JP6259902B2 - Polishing tool - Google Patents

Description

  The present invention relates to a polishing sheet manufacturing method and a polishing tool, and more particularly to a polishing sheet manufacturing method and a polishing tool used when polishing the surface of a concave or convex object to be polished.

  Conventionally, a polishing tool is used to polish the surface of a spherical lens in the manufacturing stage of a lens having a curved surface such as a spherical lens used in an optical apparatus such as a camera. A polishing sheet made of foamable polyurethane having a curved surface corresponding to the curved surface of the object to be polished is attached to the surface of the polishing tool. When polishing the object to be polished, the object to be polished is polished by relatively rotating and swinging the object to be polished and the polishing tool while supplying a polishing slurry between the object to be polished and the polishing sheet (for example, Patent Document 1).

  Further, Patent Document 1 does not describe a method for manufacturing an abrasive sheet, but the method for manufacturing an abrasive sheet used for a polishing tool for polishing a spherical lens is described in Patent Documents 2 and 3. It has been known.

JP 2001-025950 A JP 2001-162502 A JP 2001-212743 A

  In Patent Document 2, a corolla-shaped sheet is prepared, and a flat sheet is made into a three-dimensional polishing sheet by attaching side portions of the petal pieces of the sheet, and this is a tool base corresponding to the shape of the object to be polished. The polishing tool affixed to is described. Similarly, cited document 3 describes a polishing tool using a polishing sheet that is cut into a circular sheet to form a three-dimensional shape.

  However, in the method for producing an abrasive sheet described in Patent Documents 2 and 3 described above, a flat abrasive sheet is cut to form pieces such as many petal pieces, and the sides of these pieces are pasted together. By combining them, a hemispherical polishing sheet is formed, so that the polishing surface of the polishing sheet always has a bulge of the joining portion between the pieces and wrinkles of the polishing sheet when three-dimensionally formed. If the polished surface is raised or wrinkled, there is a problem that a gap is formed between the pieces of the polishing sheet, and as a result, polishing spots are generated on the object to be polished. Further, if the polishing surface of the polishing sheet is raised or wrinkled, a gap is formed between the pieces of the polishing sheet, and the polishing slurry enters between the polishing sheet and the tool base through the gap. When the polishing slurry enters between the polishing sheet and the tool base, the adhesive force between the tool base and the polishing sheet is weakened, and the polishing sheet is peeled off from the tool base.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for producing a polishing sheet and a polishing sheet in which the polishing surface does not have wrinkles due to swelling or bending between pieces. .

  In order to solve the above-described problems, a method for producing a polishing sheet according to the present invention is a method for producing a polishing sheet for a polishing tool, which is used for polishing a workpiece having a curved surface to be polished. A polishing sheet made of foamable polyurethane is formed on a surface of a tool base having a shape corresponding to a surface to be polished of an object to be polished by a wet film forming method.

  According to the present invention configured as described above, the foamed polyurethane polishing sheet can be directly formed on the surface of the tool base by the wet film forming method. Thereby, the polishing sheet of a shape suitable for the curved surface to be polished of the object to be polished can be formed. And since the surface of the polishing sheet formed in this way does not have bulges or wrinkles, it is possible to suppress polishing spots on the object to be polished.

  In the present invention, it is preferable that the polishing sheet is formed by applying a polyurethane resin solution to the surface of the tool base, rotating the tool base around a predetermined axis, and setting the surface of the tool base to which the polyurethane resin solution is applied to the coagulation bath. And the tool base is taken out of the coagulation bath, and the coagulation liquid is dried.

  In order to solve the above-described problems, a polishing tool according to the present invention is a polishing tool used for polishing an object having a curved surface to be polished, and is formed on the surface of a tool base. A polishing sheet is provided, and the polishing sheet is formed on the surface of the tool base having a shape corresponding to the surface to be polished of the object to be polished by using a wet film forming method.

  According to the present invention thus configured, an abrasive sheet made of foamable polyurethane can be formed on the surface of the tool base by a wet film forming method. Thereby, the polishing sheet of a shape suitable for the curved surface to be polished of the object to be polished can be formed. And since there is no swell or wrinkles on the surface of such a polishing sheet, polishing spots on the object to be polished can be suppressed.

  As described above, according to the present invention, it is possible to provide a polishing sheet manufacturing method and a polishing sheet in which the polishing surface does not have wrinkles between pieces or wrinkles due to bending.

3 is a side cross-sectional view showing a polishing tool having a polishing sheet according to an embodiment of the present invention. It is a figure which shows each process of the manufacturing method of the abrasive sheet by embodiment of this invention. It is a side cross section which shows the polishing tool which has the polishing sheet by the modification of embodiment of this invention. It is a figure which shows each process of the manufacturing method of the abrasive sheet by embodiment of this invention.

  Hereinafter, a polishing sheet and a method for manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing a polishing tool having an abrasive sheet according to an embodiment of the present invention.

  First, as shown in FIG. 1, a polishing tool 3 having a polishing sheet 1 is used when polishing a concave lens 5 as an object to be polished.

  The polishing tool 3 includes a tool base 9 having a convex surface that complementarily corresponds to the shape of the concave polished surface 7 of the concave lens 5. A polishing sheet 1 made of foamable polyurethane is formed on the convex surface of the tool base 9.

  At the time of polishing, the convex surface of the tool base 9 of the polishing tool 3 is pushed into a recess formed by the surface 7 to be polished of the concave lens 5, and both are supplied while supplying polishing slurry between the concave lens 5 and the polishing tool 3. The surface 7 to be polished is polished by rotating or swinging relatively.

  The polishing sheet 1 is a foamed polyurethane sheet formed on the convex surface of the tool base 9 by a wet film forming method. Hereinafter, the manufacturing method of the abrasive sheet 1 will be described in detail.

FIG. 2 is a diagram showing each step of the method for manufacturing an abrasive sheet.
As shown in FIG. 2 (a), when the polishing sheet 1 is manufactured, first, a tool base 9 having a convex surface having a shape corresponding to the polished surface 7 of the concave lens 5 that is an object to be polished is prepared. To do. Next, as shown in FIG. 2B, a polyurethane resin solution containing dimethylformamide (DMF) is applied to the convex surface of the tool base 9.

  In the step of applying the polyurethane resin solution, a polyurethane resin solution having a viscosity of 5 to 20 Pa · s is applied over the entire convex surface to a thickness of about 1 to 2 mm. At this time, for example, dip coating is preferable in which the tool base 9 is immersed in a polyurethane resin solution and pulled up, and then the excess resin solution is scraped off with a spatula so that the thickness of the resin becomes uniform. In order to make the thickness of the resin uniform, a coating method such as slit die coating or knife coating may be used.

  Next, the tool base 9 coated with the polyurethane resin solution is rotated around the axis while the convex surface is directed downward. The rotational speed of the tool base 9 is preferably set to such an extent that uncured resin is not scattered by centrifugal force. When the resin having the above-described viscosity is used, it is preferably about 5 to 200 rpm. Thereby, it can prevent that a polyurethane resin solution accumulates on the top part of a convex-shaped surface, and the film | membrane of a top part becomes thick.

  Next, as shown in FIG. 2 (c), the tool base 9 to which the polyurethane resin solution is applied is immersed in a coagulating liquid containing water as a main component. When the tool base 9 coated with the polyurethane resin solution is immersed in the coagulating liquid, first, the surface of the polyurethane resin solution that is in contact with the coagulating liquid is coagulated to form a skin layer. When the skin layer is formed, DMF in the resin solution diffuses into the coagulation liquid through the gap between the skin layers due to the osmotic pressure of DMF. At substantially the same time, the coagulation liquid flows into the resin solution through the gaps in the skin layer, and the coagulation of the resin solution starts gradually from the vicinity of the skin layer. And since the skin layer forms a hydrophobic field in the resin solution, the coagulating liquid gathers in the direction away from the skin layer, and the resin density at the position away from the skin layer decreases, while the resin density near the skin layer increases. . Thereby, a teardrop-shaped space extending substantially perpendicular to the skin layer is formed in the resin. Then, the convex surface coated with the polyurethane resin solution is immersed in the coagulation liquid, and after the DMF in the polyurethane resin solution is completely removed into the coagulation liquid, the tool base 9 is pulled up from the coagulation liquid. Next, the coagulating liquid is dried using a dryer. When the coagulating liquid in the resin space evaporates, many tear-shaped bubbles are formed in the resin.

  Through the above steps, as shown in FIG. 2 (d), a sheet-like foaming polyurethane resin layer having a uniform thickness on the convex surface of the tool base 9 and having tear-like bubbles inside is formed. Can be formed. And the polishing sheet 1 formed by using the wet film forming method in this way does not have seams, bulges, wrinkles, etc., and has a substantially uniform thickness.

  By using the polishing sheet 1 having such a uniform thickness, it is possible to suppress polishing spots on the polished surface 7 of the concave lens 5. Further, since the polishing sheet 1 is formed as a single sheet having a three-dimensional shape, the polishing slurry passes through the polishing sheet 1 and enters between the polishing sheet 1 and the convex surface of the tool base 9. Can be prevented.

  FIG. 3 shows a modification of the above-described embodiment. In the modification, the convex lens 11 is used as an object to be polished.

  A polishing tool 15 for polishing the polishing target surface 13 of the convex lens 11 is formed on a tool base 17 having a concave surface corresponding to the convex polishing target surface 13 in a complementary manner, and a concave surface of the tool base 17. And a polishing sheet 19. The polishing sheet 19 is formed of a foamable polyurethane resin having a uniform thickness, similar to the polishing sheet 1 described above.

FIG. 4 is a diagram illustrating each step of a method for manufacturing an abrasive sheet according to a modification.
As shown in FIG. 4A, when the polishing sheet 19 is manufactured, first, a tool base 17 having a concave surface having a shape that complementarily corresponds to the surface to be polished 13 of the convex lens 11 that is an object to be polished is prepared. . Next, as shown in FIG. 4B, a polyurethane resin solution containing DMF is applied to the concave surface of the tool base 17.

  Next, the tool base 17 coated with the polyurethane resin solution is rotated around the axis while the concave surface is directed upward. Next, as shown in FIG. 4C, the tool base 17 coated with the polyurethane resin solution is immersed in the coagulation liquid. As a result, a skin layer is formed on the surface of the resin, and tear-shaped bubbles extending substantially perpendicular to the skin layer are formed inside the resin. Then, after the DMF in the resin solution is removed, the tool base 17 is pulled up from the coagulating liquid, and the coagulating liquid is dried.

  Through the above steps, as shown in FIG. 4 (d), a sheet-like foaming polyurethane resin layer having a uniform thickness and having tear-shaped bubbles inside is formed on the concave surface of the tool base 17. can do. And the polishing sheet 19 formed by using the wet film forming method as described above does not have seams, bulges, wrinkles, etc., and has a substantially uniform thickness, similarly to the polishing sheet 1. .

  The present invention is not limited to the above-described embodiment, and the configuration of the above-described embodiment can be changed as appropriate without departing from the spirit of the present invention.

  In the above-described embodiment, the concave lens and the convex lens are objects to be polished, but the object to be polished may be any object as long as it has a three-dimensional shape rotated around an arbitrary axis.

1,19 Polishing sheet 3,15 Polishing tool 5,13 Polishing object 9,17 Tool base

Claims (1)

A polishing tool used for polishing an object to be polished having a curved surface to be polished,
Comprising an abrasive sheet formed on the surface of the tool substrate;
The polishing sheet is formed on the surface of the tool base having a shape corresponding to the surface to be polished of the object to be polished , and has no seam, bulge, and wrinkle, and has a uniform thickness. A polishing tool, which is a sheet, and in the polishing sheet, tear-shaped bubbles extending perpendicularly from the polishing surface of the polishing sheet are formed.

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