JP2009285791A - Wire saw and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wire saw preventing fall-off of abrasive grains. <P>SOLUTION: The wire saw 1 has: a core wire 2 of high strength; an under-coating layer 5 on the side close to the core wire 2; and an upper-coating layer 6 on the side far from the core wire 2. Abrasive grains 3 are held by the under-coating layer 5 and the upper-coating layer 6. The upper-coating layer 6 enters a space 5a between the under-coating layer 5 and the abrasive grains 3. The thickness of the upper-coating layer 6 is less than 1/5 of a value obtained by subtracting the thickness of the under-coating layer 5 from the diameter of abrasive grains 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wire saw mainly used for processing electronic materials such as slicing of silicon ingots, processing of magnetic materials and optical materials such as neodymium magnets and glass cutting, and a method of manufacturing the same.

  Conventionally, diamond slicing has been mainly used for slicing processing of silicon ingots, but recently due to the increase in diameter of silicon ingots, due to yield, productivity, work-affected layer, dimensional constraints, etc. Processing with loose abrasive grains and wire saws is often used. However, since processing using loose abrasive grains uses an oily slurry in which abrasive grains are dispersed in processing oil, there are problems in terms of environmental hygiene, and the work process becomes longer, such as requiring cleaning, and both processing efficiency and processing accuracy are improved. It is insufficient. Therefore, processing by a wire saw using a wire with abrasive grains fixed is strongly desired.

  Such a fixed abrasive type wire saw is disclosed in Japanese Patent Laid-Open No. 50-102993 (Patent Document 1). This document discloses a technique in which abrasive grains are bonded to a core wire and dressing is performed on the outer peripheral surface thereof.

  Japanese Patent Application Laid-Open No. 8-1266953 (Patent Document 2) describes in detail the characteristics of a wire saw in a silicon wafer cutting process, and proposes that a material such as polyethylene or nylon be used as the core wire in this process. Has been.

  Japanese Patent Application Laid-Open No. 9-155631 (Patent Document 3) discloses a technique for fixing diamond abrasive grains to a core wire using electrolytic plating or a synthetic resin binder.

Japanese Patent Application Laid-Open No. 10-33703 (Patent Document 4) discloses a fixed abrasive having a structure in which abrasive grains having a certain range of abrasive grain size and filler are fixed around a core wire with a resin having specific physical properties. A grain wire saw and a method for manufacturing the same are disclosed.
Japanese Patent Laid-Open No. 50-102993 Japanese Patent Laid-Open No. 8-126953 JP-A-9-155631 Japanese Patent Laid-Open No. 10-33703

  Conventionally, in a fixed-abrasive wire saw, unlike a normal cutting grindstone, the abrasive grains are almost a single layer, and dropping off of the abrasive grains has led to a problem that the cutting performance is immediately reduced.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a wire saw that can prevent abrasive grains from dropping and a manufacturing method thereof.

  The wire saw according to the present invention includes a core wire, an undercoat layer that covers the core wire, an overcoat layer that covers the undercoat layer, and abrasive grains that are held on the undercoat layer and the overcoat layer and are disposed on the core wire. And the upper coating layer is interposed between the undercoating layer and the abrasive grains.

  In the wire saw configured as described above, by forming the upper coating layer around the lower coating layer, the abrasive grains can be physically fixed and reinforced to prevent the abrasive grains from falling off. Furthermore, since the overcoat layer has entered between the undercoat layer and the abrasive grains, the overcoat layer can firmly hold the abrasive grains and prevent the abrasive grains from falling off.

  Furthermore, the thickness of the overcoat layer is less than 1/5 of the value obtained by subtracting the thickness of the undercoat layer from the average grain size of the abrasive grains. In this case, the so-called chip pocket amount is increased, the processing waste can be discharged quickly, and the cutting speed is improved. From this viewpoint, the thickness of the overcoat layer is set to be less than 1/5 of the value obtained by subtracting the thickness of the undercoat layer from the average grain size of the abrasive grains.

  As the core wire, a linear body made of a metal material, metal oxide, metal carbide, metal nitride, organic material, or carbon material can be used, but it is easily finished into a very fine wire, and is a uniform and high strength piano wire. Is most preferred.

Preferably, the undercoat layer is mainly composed of a resin having an elastic modulus of 100 kg / mm ² or more and a softening temperature of 200 ° C. or more. Moreover, in order to raise the intensity | strength of an undercoat layer, you may add additives, such as a filler other than the said resin.

  As a resin used as a bond, it is necessary to withstand the resistance and heat generated during the cutting process and hold the abrasive grains.

As such a resin, any resin having an elastic modulus of 100 kg / mm ² or more and a softening temperature of 200 ° C. or more can be used, but from the viewpoint of moldability and physical properties, alkyd resin, phenol resin, formalin resin, polyurethane Resin, polyester resin, polyimide resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, allyl resin, polyesterimide resin, polyamideimide resin, polyester urethane resin, bismaleimide resin, bismaleimide triazine resin, cyanate ester resin, Polyetherimide, polyparabenic acid, aromatic polyamide and the like are preferable.

Preferably, the overcoat layer is mainly composed of a resin having an elastic modulus of 100 kg / mm ² or more and a softening temperature of 200 ° C. or more.

  As such a resin, the same resin as the undercoat layer described above can be used. Furthermore, there is no particular problem even if fillers and abrasive grains are contained in the resin of the overcoat layer.

  Preferably, the abrasive grains held in the undercoat layer are superabrasive grains containing diamond or CBN (cubic boron nitride).

  Such super abrasive grains are preferable to other general abrasive grains in terms of both cutting performance and life. In particular, in order to improve the bonding force between the superabrasive grains and the resin bond, it is preferable that the surface of the superabrasive grains is previously plated with a metal such as nickel or copper.

Furthermore, fine diamond as filler, Al ₂ O ₃ , SiC, SiO ₂ , CBN, mica, talc, calcium carbonate, kaolin, clay, titanium oxide, barium sulfate, zinc oxide, magnesium hydroxide, potassium titanate, magnesium sulfate, It is necessary to improve the strength and wear resistance of the resin bond layer that combines the overcoat layer and the undercoat layer. Since the conductivity is also improved, the heat generated during the cutting process is quickly released to the outside, so that the abrasive grains can be prevented from falling off due to thermal softening or thermal deterioration. In this respect, the diamond filler is most preferable for extending the life of the wire saw and improving the cutting accuracy. Next to diamond, hard materials such as SiC, Al ₂ O ₃ and CBN are preferred.

  As content in the resin bond of an abrasive grain, it is preferable that they are 1 volume% or more and 30 volume% or less. Furthermore, when using a filler, it is preferable that it is 1 volume% or more and 50 volume% or less as content in the resin bond of a filler.

  As a method of manufacturing the wire saw having the above-described configuration, a method in which a coating material in which the abrasive grains and a filler are mixed if necessary in a solution in which a resin is dissolved in a solvent is applied and baked on the core wire can be employed. . An undercoat layer is formed by baking. As a result, the abrasive grains are also easily raised and protruded, which is advantageous. A solution obtained by dissolving a resin in a solvent is applied to the outside of the undercoat layer and heated to form an overcoat layer that covers the undercoat layer and the abrasive grains and enters between the abrasive grains and the undercoat layer.

  The coating and baking can be easily performed by passing the core wire through the coating tank and then introducing it into the drying section and solidifying by heating. In order to maintain uniform dispersion of the abrasive grains and uniformity of the thickness of the resin bond, it is preferable that both the introduction part to the drying part and the drying part are rigid. Moreover, it is preferable to control the adhesion state of the resin solution using a floating die for the introduction part.

  The resin used as a bond is heated and melted, and abrasive grains and filler are mixed in the melt, and this mixed melt is filled into an extruder, and the core melt is passed over the outer periphery of the core. Extrusion coating is also possible. In this case, the bulge and protrusion of the abrasive grains are reduced, and the cutting speed at the beginning of the cutting process becomes slow. However, if the processing is continued, the resin bond layer gradually recedes due to grinding wear and the abrasive grains protrude, so it can be used as a wire saw. Is possible.

Any solvent can be used as long as it can dissolve the resin, but depending on the type of resin used, alkylbenzenes such as xylene, toluene, benzene and ethylbenzene, cresols such as cresol, phenol and xylenol, alcohols such as ethanol and butanol, etc. , Ketones such as acetone, methyl ethyl ketone, cyclohexane, ethers such as tetrahydrofuran, dioxane, NM ₂ P (N-methyl-2-pyrrolidone), DMF (dimethylformamide), DMAc (dimethylacetamide), DMSO (dimethylsulfoxide) Use aprotic solvents such as

  Preferably, the step of forming the overcoat layer includes a step of applying a solution having a resin ratio of 5% by volume or more and 50% by volume or less to the outside of the undercoat layer.

  A wire saw according to the present invention is shown in FIG. The II-II cross section in FIG. 1 is shown in FIG. FIG. 1 is a schematic cross-sectional view of a wire saw according to the present invention, in which abrasive grains 3 are fixed to the outer peripheral side of a core wire 2. The undercoat layer 5 and the overcoat layer 6 are fixed to the outer peripheral side of the core wire 2, and the filler 4 is embedded in the undercoat layer 5. It is raised and fixed so that at least a part of the abrasive grains 3 is exposed from the outer surface of the overcoat layer 6.

  In the recess 5 a between the undercoat layer 5 and the abrasive grains 3, the overcoat layer 6 enters. Since the abrasive grains 3 exist when the undercoat layer 5 is baked and the undercoat layer 5 shrinks during baking, a recess 5 a is formed between the undercoat layer 5 and the abrasive grains 3. In order to apply the upper coating layer 6 on the concave portion 5a in a state where the concave portion 5a exists, the upper coating layer 6 enters the concave portion 5a and fills the concave portion 5a. As a result, the abrasive grains 3 are securely held, and the abrasive grains 3 can be prevented from falling off.

(Example 1)
A phenol resin paint (a paint in which a phenol resin is dissolved in cresol), a diamond filler having an average particle diameter of 2.6 μm, and diamond abrasive grains having an average particle diameter of 44 μm have a solid content ratio of 60% by volume, 20% by volume, and 20% by volume. %, And the solvent cresol was further added so that the amount of the solvent in the paint was 50% by volume. The above-mentioned paint is applied to a copper-plated piano wire having an outer diameter of 0.18 mm, passed through a die having a diameter of 0.28 mm, and after being baked and cured in a baking oven at a furnace temperature of 300 ° C., the phenol resin is cresoled. The melted paint (resin concentration: 10% by volume) was applied with nylon felt and again cured by baking in a baking furnace at a furnace temperature of 300 ° C., thereby producing a wire saw having a two-layer structure.

  The obtained wire saw had an outer diameter of 0.238 mm, and the layer thickness formed by baking hardening was about 19 μm for the undercoat layer and about 1 μm for the overcoat layer.

(Examples 2 and 3)
Bake hardening was performed in the same manner as in Example 1 except that the concentration of the phenol resin coating for forming the overcoat layer was 15% by volume (Example 2) and 20% by volume (Example 3), respectively. As a result, the thickness of the undercoat layer / the thickness of the overcoat layer was 20/2 μm (Example 2) and 19/3 μm (Example 3), respectively.

(Examples 4 and 5)
As a result of baking and curing in the same manner as in Example 1 except that an ester imide resin (Example 4) and an amide imide resin (Example 5) were used instead of the phenol resin paint for forming the overcoat layer, subbing was performed. The layer thickness / overcoat layer thickness was 21/2 μm and 19/2 μm, respectively.

  Furthermore, when the cross section of the wire saw in each Example was confirmed, as shown in FIG. 1 and FIG. 2, the overcoat layer 6 entered the recess 5a.

(Comparative Example 1)
A phenol resin paint (a paint in which a phenol resin is dissolved in cresol), a diamond filler having an average particle diameter of 2.6 μm, and diamond abrasive grains having an average particle diameter of 44 μm have a solid content ratio of 60% by volume, 20% by volume, and 20% by volume. %, And the solvent cresol was further added to adjust the solvent amount of the paint to 50% by volume. A paint was applied to a copper-plated piano wire having an outer diameter of 0.18 mm, passed through a die having a diameter of 0.28 mm, and then baked and cured in a baking furnace having a furnace temperature of 300 ° C. to produce a wire saw.

  The outer diameter of the obtained wire saw was 0.238 mm. The layer thickness was about 19 μm.

(Comparative Examples 2 and 3)
Baking and curing were carried out in the same manner as in Example 1 except that the concentration of the phenol resin coating for forming the overcoat layer was 30% by volume (Comparative Example 2) and 40% by volume (Comparative Example 3), respectively. The thickness / overcoat layer thickness was 20/5 μm (Comparative Example 2) and 19/8 μm (Comparative Example 3), respectively.

  The following tests were carried out using these wire saws. The results are shown in Table 1.

(Abrasive holding load)
A piano wire was set at a right angle to the wire saw, and after increasing the load applied to the piano wire, the piano wire was moved in the direction parallel to the wire saw (longitudinal direction of the wire saw), and then the load at which the abrasive grains dropped off was read.

Piano wire diameter: 0.18mm
Movement speed: 400mm / min Load: 100-220g
(Cutting test)
Using a cutting machine manufactured by Laser Technology, a wire saw cutting test was performed under the following conditions, and the cutting speed was measured.

Sample: Nd magnet (40 mm square x 20 mm thickness)
Cut surface: 20 mm x 40 mm
Wire saw travel speed: 400m / min, pressing pressure: 4N
Cutting oil: manufactured by Palace Chemicals, PS-L-30
(Function)
According to the evaluation of the abrasive grain holding load in the above examples and comparative examples, the abrasive grain holding load becomes higher as the overcoat layer becomes thicker than in Comparative Example 1 without the overcoat layer. On the other hand, from the cutting test results, the wire layers of Examples 1 to 4 are superior in cutting speed, particularly the cutting speed 45 minutes after the start of cutting, as compared with the wire saw of Comparative Example 1 because of the high abrasive grain holding load. Moreover, although the wire layer of Comparative Examples 2 and 3 having a thick overcoat layer has a high abrasive grain holding load, the cutting speed is inferior to that of Examples 1 to 4.

  This is because the abrasive grains are protruded and fixed on the outer peripheral surface of the core wire by the resin bond containing the filler, and are more firmly held by the resin layer formed thereon.

  However, since the wire saws of Comparative Examples 2 and 3 having a small amount of protruding abrasive grains have a small chip pocket amount, the cutting speed after starting cutting and the cutting speed 45 minutes after starting cutting are inferior to the wire saws of Examples. Yes. In order to ensure an effective chip pocket amount for cutting, the thickness of the overcoat layer needs to be less than 1/5 of the value obtained by subtracting the thickness of the undercoat layer from the average grain size of the abrasive grains.

Further, in order to hold the abrasive grains more firmly, the resin layer needs to have excellent heat resistance and wear resistance. Such a resin preferably has an elastic modulus of 100 kg / mm ² or more and a heat softening temperature of 200 ° C. or more.

  Further, in Table 2, the actual particle size distribution of the diamond filler having an average particle size of 2.6 μm and the diamond abrasive particles having an average particle size of 44 μm was measured by a laser diffraction particle size distribution measuring device (SALD-2000A manufactured by Shimadzu). Indicates.

  As shown in Table 2, even though the average particle size of the filler is 2.6 μm and the average particle size of the abrasive is 44 μm, there is considerable variation in the actual particle size. For this reason, there are those blended as fillers that act as abrasive grains, and conversely, those blended as abrasive grains also function as fillers.

  Therefore, the core wire diameter and resin, abrasive grains, filler type, amount, grain size, and protruding protrusion degree of the abrasive grains are optimal within the range described in the above claims according to the cutting object and cutting conditions. Needless to say, it is necessary to carry out selection.

  ADVANTAGE OF THE INVENTION According to this invention, it replaces with the conventional slicing process of the silicon wafer by a loose abrasive grain, and can provide the fixed abrasive type | mold wire saw which can perform the slicing process by a wire saw easily and economically.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic sectional drawing for demonstrating the structure of the wire saw according to embodiment of this invention. It is sectional drawing along the II-II line | wire in FIG.

Explanation of symbols

  1 wire saw, 2 core wire, 3 abrasive grains, 4 filler, 5 undercoat layer, 5a recess, 6 overcoat layer.

Claims (7)

Core wire,
An undercoat layer covering the core wire;
An overcoat layer covering the undercoat layer;
Abrasive grains held on the core layer and held on the undercoat layer and the overcoat layer,
The overcoat layer enters between the undercoat layer and the abrasive grains,
A wire saw in which the thickness of the overcoat layer is less than 1/5 of a value obtained by subtracting the thickness of the undercoat layer from the average particle diameter of the abrasive grains. The wire saw according to claim 1, wherein the undercoat layer mainly comprises a resin having an elastic modulus of 100 kg / mm ² or more and a softening temperature of 200 ° C or more. ^2. The wire saw according to claim 1, wherein the overcoat layer mainly comprises a resin having an elastic modulus of 100 kg / mm ² or more and a softening temperature of 200 ° C. or more.   The wire saw according to claim 1, wherein the abrasive grains retained in the undercoat layer are superabrasive grains containing diamond or cubic boron nitride (CBN).   The wire saw according to claim 4, wherein the superabrasive grains are metal-plated. A process of fixing the abrasive grains on the outer peripheral surface of the core wire by an undercoat layer by applying and heating a paint prepared by blending at least abrasive grains in a solution in which a resin is dissolved in a solvent. ,
A solution obtained by dissolving a resin in a solvent is applied to the outside of the undercoat layer and heated to cover the undercoat layer and the abrasive grains, and an overcoat layer that enters between the abrasive grains and the undercoat layer is provided. The manufacturing method of a wire saw provided with the process to form.   7. The method of manufacturing a wire saw according to claim 6, wherein the step of forming the overcoat layer includes a step of applying a solution having a resin ratio of 5% by volume or more and 50% by volume or less to the outside of the undercoat layer. .

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