SU1087476A1 - Method for making bent products of glass - Google Patents

Abstract

THE METHOD OF MANUFACTURING PLASTIC PRODUCTS FROM GLASS, including heating the glass blank, its initial bending in ceramic form with a radius of curvature of 1.2-1.6, the radius of the product and cooling, as well as additional heating and bending of the workpiece in the form with a radius of curvature of the product with a subsequent curvature responsible annealing in a furnace and cooling under conditions of natural convection, about t and h and with the fact that, in order to increase productivity and improve the quality of products from calcium aluminate glasses, after the initial and additional zgibani shape of the workpiece is covered with a ceramic lid and their derivatives r heating - after initial izgnbani at 120, and after dopol1shtelnogo at 120-160 ° C above the softening temperature of glass, the annealing and cooling ve.dut to form a closed lid. €

Description

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A: The invention contributes to the speci fi cacy of building materials, in particular the manufacture of curved glass, and can be used in the glass industry to obtain bent products for output windows of devices operating in the infrared region of the spectrum. One of the main requirements imposed on ggm products is compliance with a given curvature of the surface and a small amount of internal stresses in the glass after bending. This is due to the fact that after bending the workpiece, they are subjected to precise machining (grinding and polishing). In order for the bent workpieces of the glass to not be destroyed by machining operations, the inner lines in the glass should be small, usually their size should not exceed 50-70 It / cm. In addition, large internal stresses in glass change its optical parameters, which prevents the use of such glasses in precision optical devices. The closest to the proposed technical effect and the achieved effect is a method of making curved products from glass, including yagrev glass billet, its initial bending in ceramic form with a radius of curvature of 1.2-1.6 radius of the product and cooling, and Also, additional heating and bending of the billet in the form with a radius of curvature of the product followed by 1m responsible annealing in a furnace and cooling under conditions of natural convection. The known method allows to obtain products with satisfactory geometrical parameters and with small internal stresses in the glass (no more than 50 Nm / cm) after bending the blanks, which ensures their use for output windows of devices operating 1x in the infrared spectrum Q. However, the known method does not provide a high productivity of the bending process due to the considerable time of responsible annealing of the logs in the kiln-like mosp; initial bending to 30-AIA for 18-20 hours n (with a radius of cr 62 1.2–1.6 of the radius of the product, and after additional bending to 300–500 ° C for 16–18 h on the mold with In addition, the known method does not provide products from calcium-aluminum glasses with high optical parameters due to a significant degree of crisstazing during their manufacture, since such glasses are characterized by a high crystallization ability in the temperature range of their softening. This is explained by The glasses are bent at a temperature of 1,10140 ° C above the glass softening temperature, and then annealed out inertia in the first and second bending stages, and, consequently, there is a considerable time in the region of the glass softening temperature. The purpose of the invention is to increase the production capacity and improve the quality of products from calcium aluminate glasses. The goal is achieved by the fact that according to the method of making curved glass products, including heating the glass preform, its initial bending in ceramic form with radius of curvature of 1.2-1.6 radius and cooling, as well as additional heating and bending of the billet in the form with the radius of curvature of the product with subsequent responsible annealing in the furnace and cooling under conditions of natural air convection, after the initial and additional bending forge with the billet cover they are heated by the ceramic brick: after the initial bending, by 120–140 ° C, and after additional bending, by 120–1 ° C above the softening temperature of the glass, cooling and annealing are carried out in the form of a jar. It is known that during the rapid cooling of heated inorganic glasses, they are destroyed by internal thermoelastic stresses. The likelihood of destruction of products from inorganic glasses increases with uneven cooling of individual sections of products. Covering a ceramic short bending with the 1 st blank for the purpose of insulating the blank creates almost 3

Cooling conditions for all parts of the billet in the form of natural air convection. It is preferable to use a ceramic cover with the same thermal characteristics as the shape, preferably made of the same material and about the same thickness as the shape. Heating a bog billet covered with a caramel lid to a furnace temperature of 120–140 ° C or 120–160 ° C above the glass softening temperature is necessary to create almost identical cooling conditions for all parts of the bent billet in the mold when the mold is cooled in conditions of natural air convection or in case of responsible annealing in a furnace. The temperature to which the mold with the bent billet is heated is covered with ceramic is chosen experimentally depending on their overall dimensions. The larger they are, the higher the temperature is heated, as their heat emission increases upon cooling.

When cooling a billet in the form with a radius of curvature I, 21, 6 of the radius of the product, constant quenching stresses of more than 2000 Nm / cm penetrate into it. However, during the process of additional heating and bending, the quenching stresses disappear, since the glass is in a softened state and its stresses relax. Responsible annealing in a furnace of a bent workpiece in the form with a radius of curvature of the product covered with a ceramic lid, to a temperature in the furnace 100-180 ° C below the softening temperature of the glass, it is necessary to ensure that constant glass hardening does not occur.

stress, exceeding the value of 50 Nm / cm, which may occur during the rapid cooling of the glass preform. Since all the areas of the bent blank annealed in the furnace to a temperature in the latter by 100-180 ° C below the glass softening temperature, are in almost the same conditions for heat transfer — when the mold is covered with a cover plate, under conditions of natural air convection . it does not appear temporary thermo764

ynpynte internal stresses leading to the destruction of zlg-otoiki. Tetmetrature, to which the annealing of the billet in a furnace is thinned, is overlaid from the overall dimensions of the bend (1H chautowrap, mold and ceramic roofing and 3Kcnepv MenT; ui IP.1M nvTCM). on the pp table, cooling the billet in a fopme under conditions of natural air convection.

Production of curved products from calcium apuminate glass according to the MONFy method provides an increase in the manufacturer: process, as the operation of responsible annealing of the workpiece in the furnace is eliminated after its initial bending on the form with a curvature radius 1.2-1.6 of the product radius and the similar annealing operation of the annealing after additional bending on a boron with a product radius. In addition, it provides a reduction in the degree of crystallization of the workpieces from cape-shaped glass to one's glass, since by reducing their The holdings in the area of softening temperatures, when the glass has a greater tendency to crystallize., due to the exclusion of the operation of responsible annealing of the blanks after their initial bending on ibopMe with a radius of curvature of 1.2–1.6 of the product’s radius. bending on a form with a radius of the curvature of the product does not prevent 50 Nm / cm. This allows a guusley surface treatment (grinding and polishing) to use bent products as output windows of the devices, working 1 × 1 × in the front region spectrum.

The method is carried out as follows.

Heated to a temperature in the furnace, at PO-MO C exceeding the softening temperature of the st.kla, use) zuyy to bend, a form of molliroviya, made and: EY with co-silica ceramics, with a radius of curvature of 1.21, 6 of the radius of space, the glass blank is of the required size, heated to a t-bending curvature and -1. given shape curvature using a vacuum. Open under the furnace and cover forg) a kryakon of high-silica core, then close under the furnace and heat it together with the fork to a temperature in the furnace by 1–2 to 10 ° more softer than the glass used for bending. The cjjophry with a bent billet is opened under the furnace and covered with a ceramic plate, and a metal table with an asbolot backing for cooling under conditions of natural air convection. Heated to an oven temperature of 140-160 ° C above the glass softening temperature used for bending, a bending form made of high-silica ceramics, with a radius of curvature of the product, is bent to a 1, 5, 5 radius of the workpiece radius. heat it up to a bending temperature and bend it to a given curvature of the form using a vacuum. Open under the ovens and cover the forms with a bent workpiece with a lid of high-silica ceramics, close it under the ovens and heat it together with the mold to a temperature in the oven at 120-160 ° With higher temperature softening glass. The elec- tron heaters of the furnace are disconnected and the billet in the form of a covered ceramic lid is made by responsible annealing to a furnace temperature of 100–180 ° C. Open under the furnace and move the mold with a bent blank covered with a ceramic collar on a meta table with a substrate made of asbolot dp cooling under conditions of natural air convection. An example. A bent billet with a spherical curvature of the surface with a radius of curvature of 90 mm and a maximum boom of 90 mm dp producing the output window of the device operating in the infrared spectrum are obtained. The internal stresses in the bent workpiece HC should exceed 50 Nm / cm. A blank billet with a diameter of 250 mt-1, a thickness of 10 mm, made of aluminum capillary glass, having a melting point of 780 C is used. Two molliropatti Forg-s made of high-silica ceramics are used, one with a radius of curvature of the finished product of 90 mm, the other - with the radius of curvature 112.5 №1, i.e., with a radius equal to, 25 radius of curvature of the finished product. Two ceramics are used, made of high-silica ceramics, one with a diameter of 300 mm and the other with 250 mm. The thickness of the forms of bending and ceramic tiles is the same and equal to 10 mm. In a heated form of bending to a temperature in the 930 + lQ C furnace with a radius of curvature of 112.5 mm, a flat glass blank with a diameter of 250 mm is placed with a vacuum rod. Heat the oven before and maintain it at the specified temperature for 5 minutes. Then, the workpiece is bent in shape using a vacuum for 12 minutes. Open under the cave, and using a vacuum rod, cover the shape with a ceramic cover with a diameter of 300 mm for min. Close under the stove and heat up to 910 + 10 ° C for 5 minutes. Open under the furnace and unload Aopf.fy of bending with a bent workpiece covered with a ceramic cap on a metal table, insulated with asbestos cloth, for 2 minutes (for cooling under conditions of natural air convection). In a heated form of bending to a temperature in the furnace 930 + 10 C with a radius of curvature of 90 mm, a bent blank previously obtained in a herm with a curvature radius of Hbt of 112.5 mm is placed using a vacuum rod. The furnace is heated to 930ilO C and kept at the specified temperature for 5 minutes, then the workpiece is bent on the mold with the help of a vacuum for 20 minutes. Open under the stove. And using a vacuum rod, cover the form with a ceramic keg with a diameter of 250 mm for 1 min. Close under the oven and heat up to 920 + 10 ° C for 5 minutes. The furnace heaters are turned off and responsible baking of the bent workpiece in a mold covered with a ceramic lid is performed at an average speed of 1.2 C / min for 5 hours. At a furnace temperature of 670J-IO C, it is opened under the oven and the mold is unloaded.

Claims (1)

METHOD FOR MANUFACTURING BENDED PRODUCTS FROM GLASS, including heating a glass preform, initial bending it in a ceramic mold with a radius of curvature 1.2-1.6 of the radius of the product and cooling, as well as additional heating and bending of the preform in the form from the radii of curvature of the product, followed by annealing in the furnace and cooling in conditions of natural convection, about τη and especially with the fact that, in order to increase productivity and improve the quality of products made of calcium-aluminate glasses, after the initial and additional bending Ia shape of the workpiece is covered with a ceramic lid and produce their heating - after the initial bending at 120- 140 ° C, and after an additional 120-160 C at a temperature above the glass softening point, with cooling, and annealing is carried out in the form of closed lid, § O □ o h >