Etching and silk-screen printing of glass products. For a long time, the etching decoration of glass products has been carried out by thermically applying a wax layer and other reinforcing materials on the surface of the glass as an anti-corrosion layer. Then, patterns and designs are carved on the coating with needles, knives, etc., exposing the surface of the glass. Finally, hydrofluoric acid is applied to this area for corrosion. This process is still being used by some manufacturers to this day, but its processing method is time-consuming, labor-intensive and inefficient.
The silk-screen etching process makes the etching decoration of glass products simple, time-saving and labor-saving. There are two methods for etching and silk-screen printing on glass: hot printing and cold printing.
Thermoplastic etching screen printing is a process where a binder made of paraffin, asphalt, stearic acid, etc. is mixed with a small amount of anti-corrosion powder to form an anti-corrosion printing material. Through a hot printing screen, the printing material is scraped onto the glass surface according to the designed pattern to form an anti-corrosion film. The part of the anti-corrosion film that is exposed above the glass is the pattern that needs to be etched. Etching is carried out using chlorofluoric acid. After etching, the anti-corrosion layer printed on the glass should be rinsed off with boiling water
Glass screen printing etching can also be carried out by cold printing method. Anti-corrosion printing materials can be made with specially formulated asphalt paint mixed with anti-corrosion powder, or commercially available anti-corrosion inks can be purchased. After the printing is completed, when the anti-corrosion film is completely dry, hydrofluoric acid corrosion can be carried out.
Hot printing is suitable for etching two-sided continuous and four-sided continuous patterns, while cold printing is suitable for etching individual patterns.
2. Glass ice flower silk screen printing. Ice flowers, commonly known as orange peel patterns, are actually very fine low-melting-point glass particles. These fine glass particles have a high lead content and are available in both colored and colorless forms. The colored hues include red, yellow, blue, green, white, etc., and intermediate tones can also be formulated.
Silk-screened ice flower decoration is elegant and generous, and is often used for architectural glass decoration and art and craft glass decoration, such as the decoration of glassware and lamps.
Silk-screened glass ice flower decoration is achieved by first silk-screening a colored or colorless layer of glass flux (flux) on the surface of the glass, and then scattering ice flower glass particles on this layer of glass flux. Through sintering at 500℃ to 590℃, the flux layer and ice flower particle layer on the glass surface are fused together to create a relief effect. If a colored flux is silk-screened on the glass and the tiny ice flowers are transparent, through high-temperature co-melting, the flux layer at the ice flower pattern part of the glass will fade, and a colored, raised transparent relief pattern will form on the glass surface.
3. Frosted silk-screen printing on glass. Sandblasting is a decorative method in which a certain area of glass glaze powder is adhered to the glass of the product. After being baked at a high temperature of 580℃ to 600℃, the glass glaze coating melts on the surface of the glass and shows a color different from that of the main body of the glass. For adhering glass glaze powder, it can be applied by brushing with a brush or by rolling with a rubber roller.
Through silk-screen printing processing, a frosted floor pattern can be obtained. The method is to silk-screen print a pattern formed by a flux on the surface of the glassware. After the printed patterns and designs are air-dried, the sandblasting process is carried out. Then, after high-temperature baking, the frosted surface without the pattern or design melts onto the glass surface, while the frosted surface with the silk-screened pattern cannot melt into the glass surface due to the effect of the flux. After baking, the transparent floor patterns are revealed through the semi-transparent sand surface, creating a special decorative effect.
The frosted screen printing flux is composed of ferric oxide, talcum powder, clay, etc. It is ground in a ball mill with a fineness of 350 mesh and mixed with a binder before screen printing.
4. Screen printing ion exchange coloring of glass. Colored glass can be obtained by exchanging sodium ions in the glass with silver and then reducing them to form a metallic gel. On a transparent glass plate, only the part to be colored is printed with screen ink containing silver ions. After firing and cleaning, only the printed part changes from yellow to brown. Different firing conditions will cause changes in color and concentration, etc. Since there is no reflection difference between the uncolored part and the colored part, there is no sense of unnaturalness at all, just like melting and coloring glass. The coloring of the text and marks on the glass, the anti-heat treatment of the rear window glass of the car, and the brown color presented by the scale used in the comparison experiment were all achieved by this method.
The screen printing ink (printing material) for this decorative technique is mostly composed of silver carbonate, copper sulfate (burned powder), ferric oxide, talcum powder, etc., with a small amount of zinc powder as a catalyst.
5. Silk-screen contact control panel. When designing the temperature program for the microwave oven, a switch combined with a microcomputer was used. This type of switch is different from the common mechanical switches. It is a switch printed on a glass plate, with no movable parts and no protrusions or recesses. It is very smooth, easy to remove dirt, and can be turned on and off by touching it with your hand. The surface of this control panel is covered with a conductive film, and around it, ceramic ink is screen-printed for decoration and text display. Its advantages are that it is resistant to mechanical wear, chemical corrosion and easy to clean. In addition, when designing, to color the glass, organic coatings can be printed on the back. Since the back cannot be in direct contact, it has strong durability and offers a wider range of ink options.
6. Matte silk-screen printing on the glass surface. Print the matting ink on the glass surface (made in Belgium) onto the soda-lime glass with a screen printing plate. After a few minutes, wash it with water. The effect is just like tea-colored glass. Fluoric acid is usually used for etching glass, which poses certain risks. This type of ink does not contain strong acid and is relatively easy to operate. Its matting effect is similar to that of etching.
7. Screen printing of the electric heating demister device. To prevent water vapor from condensing on the rear window glass of cars, more and more electric heating defogging devices are being used for printing. This silk-screen printing method involves applying silver paste into lines on smooth glass and firing the glass while bending it. When the rear window is blurred and foggy, let the lines generate heat through electric current, increase the temperature of the glass surface and remove the moisture.
When this electric heating defogging device is powered on, some cars do not use a manual switch but automatically power on and off. The sensor of this automatic device is made by printing serrated electrodes on thin plate glass with a silk screen and then covering them with a moisture-sensing body. It automatically controls the power-on and power-off by the ratio of humidity.
8. Screen printing of liquid crystal display components. The liquid crystal digital display element has an interval of approximately 10μn. It is made by sealing the four sides of two thin glass plates, injecting liquid crystal and sealing the injection port. On the surfaces of these two pieces of glass, transparent conductive strands in the shape of an "8" are silk-screened. This "8" is composed of seven parts and can partially increase the voltage to display the number (0 to 5). The process of making this "8" shaped pattern first involves using acid-resistant ink to screen print only on the "8" shaped part of the field glass with the entire conductive element, and then etching with acid to remove the conductive element from the unprinted part.
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