CS255930B1 - The method of fixing the shape of small glass products and / or semi-finished products at their thermal exposure - Google Patents

Abstract

The present invention relates to a method for fixing the shape of small glass articles and / or blanks made of glass, requiring temperature exposure at higher transformation temperatures to achieve final coloration and / or haze. The surface of the objects is coated with a fixative mass prior to thermal exposure. The molds thus formed are removed after the exposure to either the chemistry or the mechanical route.

Description

The present invention relates to a method of providing the shape of small glassware and / or semi-finished products to prevent their deformation during thermal exposure.

The set of articles is made, in particular in the field of glass costume jewelery, from glass, which requires thermal exposure of the article and / or semifinished product formed therefrom to achieve final color and / or turbidity. Thermal exposure takes place after the product and / or semi-finished product has been heated above their transformation temperature. In this case, the shape of the exposed article and / or the semi-finished product can and will be considerably changed.

To date, to prevent or reduce deformation of the tiny glass beads during thermal exposure, heating above their transformation temperature, self-hold at the desired temperature, and subsequent cooling, are performed under forced movement of the beads or in a backfill of a separating agent such as ground dolomite. The disadvantage of this method is its limited applicability, for example only for the production of rocailles by so-called rounding or bead-shaped blanks for the production of chaton stones by grinding, since the surface tension value of the glass exposed to thermal exposure does not allow processing of bodies of any size and shape. The bodies in the shape of the finished product cannot be processed in this way at all.

The described drawbacks eliminate or significantly reduce the method of fixing the shape of small glass products and / or semi-finished products at their temperature exposure according to the invention, which consists in that the glass bodies in the shape of the finished product or semi-finished product are. prior to thermal exposure, provide the entire surface or at least a large portion of the surface with a water-based fixative layer or other suspension of a suitable substance, solution, emulsion, paste, powder, and the like to form a solid mold on each body after solidification and curing. A material with a glass adhesion is used as the fixation material so that the integrity of the layer is not compromised until it solidifies, yet it is resistant to thermal action to such an extent that it does not become noticeable during the thermal exposure to the glass used. The molds formed by the molds, which themselves cannot be deformed by temperature exposure, prevent the glass-shaped bodies enclosed therein from changing even at temperatures higher than their transformation temperatures. . A layer of fixative mass on the surface of the glass beads is formed, for example, by immersing the beads in the selected fabric, moving the beads in the fabric, rolling or spraying the fabric onto the beads, and the like. Removal of the layer of fixative material from the surface of the bodies during the thermal exposure is accomplished either by chemical means, eg by dissolving it, or by mechanical means, eg by tumbling. As a rule, the surface quality of the glass beads will change somewhat, but their original shape will remain substantially unchanged.

The advantage of the method of fixing the shape of small glass products and / or semi-finished products at their thermal exposure according to the invention is the possibility of thermal exposition of glass beads of various shapes intended either as a semi-finished product for further processing, eg grinding on cut jewelery quartz or as finished products. eg, uncut jewelery stones. Advantageously, this method can also be used for the thermal exposure of glass bodies made of bars up to 14 millimeters in diameter and intended for further processing by known hand-squeezing or machine-forming technologies.

The following examples illustrate the nature of the shape fixing method of the invention without, however, limiting it.

Example 1 ·

Double cone bodies with a diameter of 5 millimeters and a height of 5 millimeters, intended for the manufacture of costume jewelery stones by grinding and polishing, are made of glass containing zinc oxide and with the addition of 1 percent cadmium sulfide and 0.5 percent selenium by weight final coloring requires a temperature exposure of the bodies of 5-15 minutes at 600-750 ° C. To fix the shape of the beads during thermal exposure, the beads placed in the basket are immersed in an aqueous kaolin suspension before being removed and treated with a dry air jet at 80 ° C after removal. After evaporation of water from the suspension layer adhering to the surface of the bodies, sufficiently solid and resistant molds form on the bodies. The bodies provided with these molds are subjected to thermal exposure after being removed from the basket and placed on the ceramic support. After this, the layer of kaolin with the surface of the bodies is removed mechanically by so-called rumpling.

Example 2 ..

Double-cone bodies with a diameter of 4 millimeters and a height of 4 millimeters, designed for the manufacture of costume jewelery stones by grinding and polishing, are made of glass containing 0.003 percent gold and 0.0003 percent selenium by weight, which requires temperature to achieve final color exposure for 10 minutes at 650 ° C and then for 5 minutes at 750 ° C. To fix the shape of the bodies during thermal exposure, the bodies placed in the mixing drum are wrapped with an aqueous kaolin slurry before moving them, and the layer adheres to the surface of the bodies, after being transferred to a screen, dried with a warm, dry air. After the temperature exposure, the layer of kaolin with the surface of the bodies is removed mechanically by so-called rumping.

Example 3 '

Roller bodies 12 mm in diameter and 20 millimeters in height, for pressing jewelery stone blanks, are prepared by chopping rods made by drawing from glass according to Example 2. To fix the shape of the bodies during thermal exposure, they are placed on spray, eg with a spray gun, a water suspension of kaolin, whereupon the layer adhering to the surface of the bodies is dried

- 4 warm air. After thermal exposure, the surface layer of kaolin 8 is removed chemically in a hydrofluoric acid solution.

Claims (1)

SUBJECT OF THE INVENTION Method for fixing the shape of small glassware and / or semi-finished products at their thermal exposure after heating the products and / or semi-finished products above their transformation temperatures, characterized in that the glass articles in the shape of the final product and / or semi-finished are or at least a larger part of the surface with a layer of fixative material which, when solidified α hardens, forms a solid mold on each body.