion of the fixed abrasive saw wire of the present invention. FIG. 3 shows an example of the manufacturing process of the fixed abrasive saw wire of the present invention. FIG. 4 is a schematic view of a temporary nickel plating process. FIG. 5 is a schematic view of a saw machine.

Hereinafter, a preferred embodiment of the fixed abrasive saw wire of the present invention will be described together with its manufacturing method while referring to the drawings as appropriate.

FIG. 1 is a schematic diagram showing a vertical cross section with respect to a wire central axis in a fixed abrasive saw wire 10 of the present invention. Reference numeral 11 is a wire, 12 is brass plating, 13 is temporary nickel plating, 14 is abrasive grains, 15 is a base portion, and 16 is fixed nickel plating.

In order to ensure strength, the wire 11 is preferably a high carbon steel wire containing 0.8 wt% or more of C, for example.

A brass plating 12 may be provided on the outer peripheral portion of the wire 11 in order to improve wire drawing workability.

In the fixed abrasive saw wire 10, the abrasive grains 14 are temporarily attached to the outer peripheral portion of the temporary nickel plating 13. By melting the temporary nickel plating 13, the lower part of the abrasive grains is buried in the temporary nickel plating layer so that the abrasive grains 14 are closer to the center of the wire. When the temporary nickel plating is hardened again, the base portion 15 having a hem-opening shape is obtained. Fixed nickel plating 16 is applied to the outer periphery.

Here, the thickness of the temporary nickel plating 13 is preferably 0.1 to 2.0 μm. When the thickness is less than 0.1 μm, the plating is too thin and it becomes difficult to temporarily attach the abrasive grains, and the base portion cannot be formed. If the thickness exceeds 2.0 μm, the plating becomes thick and the cost increases.

A more preferable thickness of the temporary nickel plating 13 is 0.5 to 1.5 μm.

The thickness of the fixed nickel plating is preferably 0.1 to 0.8 times the average abrasive grain size. If the thickness is less than 0.1 times the average abrasive grain size, sufficient adhesion cannot be obtained, and the abrasive grains may fall off during cutting. If the thickness exceeds 0.8 times the average abrasive grain size, the fixing force becomes very strong, but the cost is also increased, so it is made 0.8 times or less.

The tensile strength of the fixed abrasive saw wire is preferably 3500 MPa or more. If the tensile strength is less than 3500 MPa, the saw wire may be disconnected at the time of cutting.

More preferably, the tensile strength is 3800 MPa or more.

The twist value of the fixed abrasive saw wire is preferably 35 times / 100 d or more. If the twist value is less than 35 times / 100 d, when the saw wire is twisted during cutting, it may be twisted as it is.

The average abrasive grain size of the abrasive grains is preferably 5 to 60 μm. If it is less than 5 μm, the abrasive grains are too small and the cutting efficiency is deteriorated. If it exceeds 60 μm, the machinability is improved, but the abrasive grains are too large and a large amount of chips are generated, resulting in a reduction in the number of wafers obtained. Therefore, the average abrasive grain size is set to 5 to 60 μm.

It is preferable that 20 to 70% of the average abrasive grain size is covered with the base portion 15 having a hem-extended shape. If the base portion is less than 20% of the average abrasive grain size, sufficient fixing force cannot be obtained, and the abrasive grains may fall off during cutting. If the base part exceeds 70% of the average abrasive grain size, the base part will be very thick. Since the performance of the abrasive grains cannot be utilized and the cutting efficiency is deteriorated, the content is set to 70% or less.

The figure for demonstrating the angle of the base part of a fixed-abrasive-type saw wire to FIG. 2 is shown.
As shown in FIG.
As shown in FIG. 2B, the line A is drawn so as to follow the substantially linear portion on the outside of the base portion 15.
As shown in FIG. 2 (c), the point of intersection between the line A and the abrasive grains is defined as a point B.
As shown in FIG. 2D, a line C is drawn at point B so as to follow the substantially linear shape of the abrasive grains.
Here, an angle θ formed by the line A and the line C is an angle θ formed by the base portion and the abrasive grains.
In FIG. 2, the angle θ formed for the sake of explanation is shown large, but actually it is much smaller than this angle.

The angle θ formed by the base portion and the abrasive grains is preferably 0 ° or more and less than 5 °.
If the angle θ formed is 5 ° or more, the abrasive grains are stable, but the chip discharge efficiency is deteriorated and the cutting efficiency is deteriorated.

A more preferable angle θ between the base portion and the abrasive grains is 1 ° or more and less than 4 °.

In FIG. 3, an example of the manufacturing process of the fixed-abrasive saw wire of the present invention is shown, and the manufacturing method will be described along this.
The wire 22 fed out from the feeding reel 21 is cleaned in the cleaning tank 23. Next, abrasive grains are temporarily attached together with nickel plating in a temporary nickel plating tank 24. Thereafter, the abrasive grains are completely fixed in the fixed nickel plating tank 25, cleaned through the cleaning tank 26, and taken up on the take-up reel 27.

FIG. 4 shows a schematic diagram of the temporary nickel plating process.
FIG. 4 shows the wire passing through the temporary nickel plating tank.
22 is a wire, 31 and 33 are power supply rollers, 32 is an anode, and 24 is a temporary nickel plating tank in which abrasive grains and nickel are mixed.

The wire 22 is energized through the feed rollers 31 and 33, and the wire 22 itself is used as a cathode. When the wire 22 is continuously sent in the direction of the arrow, it is energized between the anode 32 and the anode 32 in the temporary nickel plating tank 24, whereby nickel plating is applied and at the same time, abrasive grains are temporarily attached. In the power supply roller 33, resistance heating is applied to the nickel plating portion to which the abrasive grains are temporarily attached, the nickel plating is melted, and the lower portion of the abrasive grains is embedded in the nickel plating layer. When the nickel plating is hardened again, a base portion having a flared shape is provided.

The resistance heating is generated by adjusting the voltage and the position and shape of the roller.

By melting and re-hardening nickel plating and providing a base portion, it becomes possible to increase the adhesive strength of abrasive grains even if the plating thickness to be temporarily attached is thin, and shorten the temporary nickel plating tank 24. It is possible to reduce the current density and increase the linear velocity. In addition, since the nickel plating is melted and re-cured in a moment by the power supply roller 33, the fixing force of the abrasive grains that come into contact with the power supply roller 33 is increased. Can be prevented.

In the temporary nickel plating tank shown in FIGS. 3 and 4, temporary nickel plating is performed by sending a wire from below to above. This is to make the abrasive grains uniformly adhere to the wire in the circumferential direction, but the temporary attachment nickel plating is performed in the horizontal direction in the same manner as the fixed nickel plating tank regardless of the temporary attachment method. Also good.

After the foundation part is provided on the abrasive grains, fixed nickel plating is applied so as to cover the abrasive grains in the fixed nickel plating tank 25, and the abrasive grains are completely fixed. Thereafter, the film is washed in the washing tank 26 and taken up on the take-up reel 27.

In the temporary nickel plating step of the abrasive grains, since the base portion is provided on the abrasive grains, the adhesive strength of the abrasive grains is strong at this point, and the thickness of the subsequent fixed nickel plating can be reduced. . That is, the fixed nickel plating tank 25 can be shortened compared to the conventional case.

Note that resistance heating has been conventionally performed to reduce the physical properties of the wire and has been plated so as not to occur, but in the present invention, resistance heating is applied to the nickel plating portion and the wire is heated. The physical properties of the wire are not lowered.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail according to an Example, this invention is not limited to a following example.

The steel wire subjected to brass plating having a wire diameter of 0.18 mm was subjected to nickel plating together with abrasive grains having an average abrasive grain size of 20 μm in a temporary nickel plating tank. Here, the length of the plating tank was 1 m, and plating was performed within a voltage range of 4 to 10V.

After leaving the plating tank, resistance heating was applied with a power supply roller, and the nickel plating was melted and hardened again to form a base portion.

Then, fixed nickel plating was performed so as to cover the abrasive grains in a fixed nickel plating tank, and a fixed abrasive saw wire was manufactured.

Table 1 shows the results of cutting the silicon ingot using the fixed abrasive saw wire produced by the above method. The length of the temporary nickel plating tank and the length of the fixed nickel plating tank in Table 1 indicate that the length of the plating tank is shorter when the numerical value is lower than that of the conventional example 1. The wire linear velocity indicates that the linear velocity is faster as the numerical value is larger than the conventional example of 1. As for the life, it is shown that the life is longer (the number of repeated use is larger) when the numerical value is higher than that of the conventional example 1.

From Table 1, compared with the prior art, Invention Examples 1 to 5 have a shorter service life despite the fact that the length of the temporary nickel plating tank and the length of the fixed nickel plating tank are shorter and the wire line speed is faster. It was confirmed that the length was 1.2 to 2 times longer.

DESCRIPTION OF SYMBOLS 10 Fixed abrasive type saw wire 11 Wire 12 Brass plating 13 Temporary nickel plating 14 Abrasive grain 15 Base part 16 Fixed nickel plating 21 Feeding reel 22 Wire 23 Cleaning tank 24 Temporary nickel plating tank 25 which mixed abrasive grain and nickel Fixed nickel Plating tank 26 Cleaning tank 27 Take-up reel 31 Feed roller 32 Anode 33 Feed roller 40 Saw machine 41 Fixed abrasive saw wire 42 Supply reel 43 Main roller 44 Discharge reel 45 Cut object

Claims (6)

A fixed abrasive saw wire in which abrasive grains are fixed in the longitudinal direction of the wire,
Abrasive grains are temporarily attached with a temporary nickel plating layer, and the lower part of the abrasive grains is buried in the nickel plating layer by melting of the nickel plating, and fixed nickel plating is applied to the outer peripheral portion thereof.
The thickness of the temporary nickel plating is 0.1 to 2.0 μm,
The thickness of the fixed nickel plating is 0.1 to 0.8 times the average abrasive grain size,
A fixed abrasive saw wire having a tensile strength of 3500 MPa or more. 2. The fixed abrasive saw wire according to claim 1, wherein the temporary nickel plating layer has a base portion that spreads toward the bottom. 3. The fixed abrasive saw wire according to claim 1, wherein an average abrasive particle diameter of the abrasive grains is 5 to 60 μm. The fixed abrasive saw wire according to claim 1, wherein 20 to 70% of the average abrasive grain size is covered with a base part. 5. The fixed abrasive saw wire according to claim 1, wherein an angle θ formed by the base portion and the abrasive grains is 0 ° or more and less than 5 °. A method for manufacturing a fixed abrasive saw wire in which abrasive grains are fixed in the longitudinal direction of the wire,
After temporarily attaching the abrasive grains to the surface of the wire by temporary nickel plating together with the abrasive grains,
Applying resistance heating to the temporary nickel-plated part to melt the nickel plating and bury the lower part of the abrasive grains in the nickel-plated layer, and further fix the abrasive grains by providing a base part with a flared base,
6. The method of manufacturing a fixed abrasive saw wire according to claim 1, wherein the outer peripheral portion is fixed nickel-plated so as to cover the abrasive grains.