JP6245833B2 - Wire saw manufacturing method - Google Patents

Description

  The present invention relates to a wire saw used for cutting a product such as a silicon wafer, a crystal resonator, and a substrate from an ingot of a hard brittle material such as silicon, crystal, and sapphire, and a method for manufacturing the wire saw. The present invention relates to a fixed abrasive type wire saw in which abrasive grains such as diamond are attached to a core wire such as a piano wire or a hard steel wire by electrodeposition, and a manufacturing method thereof.

  Conventionally, when cutting products such as silicon wafers, crystal units and substrates from hard and brittle materials such as silicon, quartz and sapphire ingots, "wire saws" have been used.

  As a cutting method using this wire saw, a wire saw made of piano wire or the like that does not have abrasive grains on its surface is used, and a work piece is applied at a high speed while applying a slurry that is a suspension of abrasive grains and water or oil to this wire saw. Using a "free abrasive grain method" in which the workpiece is cut by abrasive grains rolling between the wire saw and the workpiece, and a wire saw in which diamond or other abrasive grains are previously attached to the core wire, There is a “fixed abrasive method” in which the wire saw is cut by bringing it into contact with the workpiece at high speed while applying a cooling medium such as water or oil for lubrication and cooling.

  In addition, the method of adhering abrasive grains to the wire saw used in such a fixed abrasive system includes adhesion of abrasive grains by resin bond, electrodeposition of abrasive grains by electroplating, combination of adhesion by bond and electrodeposition, etc. Has been proposed.

  As an example, as a combination of bonding by bonding and electrodeposition, an adhesive layer is formed in a spiral shape with an organic adhesive on the outer peripheral surface of a conductive core wire, and abrasive grains are adhered to the adhesive layer to form an abrasive. There is one in which the grains are primarily fixed to the surface of the core wire and the abrasive grains are secondarily fixed from above by a metal plating layer formed by electrodeposition (Patent Document 1).

JP 2011-230258 A

  Hard brittle materials such as semiconductors, quartz and sapphire that are cut with a wire saw are expensive materials, and it is required to cut out as many products as possible when cutting.

  Here, when a product is cut out from a workpiece W such as a silicon single crystal ingot by the wire saw 1 as shown in FIG. 6 (A), the ingot of the portion through which the wire saw 1 passes is shown in FIG. 6 (B) as an enlarged view. Since it is lost by cutting, it is necessary to secure the amount of wear generated during the cutting as the cutting allowance δ.

  Further, since the surface of a product cut out with a wire saw is rough, it is necessary to polish the surface after cutting. Therefore, it is necessary to secure the amount of wear due to this polishing as the polishing allowance t.

  Therefore, the interval d of the wire saw 1 used for cutting the workpiece W is set to an interval obtained by adding the cutting allowance δ and the polishing allowance t to the thickness X of the final product. When trying to cut out many products, the wire saw 1 to be used is thinned to reduce the cutting allowance δ and / or the surface roughness of the product after cutting is reduced to reduce the polishing allowance t. As a result, the distance d between the wire saws is reduced, and the number of products that can be cut out from the workpiece W of the same size is increased.

  However, the wire saw 1 with a small wire diameter has a low strength and a short service life, and also easily breaks. Therefore, the wire saw diameter is simply reduced without improving the wire saw strength by reviewing the material and structure. If this is the case, frequent replacement of the wire saw is required, and the work is interrupted each time, resulting in a decrease in workability. In addition, replacement of the expensive wire saw increases the manufacturing cost of the product.

  Even if the wire saw is reduced in diameter by reducing the wire diameter of the wire saw, if the roughness of the cross section obtained after cutting increases, it is necessary to increase the polishing allowance t described above. As a result, not only can the number of products that can be cut out be increased, but also the time and labor required for the polishing work are increased, resulting in a decrease in productivity. In particular, if a defect such as chipping occurs at the time of cutting, it cannot be shipped as a defective product even if it is cut out as a folded product, and the yield is further deteriorated.

  Here, in the wire saw in an unused state after the abrasive grains are attached by electrodeposition, the abrasive grain electrodeposited layer 3 formed on the core wire 2 has the abrasive grains 31 made of plated metal 32 as shown in FIG. When the use is started in this state, the portion of the plated metal 32 ′ covering the abrasive grains 31 is removed by contact with the surface of the workpiece W, and the abrasive grains 31 are exposed to the surface. Since a large cutting force is exerted by forming the cutting blade, the cutting force by the wire saw 1 is relatively low at the start of use before such a cutting blade is formed. Yes.

  Therefore, there is a large difference in the cutting amount between the cutting performed with the abrasive grains 31 covered with the plated metal 32 ′ and the cutting performed with the abrasive grains 31 exposed and the original cutting force exerted thereafter. Therefore, if the workpiece W is cut at a constant feed speed in the cutting direction, the workpiece W is pressed against the wire saw 1 with an excessive force immediately after the wire saw 1 is replaced. The initial failure such as disconnection of the wire or damage to the workpiece W more than necessary to make the cross section rough is likely to occur.

As a method for avoiding the occurrence of such an initial failure, after forming the abrasive electrodeposition layer 3 by plating, before using it for cutting, the plating metal 32 'covering the surface of the abrasive grains 31 is removed in advance. As such a method, for example, surface polishing of a wire saw using Al ₂ O ₃ or SiC grindstone, etching by sand blasting using Al ₂ O ₃ abrasive grains, immersion in chemicals such as acid, etc. Etching to be performed is conceivable.

  However, when the abrasive grains 31 are exposed by the above method, in the polishing by the grindstone or the etching by sandblasting, a large external force is applied to the abrasive electrodeposition layer 3 to scrape off the plated metal 32 'covering the abrasive grains. Since the abrasive grains 31 are exposed by the above method, if the treatment is performed by this method, not only the plating metal 32 'covering the abrasive grains 31, but also the abrasive electrodeposition layer 3 itself may be peeled off, or The abrasive grains 31 will fall off, and the performance of the wire saw 1 after processing will be reduced.

  In addition, since the surface of the plated metal 32 ′ remaining on the core wire 2 after the treatment is left with a number of scratches and the like, the abrasive electrodeposition layer 3 starts from the scratch during use of the wire saw 1. It breaks and peels off, and the wire saw 1 is easily broken.

  On the other hand, in etching using chemicals such as acid, no mechanical force is applied to the abrasive electrodeposition layer 3, but the surface becomes rough (countless scratches) by etching with chemicals. The point that the strength of the electrodeposition layer 3 is reduced and the life of the wire saw 1 is reduced is the same as in the case of the above-described polishing by a grindstone or the etching by sandblasting.

  In addition, in the etching with chemicals, the metal portion is etched substantially uniformly, so that not only the plating metal 32 ′ covering the abrasive grains 31 but also the plating metal 32 of the portion to be left as a base for fixing the abrasive grains 31. Also, the life of the wire saw is shortened in that it is also etched, and the holding power of the abrasive grains is reduced so that the abrasive grains easily fall off during etching and use as a wire saw.

  As described above, any of the above-described processes assumed to be performed on the wire saw 1 in order to expose the abrasive grains 31 is a process that leads to a decrease in the strength of the wire saw 1. In order to maintain the same strength as the previous wire saw 1, it is necessary to increase the wire diameter of the wire saw 1.

  Therefore, the process assumed above as a process for pre-exposing the abrasive grains 31 electrodeposited on the wire saw 1 and the reduction in the diameter of the wire saw 1 are contradictory requirements and cannot be made compatible. ， Cannot meet the demand for yield improvement.

  Therefore, the present invention provides a wire saw with improved strength and life of a wire saw, and a method of manufacturing the wire saw, wherein the abrasive grains electrodeposited on the core wire have a structure in which a part thereof is exposed. Objective.

  Means for solving the problems will be described below together with reference numerals used in the embodiments for carrying out the invention. This code is used to clarify the correspondence between the description of the scope of claims and the description of the mode for carrying out the invention. Needless to say, it is used in a limited manner for the interpretation of the technical scope of the present invention. It is not a thing.

In addition, the method for manufacturing the wire saw 1 of the present invention is a process of forming an abrasive electrodeposition layer 3 that is a nickel plating layer in which abrasive grains 31 having an average particle diameter of 8 to 35 μm are dispersed in the core wire 2 by electrodeposition in a spiral shape. When,
A ceramic spherical shot having a hardness of HV 500 to 1000, a specific gravity of 2.0 to 3.0, and an average particle diameter of 10 to 62 μm is sprayed on the core wire 2 on which the abrasive grain electrodeposition layer 3 is formed at an injection pressure of 0.15. Including a surface treatment step of injecting and colliding with 0.30 MPa,
In the surface treatment step, a portion of the abrasive grain 31 is exposed on the nickel plating layer by collision with the spherical shot to form a cutting edge 31a in the abrasive electrodeposition layer 3,
By colliding with previous SL shot enhance the nickel plating layer at the base of the abrasive grains 31, and the nickel plating layer, characterized in that the hardness was formed to a thickness 4~10μm elevated (claim 1 ).

In the above production method, the above-mentioned electrodeposition of the abrasive electrodeposition layer 3 is preferably carried out using a sulfamic acid bath (claim 2 ).

  With the configuration of the present invention described above, according to the wire saw 1 of the present invention, the following remarkable effects can be obtained.

  By performing a surface treatment by injecting a spherical shot of a predetermined hardness, specific gravity, particle size, and material, a cutting blade 31a is formed by a part of the abrasive grains 31 exposed from the nickel, and the collision with a spherical shot causes the above-mentioned By improving the hardness of the nickel layer 32 that fixes the base of the abrasive grain 31 onto the core wire 2, the wire saw 1 of the present invention exhibits high machinability from the beginning of use and suppresses the occurrence of initial defects. In addition, the strengthening of the nickel layer 32 not only made it difficult for the abrasive electrodeposited layer 3 to peel off or the abrasive grains 31 to fall off, but also improved the strength of the wire saw 1 as a whole.

  As a result, in the wire saw 1 of the present invention, the strength is higher than that of a conventional wire saw having the same wire diameter, and as a result, the workpiece W is cut using a wire wire having a smaller diameter than the conventional wire saw. Since this can be performed, the cutting allowance δ described with reference to FIG. 6B can be narrowed, and more products can be cut out from the ingot of the same size.

  In addition, when compared with known wire saws of the same diameter, the service life can be extended by 1.5 times, and the contact speed of the wire saw with the ingot can be increased, so that the time required for cutting is shortened. Was also possible.

  Moreover, in the wire saw 1 of the present invention, the cutting blade 31a is exposed from the start of use, the cutting surface is not rough due to the initial failure, the cross section after cutting is clean, and there is little occurrence of chipping, Since cutting can be performed straight, the polishing allowance t (see FIG. 6B) to be removed by polishing after cutting can be set small. In this respect as well, the yield can be improved and the time and labor of the polishing process can be reduced. It has become possible.

  When the electrodeposited abrasive layer 3 is formed using a sulfamic acid bath, the nickel plating layer thus formed has high hardness and low internal stress. Separation of the deposition layer 3 could be prevented, and the life of the wire saw 1 could be further extended.

The principal part sectional drawing in the axial direction of the wire saw of this invention. Explanatory drawing of the injection method of a spherical shot. The perspective view of the processing apparatus used for injection of a spherical shot. Explanatory drawing of the injection method of the spherical shot in a processing apparatus. Explanatory drawing of the injection method of the spherical shot in a processing apparatus. (A) is explanatory drawing of the cutting method of the workpiece | work with a wire saw, (B) is the principal part enlarged view of (A). The principal part sectional drawing in the axial direction of the wire saw with the state which electrodeposited the abrasive grain. The microscope picture of the wire saw surface of Example 1 (before use). The microscope picture of the silicon ingot cutting part cut | disconnected with the wire saw of Example 1. FIG. The microscope picture of the wire saw surface of Example 1 (after use). The principal part sectional drawing in the axial direction of the wire saw in embodiment which provided the abrasive electrodeposition layer in spiral form. Surface micrograph (before use) of the wire saw of Comparative Example 2 (without surface treatment after electrodeposition of abrasive grains). The microscope picture of the silicon ingot cutting part cut | disconnected with the wire saw of the comparative example 2. The surface micrograph of the wire saw of the comparative example 2 (after use).

  Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

  In FIG. 1, reference numeral 1 denotes a wire saw of the present invention.

  The wire saw 1 includes a core wire 2 as a base material and an abrasive electrodeposition layer 3 formed by electrodepositing abrasive grains 31 on the surface of the core wire 2 by nickel plating.

  As the above-described core wire 2, it is possible to use a steel wire such as a hard steel wire in addition to a piano wire generally used for an abrasive electrodeposition type wire saw. Moreover, in the conventional general wire saw, the core wire 2 having a wire diameter exceeding 0.2 mm was used in order to ensure the necessary strength. However, in the wire saw 1 of the present invention, As will be described later, the nickel layer 32 is reinforced by the surface treatment on the abrasive electrodeposition layer 3 and, as a result, the strength of the wire saw 1 can be improved, so that the core wire is 0.2 mm or less, preferably 0.05. The diameter of the core wire to be used in this way is reduced to reduce the ingot cutting allowance δ (see FIG. 6B), and from an ingot of the same size. A larger number of products can be cut out.

  As shown in FIG. 1, the electrodeposited abrasive grain layer 3 formed on the core wire 2 has an abrasive grain 31 having an average grain size of 8 to 35 μm and a base portion of the abrasive grain 31 fixed on the core wire. It is constituted by a nickel layer 32 of 10 μm.

As the abrasive grains provided in the abrasive grain electrodeposition layer 3, not only ultra-hard abrasive grains such as diamond abrasive grains and cBN (cubic boron nitride) abrasive grains but also the material of the workpiece to be cut, Al ₂ O _3. It is also possible to use ceramic abrasive grains such as SiC, and diamond abrasive grains are used in this embodiment.

  Electrodeposition of the nickel plating layer in which the abrasive grains are dispersed can be performed by a known electroplating method. In nickel plating, the hardness of the nickel plating film obtained varies depending on the type of plating bath, but the nickel plating film obtained is preferably as hard as possible.

  In addition, since the formed plating layer is easily peeled off from the core wire 2 when the internal stress of the formed plating layer is large, the hardness of the formed plating layer is high in this embodiment, Film formation is performed in a sulfamic acid bath capable of forming a plating layer having a low internal stress, and a nickel plating layer having a hardness of about HV 400 to 500 is formed.

  In the state before the surface treatment described later is performed, the abrasive grain electrodeposition layer 3 is dispersed in a state where the abrasive grains 31 are buried in nickel as the plating metal 32 'as shown in FIG.

  As described above, as a method of combining nickel as the plating metal 32 ′ and abrasive grains 31 as the dispersed particles and attaching them to the core wire 2, dispersed particles suspended on the surface of the continuously growing plating are used. "Suspension eutectoid" in which the deposited metal is adsorbed and continuously taken into the plating film by the deposited metal, and the dispersed particles settle on the horizontal plating surface and the particles are forcibly brought into contact with the core wire surface. In this application, it is necessary to form the abrasive electrodeposition layer 3 on the entire circumference of the core wire 2 which is a wire having a circular cross section. The electrodeposition layer 3 is formed.

  In the embodiment shown in FIGS. 1 and 7, the above-described abrasive electrodeposition layer 3 is formed so as to completely cover the entire surface of the core wire 2, but as shown in FIG. 11, the surface of the core wire 2 is formed. It can also be formed in a spiral shape.

  In this way, when the abrasive electrodeposition layer 3 is formed in a spiral shape (see FIG. 11), water, oil, or the like poured into the wire saw 1 as a lubricating and cooling medium is applied to the non-formed portion of the abrasive electrodeposition layer 3. Since it is easy to be held, and the cutting waste generated at the time of cutting is easily discharged through the non-formed part of the abrasive electrodeposition layer 3, further improvement in cutting ability and life can be obtained. In the configuration in which the low friction material layer 4 such as a fluororesin is provided on the non-formed portion of the abrasive electrodeposition layer 3, further reduction in friction and longer life of the wire saw are achieved. be able to.

  Further, by forming the base nickel plating layer 5 on the surface of the core wire 2, baking is performed when the low friction material layer 4 is formed, and the grinding stone is removed when the low friction material is cut and peeled spirally. Damage to the core wire 2 can be reduced.

  In this embodiment, in order to form the abrasive electrodeposition layer 3 in a spiral shape, in this embodiment, a low friction material layer 4 made of a material having an insulating property and a low friction coefficient, for example, a fluororesin. Can be attached to the surface of the core wire in a spiral shape, and the above-described abrasive electrodeposition layer 3 can be formed on the non-formed portion of the low friction material layer 4 by electrodeposition.

  As an example, in this embodiment, prior to the formation of the above-described low friction material layer 4, a base nickel plating layer 5 of about 20 μm is uniformly formed on the surface of the core wire 2, and the surface of the base nickel plating layer 5 is formed. After the entire surface is baked and coated with fluororesin, the portion of the fluororesin film on which the abrasive electrodeposition layer 3 is formed is spirally scraped off by a grinding wheel, and the remaining fluororesin film is not scraped off as described above. It can be layer 4.

  The base nickel plating layer 5 formed before the coating of the low friction material protects the core wire 2 from the heat generated when the fluororesin is baked and coated, and cuts and removes a part of the fluororesin film against the core wire 2. It has the effect of preventing cutting.

  In this embodiment, after the nickel plating for eliminating surface irregularities is performed on the underlying nickel plating layer 5 exposed on the surface in this way, the above-described abrasive electrodeposition layer 3 is formed by electrodeposition. By doing so, the abrasive electrodeposition layer 3 can also be formed in a spiral shape.

  The abrasive electrodeposition layer 3 immediately after electrodeposition is in a state in which nickel as a plating metal 32 'covers the abrasive grains 31 as schematically shown in FIG. 7, and the workpiece W is cut during cutting. In this state, the diamond abrasive grains 31 having the function to act are not exposed on the surface.

  Then, after forming the abrasive electrodeposition layer 3 by electrodeposition, the surface of the wire saw 1 is subjected to a surface treatment for injecting and colliding a spherical shot, so that diamond abrasive grains are obtained as shown in FIG. 1 or FIG. A part of 31 is exposed to form a cutting edge 31a, and the base portion of the diamond abrasive grain 31 is fixed on the core wire 2 by a nickel layer 32 of 4 to 10 μm hardened by collision with a spherical shot.

  As the spherical shot to be used, those having a hardness of HV500 to 1000, a specific gravity of 2.0 to 3.0, and an average particle diameter of 10 to 62 μm can be used. As a material corresponding to the above hardness and specific gravity, Ceramic (including glass) beads can be used.

  Further, when the spray pressure of the spherical shot is less than 0.15 MPa, the exposure of the abrasive grains 31 and the increase in the hardness of the nickel layer 32 cannot be obtained. On the other hand, when the spray pressure exceeds 0.30 MPa, the abrasive electrodeposition layer 3 is damaged. The amount of abrasive grains 31 is large and the nickel layer 32 is peeled off. Therefore, the pressure is set to 0.15 to 0.30 MPa.

  It is preferable to select an optimum injection pressure from the range of 0.15 MPa to 0.30 MPa in relation to the spherical shot to be used. The optimum injection pressure is determined based on the specific gravity and hardness of the spherical shot to be used. The higher the value, the lower the pressure, and the lower the specific gravity and hardness of the spherical shot, the higher the pressure.

  In order to uniformly inject and collide a spherical shot over the entire surface of the wire saw 1 that is a wire rod, it is necessary to inject the spherical shot from all directions of the wire saw 1. In this case, as shown in FIG. 2, three injection nozzles 6 are arranged at an equal angle of about 120 ° around the wire saw 1, and a spherical shot is obtained from each injection nozzle 6 together with a compressed gas, for example, compressed air. By injecting and colliding, a spherical shot can be injected and collided over the entire circumference of the wire saw.

  In the example shown in FIG. 2, a processing example using three injection nozzles 6 is shown. However, the processing may be performed by providing a larger number of injection nozzles 6. By passing through the center of the injection nozzle 6 while rotating around the center of the wire, it may be possible to perform a more uniform process over the entire surface of the wire saw 1.

  Reference numeral 7 in FIG. 3 is a processing device for injecting and colliding a spherical shot with respect to such a wire saw 1, and in a cabinet 71 having an internal work space, as shown in FIG. A T-shaped mounting table 72 for mounting 1 is disposed at a predetermined interval between a wire introduction hole 73 formed on the side surface of the cabinet 71 and a wire drawing hole (not shown), and on the mounting table 72. A cylindrical tube 74 for guiding the wire saw 1 is attached.

  This cylindrical tube 74 is partially interrupted, and by placing the spray nozzle 6 toward this interrupted portion, a spherical shot can be made to collide with the wire saw 1 introduced into the cabinet 71. Yes.

  In the embodiment shown in FIG. 4, a single cylindrical tube 74 is attached on the mounting table 72 so that only one wire saw 1 is processed. As shown in FIG. 5, a plurality of the cylindrical tubes 74 may be attached in parallel to each other. With this configuration, a plurality of wire saws 1 are simultaneously fed and processed in parallel. , Productivity can be greatly improved.

  By injecting a spherical shot onto the abrasive electrodeposition layer 3 in this way, the diamond abrasive grains 31 buried in the nickel as the plating metal 32 'as shown in FIG. A portion thereof is exposed to form a cutting edge 31a, and the hardness of the nickel layer 32 for fixing the base of the diamond abrasive grains 31 is increased. This prevents not only the diamond abrasive grains 31 from falling off. The entire wire saw 1 is strengthened.

  Below, the manufacture example of the wire saw of this invention is described.

[Example 1]
Formation of an electrodeposited abrasive layer An electrodeposited abrasive layer with a 0.12mm diameter hard steel wire as the core and dispersed diamond abrasive grains with an average particle size of 30μm over the entire surface is formed by electrodeposition using a sulfamic acid bath. As a result, a diamond electrodeposited wire saw having a diameter of 0.12 mm was obtained.

  The thickness of the nickel plating formed on the surface of the core wire in the unadhered portion of the abrasive grains is about 5 μm, and the hardness of the nickel layer as the parent metal of the abrasive electrodeposition layer before the surface treatment described later is HV It was 450.

Surface treatment conditions Surface treatment was performed by injecting spherical shots onto the diamond electrodeposited wire on which the above-mentioned abrasive electrodeposition layer was formed.

  A spherical shot is projected using a commercially available shot peening machine ("SC-4S-303 (for fine powders)" manufactured by Fuji Seisakusho). Three nozzles with a nozzle hole diameter of 7 mm are centered on a wire saw at 120 °. Were fixed at the same angle and the position was fixed, and a spherical shot was sprayed at a nozzle distance of 130 mm. The feeding speed of the wire saw is 15 m / min.

  As a spherical shot, ceramic hard beads (FHB series manufactured by Fujiki Sales) # 400 (particle size 53-38 μm) were used, and the injection pressure was 0.15 MPa, 0.20 MPa, and 0.25 MPa. In each case, the surface state of the treated electrodeposited abrasive layer was evaluated.

  Table 1 shows the composition and physical properties of the spherical shot used in Example 1.

Test results Table 2 shows the results of confirming the state of the abrasive electrodeposition layer obtained according to the production conditions of Example 1 described above.

  As a result of the above, it was confirmed that the cutting edge was formed and the hardness of the nickel layer was increased by exposing a part of the abrasive grains in the entire range of the changed injection pressure of 0.15 to 0.25 MPa.

  However, when the surface treatment is performed at an injection pressure of 0.15 MPa, although the abrasive grains are exposed, there is a slight shortage in the exposed state, and the nickel layer hardness increases by 0.20 MPa. Compared with the case where the surface treatment is performed with an injection pressure of 0.20 MPa, although the performance is improved as compared with the wire saw not subjected to the surface treatment. The improvement in the effect was low.

  On the other hand, even in the case where the injection pressure is 0.25 MPa, the formation of the cutting edge due to the exposure of the abrasive grains and the improvement of the hardness of the nickel layer have been confirmed, and the performance is improved compared to the untreated wire saw. However, the occurrence of slightly dropped abrasive grains and slight peeling of the abrasive electrodeposition layer were confirmed, confirming that the surface treatment was somewhat excessive.

  Therefore, in relation to the spherical shot used in Example 1, it was confirmed that the abrasive electrodeposition layer can be processed in an optimum state when the injection pressure is 0.20 MPa.

[Example 2]
Test conditions Glass beads (“FGB” manufactured by Fuji Seisakusho) # 400 were used as spherical shots used in the surface treatment, and the injection pressure was measured in three patterns of 0.20 MPa, 0.25 MPa, and 0.30 MPa. Except for this point, the second embodiment is the same as the first embodiment.

  The composition and physical properties of the spherical shot used in Example 2 are as shown in Table 3.

Test Results Table 4 shows the results of confirming the state of the electrodeposited abrasive layer of the wire saw obtained according to the manufacturing conditions of Example 2 described above.

  As a result, it was confirmed that the effects of forming the cutting edge due to the exposure of the abrasive grains and increasing the hardness of the nickel layer were obtained in the entire range of the injection pressure of 0.20 to 0.30 MPa.

  Further, in relation to the spherical shot used in Example 2, it was confirmed that the abrasive electrodeposition layer can be processed in an optimum state when the injection pressure is 0.25 MPa.

  In comparison with Example 1 above, in Example 2 using a low-density, low-hardness spherical shot compared to the spherical shot used in Example 1, the optimum injection compared to Example 1 was used. It was confirmed that the pressure shifted to the high pressure side.

Example 3
Test conditions The same as in Example 1, except that ceramic hard beads (“FHB” manufactured by Fujiki Sales Co., Ltd.) # 600 (particle size 38 to 10 μm) were used as the spherical shot used in the surface treatment.

  The composition and physical properties of the spherical shot used in Example 3 are as shown in Table 1 except for the particle size.

Test Results Table 5 shows the results of confirming the state of the electrodeposited abrasive layer of the wire saw obtained according to the manufacturing conditions of Example 3 described above.

  As a result of the above, as in Example 1, it was confirmed that the effect of forming the cutting edge by exposing the abrasive grains and increasing the hardness of the nickel layer was obtained in the entire range of the injection pressure of 0.15 to 0.25 MPa. .

  The shot used in Example 3 is the same as the spherical shot used in Example 1 except that the particle size is small. The optimum value of the injection pressure in this spherical shot is the same as that in Example 1. Similarly, it was 0.20 MPa.

  From the comparison results of Example 1 and Example 3, it can be seen that the change in the particle size of the spherical shot used has little effect on the change in the optimum value of the injection pressure.

[Comparative Example 1]
Test conditions Instead of the surface treatment in Example 1, a grid made of alumina (“White Alundum” manufactured by Fuji Seisakusho) # 400 (particle size 44 to 37 μm), hardness HV2000, injection pressure 0.10 MPa, 0 Etching was performed by sandblasting at 15 MPa. Other conditions are the same as in the first embodiment.

Test Results Table 6 shows the results of observing the state of the abrasive electrodeposition layer after etching by sandblasting according to the production conditions of Comparative Example 1 described above.

  As a result, it was confirmed that the etching by sand blasting using the grid made of alumina did not provide a suitable exposure of the abrasive grains and an increase in the hardness of the nickel layer.

  In addition, in the abrasive electrodeposition layer treated by the method of Comparative Example 1, the surface of the nickel layer is roughened in a satin state, and scratches that are the starting points of fracture are formed throughout. As a result, the strength of the nickel layer is lowered, and further, the strength of the wire saw itself is lowered.

Silicon ingot cutting test [Comparative Example 2]
The wire saw of the present invention manufactured by the method described in Example 1 (Example 1) and the wire saw in which no surface treatment is performed after forming the electrodeposited abrasive layer by the same method as in Example 1. Each (Comparative Example 2) was used to cut the silicon ingot.

  The cut surface of the silicon ingot cut using the wire saw of Example 1 (see FIG. 9) is clearer than the cut surface of the silicon ingot cut using the wire saw of Comparative Example 2 (see FIG. 13). In addition, the cutting width was small, the roughness of the cut surface was small, the unevenness was small and clean, and it was able to cut straight.

  Therefore, by using the wire saw of the present invention, it is possible to reduce both the cutting allowance δ and the polishing allowance t described with reference to FIG. 6B. As a result, the ingot having the same length can be reduced. It can be seen that more products can be cut and the polishing time after cutting can be shortened.

  Moreover, in the wire saw of Comparative Example 2, the surface protrusions are almost eliminated after use (see FIG. 14), compared to the state before use (see FIG. 12) where many protrusions existed on the surface. By cutting the silicon ingot, most of the abrasive grains adhered to the surface by electrodeposition had fallen off and could not be reused.

  On the other hand, in the wire saw of Example 1, it was confirmed that the convex portion remained in the same state as before use (see FIG. 8) even after being used for cutting (see FIG. 10). In addition, according to the present invention, it is possible to provide a long-life wire saw that not only provides a clean cut surface with no roughness but also prevents abrasive grains from falling off.

DESCRIPTION OF SYMBOLS 1 Wire saw 2 Core wire 3 Abrasive electrodeposition layer 31 Abrasive grain (diamond abrasive grain)
31a Cutting blade 32 Nickel layer 32 'Plating metal 4 Low friction material layer 5 Underlying nickel plating layer 6 Injection nozzle 7 Processing device 71 Cabinet 72 Mounting table 73 Wire introduction hole 74 Cylindrical tube δ Cutting allowance d Wire saw interval t Polishing allowance

Claims (3)

Forming an abrasive electrodeposition layer, which is a nickel plating layer in which abrasive grains having an average particle diameter of 8 to 35 μm are dispersed in a core wire by electrodeposition, in a spiral shape;
A spherical shot having a hardness of HV500 to 1000, a specific gravity of 2.0 to 3.0, and an average particle diameter of 10 to 62 μm is sprayed to the core wire on which the abrasive electrodeposition layer is formed at an injection pressure of 0.15 to 0.30 MPa. And a surface treatment process for colliding,
In the surface treatment step, a part of the abrasive grains are exposed on the nickel plating layer by collision with the spherical shot to form a cutting edge in the abrasive electrodeposition layer,
By colliding with previous SL shot enhance the nickel plating layer at the base of the abrasive grains, and a wire saw method for producing characterized in that said nickel plating layer, the hardness was formed to a thickness of 4~10μm elevated . Wire saw method of manufacturing according to claim 1, characterized in that the electrodeposition of the abrasive grains electrodeposited layer by sulfamic acid bath. The spherical shot, wire saw method of manufacturing according to claim 1, characterized in that it consists of ceramic or glass.