RU128154U1 - DEVICE FOR HIGH-TEMPERATURE DEFORMATION POLISHING OF OPTICAL ELEMENTS - Google Patents

Abstract

Device for high-temperature deformation polishing of optical elements, characterized in that it contains a guide cylinder and a punch with an optically polished contact part of refractory oxides or carbides.

Description

The utility model relates to equipment for the economical manufacture of optical parts with increased resistance to damaging environmental influences by means of deformation effects. Of the similar design and purpose of the subject of this patent, which are taken as a prototype of the proposed product, the known molds for the manufacture of spectacle glasses by deformation of thermoplastic organic materials [1] and molds for forming blanks from optical glass through the so-called bending [2] . In both cases, the process temperatures are selected corresponding to the softening of the deformable materials (for plastics - up to 200 ° C, for inorganic glasses - up to 800 ° C).

During thermoplastic molding of spectacle glasses made of organic materials in molds with optically polished punches, it is possible to achieve the quality of optical surfaces that meet the requirements of GOST 11141-84 in terms of cleanliness and roughness. However, when bending optical blanks from inorganic glasses, which occurs at higher temperatures, the surface quality required by the above GOST is not achieved. Therefore, the billets obtained by bending for the manufacture of optical quality products from them are subjected to abrasive grinding and polishing operations. The main reason that the direct deformation of the materials, which become plastic at temperatures above 500 ° C, failed to obtain the required quality of the optical surfaces, is the adhesion of the punch surface in the surface of the workpiece. As a result, when the punch and the part are opened at the end of the molding process, as a rule, local detachments of sections of the processed surface occur, which significantly degrade its optical quality. Another reason that makes the precision molding of optical surfaces at elevated temperatures problematic is the fact that the materials of the forming punches also begin to soften, which, under the influence of an external load, leads to a deviation of the shape of the part from the given geometry.

The disadvantages of the molds used in the plastic molding of optical parts from materials that plasticize at elevated temperatures are the local adhesion of their punches to the machined surfaces and the distortion of their geometry due to the softening of the material of the punches.

The technical result, which is achieved by the claimed utility model, is to create such a device in which in the required temperature range the optically polished surfaces of the forming punches do not adhere to the surface of the workpiece when an external load is applied. For this purpose, it is proposed to use solid-state materials that retain chemical inertness at temperatures up to 1000 ° C, when most of the materials used for the manufacture of optical parts soften. Such high-temperature inert materials include, in particular, synthetic aluminum oxide (in single-crystal form - leucosapphire), silicon carbide, tungsten carbide. These materials can be used for forming punches in two ways: by manufacturing monolithic products entirely from the selected material or by coating from it onto a workpiece of the required geometry from a material that maintains hardness in the working temperature range.

Distinctive features of the proposed device are:

1) The presence of a forming punch with an optically polished surface made of a material that does not adhere to the surface of the workpiece under conditions of plastic molding at an elevated temperature, when the material of the part becomes sufficiently plastic. For example, for most metals, alumina, silicon carbides, and tungsten are acceptable materials for the punch surface.

2) At the plasticization temperature of the material of the workpiece, the punch bulk material retains the hardness necessary for molding. For example, the punch body may be made of the same alumina, silicon carbides, or tungsten. Or, the punch body can be made of a heat-resistant metal alloy coated with a coating of one of the above materials on the contact surface.

A schematic representation of the proposed mold is shown in figure 1:

Where 1 is the guide cylinder of the mold,

2 - Lower support punch with a flat surface (the quality of which does not have any special requirements),

3 - Metal mirror subjected to deformation polishing.

4 - The stem of the mold punch, transferring the load on the workpiece.

5. Optically polished contact part of the punch made of refractory oxides or carbides - materials that do not adhere to the surface of the workpiece and retain mechanical hardness during high-temperature deformation polishing.

Information sources:

1. "The technology of manufacturing glasses", ed. L.S. Urmacher, Moscow, Medicine, 1990.

2. "Technology of optical parts" under. ed. M.N.Semibratova, "Engineering", Moscow, 1978;

Claims (1)

Device for high-temperature deformation polishing of optical elements, characterized in that it contains a guide cylinder and a punch with an optically polished contact part of refractory oxides or carbides.

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