JP2011062762A - Abrasive grain holding sheet for embedding in flexible polishing surface plate, and method for manufacturing abrasive grain embedded flexible polishing surface plate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To embed a predetermined amount of abrasive grains required for finish-polishing in the surface of a flexible polishing surface plate in a manner of dispersing uniformly. <P>SOLUTION: An abrasive grain holding sheet for embedding in flexible polishing surface plate includes: a sheet-like base material 11; abrasive grains 13 dispersed so as to be a single layer on the surface of the base material 11; and a binder layer 12 fixing a part of each abrasive grain 13 in an exposed state to the top of the base material 11. By using the abrasive grain holding sheet in which the binder layer 12 is formed with a water-soluble binder or an organic oxide soluble binder, the grains are embedded in the flexible polishing surface plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an abrasive holding sheet for embedding in a soft polishing surface plate and a method for producing an abrasive embedded soft polishing surface plate using the same.

  Electronic and optical devices such as magnetic heads and optical fiber connectors are composite parts made of a plurality of materials. In a thin film magnetic head, which is one of the composite material parts, the substrate, insulating film, magnetic element part, protective film, etc. formed in a short rail shape have different mechanical hardness. Final polishing is extremely difficult.

  Conventionally, in the above-mentioned finish polishing, free abrasive grains contained in a polishing liquid supplied to the surface of a soft polishing surface plate such as tin are removed by a cylindrical abrasive-embedded ring (also referred to as a “correction ring” on the surface plate surface). A method of pressing and embedding in the surface of a soft polishing surface plate and finish polishing with both the embedded fixed abrasive grains and the non-embedded free abrasive grains is used (for example, JP-A-11-213367). JP, 2001-232558, A).

  In this polishing method, a cylindrical guide ring (also referred to as a “holding ring”) in which an object to be polished is rotatably placed is arranged on a rotating soft polishing surface plate, and this guide ring is polished. The polishing is performed by supplying a polishing liquid containing abrasive grains to the surface of the polishing surface plate while rotating around the position away from the rotation center of the surface plate and further rotating the object to be polished.

  A plan view of a polishing apparatus using the above polishing method is shown in FIG. As shown in FIG. 6, the polishing surface plate 51 is attached to a rotating shaft 50 connected to a motor (not shown). A concentric groove 54 is formed on the surface of the polishing surface plate 51 (a spiral groove may be used), and a convex portion sandwiched between adjacent grooves 54 and 54 is a soft polishing surface plate. A polished surface 53 of 51 is formed.

  A polishing liquid supply / supply nozzle 58 for supplying a polishing liquid is disposed on the soft polishing surface plate 51, and a predetermined amount of polishing liquid 59 is supplied from the tip of the polishing liquid supply nozzle 58 from a polishing liquid supply device (not shown). It is supplied to the surface of the soft polishing surface plate 51.

  On the surface of the soft polishing surface plate 51, a pair of rotatable rollers 57a and 57b are respectively attached to rod-shaped guide jigs 56a. The rollers 57 a and 57 b are arranged so as to be in contact with the outer cylindrical surface of the cylindrical guide ring 63 placed on the soft polishing surface plate 51 and to rotate in contact with the rotation of the soft polishing surface plate 51.

  On the inner surface of the guide ring 63, a polishing jig 62 for fixing a magnetic head (indicated by a broken line in FIG. 6) to be polished is fitted to the inner peripheral surface of the guide ring 63 so as to rotate with the guide ring 63. It is included. When the guide ring 63 placed on the soft polishing surface plate 51 rotates due to the speed difference between the outer periphery and the inner periphery of the soft polishing surface plate 51, the polishing jig 62 also rotates, and the magnetic head of the object to be polished is soft polished. It slides on the surface plate 51 and is polished.

  Further, on the surface of the soft polishing surface plate 51, a pair of rotatable rollers 57c and 57d are respectively attached to a rod-shaped guide jig 57b. The rollers 57 c and 57 d are disposed so as to contact the outer cylindrical surface of the cylindrical abrasive grain embedding ring 55 placed on the soft polishing surface plate 51 and to rotate in contact with the rotation of the soft polishing surface plate 51. Yes.

  In this polishing method, an abrasive liquid 59 containing free abrasive grains is supplied to a surface plate, and a part of the free abrasive grains is embedded in the surface plate by an abrasive embedding ring 55 to form fixed abrasive particles. Polishing with abrasive grains. The fixed abrasive embedded in the soft polishing surface plate is suitable for uniform and precise finish polishing.After the fixed abrasive is worn, the surface of the soft polishing surface plate is scraped, and after the groove processing, free abrasive particles are again removed. It is embedded in the surface of the polishing surface plate with an abrasive embedding ring and repeatedly used for finish polishing.

  Polishing with this polishing method gives a polished surface with few steps, but not all supplied abrasive grains are embedded in the soft polishing surface plate, and most of the abrasive grains are soft polishing surface plate and non-polished material Because of rolling and polishing between the two, the generation of scratches increased, and high-precision finish polishing was difficult.

  In order to suppress the generation of scratches due to rolling of the above-mentioned free abrasive grains, conventionally, as another polishing method, after performing the step of embedding abrasive grains in the soft polishing surface plate, the surface of the soft polishing surface plate is cleaned and embedded A polishing method that removes the abrasive grains that have not been removed and uses only fixed abrasive grains that are embedded abrasive grains to obtain a highly accurate polished surface is used (for example, JP-A-62-292358, JP-A-7-297737).

  FIG. 7 (a) is a plan view of a polishing apparatus in another polishing method of the above conventional example, FIG. 7 (b) is a schematic cross-sectional view of embedding free abrasive grains in a polishing surface plate by an embedding ring. FIG. 7C shows a schematic cross-sectional view of the embedded polishing surface plate.

  As shown in FIG. 7A, the polishing liquid 59 is supplied from the polishing liquid supply nozzle 58 to the surface of the soft polishing surface plate 51, and the free abrasive grains 52 a contained in the polishing liquid 59 are embedded in the soft polishing surface plate by the embedded ring 55. It is embedded in the polishing surface 53 of 51, and becomes the fixed abrasive 52b of the soft polishing surface plate 51 (FIG. 7B).

  The abrasive grains remaining as free abrasive grains 52a without being embedded in the polishing surface 53 are washed away with a detergent or water, and the fixed abrasive embedded in the polishing surface 53, which is the convex surface of the surface plate, as shown in FIG. A polishing surface plate 51 in which only the grains 52b are left is obtained.

  Using the polishing surface plate 51 thus subjected to the abrasive grain embedding process, only the diluent or lubricant liquid that does not contain abrasive grains is supplied, and the workpiece fixed to the polishing jig provided on the inner periphery of the guide ring is removed. Polish (not shown).

  According to the above other polishing methods, the surface of the object to be polished can be finished without scratches or steps, but it takes a long time to fully embed the abrasive grains in the polishing surface plate. Further, it is accompanied by technical difficulties to embed the abrasive grains uniformly. In addition, if the amount of embedded abrasive grains is not sufficient, the scratch can be reduced, but the polishing efficiency is deteriorated. Further, if the polishing time is increased, the so-called surface sag in which the end of the object to be polished becomes a curved surface increases. End up. In addition, high-precision finish polishing cannot be obtained when non-uniform abrasive grains are embedded. Further, this polishing method has a problem that the abrasive particles that flow out and are discarded are much larger than the abrasive particles fixed to the surface plate, which is not economical.

  Note that the occurrence of scratches is reduced to some extent by using a polishing liquid in which the abrasive particles are refined in order to reduce scratches. However, in this method, if the laminated surface of the magnetic head that is the object to be polished is finish-polished, a problem arises that the dent of the soft magnetic element portion becomes large and the flying characteristics of the magnetic head deteriorate.

  In polishing single crystal difficult-to-process materials such as sapphire, if the surface is polished in the form of loose abrasive grains (rolling abrasive grains), a work-affected layer is formed on the surface, resulting in a disordered surface. However, even if a device film is formed, a high-quality element cannot be obtained and the yield deteriorates.

JP-A-11-213367 JP 2001-231558 A JP-A-62-292358 JP-A-7-299737

  In order to solve the above-mentioned problems, an object of the present invention is to provide a technique capable of uniformly dispersing and embedding a predetermined amount of abrasive grains necessary for finish polishing on the surface of a soft polishing surface plate. It is in.

  In order to solve the above problems, the present invention provides a sheet-like substrate, abrasive grains dispersed in a single layer on the surface of the substrate, and a state in which a part of each of the abrasive grains is exposed. And a binder layer fixed on the base material, wherein the binder layer is formed of a water-soluble binder or an organic acid-soluble binder, and is an abrasive-holding sheet for embedding in a soft polishing surface plate.

  A part of each abrasive grain exposed from the binder layer of the abrasive holding sheet for embedding in the soft polishing surface plate is pressed against the soft polishing surface plate and pressed from the back side of the base material to expose one individual abrasive particle. By embedding a part in a soft polishing surface plate, peeling the base material, and dissolving and removing the binder layer with water or an organic acid, the abrasive grains can be embedded on the surface of the soft polishing surface plate.

  When abrasive grains are embedded in a soft polishing surface plate using such an abrasive holding sheet for embedding in a soft polishing surface plate (hereinafter, abbreviated as “abrasive holding sheet” as appropriate), an abrasive holding sheet is preliminarily used. Since a predetermined amount of abrasive grains for embedding can be uniformly dispersed on the surface, a predetermined amount of abrasive grains necessary for finish polishing is uniformly dispersed and embedded on the surface of the soft polishing surface plate. And finish polishing as designed.

  Since the abrasive grains embedded in the soft polishing surface plate are provided on the abrasive grain holding sheet in advance, the loss of abrasive grains due to runoff is less than in the conventional case of supplying the slurry by including it in the slurry, thereby suppressing economic loss. be able to.

  Since the binder layer of the abrasive grain holding sheet is formed from a water-soluble binder or an organic acid-soluble binder, the abrasive grains are embedded in a soft polishing surface plate, and then the binder layer is removed to provide individual abrasive grains that become cutting blades. It is easy to expose a part of.

  Since the binder layer is formed of a water-soluble binder or an organic acid-soluble binder, the abrasive grains of the abrasive grain holding sheet are in a state where their tips are in contact with the base material, and are embedded in a soft polishing surface plate, When the material and the binder layer are removed, the tips that become the cutting blades are aligned, which is suitable for high-precision finish polishing.

  The soft polishing surface plate is made of one or more kinds of alloys of tin, copper, lead, antimony, bismuth, and copper, all of which are capable of embedding abrasive grains.

  The water-soluble binder is 1 or 2 selected from polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropylmethylcellulose, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, polyethylene oxide, hyaluronic acid, starch and other polysaccharides, dextrin, albumin, gelatin casein and alginic acid. Preferably, the organic acid-soluble binder is a binder composed of one or two kinds of chitin or chitosan. This is because the abrasive grains are held on the base material and can be easily removed after the abrasive grains are embedded in the soft polishing surface plate.

As the abrasive grains, used _{diamond, cBN,} B ₄ C, those consisting of Al 2 O _3, at least one kind selected from SiO 2, in the SiC. These are abrasive grains suitable for finish polishing.

  A metal sheet is preferred as the substrate. By pressing the back surface of the base material of the metal sheet, it is possible to easily embed individual abrasive grains in a soft polishing surface plate.

  It is preferable to use a metal having a relatively high hardness and good corrosion resistance, such as stainless steel, steel, phosphor bronze, beryllium copper, and the like, which is sufficiently harder than the soft metal used for the polishing surface plate.

  The layer thickness of the binder layer is in the range of 1/10 to 2/3 of the average particle diameter of the abrasive grains.

  When the ratio exceeds 2/3, the abrasive grains buried in the binder increase, the embedding depth in the soft polishing surface plate cannot be sufficiently obtained, and when it is less than 1/10, the abrasive grains may fall off from the binder.

  In the abrasive grain holding sheet, it is preferable that a moisture absorption preventing film is stuck on the abrasive grains so as to be peelable from the abrasive grains. This is to prevent adhesion of dust in the air. Further, when stored in a high humidity environment, it prevents the abrasive grains from falling off due to the dissolution of the binder.

  The present invention further provides a method of manufacturing an abrasive-embedded soft polishing surface plate embedded with a part of each abrasive grain exposed on the surface of the soft polishing surface plate, the method described above A first step of placing any of the abrasive holding sheets for embedding in the soft polishing surface plate on the surface of the soft polishing surface plate with the abrasive grains in contact with the surface of the soft polishing surface plate; A second step of pressurizing the back surface of the base material of the abrasive holding sheet for embedding in the soft polishing surface plate to embed a part of the abrasive particles in the soft polishing surface plate; and the soft polishing A third step of peeling the base material from the abrasive grains and the binder layer embedded in the surface plate, and a fourth step of dissolving and removing the binder layer with water or an organic acid. It is a manufacturing method of an abrasive embedding soft polishing surface plate.

  The soft polishing surface plate may be one or more kinds of alloys of tin, lead, antimony, bismuth and copper.

  According to the present invention, a soft polishing surface plate capable of embedding a predetermined amount of abrasive grains necessary for finish polishing on the surface of the soft polishing surface plate by exposing a part of the abrasive grains and uniformly dispersing and embedding them. An abrasive holding sheet for embedding and a soft polishing surface plate in which abrasive grains are embedded by this abrasive holding sheet can be provided.

FIG. 1 is a schematic cross-sectional view of an abrasive-holding sheet for embedding in a soft polishing surface plate according to the present invention. FIG. 2A to FIG. 2C are schematic cross-sectional views showing a series of manufacturing steps of an abrasive holding sheet for embedding in a soft polishing surface plate according to the present invention. FIG. 3A to FIG. 3D are schematic steps showing a series of schematic steps of a method of embedding abrasive grains in a polishing surface plate using a holding sheet for embedding abrasive grains in the polishing surface plate according to the present invention. FIG. FIG. 4A is a perspective view of a soft polishing surface plate in which abrasive grains are embedded using the abrasive holding sheet for embedding in the soft polishing surface plate according to the present invention, and FIG. FIG. 4A is a schematic cross-sectional view of a soft polishing surface plate (without grooves) in which abrasive grains of a) are embedded, and FIG. 4C is a cross section of a soft polishing surface plate (with grooves) in which abrasive particles of FIG. 4A are embedded. It is a schematic diagram. FIG. 5 is a schematic perspective view of an electrostatic spraying device for electrostatically spraying abrasive grains. FIG. 6 is a schematic plan view of a conventional finish polishing apparatus using a soft polishing surface plate. FIG. 7A is a schematic plan view of another conventional finish polishing apparatus using a soft polishing surface plate, and FIG. 7B is a schematic cross-sectional view of embedding free abrasive grains in the polishing surface plate using an embedding ring. FIG. 7C is a schematic sectional view of a polishing surface plate in which abrasive grains are embedded. 8 (a) and 8 (b) show the distribution of abrasive grains on the surface of a soft polishing surface plate in which abrasive grains are embedded using the abrasive holding sheet for embedding in the soft polishing surface plate according to the present invention. FIG.

Embodiments of an abrasive holding sheet for embedding in a soft polishing surface plate and a method for manufacturing an abrasive embedded soft polishing surface plate using the abrasive holding sheet according to the present invention will be described below with reference to the accompanying drawings.
<Abrasive grain holding sheet for embedding in soft polishing surface plate>
As shown in FIG. 1, an abrasive holding sheet 10 for embedding in a soft polishing surface plate includes a sheet-like base material 11, abrasive grains 13 dispersed in a single layer on the surface of the base material 11, and abrasive grains 13. And a binder layer 12 that is fixed on the substrate 11 in a state where each part is exposed.

  The substrate 11 is made of stainless steel, steel, phosphor bronze, or surface hardened metal. In order to embed abrasive grains fixed on the surface of the base material 11 by pressing from the back surface of the base material 11 in the soft polishing surface plate, the base material 11 is required to have a hardness exceeding that of the soft polishing surface plate.

  Since the abrasive grains 13 are electrostatically dispersed (described later) on the binder layer 12, there is no aggregation and the abrasive grains 13 are dispersed in a single layer. Therefore, the abrasive grains 13 are held on the substrate 11 in a state where they are not in close contact with each other and are separated by a predetermined distance.

  The area density of the abrasive grains to be dispersed is preferably 30 to 80%. When the area density of the abrasive grains is 30% or less, the polishing efficiency of the surface plate in which the particles are embedded is reduced, and the distance between adjacent abrasive grains becomes too wide to make it difficult for the polishing debris to be discharged outside during polishing. Further, the metal of the soft polishing surface plate is likely to adhere to the object to be polished on the polished surface. On the other hand, even if the area density of the abrasive grains is 80% or more, it does not affect the improvement of the polishing efficiency so much and is not economical.

The binder layer 12 is formed of a binder made of a water-soluble (including warm water) or organic acid-soluble material. The binder layer 12 is finally dissolved by water or an organic acid after embedding abrasive grains in a soft polishing surface plate.
<Method for producing abrasive holding sheet for embedding in soft polishing surface plate>
The manufacturing process of the abrasive grain holding sheet 10 for embedding in the soft polishing surface plate according to the present invention is shown in FIG.

  As shown to Fig.2 (a), the sheet-like base material 11 is prepared. As a material of the base material 11, it is preferable to use a relatively hard metal material such as stainless steel, steel, phosphor bronze or the like. A material harder than the material used for the polishing surface plate is suitable for the base material 11. For example, when the surface plate is made of tin (Sn), the material used for the substrate 11 is preferably a numerical value that greatly exceeds the Young's modulus (about 50 Gpa) of tin.

  Moreover, the surface of the base material 11 needs to be smooth. This is because if the surface of the substrate 11 is not smooth, the cutting edges of the abrasive grains embedded in the soft polishing surface plate are not aligned. The smoothness of the surface of the substrate 11 depends on the size of the abrasive grains used. For example, when the average diameter of the abrasive grains is 10 microns, the average surface roughness is about 1 micron or less. In the case of 5 microns, a smoothness of 0.5 microns or less is required.

  The substrate 11 only needs to have a shape having dimensions larger than the width and length of the polishing surface plate, and a substrate having a predetermined shape obtained by cutting a circular shape, a square shape, or a long shape is used as the substrate 11. The thickness of the base material 11 is not specifically limited, The thing of the range of 0.05 mm-1 mm is used as the base material 11 by a use.

  Next, as shown in FIG. 2B, a binder layer 12 is formed on the substrate 11 with a water-soluble or organic acid-soluble binder. As the water-soluble material, polymer synthetic materials such as polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, polyethylene oxide, and hyaluronic acid, polysaccharides, glue, starch, gelatin and the like are used. Specific examples include polysaccharides such as glycogen, cellulose, and dextran, starch produced from plants such as corn and straw, and gelatin composed of animal protein.

  Moreover, although it is hard to melt | dissolve in water, the organic acid soluble material is also useful, for example, poly (beta) 1,4 glucosamine (chitosan) which removed the acetyl group from chitin can be used. In particular, chitosan can be used as a material for the binder of the abrasive grain holding sheet 10 of the present invention because it is soluble in vinegar and has no safety problem.

  As a method for applying these water-soluble binders or organic acid-soluble binders to the substrate 11, known application methods can be applied, and generally, spray coating and roll coating application methods are mentioned. It is done. The adjustment of the thickness of the binder layer 12 is controlled by the concentration, temperature, coating speed, etc. of the binder liquid, and the coating thickness is preferably 1/10 to 2/3 of the average grain diameter. If it exceeds 2/3, the amount of abrasive grains protruding from the binder is small, so that the abrasive grains may not be sufficiently embedded in the soft polishing surface plate. If it is less than 1/10, the abrasive grains may fall off. is there.

Next, as shown in FIG. 2C, a plurality of abrasive grains 13 are embedded in the binder layer 12 with some of the abrasive grains exposed. The material of the abrasive grains can be selected in accordance with the relationship between the object to be polished and the polishing performance of the abrasive grains. Diamond, alumina (Al ₂ O ₃ ), silica (SiO ₂ ), boron nitride (cBN), silicon carbide Inorganic particles having a new Mohs hardness of 7 or more, such as (B ₄ C), are preferred. In particular, since abrasive grains are pressed and embedded in a soft polishing surface plate, the abrasive grains need to have a strength that does not cause destruction by the pressurization. Further, the abrasive grain shape is preferably one having a corner rather than a spherical shape (polygon, cubic crystal, block shape, pyramid, truncated pyramid, cone, etc.). If it is such a shape, when embedding an abrasive grain in a soft polishing surface plate, it is easy to stick and it can fix stably. Moreover, the part exposed to the surface from a soft polishing surface plate becomes a cutting blade, and processing capability improves.

  The method of uniformly dispersing the abrasive grains on the binder layer is not particularly limited. To disperse the abrasive grains as a single particle layer and embed them in the binder layer 12, the abrasive grains are electrostatically charged and the substrate Electrostatic spraying with 11 being ground potential is suitable. The electrostatic spraying referred to here is performed using the electrostatic spraying apparatus shown in FIG.

  As shown in FIG. 5, an electrostatic spraying device 30 for electrostatically spraying polishing abrasive grains includes an abrasive supply unit 31 that adjusts and supplies a predetermined amount of abrasive grains, and a spraying unit 37 that sprays charged abrasive grains. And. The abrasive grains are supplied from the supply chamber 32 to the abrasive grain adjustment chamber 33, and the abrasive grains are charged to the same polarity, positive or negative, in the pressure feeding tube. Which polarity is charged depends on the material of the abrasive grains. For example, when the abrasive is diamond, it is charged to a negative potential, and when it is alumina, it is charged to a positive potential.

  The charge amount of the abrasive grains is detected by the charge measuring device 35, and the abrasive grain supply amount is controlled by the abrasive grain amount control box 36 so that the charge amount becomes an appropriate value. The abrasive grains whose supply amount is controlled to an appropriate amount are sprayed from the spray nozzle 38 toward the substrate stage 40 after passing through the pressure feed pipe 34. The spray nozzle 38 is provided with nozzles that spray in four directions so that the charged abrasive grains are uniformly sprayed. Abrasive grains are blown out in the direction of the arrow 41 from the nozzles sprayed in the four directions and sprayed to the respective spray areas 42 (dotted line areas).

  Since the container inner wall 39 of the spraying unit 37 is charged to the same polarity as the charged abrasive grains, the charged abrasive grains sprayed from the nozzle receive a repulsive force from the inner wall 39 and efficiently adhere to the container inner wall 39. It reaches the substrate 11.

  As a method for preventing pressure loss in the pressure feed pipe 34 and promoting friction between the inner wall of the pressure feed pipe 34 and the abrasive grains, (a) supply of replenishing gas (dry air, nitrogen gas, etc.) in the middle of the pressure feed pipe There are methods for increasing the friction efficiency such as adding a function, (b) providing a mechanism for making the inside of the pressure feeding pipe a negative pressure, and (c) providing a plurality of branch pressure feeding pipes.

  When spraying, the charged particles are sprayed toward the substrate 11 together with the compressed gas (carrier gas) discharged from the spray nozzle arranged around the spray nozzle 38. As the compressed gas, dry air, nitrogen gas or the like is selected and supplied from a normal compression cylinder. By using a corona discharge mechanism in the vicinity of the spray nozzle 38, the charging efficiency can be further improved.

  The base material 11 on which the binder layer 12 is formed is placed on the base material stage 40 and kept at the ground potential. The abrasive grains sprayed from the spray nozzle 38 are charged with a potential of the same polarity of 1 to 50 kV. Therefore, each abrasive grain receives an electrostatic repulsive force, so that it falls and flies toward the binder layer 12 on the substrate 11 in a state where aggregation is released, and is dispersed in a dispersed state.

  At this time, the abrasive grains charged to the same polarity are strongly and electrically attracted toward the binder layer 12 maintained at the ground potential, and collide with the binder layer 12 with a large kinetic energy together with the energy by dropping.

  Since the binder layer 12 is formed of a water-soluble binder or an organic acid-soluble binder, abrasive grains having large kinetic energy can easily bite into the binder layer 12, as shown in FIG. 2 (c). The tips of the abrasive grains abut against the surface of the substrate 11, and the tips are arranged on the surface of the substrate 11.

  If the potential at which the abrasive grains are charged is 1 kV or more, the abrasive grains 13 can sufficiently penetrate the binder layer 12 so that the tips thereof are aligned on the surface of the base material 11. Although the effect can be obtained even at 50 kV or more, a potential range of 1 to 50 kV is preferable in practice.

  Since each of the abrasive grains 13 is charged to the same polarity, the binder layer 12 repels each other and does not cause new agglomeration. Fixed inside.

  After dispersing abrasive grains on the binder layer 12 as described above, the binder layer 12 is dried by a drier to remove liquid components in the binder layer 12, and the abrasive grains for embedding in the soft polishing surface plate The holding sheet 10 is completed.

If necessary, a moisture absorption preventing film is detachably attached to the surface of the abrasive grain holding sheet 10. When the abrasive grains are embedded in the soft polishing surface plate 21, the moisture absorption preventing film is peeled off and used. This moisture absorption prevention film can prevent the adhesion of dust in the air. Moreover, when preserve | saving in a high humidity environment, depending on the kind of binder, the surface binder may melt | dissolve and this melt | dissolution can be prevented by sticking a moisture absorption prevention film.
<A manufacturing method of an abrasive embedding soft polishing surface plate using an abrasive holding sheet>
Next, referring to FIGS. 3A to 3D, which show a series of manufacturing steps, for a method of manufacturing an abrasive-embedded soft polishing surface plate using an embedding grain holding sheet for embedding in a soft polishing surface plate. I will explain.

  FIG. 3A is a schematic cross-sectional view of the abrasive holding sheet 10 for embedding in the soft polishing surface plate of the present invention with the base material 11 facing up and the abrasive grains 13 facing down.

  As shown in FIG. 3 (b), the abrasive grain holding sheet 10 is soft polished so that the tips of the abrasive grains 13 exposed from the binder layer 12 of the abrasive grain holding sheet 10 are in contact with the surface of the soft polishing surface plate 21. Overlay the surface of the surface plate 21.

  Further, the back surface of the base material 11 of the abrasive grain holding sheet 10 is rolled while applying a load in the direction of the arrow 14 with a roller or the like, and a part of the abrasive grains 13 exposed from the binder layer 12 is soft-polished surface plate 21. Embed in the surface of. In addition to the method of rolling the roll while pressurizing the back surface, the abrasive holding force by the soft polishing surface plate 21 is further improved by applying mechanical, electrical or electromagnetic vibration.

  Next, as shown in FIG. 3C, when only the base sheet 11 is peeled off, the abrasive grains 13 embedded in the soft polishing surface plate 21 and the binder layer 12 for fixing the abrasive grains 13 are softly polished. It is left on the board 21.

  Next, when the binder forming the binder layer 12 is water-soluble, the binder layer 12 is washed and removed by spraying water or warm water on the polishing surface plate 21. As shown in FIG. 3D, the respective tips of the abrasive grains 13 embedded in the soft polishing surface plate 21 are exposed in a state where they are aligned on the same plane.

  Moreover, when the binder which forms the binder layer 12 is organic acid soluble, the solution which added the organic acid is sprayed and the binder layer 12 is removed by washing | cleaning.

  In this way, the abrasive-embedded soft polishing surface plate according to the present invention is manufactured.

  As shown in FIG. 4A, the abrasive-embedded soft polishing surface plate 21 according to the present invention is provided with a rotating shaft 24 of the polishing surface plate unit 20. Abrasive grains 22 are uniformly dispersed and embedded in the surface of the soft polishing surface plate 21, and the tips of the exposed portions of the abrasive grains 22 are aligned on the same plane.

  The abrasive-embedded soft polishing surface plate 21 according to the present invention may be a groove-free soft polishing surface plate 21A (FIG. 4B) having no grooves on the surface, and provided with radial or concentric grooves 23. A grooved soft polishing surface plate 21B (FIG. 4C) may be used. It can select suitably according to the use of final polishing.

  In the grooved soft polishing surface plate 21B, the groove portion and the polishing surface which is a convex portion between adjacent grooves are preferably in the range of 1: 1 to 1:10 as an area ratio. The groove only needs to have an area necessary for discharging polishing debris, lubricating liquid, and the like. If the groove area is widened, the polishing efficiency decreases.

  As shown in FIGS. 4B and 4C, the abrasive grains 22 embedded in the soft polishing surface plate are dispersed in both the groove-free soft polishing surface plate 21A and the grooved soft polishing surface plate 21B. A single layer is formed.

  Thus, in the abrasive embedding soft polishing surface plate according to the present invention, the density of abrasive grains necessary for embedding can be adjusted in advance at the manufacturing stage of the embedding abrasive holding sheet on the soft polishing surface plate. Therefore, as compared with the conventional method in which loose abrasive grains are supplied in a slurry state and a part of the abrasive grains are embedded with a correction ring, the abrasive grains can be embedded uniformly and the loss of non-embedded abrasive grains is greatly reduced. Therefore, the present invention can achieve a great effect economically.

Hereinafter, examples of the abrasive holding sheet for embedding in the soft polishing surface plate according to the present invention, and a method for producing the abrasive embedding soft polishing surface plate using the abrasive holding sheet will be described, and a comparative example will be described. Comparative test results are shown.
<Example>
Example 1
1) Application of binder on substrate A 15-inch disk of stainless steel (SUS301) having a thickness of 50 μm and good smoothness was prepared as a substrate. When the surface roughness of this substrate was measured with a stylus type surface roughness meter, the average surface roughness Ra was 0.4 microns. This stainless steel substrate was thoroughly degreased and washed, and then an aqueous solution (15% by weight) of starch (product name: Amicol DNK) manufactured by Nissaku Chemical Co., Ltd. was applied to the surface of the substrate as a water-soluble binder. . Application was performed using a spray method, and the application thickness was adjusted to be in the range of 3 to 5 μm.
2) Scattering of abrasive grains and solidification of binder Polycrystalline diamond particles having an average particle diameter of 6 μm were used as abrasive grains. The abrasive grains were electrostatically sprayed on the starch binder layer. The spraying nozzle diameter was set to 5 mm, the carrier gas was discharged at a rate of 3 kg / cm ² for 5 seconds, and this discharging was repeated 10 times for spraying. The charging voltage at this time was 5 kV.

  Then, it heated at 110 degreeC for 2 minute (s) with the dryer, and removed the liquid component of the binder layer. FIG. 8A shows a photograph of an SEM image of diamond abrasive grains adhered to the starch binder layer after the diamond particles were dispersed.

The average dispersion density of the diamond particles at this time was about 40 particles / 100 μm □. As can be seen from the SEM photograph shown in FIG. 8 (a), it can be seen that the abrasive grains are not aggregated and are arranged in a single layer. Further, it can be seen that the diamond abrasive grains are spaced apart from each other when seen in the plane direction and are in a state of being uniformly dispersed and dispersed.
3) Embedding of abrasive grains in soft polishing surface plate The above-mentioned 15-inch diameter stainless steel substrate (SUS301), in which abrasive particles are embedded in the formed binder layer, is superimposed on the surface of a 15-inch tin surface plate, A load was applied to a cast iron roll having a diameter of 100 mm on the back surface of the substrate and rolled several times to embed diamond abrasive grains on the surface of the tin surface plate.
4) Peeling of base material and removal of water-soluble binder After embedding abrasive grains on the surface of the tin surface plate, the base plate could be easily peeled off by immersing the tin surface plate in a water bath for about 20 minutes. After the substrate was peeled off, the starch was dissolved from the surface of the tin surface plate, but since the remaining starch was observed, it was dissolved in water. Furthermore, by spraying tap water for 5 minutes at room temperature, the binder layer was removed to such an extent that no starch remained on the appearance, and the production of the abrasive polishing soft polishing surface plate was completed.

The metal substrate of the abrasive holding sheet for embedding in the soft polishing surface plate according to the present invention can be reused (regenerated) simply by washing and removing the attached binder with water.
5) Finish polishing using a soft polishing surface plate embedded with abrasive grains As a polishing apparatus, a 15-inch (381 mm) grooved tin surface plate was used for SPL-15 manufactured by Okamoto Machine Tool Co., Ltd. In this grooved tin surface plate, diamond abrasive grains are embedded by the procedures 1) to 4).

  A sapphire substrate having a diameter of 50.8 mmφ and a thickness of 0.4 mm was used as a substrate that is an object to be polished. The average surface roughness (Ra) of the sapphire substrate before polishing was 60 nm.

  In addition, without polishing the sapphire substrate for several minutes before polishing, an operation of fixing the embedded diamond abrasive grains more stably with a correction ring while dropping a water-soluble lubricant was performed.

  Final polishing was performed under the following conditions. During polishing, a lubricating liquid containing no abrasive grains was dropped and supplied. For this lubricating liquid, a 5% by weight aqueous solution containing a glycol compound, a higher fatty acid, and an alkanolamine was used.

(Polishing conditions)
Plate rotation speed: 200 rpm
Lubricating liquid drop amount: 3ml / min Load: 500g
Polishing time: 60 minutes (Example 2)
In Example 2, the spraying density of the abrasive grains was changed, the spraying conditions were the same as in Example 1, and the number of spraying was 5 times (in Example 1, the number of spraying was 10 times). FIG. 8B shows a photograph of an SEM image of diamond abrasive grains adhered to the starch binder layer after the diamond particles according to Example 2 were dispersed. At this time, the average dispersion density of the diamond particles was about 20/100 μm □. Others were the same as in Example 1 including the polishing conditions.
(Comparative Example 1)
In Comparative Example 1, a slurry containing free abrasive grains is supplied to a tin surface plate, and the free abrasive grains are embedded in the tin surface plate by an abrasive embedding ring. A tin surface plate in which abrasive grains are embedded by the conventional method shown in FIG. used.

  As the polishing apparatus, the same apparatus as in the example was used. An abrasive grain embedding ring 55 is placed on a 15-inch grooved tin surface plate 51 and diamond abrasive grains having an average particle diameter of 5 to 10 μm are embedded under the following conditions, and then polished using this tin surface plate. did.

  As the abrasive grains, diamond slurry having an average particle diameter of 5 to 10 μm (manufactured by Shuwa Kogyo Co., Ltd .: SP-1107: concentration 0.5% by weight) was used. Polishing was performed under the following conditions. Before starting the polishing, without setting the jig 62 for the object to be polished (sapphire substrate), the abrasive grains were embedded only for 5 minutes with the abrasive-embedding ring 55 under the following conditions, and then the sapphire substrate was set. And polished. Polishing was performed while dripping a lubricating liquid containing no abrasive grains.

(Polishing conditions)
Surface plate rotation speed 200rpm
Lubricating liquid drop amount 3ml / min Load: 500g
Polishing time 60 minutes (Comparative Example 2)
In Comparative Example 2, a slurry containing free abrasive grains is supplied to a tin surface plate, and the free abrasive grains are embedded in the tin surface plate by an abrasive embedding ring. The tin surface plate in which abrasive grains are embedded by the conventional method shown in FIG. It was used.

As the polishing apparatus, the same apparatus as in the example was used. An abrasive grain embedding ring 55 is placed on a 15-inch tin surface plate 51, and after embedding diamond abrasive grains having an average particle diameter of 5 to 10 μm under the following conditions, the surface is washed with a diluent of a lubricant, The floating abrasive was removed by lightly wiping with a nonwoven fabric.
The abrasive grains were the same as in Comparative Example 1, and diamond slurry having an average particle diameter of 5 to 10 μm (Shuwa Industrial: SP-1107: concentration 0.5% by weight) was used.

(Polishing conditions)
Plate rotation speed: 60rpm
Lubricating liquid drop amount: 3ml / min Load: 500g
Polishing time 30 minutes Polishing was carried out in the same manner as in Example 1 while dripping a lubricant containing no abrasive grains.
6) Evaluation results The evaluation results of Examples and Comparative Examples are shown in Table 1 below.

  As shown in Table 1, in the final polishing by the abrasive embedding soft polishing surface plate manufactured using the abrasive holding sheet for embedding in the soft polishing surface plate of Examples 1 and 2 according to the present invention, The average surface roughness (Ra) and maximum surface roughness (Rmax) of the polished product were small, and a sufficient polishing amount could be obtained.

  On the other hand, many scratches were observed in Comparative Example 1, but only one or two shallow scratches were observed in Examples 1 and 2 and Comparative Example 2. In Comparative Example 2, although the surface roughness was low, the polishing efficiency was low and clogging occurred.

  As can be seen from the above detailed description, the abrasive holding sheet for embedding in the soft polishing surface plate according to the method of the present invention has the necessary surface because the abrasive grains are dispersed at the required density on the surface of the base material. Density abrasive grains can be uniformly embedded in the surface of the soft polishing surface plate. For this reason, it is possible to manage polishing performance uniformly. As a result, the polishing efficiency is improved, and an abrasive-embedded soft polishing surface plate having a uniform polishing surface can be manufactured.

10 Abrasive grain holding sheet for embedding in soft polishing surface plate (Abrasive grain holding sheet)
DESCRIPTION OF SYMBOLS 11 Base material 12 Binder layer 13 Abrasive grain 20 Polishing surface plate unit 21 Soft polishing surface plate 21A Groove-free soft polishing surface plate 21B Grooved soft polishing surface plate 22 Abrasive grain 23 Groove

Claims (8)

A sheet-like base material, abrasive grains dispersed in a single layer on the surface of the base material, and a binder layer that is fixed on the base material in a state where a part of each of the abrasive grains is exposed,
An abrasive grain holding sheet for embedding in a soft polishing surface plate, wherein the binder layer is formed of a water-soluble binder or an organic oxidation-soluble binder. The water-soluble binder is one or more selected from polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropylmethylcellulose, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, polyethylene oxide, hyaluronic acid, polysaccharides, dextrin, albumin, gelatin casein and alginic acid. A binder consisting of
The abrasive holding sheet for embedding in a soft polishing surface plate according to claim 1, wherein the organic acid-soluble binder is a binder composed of one or two kinds of chitin or chitosan. _3. The soft polishing surface plate according to claim 1, wherein the abrasive grains are made of at least one selected from diamond, cBN, B ₄ C, Al ₂ O ₃ , SiO ₂ , and SiC. Abrasive grain holding sheet for embedding.   The abrasive holding sheet for embedding in a soft polishing surface plate according to any one of claims 1 to 3, wherein the substrate is made of a metal sheet.   The layer thickness of the binder layer is in the range of 1/10 to 2/3 of the average particle diameter of the abrasive grains. To the soft polishing surface plate according to any one of claims 1 to 4, An abrasive holding sheet for embedding.   6. An abrasive holding for embedding in a soft polishing surface plate according to any one of claims 1 to 5, wherein a moisture absorption preventing film is stuck on the abrasive so as to be peelable from the abrasive. Sheet. A method for producing an abrasive-embedded soft polishing surface plate embedded in a state in which a part of each abrasive grain is exposed on the surface of the soft polishing surface plate,
The state in which the abrasive holding sheet for embedding in the soft polishing surface plate according to any one of claims 1 to 6 is in contact with the surface of the soft polishing surface plate, and the abrasive particles are in contact with the surface of the soft polishing surface plate. A first step of mounting, and
A second step of pressurizing the back surface of the substrate of the abrasive holding sheet for embedding into the soft polishing surface plate and embedding some of the abrasive particles in the soft polishing surface plate;
A third step of peeling the substrate from the abrasive grains and binder layer embedded in the soft polishing surface plate;
A fourth step of removing the binder layer by dissolving it with water or an organic acid;
A method for producing an abrasive-embedded soft polishing polishing surface plate comprising: The method for producing an abrasive-embedded soft polishing surface plate, wherein the soft polishing surface plate is made of one or more kinds of alloys of tin, lead, antimony, bismuth and copper.