The production of lithographic screen frames is still very important in the screen printing process. How to choose and what kind of use. How to stretch the net is very important.
1 The important process of screen printing is the choice of screen frame and the choice of materials. The previous type of screen frame has been eliminated, and now the aluminum frame is popular. The width and the area of the unit pattern of the printed fabric as well as the factors of the blade and the equipment are determined. The size of the screen frame is very important. Doing this step will affect the finished product. Hand-printing is based on the size of the printed fabric or the size of the pattern, mostly based on wooden materials. For example, the sheet printing is based on the size of the flower, and the screen frame is not made according to the size of the sheet. Machine printing is made of aluminum alloy material. If you need to use extra large frame, you should use special-shaped steel pipe.
2 printing screen specifications are expressed in root / cm. For convenience, it is usually stated by "number". The higher the number, the more holes per cm. For example, the hot platen is usually a No. 9 or No. 10 sieve, which is 40.8 pieces/cm and 43.6 pieces/cm, respectively. Corresponding to the sp38 and sp40 of the spun of the chemical fiber screen. The cold platen is generally selected from the No. 15 and No. 16 screens, which are sp56 and sp57. The selection of the screen of the automatic screen printing machine should take into account the characteristics of mechanical scratching. And according to the size of the flower area, the thickness of the fabric and the hygroscopicity of the fabric. When printing large-area patterns, due to the large amount of color paste required, a sieve with a small model and a large aperture should be used. On the contrary, small-sized flower patterns or fine flower patterns should be selected from large-sized screens with small apertures. Thick fabrics require a large amount of colorant, and a sieve with a small size and a large aperture is used. Due to poor hygroscopicity, the chemical fiber fabric has a small amount of suction. A large-sized screen with a small aperture should be selected. Screen selection should be based on a combination of various factors, combined with the actual production situation to choose. Plate making is to accurately separate the pattern to be printed and find the loop unit. The same color on each pattern is separately made on the screen according to the integer multiple of the
cycle unit. The flower part is hollowed out, and the non-flower part mesh is blocked to prevent the color paste from being transferred to the fabric during printing. Commonly used plate making methods are anti-painting method, sensitization method and wax method. At present, all dyeing factories mainly use photosensitive plate making, so only the sensitization method will be introduced here.
The principle of photographic method is the principle of sensitization method. The light is irradiated on the surface of the rabbit photographic adhesive. The non-flower-shaped part is sensitized by the photosensitive glue, and the brilliance will occur. The photosensitive glue will become the water-insoluble film. The mesh is blocked and then reinforced and plated. This is a production process of the sensitization method.