Screen printing 150 ask (84-100)

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. Use ordinary fluorescent lamps should pay attention to matters?

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–¼ 86. 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.

â–¼87. UV cold light, how long life?

Generally speaking, the service life of ultraviolet luminescent tubes is 1000 hours. Accumulative working time, more than 1000 hours or nearly 1000 hours, the lamp tube should be replaced. Usually the cumulative working time reaches 750 hours, the new tube should be replaced to ensure the sun. Edition quality. (Specifically, the light source it emits needs to be replaced if it is white.)

â–¼88 . How to use exposure scale?

The exposure ruler is a comparison of the effects of five exposures at a time, selecting the best exposure time. (The company has this equipment and can negotiate with this company.) It consists of five sets of resolution standard boards and numbers.

The first group was followed by no color filter, the exposure coefficient was 1, and the other four groups were each followed by a neutral gray filter, the coefficients were 0.7, 0.5, 0.33, and 0.25, respectively. Comparison of exposure time.

If the best time is measured on a printing machine, the exposure calculation rule is printed for a certain time, such as 4 minutes when observed, which group is effective, if 0.7 is the best, multiply it by 0.7 is equal to 2.8 minutes is the best, the actual exposure time multiplied by the best factor to get the best print time.

â–¼89. Is the screen too tight and is there any disadvantage?

Too much tension, laborious when scraping ink, and tearing the screen easily. (Master the correct tension)

â–¼90. What is wrong with the net stretching too loose?

The tension is too small, the springback force is small when printed, and the springback effect cannot be achieved. It is easy to rub the dots and fine lines.

â–¼91. How to measure tension?

For a small network box, only one point in the center of the screen, medium screen, it is best to measure five points, large screen measure six points.

â–¼92. What kind of stretch angle is the worst?

The screen and frame edges are 5-10 degrees and the plate making effect is the worst.

â–¼93. Which kind of stretch angle is the most provincial screen?

90-degree angle stretch net most of the material, so the general screen printing accuracy is not high, do not have to use 45 degrees, 22.5 degrees stretch net.

â–¼94. How to dissolve the release powder?

The release powder dissolves slowly in water and cannot be dissolved at one time. The correct method of dissolution should be water multiple times, first dissolve a part of the decantation, then add fresh water, stir and dissolve, then pour it out, so that it can be divided into 4-5 times, and it can completely dissolve completely.

â–¼95. Dissolving release powder, with or without solvent, speed up the dissolution rate?

When the stripping powder is dissolved, a small amount of acid can be added, and 1-2 ML per kg of water can effectively accelerate the dissolution rate.

â–¼96. Is latex toxic? Photosensitive powder?

Latex is a basically non-toxic colloid, and the photosensitive powder is also non-toxic, but it cannot be imported.

â–¼97. Is it fast or slow?

The speed of coating the photosensitive adhesive should not be too slow, the glue can easily leak to the ink surface, and it can easily cause uneven glue, too fast speed, easy to produce pinholes. The emulsion should be coated at a suitable coating speed. Medium uniform coating is generally used.

â–¼98. Can you brush with a brush?

Brush can not be used to brush sensitized plastic, one brushing is uneven, and the second is the surface of the brush is not smooth. Can only be hard, preferably coated with stainless steel gluing.

â–¼99. How to apply the screen below 100 mesh?

Screens coated with coarse mesh, such as screens of 30 mesh and 50 mesh, often have many pinholes. To compensate for the fact that the number of coarse meshes is difficult to apply, one is that the photosensitive adhesive is thicker and the first coating is used. The printing surface should be scraped back and forth several times to make the screen fully wetted, and then the ink surface should be evenly glued. After drying, on the printing surface, it should be applied 2-3 times in a row, and the speed should be slightly faster.

â–¼100 . How many lines can be reached in screen printing?

Generally can reach 80 lines, up to 100 lines, from the print definition, 80 lines and 65 lines of visual effects are better, the number of lines is high, the network is easy to paste.