Stretching net

 It is better to use pneumatic tension mesh machine. The quality requirements of tension mesh are as follows:

 1. Proper and even tension

 (1) When using the pneumatic tension mesh, it must be kept for 3-6 hours before applying the mesh glue;

 (2) The stretched net shall be placed for at least 24 hours, especially for the large goods or machine printed net, so as to ensure equal stress at each point and prevent deformation. The higher the mesh, the longer the time required to be placed, generally 2-3 days is appropriate. After placement, the tension of the screen is stable and the stress of the famous points is equal, so as to ensure that the screen is not deformed and easy to be damaged.

 2. Keep the warp and weft wires vertical

 3. Prevent relaxation

 4、 Screen stencil process

 At present, the direct method is the most widely used to make the screen template. In this process, pay attention to the appropriate thickness of the adhesive coating, uniform sizing, strict control of drying, exposure, development and other links, so as to obtain high-quality screen template.

 requirements for photosensitive materials in screen printing

1. Requirements for sensitive materials in screen plate making: good plate making performance, easy to coating, appropriate sensitive spectrum range, generally 340-440 μ m, sensitive wavelength, strict darkroom conditions for plate making operation and plate storage; too short wavelength, the selection of light source and protection of personnel will become more difficult; high sensitivity, energy saving and rapid plate making; development performance Good, high resolution, good stability, easy to store, less waste.

 2. Requirements for photosensitive materials in screen printing: the plate film formed by photosensitive materials shall meet the performance requirements of different types of inks, have considerable printing resistance, and be able to withstand the scraping of ink for a considerable number of times; the combination ability with the screen is good, and there is no film failure in printing; it is easy to peel off, and it is not easy to produce ghost, which is conducive to the regeneration and use of screen plates. For non drying ink, it is required that the thickness of the photosensitive film on the substrate should be 10-40 μ m, about 1-2 pieces of 80g copy paper.

light source and equipment for plate printing

 1、 Selection of light source for plate printing.

 In the process of photosensitive screen making, printing is a very important process. If we choose and use the light source correctly, it is very important to improve the quality of the screen printing plate, save energy effectively, simplify the operation, maintain the health of the operator and reduce the cost. Due to the different types of photosensitive resin materials, we should choose to use light sources that meet the needs of various photosensitive materials.

 At present, the color sensitivity of all kinds of silk screen photosensitive materials is mostly between 250-510 μ M. Therefore, theoretically, any light source with the peak wavelength of 250-510 μ m on the energy release curve of light emission spectrum can be used for screen printing. In addition, when printing, we should fully study the size of the plate, the output power of the light source, the distance between the plate and the light source, and pay special attention to the role of the light reflecting plate.

 2、 Considerations when selecting a light source

 1. The emission spectrum of the light source shall match the absorption characteristics and color sensitivity of the photosensitive material. The energy of light varies with the frequency of the wavelength. The shorter the wavelength, the higher the frequency and the greater the photon energy. When light is absorbed by matter in the process of radiation, because photon has certain energy, it will cause physical and chemical changes of matter. The chemical reaction caused by light energy is called photochemical reaction. The so-called photochemical matching refers to that the spectral output distribution of the selected light source should match the spectral color sensitivity of the photosensitive material. That is to say, the wavelength range of light-emitting photochemical reaction absorbed by photosensitive material is exactly the output range of light-emitting spectrum of light source, and the maximum absorption peak of photosensitive material is exactly at the output peak of light source. In this way, the light of the light source can be absorbed by the photosensitive material to produce photochemical reaction.

 2. High luminous efficiency and intensity. In other conditions, the greater the power and luminous efficiency of the light source, the greater the luminous intensity or brightness, the greater the illuminance of the exposure surface, and the shorter the time required for the sensitive material to obtain the same amount of exposure.

 3. The thermal radiation of the light source is small. The thermal radiation of the light source should be as small as possible on the premise that the light source has enough luminous intensity or light. When using high power and strong light source, it is necessary to take measures such as forced cooling (air cooling, water cooling) and other measures to make the light-sensitive material exposed and the temperature controlled below 32 ℃.

 4. The luminous intensity is uniform. The luminous intensity of the illuminating surface of the light source shall be as uniform as possible. The design of the exposure device shall ensure that the illumination difference of each point on the exposure surface of the photosensitive material does not exceed 15%. The light source environment has strong adaptability. The light source shall have strong adaptability to the environment, and can work normally under various changes of temperature, air flow and voltage. Of course, in the actual production, it is unrealistic to choose a light source that can fully meet the above requirements. The purpose of the above selection principle is only to hope that when the plate making operator chooses to use the plate making light source, he / she should consider the influence of the light source on the exposure quality of the photosensitive material, so as to achieve a targeted goal.

Special attention:

 (1) When drying high mesh fine dots, the exposure time will be reduced by 5% on the basis of the above table, and the exposure (without film) will be done again after washing to ensure the printing plate’s printing resistance. The time is 2-3 times of the normal exposure time.

 (2) If the photoresist is a thick film photoresist, the exposure time shall be extended, for example, the exposure time shall be extended by 50% if the photoresist is 40 microns thick and 120 meshes thick, and so on.

 (3) If you want to make a high quality print, please use the exposnrecealculator