JPS621330B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the treatment of glass products, and in particular to a method for grinding the surface of the glass after shaping or for thermally polishing the surface of patterned cut glass products obtained by a combination of these two operations.

The present invention is primarily applicable to the need for a perfect surface finish. Lead glass, such as large cups, pedestal cups, vases, lighting glass products,
For example, the glass industry produces fully decorated glassware such as wall hangings, luminaires, chandelier parts, etc.

Many methods are known for polishing the frosted cut surfaces of decorative designs on glass products.

Chemical polishing of glassware using hydrofluoric acid and sulfuric acid is widely practiced.

The purpose of this method is to eliminate the rough surface of the cut portion by eliminating surface irregularities.

This method involves immersing the glassware to be polished in a bath of a mixture of hydrofluoric acid and sulfuric acid, then
It is done by washing.

This method is associated with a number of drawbacks, to name a few: the high cost of equipment for carrying out the method; poor working conditions for the workers; and the negative impact of the chemical process on the environment.

Furthermore, it is difficult to precisely limit acid polishing of glass products during mass production of glass products.

Various methods are also known for thermally polishing the surface of glass products.

In this thermal polishing method, heat is applied to the surface of a glass product to create a flow, which is then straightened by surface tension.

However, applying such intense heat to the product must not deform its structure. This process is
This is done by keeping the temperature of the wall structure of the glassware substantially lower than the surfaces to which high heat is applied, reducing the thermal conductivity of the glass. When thermally polishing a smooth surface such as sheet glass, good working conditions can be obtained relatively easily since the surface of sheet glass is uniform. Furthermore, the shape of the heat stream and its precise positioning relative to the glass material to be polished do not have to meet stringent requirements.

The problem is further complicated in the case of glass products with decorative design cuts that lack surface uniformity in each direction. Furthermore, when a design cut is made on a glass product using a grinder, a transparent part with a transparent finished surface is created in combination with a translucent frosted cut with a rough surface, and this design cut is characterized by having both large and small elements. do.

Conventional thermal polishing methods have not been able to achieve the above-mentioned characteristics for cut-shaped patterns, and instead cover as much of the surface of the glass product as possible and apply a strong distributed heat flow to the glass product being polished. Therefore, conditions were poor for obtaining a uniform polished surface without deforming the structure of the glass product or distorting the design cut.

The application of intense heat flow to a glass product having a design that combines a frosted cut with a smooth transparent finish results in deviations from optimal working conditions as follows.

(1) Some parts of the product being polished are overheated, in which case the product is heated throughout its wall thickness, deforming the product and distorting the design cut, regardless of the low thermal conductivity of the glass.

(2) Some parts of the design cut have melted considerably,
As a result, the edge of the design cut, which is exposed to high heat, flows and distorts the design pattern.

(3) Insufficient polishing of certain areas of the design, in which case the design cut areas that are far away from the outer surface of the product may also be affected by the formation of stagnation areas that are filled with combustion materials and the volatile content of each glass component. Due to the escape, sufficient heat flow effect cannot be obtained.

The above-mentioned adverse effects occur due to the duration and intensity of heat application to the design cut area.

In the thermal shock polishing method (Ciekoslovakia Patent No. 11865; class C03, cf. No. 129360), the glassware is subjected to a fairly intense and short-term heat flow from essentially all directions.

Melting of the surface of the product being polished causes the structure to deform as the entire structure is heated by the infrared radiation passing through it.

Additionally, the flame of the burner was directed at the design cut, making the width of the flame essentially equal to the width of the cut.
A method of flame polishing decorative designs on glassware is also known, in which the cut portions of the design are polished with a fine grinder. While being polished, the glassware is rotated and moved gradually through the flame.

In this method, the flame is almost always directed approximately tangentially to the design cut. Moreover, the design parts of the cut that are farthest away from the transparent finished surface of the glass product are not directly exposed to the flame, while the transparent finished surface that is adjacent to the cut and is not polished is subjected to intense heat. In the parts of the design where the flame is directed vertically, stagnation areas containing combustion material are formed, resulting in incomplete polishing of the cut faces of the design.

Further application of heat to the design by increasing the duration of heat application to the design causes its outer surface to melt and the entire structure of the product to be polished to a point where the walls of the product are essentially above the softening point of glass throughout their thickness. It deforms because it is heated to a certain temperature. The disadvantages of this method become even more pronounced when the glass article to be polished consists of a combination of both large and small cuts whose surfaces are to be ground. In addition to the deformation of the glassware and the melting of the cut edge, the flow of heat moving around the contour of the product does not promote the abrasive action, but maintains an increase in the temperature of the wall section facing the area subjected to the heat flow. The goal is to make it easier.

It is therefore an object of the invention to eliminate the above-mentioned drawbacks.

The present invention relates to an improved method of polishing patterned cut glass products by selecting a heat flow having a predetermined shape and intensity that is directed toward the cut pattern.

The present invention is a method of thermal polishing of patterned cut glass products by applying high heat to the surface of the glass product. The effective width of this heat flow is such that it heats only a small portion of the three-dimensional pattern on the polished product, applying a concentrated heat flux only once to each portion of the cut pattern.

Preferably, the predetermined width of the concentrated heat stream is in the range of 0.5 mm and 6.0 mm when thermally polishing various glass products with different designs cut into the surface.

Preferably, each section of the cut pattern receives a single pass of concentrated heat flow.

The polishing of glass products according to the invention is performed at least 2 times
This is done by adding two concentrated heat fluxes.

The gist of the present invention will be explained below.

A heat flow of sufficient strength melts the surface of the glass product to be polished as well as its pattern cuts, thereby smoothing out surface irregularities due to the action of surface tension.

When polishing glassware made of glass-containing lead, the heat stream must not contain reducing gas, because the action of the reducing gas reduces the lead oxide on the glass surface to metallic lead, which clouds the appearance and reduces its appearance. result,
This is because the final product will be defective.

In order to improve the efficiency of applying the gas flow to the patterned cut surface of the glass product to be polished, the flow is preferably concentrated into one beam, the effective width of which is smaller than the circumference of the glass product to be polished.

Using the burner gas as a heat carrier,
During thermal polishing, heat transfer throughout the depth of the cut pattern is facilitated, and all cut portions of the pattern are evenly polished.

Using other concentrated heat flows, the main surface of the product to be heated is accordingly a severely restricted area.

Each portion of the surface of the glass article to be polished is subjected to the concentrated heat flow only once, thus preventing deformation of the glass article due to the low thermal conductivity of the glass.

Only the restricted parts of the glass product are exposed for a certain period of time during the process.
Since it is affected by heat, a concentrated heat flow at a considerably high temperature can be applied, improving the efficiency of the entire process.

As a high heat source, gas burner, plasma generator,
Radiant heaters or other suitable equipment may be used.

If the operating conditions described above are followed, a highly efficient method of thermal polishing of patterned cut glass products is obtained.

A specific example of implementing the method according to the invention will be described below.

Example 1 A glass product made of lead glass, such as a large chip with a design-shaped cut on the surface and the width of the cut part of the design being 3 mm, was heated to a temperature below the softening point of the glass in an ordinary slow cooling oven or kiln. Temperature, e.g.
Heated to 480°C. Then, a concentrated heat flow was applied to the product attached to the turntable, and the width of the heat flow was within 1.0 to 2.5 mm, and the temperature reached 1580℃. The product is rotated while maintaining the specified rotation speed.
Thermal polishing was performed by rotating 360°-390°.

A gas burner was used as the heat flow source.

This heat flow covered the entire height of the product along the main surface of the product.

By heating a portion of the surface area of the product that is smaller than the total surface area of the product, the action of a concentrated heat flow heats that portion to a temperature at which flow begins.

The shape of the heat flow and the heating time for the limited surface area of the product are such that the wall structure of the product or its remainder is not heated over its entire thickness to the temperature obtained by the surface area subjected to the heat flow. , to prevent product deformation and cut pattern distortion.

Since the heat flow starts from the parts that make up the cut pattern, each part of the cut pattern experiences an equal amount of thermal stress. Figures 2 and 3 schematically illustrate the effect of heat flow on each part of the cut pattern.

After the concentrated heat flow passes continuously over the entire surface area of the patterned cut glass product, a smooth transparent finished surface with no deformation or distortion in the design is obtained.
A certain shape is maintained.

The thus polished product is then transferred to a conventional lehr or kiln to anneal or de-strain the product.

Example 2 A lead glass product such as a cup with a stand having a design pattern whose outer surface is ground and the width of the cut-shaped pattern part ranges from 1.0 to 2.5 mm was thermally polished according to the operating conditions described above for Example 1. The width of the heat flow is 0.5.
It was between 1.5mm and 1.5mm. The abdomen and base of the product were not heat treated.

Example 3 Having a design on the surface cut by grinding,
Large lead glass products, such as vases and fruit containers, whose design width is within the range of 4 mm to 12 mm, are heated in a normal slow cooling oven or kiln to a temperature that does not exceed the softening point of the glass, e.g. 460°C. did. The product mounted on the turntable was then subjected to a concentrated heat flow, the width of which ranged from 3 to 6 mm. Two or three gas burners were used as heat flow sources. When using two burners, rotate the product 180 degrees, and when using three burners, rotate the product 180 degrees.
Rotates 120 degrees. The thermal polishing conditions were as in Example 1.

Example 4 Lead or soda lime glass products, such as commercially available molded products, which are not ground but have design indentations within the ranges shown in Examples 1 to 3, are
Thermal polishing was performed according to the operating conditions described in each of the examples above. The thermal polishing performed here improved the surface quality as well as the mechanical and thermal strength of the glass products.

Therefore, compared with traditional methods, this method of thermally polishing patterned cut glass products has the following excellent technical, economic and ecological benefits;
It is a creative potential for simplifying process technology, improving the quality of the final product, saving materials, energy and labor, reducing equipment costs, improving sanitary conditions for workers, protecting the environment, and automating processing.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the general principle of carrying out the method of thermally polishing glass products according to the present invention, and FIGS. 2 and 3 are schematic diagrams showing the influence of heat flow on various parts of a cut-shaped pattern.

Claims (1)

[Claims] 1. A method for thermally polishing patterned cut glass products by applying high heat to the surface of the patterned cut glass product, in which the heat flux is continuously moved along the entire surface of the glass product to be polished by means of a concentrated heat flux. The method is characterized in that the predetermined effective width of the concentrated heat flow is such that only a small part of the three-dimensional pattern of the product to be processed is heated, and the concentrated heat flow is applied only once to each part of the cut-shaped pattern. A method for thermal polishing of cut glass products.