Calculate the most accurate exposure to solve the

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Calculate the accurate exposure -- solve the exposure problem

tina Scarpelli contributed "what is the correct exposure time of this photosensitive emulsion?" I don't know how many people ask this question. If you can get a dollar every time you answer this question, Bill Gates will ask you for money. Some people say that the so-called correct exposure time is only an estimate. Indeed, they are definitely not lying to you. Because of the instability of the operation process, it is difficult to find a series of comprehensive accurate exposure time of the fixed nail on the board. Therefore, taking the exposure time recommended by the manufacturer as the starting point, and then calculating the car suitable for you bothers every screen printing workshop of several households. It's terrible. One emulsion manufacturer said that 50% of the technical inquiries they received were related to exposure. When silk is overexposed, they must be remade before printing. Underexposure is a very common problem, which causes the whole production process to stop. On the plate, underexposure is mainly manifested in pinholes, rough edges or template delamination. In printing, 3. The measurement of friction force should accurately show that there are sawtooth, uneven thickness of lines and inconsistent color of halftone point copies. What is worse is that the original sharpness of the puncture device of the electronic universal experimental machine should not be damaged because the wire is damaged due to insufficient exposure, and the template cannot be removed (generally speaking, the template can be used after delamination). This article mainly analyzes several basic exposure problems. The following begins with the most common problems in the silk workshop. 1. when the exposure and fineness conflict, the plate shall be able to obtain durable and high-quality images and be able to be recycled. The material used to make silk is only one factor. The key factors that determine the quality of the plate are the quality of the equipment, the correctness of the selection of materials and the control of the silk production process. A poor light source is enough to cause exposure problems. Emulsion and silk that do not match the picture requirements are also the source of the problem. But the main reason for the exposure problem is to reduce the exposure in order to deal with the details. Have all the above problems occurred in your work? Yes, they all appeared, and it brought disastrous consequences. Never think that you can get an image suitable for printing when you emphasize multiple details. In fact, the opposite is true. Today's light source performance and the huge selectivity of silk and image plates almost guarantee the best exposure to obtain fine details. Yes, you can avoid underexposure, especially if your emulsion has a tolerance. Post exposure is a commonly used method for supplementary exposure of underexposed versions. Some emulsion manufacturers say this method is not good, but others say it helps to improve the firmness of the edges. However, it is recognized that it has no effect on repairing the point loss caused by insufficient exposure. They also agree that only a little underexposure can see the effect. The first step to solve the exposure problem is to expose the wire correctly. They also said that one or several of the parameters should be adjusted frequently during the exposure process. Let's explain the exposure parameters below. 2. the parameter "deep curing", which affects exposure, is as important to UV curing ink as plate exposure, and so is other inks. The plate is sensitive to photochemical light, ultraviolet light and blue violet light in the spectrum. A good version needs to be well cured, properly combined with silk, and can stand the use of printing. The complete curing of the printing plate should be treated the same as the complete curing of the ink. It is mainly affected by the following parameters: light intensity, quality and quantity of light are of the same importance to the rapid and effective curing. The image version is sensitive to the nm band light in the UV spectrum. It needs a certain amount of energy to harden it completely every time. Some people call this "spectral appetite". Incandescent lamps and floodlights cannot emit energy at these wavelengths. Metal halogen lamps, mercury lamps and some fluorescent lamps emit photochemical light, which can meet the requirements. You can also use ultraviolet light or blue violet light (except a small amount), but you can see that they differ in exposure time and image quality, which is mainly related to the light emitted. Light intensity is not the brightness of light in the eyes of people. Don't forget, ultraviolet light is invisible light. The light intensity is obtained by measuring the light reaching the fluorescent screen. Since the service time of the bulb, the power supply of the exposure unit and the distance between the lamp and the fluorescent screen all affect the measurement of light intensity, the conditions must be the same when measuring. The inverse square law of the distance between the lamp and the fluorescent screen is used to calculate the exposure time at different distances. The formula is as follows: original exposure time × (square of new distance ÷ square of original distance) = new exposure time. For example, when the distance is doubled, the exposure time becomes 4 times of the original to compensate for the light intensity. On the contrary, when the distance is doubled, the exposure time becomes 1/4 of the original. The type of emulsion that affects the imaging speed and resolution and the thickness of the coating also affect the exposure time. Version materials are designed to make products better, but no product is perfect. The thickness of the plate affects the depth of the internal mineral aspect of the curing, just as the thickness of the ink affects the drying and curing time. The exposure emulsion layer contains a moisture-proof agent that can quickly and accurately test the hardness of stainless steel plates, stainless steel strips and seamless steel pipes as thin as 0.05mm and as thin as 4.8mm. It can keep the emulsion dry, but the residual moisture-proof agent will inhibit the cross-linking process. Therefore, if you do not consider increasing the exposure time, the version may be underexposed. The amount of emulsion deposited on silk is determined by the mesh number and color blank area, the density of silk fabric produced by mesh number and the thickness of silk. White silk will produce halo or astigmatism, which will shorten the exposure time. Any silk fabric will produce different degrees of halo. For different picture features, halo may or may not be a problem. Anode density this is not a silk parameter, but it may damage the silk if the background color density is too high or the image density is too low. Reese film has transparent background color and opaque image area, which is exactly what we want. Another positive is parchment, which has a translucent base and image density that prevents light from passing through

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