What Is Screen Printing Technology?
Screen printing belongs to stencil printing, which is called the four major printing methods together with lithographic printing, letterpress printing and gravure printing. Stencil printing includes transcription, perforated pattern, spray pattern and screen printing. The principle of stencil printing is: during printing, the printing plate (paper film plate or other plate base with holes through which the ink can pass through) transfers the ink through the holes of the stencil to the substrate (paper, ceramics, etc.) through a certain pressure. ) to form images or text.
During printing, through the extrusion of the scraper, the ink is transferred to the substrate through the mesh of the graphic part to form the same graphic as the original. Screen printing equipment is simple, easy to operate, easy to print and plate making, low cost, and strong adaptability. Common prints used in screen printing applications include: color oil paintings, posters, business cards, binding covers, commodity signs, and printed and dyed textiles, etc.
There are 3 kinds of plate-making methods commonly used: direct plate-making method, indirect plate-making method, and direct-mixed plate-making method.
1. Direct plate making method
Method: The method of direct plate making is to first place the photosensitive film on the wrist film base coated with photosensitive material on the worktable with the photosensitive material facing up, and place the stretched wrist screen frame on the film base, and then place it in the screen frame. Enter the photosensitive paste and apply pressure with a soft scraper. After drying, the plastic base is removed, and the photosensitive film wrist screen can be used for printing. After developing and drying, the screen printing screen is made.
Technological process: stretched net - degreasing - drying - stripping film base - exposure - developing - drying - revision - sealing net
2. Indirect plate making method
Method: The method of indirect plate making is to expose the indirect film, harden it with 1.2 H2O2 and then develop it with warm water. After drying, a strippable graphic negative is made. Squeeze to make the film stick to the wet screen, peel off the film base, and dry it with the wind to make the screen printing screen.
Process flow:
1). Stretched - degreasing - drying
2). Indirect film - exposure - hardening - developing
1and2 - Fitting - Drying - Revision - Netting
3. Straight mixing plate making method
First, paste the photosensitive adhesive layer on the screen frame with water, alcohol or photosensitive adhesive. After drying with hot air, remove the base of the photosensitive film, and then print the plate. After developing, the screen plate is made.
Advantages of screen printing:
(1) Not limited by the size and shape of the substrate
General printing can only be carried out on a flat surface, while screen printing cannot be carried out on a flat surface. It can also be printed on special-shaped moldings such as spherical curved surfaces. Anything with shapes can be printed on a flat surface.
(2) The layout is soft and the printing pressure is small
The wire mesh is soft and elastic.
(3) The ink layer has strong coverage
It can be printed in pure white on all black paper, with a strong three-dimensional effect.
(4) Applicable types of ink
(5) Strong resistance to optical rotation
It can keep the gloss of the printed matter unchanged. (air temperature and sunlight have no effect). This makes printing some self-adhesives without the need for additional lamination and other processes.
(6) Flexible and diverse printing methods
(7) Plate making is convenient, cheap and easy to master
(8) Strong adhesion
(9) It can be screen printed by hand or machine printed
