Screen Printing and Its Major Types

Screen printing is the most multipurpose process among all the printing processes. It is utilized on different mediums of substances like paper, paper board, metals, fabrics, and numerous other substances like plastics, glass, nylon and even cotton. The products produced as finished goods from the printing press include a wide range of products like posters, labels, signage and all types of textiles and electronic boards. The main merit which makes screen printing stand apart from rest of the other printing process methods is that it can print on different surfaces of any shape, size. Another important merit encompassed in the screen printing is that a thicker ink can be used than the other printing techniques. This feature facilitates some of the very interesting designs which are not practicable in other forms of the printing. The application process of the technique is so simple that it facilitates a wider usage of inks and dyes for its usage in screen printing than the other printing press usage options. With the utilization of the screen printing, the production rates have improved this also implies that screen printing is a quick process too and it is more flexible. This is an outcome of the development of the rotary printing press, better inventions of dryers, and U.V curable ink. The chemicals which are utilized in the screen printing process are the screen emulsions, inks, and solvents, surfactants, caustics and oxidizers used in screen reclamation. Types of screen printing pressesScreen printing presses are of three main kinds viz: • The flat bed• Cylinder• RotaryFlat bed and cylinder pressesFlat bed is one of the most widely used types of screen printing. The flat bed and the cylinder press have the same features that are they both use flat screens as well as a three step reciprocating process of performing the printing operation. The screen is moved onto the substrate, then the squeegee is pressed on the mesh and taken over the image area, and finally the screen is taken away from the substrate thus ensuring the completion of the process. Using the flat-bed press the thing to be printed is placed on a horizontal print bed parallel to the screen. Incase of the cylinder press the thing to be printed is placed on the cylinder.Rotary screen presses These presses are developed to facilitate a continuous, high speed web printing. The screens in these presses are very thin metal cylinders. The cylinders are open ended and they are covered at both the ends and these covers are fitted in blocks in the side of the press. In the course of printing the ink is pumped into through one end of the cylinder so that there is continuous inflow of the ink. The squeegee is a continuous free floating bar inside the cylinder. The pressure of the squeegee is maintained by the magnet bars which are placed under the press bed. These are most often used for printing textiles, wallpapers and other substances which require unbroken continuous patterns.