Screen printing belongs to stencil printing, and it is called the four printing methods together with lithographic, embossing, and gravure printing. Perforated printing includes transcription, perforated pattern, spray and screen printing, etc. The principle of stencil printing is: the printing plate (the perforations that can pass ink are made on the base of the paper film plate or other plates). When printing, the ink is transferred to the substrate (paper, ceramics, etc.) through the perforations of the stencil under a certain pressure. ) To form an image or text.

　　 Through the squeeze of the squeegee during printing, the ink is transferred to the substrate through the mesh of the graphic part to form the same graphic as the original. The screen printing equipment is simple, convenient to operate, simple in printing and plate making, low in cost, and strong in adaptability. Screen printing has a wide range of common printed materials: color oil paintings, posters, business cards, binding covers, commodity signs, printed and dyed textiles, etc.

　　3 commonly used plate making methods: direct plate making method, indirect plate making method, direct mixed plate making method.

　　1, direct plate making method

Method: The method of direct plate making is to first place the photosensitive film of the wrist base coated with photosensitive material on the work surface, and place the stretched wrist screen frame flat on the base, and then place it in the screen frame. Fill in the photosensitive paste and apply pressure with a soft squeegee. After it is fully dried, the plastic film base is removed, and the photosensitive film wrist screen can be used for printing. After development and drying, a screen printing screen is produced.

　　 Process flow: stretched net-degreasing-drying-peeling off the base-exposure-developing-drying-retouching-sealing

　　2, indirect plate making method

Method: Indirect plate making is to expose the indirect film first, harden it with 1.2% H2O2, develop it with warm water, and dry it to form a peelable graphic film. The film surface of the graphic film is tightly attached to the stretched screen during plate making. , By squeezing to make the glue film and the wet silk screen adhere to each other, peel off the film base, and dry it with air to make the screen printing screen.

　　 Process flow:

　　1). Stretched net-degreasing-drying

　　2). Indirect film-exposure-hardening-development

　　1and2——fitting——blowing-drying——revision——screening

　　3, direct mixed plate making method

　　 The photosensitive adhesive layer is first pasted on the screen frame with water, alcohol or photosensitive glue. After drying with hot air, the base of the photosensitive film is removed, then the plate is exposed, and the screen plate is made after development.

　　The advantages of screen printing:

　　(1) Not limited by the size and shape of the substrate

　　General printing can only be performed on a flat surface, while screen printing can not only print on a flat surface, but also print on a molded object with a special shape, such as a spherical curved surface. Anything with a shape can be performed by screen printing.

　　(2) The layout is soft and the printing pressure is small

　　The silk mesh is soft and flexible.

　　(3) Strong ink coverage

　　 can be printed in pure white on all black paper, with strong three-dimensional effect.

　　(4) Suitable for various types of ink

　　(5) Strong anti-rotation performance

　　 can keep the gloss of printed matter unchanged. (Neither temperature nor sunlight has any effect). This eliminates the need for additional laminating and other processes when printing some stickers.

　　(6) Flexible printing methods

　　(7) Convenient plate making, low price, easy to master technology

　　(8) Strong adhesion

　　(9) can be silk-printed by hand or machine-printed