Screen Printing Technology Decorative Flat Glass

Stretching → Sizing → Drying → Printing → Developing → Drying

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Flat glass → Cut → Edging → Drying → Printing

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sintering

Suitable for printing glass

According to the user's requirements, the glass can be cut into regular shapes or irregular shapes, and then it can be processed by edge grinding, then cleaned and dried. Special attention should be paid here to the fact that there must be no water marks on the surface of the plate glass.

Screen selection

The screen printing plate printing plate uses the same as the general screen printing plate, the glass printing plate uses the synthetic fiber mesh, the stainless steel mesh, the natural fiber mesh. When printing general color materials, the above-mentioned screens can all be used, and inexpensive synthetic fiber screens are generally used; when used as gold and silver decorations, stainless steel screens cannot be selected. Wire mesh specifications generally use 270-300 mesh.

Frame selection

At present, the more formal and less deformable frame is an aluminum alloy frame, and its size should be larger than the pattern. The specific size should be the pattern of the outer edge of the frame should be between 70 ~ 100mm. In addition to the selection of the frame, its strength is very important, the key is that the rigidity in the horizontal direction is sufficient.

Stretch net

The net and the box were chosen to combine the two. This is the stretch net. There are many ways to stretch the net, and manual, mobile, and pneumatic methods can be used. At present, advanced pneumatic screens that can stretch high-quality screens are pneumatic stretching machines. The requirement of the stretch net is uniform tension, the vertical and horizontal lines of the wire mesh are kept vertical, and the adhesive net glue must be firm and cannot be relaxed.

Choose photosensitive adhesive

At present, commercially available photosensitive adhesives include dichromate type, diazonium type, and iron type. Silk screen printing plate requirements for photosensitive adhesives: plate making performance, easy coating. Sensitive spectral range of 340 ~ 440nm, developing performance, high resolution, good stability, easy storage, and economic health, non-toxic and pollution-free. The requirement for printing on photosensitive materials is that the film formed by the photosensitive material is adapted to the performance requirements of different types of ink. Has a considerable resistance to printing force, can withstand a considerable number of squeegee scraping pressure; good bonding force with the screen, printing does not produce film failure; easy to peel, conducive to the use of screen plate material recycling. The DS series emulsion produced by Beijing Taipingqiao Printing Material Factory works well and basically satisfies the requirements for flat glass screen printing.

Printing

After selecting the above materials, the sensitized adhesive is coated in a dark room; it is required to be uniform and then dried, and it is generally required to coat it twice. Shaiban requires exposure on a cold light source plate, and the exposure time is determined according to the pattern, generally between 12 and 30 minutes. After the exposure and development, a screen printing screen was prepared.

print

Flat glass presses are available in manual, semi-automatic, fully automatic types. Manual presses are suitable for small-batch, small-format flat glass. Semi-automatic, full-automatic printers are suitable for printing large quantities of large-format, multi-color printing with the advantages of accuracy and speed. The largest semi-automatic printer can print 2000 x 1500mm size glass. Fully automatic printers are generally used for the printing of automotive windshields, and several companies abroad can provide such devices.

Ink

Flat glass decorative ink is divided into: organic ink and inorganic ink two. Organic ink colorants and binders are all organic materials. This type of ink has a good effect of flat glass decoration, but it has poor film firmness and poor chemical stability. It is a short-lived decoration method. The inorganic ink is composed of a colorant, a flux, and a binder. The colorant is an inorganic colorant such as chromium oxide, cobalt oxide, or the like. The flux is a low-melting glass, and common lead oxide and borosilicate glasses. The most important factor in the performance of the flux is the difference in thermal expansion coefficient with the printed glass. Typical components of the flux: SiO2 19182 %, As2O3 2113 %, MgO 0146 %, PbO 62110 %, CaO 0127 %, K2O 1183 %, B2O3 10175 %, Al2O3 1163 %, Na2O 1176 %. The linking agent in the inorganic ink—the scraper oil is an organic substance that is completely burned during the sintering process, but has no effect on the decorative effect.

The composition of the scraper oil is: ethyl cellulose 3g, terpineol 100ml, turpentine 10ml, alkyd resin 5ml. The ratio of pigment to linking agent of the inorganic ink is 10 g: 8 ml, which can be obtained by stirring and grinding.

sintering

Glass is an amorphous inorganic material that softens as the temperature increases, and the glass deforms when heated to the softening temperature of the glass. The glass glaze is decorated on the surface of the flat glass by screen printing, and it needs to be sintered on the glass surface by high-temperature sintering, but the sintering temperature must be lower than the softening temperature of the glass being decorated to ensure that the decorative glass does not deform. The sintering temperature of general glass glazes is not higher than 520 °C and is usually controlled at 480-520 °C.

Low-temperature glass glazes are produced by several domestic manufacturers and are relatively inexpensive. There are several companies in the world that can provide similar products, but the price is one to twenty times worse than domestic ones. Domestic consumption levels have not yet reached the level of using such glazes, but glazes provided by foreign countries are indeed much better than domestic colors and levels. To improve the quality of decorative glass, it is inevitable to improve the grade of glaze. Sintering equipment includes a flame furnace and a resistance furnace. The resistance furnace is divided into a vertical suspension type and a horizontal roller type according to the hanging manner of the glass. The vertical hanging sintering furnace has the advantages of small sintering distortion and a yield of 95% or more, but the equipment is complicated. Horizontal roller type adjustment is not easy to produce large deformation, low yield, etc. In addition, the use of horizontal tempering furnace production of decorative glass is also feasible, product quality is improved, safety is also guaranteed, is the ideal sintering method

Source: China Silk Screen Professional Network