Understand The Glass And Sand Screen Printing Technology

Introduction: Glass-covered sand products because of its uniform and delicate surface, smooth feel, hazy and beautiful appearance, soft light transmission and other characteristics by the majority of consumers love. In recent years, cosmetic bottle packaging also uses a large number of covered sand bottle packaging.

This paper describes the relevant knowledge of glass sand net printing, the content for the superior packaging system for friends reference:

Glass covered sand refers to the method of using chemical method to obtain the effect of glass sand surface.

Chemical sand is essentially a gross etching method, and glass sand is also a type of glass etching. The difference from etching is that the sand is shallow and etched; the etching layer is deep and the etching layer is transparent. Trough etching is limited to the glass products, and sand is the erosion of the outer surface of the glass products. The refractory reactants become small particle crystals, firmly attached to the glass surface, the degree of contact with the glass surface and acid under the particle gap, and the degree of erosion will be different, making the surface uneven. Rough and delicate hairs can be obtained by controlling the size and number of crystals attached to the glass surface. Chemical sand is made of sand liquid (powder) or plaster, using immersion method, net printing method, spraying method and placement method.

This paper introduces a paste made of chemical drugs with corrosion effect on glass, which is printed on the glass by screen printing of glass. After obtaining the pictures and pictures, the printing material is removed by water, and the sand surface appears on the glass surface. This paste is generally called a glass-covered mortar.

Glass surface treatment before printing

Glass surface has a slight oil, dust and other general influence on the sand is not very big, usually only use cotton wipe can be printed, if you want to get fine sand effect, can use industrial sulfuric acid into 5% solution for pickling process, best equipped with compressed air mixer, to the acid pool acid turbulent cleaning, cleaning time about 2min. Especially when the large area of net printing sand, in order to ensure the uniformity of the surface, the cleaning link can not be ignored. After the treatment, hang the glass on the bracket for natural cooling and drying.

Glass surface treatment during printing and after printing

Glass-coated screen printing can be used by manual and mechanical printing. General screen printing machinery has an automatic or semi-automatic machine. Full automatic machine has multi-color sleeve brush use, equipped with photoelectric tube control automatic stop device, is very suitable for printing glass products and all kinds of sheets. Scraper selection mainly depends on its acid resistance and hardness, generally speaking, the mechanical printing speed is fast, convenient operation, high printing accuracy, but the equipment investment is large. Manual printing is the opposite.

In order to ensure the quality of manual printing, the key is to control the thickness of sand printing material and maintain a certain time. In order to ensure the smooth operation of the scraper during the printing process and the remaining seal will be stored in a certain position after the scraping, the empty screen in the net plate should be larger than the printed area in the plate making.

Before the formal printing, the first test printing is carried out to test the position of the web plate, the bearing, the scraper Angle, intensity and travel are appropriate, in order to make necessary adjustments before the formal printing. After printing, let the printing material stay on the glass surface, the time should not be too long, otherwise the printing material will make the corrosion increase is not easy to clean, and will affect the whole glass surface sand effect, produce heterogeneity.

In the process of sand printing, attention should be paid not to splash the pulp on the human body because the pulp is a strong acid substance, which will burn the skin. After printing, wash the printing ink with water flow, leaving corrosion traces. If necessary, wipe it with a brush, and put the postprinting glass on the bracket for natural drying, which is the finished product.

Attention

Pay attention to personal safety in the operation of coated glass screen printing

Because the sand liquid (paste) are strong acid substances, have a certain corrosion to the human body. In order to avoid contact with people, acid-resistant rubber gloves, protective masks, glasses, aprons, etc., should be worn during the operation. The operation action should be stable, accurate, slow, concentrated sulfuric acid is a strong dehydration agent, has a serious burning effect on the skin, in the deployment and use of printing materials to pay attention to. For the large concentration of sandagent, a lot of heat is released when dissolved in water, so when adding, can only be slowly added to sandagent, while stirring, to prevent boiling splashing. If it is accidentally splashed on the skin or splashed in the mouth, nose, eyes should be immediately washed with a lot of water. The wastewater after washing and printing glass is still acidic, which can be neutralized by hydrated lime to neutral (about pH = 7) and then discharged.

Glass-coated screen printing is different from ordinary printing

Ordinary printing is to retain the image formed by the printing ink, while the final product of etching net printing is the corrosion trace left by washing the ink off the mark, and the washing to remove the attached sediment (printing paste), to expose the pattern of corrosive glass.

Generally printing 1 min can be cleaned and drying.

Using fluoride, fluorine silicate sand, uniformity is relatively poor and easy to precipitate.

In order to overcome this shortcoming, some thickeners such as barium sulfate, sawdust powder, modified starch, cellulose, cryolite and organic matter can be added appropriately, to increase the effect of covered with sand.

The degree of hydrofluoric acid corrosion on silicate glass varies

For ordinary sodium calcium glass is easier to sand, especially high calcium glass is more prone to sand. Borate glass and phosphate glass are not suitable for sand because they contain Si02.

Be careful when using the plaster

1) The glass surface before printing should be depolluted, defrosted and demoistened, so as to avoid directly touching the cleaning surface to be printed by hand.

2) The plaster should be fully stirred evenly, such as crystals in the pulp should be treated with hot water.