Screen printing 1000 questions (79-86)

â–¼79. What are the drying methods of ink?

The ink drying method can be divided into natural drying, heat drying, ultraviolet drying, electron beam irradiation drying, infrared drying, microwave drying and other forms.
In addition to the drying method described above, two types of physical drying and chemical drying may be used depending on the type of ink contained in the ink. Second, according to the different properties of ink can be divided into infiltration drying, oxidation and conjunctiva drying, volatile drying and other forms.
The inks with special properties in the dry form include photopolymerization drying and UV drying. Most ink drying methods usually use only one drying method, but some of the inks are dried in a certain dry form, and they are also dried together with other auxiliary drying forms. The drying type of ink is shown on the previous page.
Under normal circumstances, volatile drying inks, water-based inks, oxidative polymerization inks, and two-liquid reaction inks are dried by natural drying, hot-air drying, or infrared irradiation. The heat-curable ink is dried by infrared irradiation. Ultraviolet curing inks are dried using ultraviolet radiation.
Which drying method is used in actual printing production depends on the actual conditions of the used ink, drying equipment, and site.

â–¼80. There are several ways to dry glass after printing.

After printing, glass products are dried differently from other substrates by two methods, namely, natural drying and forced drying.
Natural drying is to place the printed glass product in a proper place and allow it to dry naturally. Because of the different conditions of air temperature and air circulation, the speed of drying is also slow, sometimes to speed up drying, and it can also be dried by cold and warm air. After the glass products are printed, they must be fully dried before firing. The firing temperature should not exceed 120 °C. And the firing temperature should be gradually increased from low to high. This must be noticed.
When printing in high-volume multicolor glass products, forced drying methods are often used. The most commonly used is electrothermal drying. For multi-color printing, dry one time for each color of the ink, only after four colors are printed, can the firing be performed. The firing temperature should not exceed 120°C.

â–¼81. Which lamp source is ideal in silk screen platemaking?

Ultraviolet cold light is an ideal light source. If there is a strong ultraviolet light, the effect is better. Domestic mainly by 20W/A, 30W/A
Branches, 40W/A branch, 80W/A branch, 8W/branch, followed by high-pressure mercury lamps, high-pressure xenon lamps, high-pressure mercury lamps are not common small sun lamps, and are special plate-making lamps.
Use these two kinds of lamp plates, pay attention to the temperature of the glass surface in the hot season, if necessary, add fan cooling to prevent cross-linking caused by overheating and photoresist.
And can not be started continuously, that is, after the lamp is turned off, it can not be restarted after at least 5 minutes.

â–¼82. With ultraviolet light exposure, how long should the printing time be? What is the high pressure mercury lamp and high pressure xenon lamp?

Ultraviolet light cold light printing time is generally controlled between 3-6 minutes (referring to 1000W- mercury lamp or xenon lamp), thick glue layer, long time, glue layer book, shorter time, slightly longer winter, summer Shorter, for high-pressure mercury lamps and high-pressure xenon lamps, the grid voltage is high and the light is strong, and the printing time can be shorter, and vice versa. Specifically, the correct time can be calculated.

â–¼83. What are the advantages of the external cold light?

Ultraviolet cold light, using electronic rectifier, the light intensity emitted is not affected by the level of the grid voltage, only 130 volts can start. The range of light it emits is exactly what the photosensitive material needs. The lamp can run continuously, start continuously, and has low heat output and low investment at one time. Silk screen printing is the best light source. (This company sells)

â–¼84. What are the main types of printing lights?

UV cold light. The distance between the lamp and the glass is generally controlled between 7-10CM. The distance between the high pressure mercury lamp and the high pressure xenon lamp and the glass must be controlled between 50-70CM. The design height of the lamp distance should be based on the relationship between the lamp distance and the light intensity. Second, the uniformity of the lamp distance and light should be taken into consideration. Thirdly, the heat value of the lamp should be considered.

â–¼85.

Ordinary fluorescent lamps are the most unsatisfactory light sources, because the light between the 3800A-4300A is very weak, only about one-twentieth of the UV cold light, the printing time is long, the light cross-linking effect is poor, the grid voltage is low, light The strength is weaker, and only a small part of the photosensitive resin can produce a chemical reaction. When the film is formed, the film will fall off automatically, and it will also cause a large amount of transparent adhesive. When printing, most or part of the ink will not be printed, and the number of times of printing is low. Sawtooth serious.

â–¼86. What should you watch out for when using an electronic rectifier?

The biggest characteristic of the electronic rectifier is that the starting voltage is low, and the voltage of 130 volts can be started. The voltage of the power grid is generally about 200 volts, so there is no obvious difference between strong and weak light. The light emitted is also stable and there is almost no flash.
The disadvantage is that the electronic rectifier is afraid of heat and is afraid of moisture. When installing an electronic rectifier, consider ventilating and placing it in a dry place. Do not operate continuously for a long time in high temperature weather.

--Qi Lu Graphic Arts