Local polishing method, local polishing device, and corrective polishing apparatus using the local polishing device

Abstract

Provided is a local polishing technique suitable for corrective polishing. Press polishing is performed while supplying a polishing solution between a work and a work-polishing rotating tool locally pressed against the work, the polishing solution having abrasive grains composed of organic particles with an average particle size of 5 μm or more dispersed in a liquid. The rotating tool is made of an elastic material.

Description

TECHNICAL FIELD[0001]The present invention relates to a local polishing method and a local polishing device, which can be suitably used for corrective polishing.BACKGROUND ART[0002]In machining of an optical element such as an optical lens, for example, corrective polishing is performed. In the corrective polishing, a work (workpiece) is entirely scanned while a rotating tool, which is capable of local polishing, is being pressed against the work at the same time of supplying polishing slurry composed of fine abrasive grains with an average particle size of approximately 1 μm between the work and the rotating tool. In the corrective polishing, a static machining mark is obtained by polishing a material of the same quality as the work in advance without scanning the rotating tool, and a shape of the static machining mark per unit time is obtained. Then, corrective machining to a desired shape is performed by a process of performing deconvolution (deconvolution integral) calculation f...

AI Technical Summary

Benefits of technology

The present invention relates to a tool for local press polishing, which prevents wear and maintains surface texture and roughness without pretreatment and maintenance. The use of an elastic material for the tool surface improves surface roughness and machining stability. The use of a liquid containing organic particles as abrasive grains improves interaction with the work material and further enhances machining stability and surface roughness. The rotating tool has a curved shape stabilized by elastic restoring force, which ensures consistent and stable contact with the work material. The use of an outer diameter of 5.0 mm or less for the polishing action region allows for higher resolution local polishing.

Problems solved by technology

However, in the conventional corrective polishing, there has been a problem that it is difficult to obtain a stable machining amount since the rotating tool itself that is locally pressed against the work is worn and pressing force is liable to fluctuate.

Moreover, since a surface texture of the tool largely affects transportation and retention of the fine abrasive grains, discharge of chips, and the like, the rotating tools are used for the polishing after the surface texture is prepared by pretreatment such as truing (shape formation) and dressing (toothing).

However, such pretreatment causes a decrease in machining efficiency and an increase in cost.

In addition, since the rotating tool is easy to wear as described above, it is necessary to frequently perform a maintenance operation on the surface shape, which causes a further decrease in efficiency and a further increase in cost.

However, these non-contact machining methods require a circulation device that thoroughly controls viscosity and concentration of the polishing slurry, and equipment thereof tends to become large in size.

Moreover, in order to speed up a flow of the slurry passing through the gap, it is necessary to set an outer diameter of an outer peripheral surface of the rotating tool, which faces the work, to a predetermined value or more, and also to set a rotation speed of the rotating tool to a predetermined value or more, and there also occurs a certain limit to a correctable spatial resolution.

The non-contact corrective polishing technique cannot cope with correction of such small undulations of the spatial wavelength.

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