Abrading – Flexible-member tool – per se – Work face variegated or on projecting backing
Reexamination Certificate
2002-03-26
2004-06-29
Nguyen, Dung Van (Department: 3723)
Abrading
Flexible-member tool, per se
Work face variegated or on projecting backing
C451S539000
Reexamination Certificate
active
06755728
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to an abrasive film, and more particularly to such an abrasive film which is advantageously used to polish a magnetic disk, an end face of an optical fiber or other object or workpiece with high precision.
2. Discussion of the Related Art
There is known an abrasive film which is used to polish a magnetic disk, an end face of an optical fiber or other object or workpiece, with application of a polishing fluid to the abrasive film and/or the workpiece. Such an abrasive film includes (a) a substrate, (b) a binder and (c) a multiplicity of abrasive grains which are fixed to a surface of the substrate by the binder, and is commonly formed to take a roll, sheet or disk shape. In a polishing operation with the abrasive film, the abrasive film and the workpiece are moved relative to each other while being forced to each other, with the application of the polishing fluid, so that the workpiece is polished by the abrasive film. As one example of such an abrasive film, JP-A-2000-354944 (publication of unexamined Japanese Patent Application laid open in 2000) discloses an abrasive film which is used to polish end faces of an optical fiber and a ferrule that is a component of a connector connecting the optical fiber with another optical fiber. In general, the size of the abrasive grains of the abrasive film is reduced with an increase in a required degree of surface smoothness of the workpiece to be polished. For polishing the end face of the ferrule which is commonly required to have a so-called “mirror-finished surface”, for example, fine grains having an average size of not larger than 10 &mgr;m are used as the abrasive grains of the abrasive films.
However, the applied polishing fluid is more likely to be repelled by a polishing surface of the abrasive film, as a degree of surface smoothness of the polishing surface is increased as a result of the reduction in the size of the abrasive grains. This means that the applied polishing fluid is less likely to be held between the polishing surface of the abrasive film and a surface of the workpiece that is to be polished during the polishing operation, whereby a frictional heat generating between the abrasive film and the workpiece is undesirably increased, thereby causing the resin binder to be fused and stuck onto the surface of the workpiece, causing the polishing surface to be glazed and/or causing the surface of the workpiece to be burnt. The sticking of the fused binder on the surface of the workpiece inevitably reduces the polishing performance, leading to a problematic reduction in a reliability of the polished workpiece as a product. For example, if the end face of the ferrule is polished in such a condition of the reduced polishing performance, there will be caused a considerable loss in an optical transmission between the optical fibers through the connector which is provided by the polished ferrule.
It might be possible to form pits and projections in the polishing surface of the abrasive film, for example, by roughening a surface of the substrate of the abrasive film, in the interest of facilitating the polishing fluid to be held between the abrasive film and the workpiece during the polishing operation. However, the roughened surface of the substrate is smoothed as the abrasive film is repeatedly used for the polishing operation. The polishing fluid can not be sufficiently held between the abrasive film and the workpiece, once the surface of the substrate of the abrasive film is smoothed. That is, the formation of the pits and projections in the polishing surface of the abrasive film does not provide a fundamental solution to the above-described problem.
SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide an abrasive film which includes fine abrasive grains and which is capable of reliably exhibiting an excellent polishing performance without causing a binder to be fused to be stuck onto a polished surface of a workpiece and without causing the polished surface of the workpiece to be burnt, owing to provision for facilitating a polishing fluid to be held between the abrasive film and the polished workpiece in spite of the fineness of the abrasive grains. It is a second object to the invention to provide a polishing method by using the abrasive film having the above technical advantage. The first object may be achieved according to any one of first through tenth aspects of the invention which are described below. The second object may be achieved according to any one of eleventh through fourteenth aspects of the invention which are also described below.
The first aspect of this invention provides an abrasive film for grinding or polishing an object or workpiece, comprising: (a) a substrate; (b) a binder; (c) a multiplicity of abrasive grains which are fixed to a surface of the substrate by the binder; and (d) a water-soluble inorganic compound which is added to the binder.
According to the second aspect of the invention, in the abrasive film defined in the first aspect of the invention, the abrasive grains have an average size of not smaller than 0.01 &mgr;m and not larger than 10 &mgr;m.
According to the third aspect of the invention, in the abrasive film defined in the first or second aspect of the invention, the water-soluble inorganic compound is added in an amount of 1-15 parts by weight per 100 parts by weight of the binder.
According to the fourth aspect of the invention, in the abrasive film defined in any one of the first through third aspects of the invention, the water-soluble inorganic compound consists of a weak-alkali metal salt which is formed of a combination of an alkali metal and a weak acid.
According to the fifth aspect of the invention, in the abrasive film defined in any one of the first through third aspects of the invention, the water-soluble inorganic compound consists of a weak-acid metal salt which is formed of a combination of a metal and a strong acid.
The sixth aspect of the invention provides an abrasive film for grinding or polishing an object or workpiece, comprising: (a) a substrate; (b) a binder; (c) a multiplicity of abrasive grains which are fixed to a surface of the substrate by the binder; and (d) a water-soluble organic acid alkali metal salt which is added to the binder; wherein the water-soluble organic acid alkali metal salt is a solid at an ordinary temperature.
According to the seventh aspect of the invention, in the abrasive film defined in the sixth aspect of the invention, the abrasive grains have an average size of not smaller than 0.05 &mgr;m and not larger than 10 &mgr;m.
According to the eighth aspect of the invention, in the abrasive film defined in the sixth or seventh aspect of the invention, the water-soluble organic acid alkali metal salt is added in an amount of 1-10 parts by weight per 100 parts by weight of the binder.
According to the ninth aspect of the invention, in the abrasive film defined in any one of the sixth through eighth aspects of the invention, the water-soluble organic acid alkali metal salt consists of an anionic surface-active agent.
According to the tenth aspect of the invention, in the abrasive film defined in any one of the sixth through eighth aspects of the invention, the water-soluble organic acid alkali metal salt consists of a carboxylic acid alkali metal salt.
The eleventh aspect of this invention provides a method of grinding or polishing an object or workpiece, by using the abrasive film defined in any one of the first through fifth aspects of the invention. The method comprises steps of moving the workpiece and the abrasive film relative to each other, while forcing the workpiece and the abrasive film against each other; and applying a polishing fluid or liquid including a water, to at least one of the workpiece and the abrasive film.
According to the twelfth aspect of the invention, in the method defined in the eleventh aspect of the invention, the abrasive grains have an average size of not smaller than 0.0
Nguyen Dung Van
Noritake Co. Ltd.
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