Screen Printing / Porous Printing

SCREEN PRINTING (POROUS PRINTING)

It is also called silk screen printing because earlier the screen used to be made of silk cloth and hence called silk screen printing.

The process is used extensively for printing both flat and same curved surface of moulded parts.

BASIC PARTS

Backer board on supporting frame

Screen Frame

Screen Mesh

Squeegee etc.

(1) BACKER BOARD

The backer board is used for movement of screen frame and it is fixed both by a vice.

(2) SCREEN FRAME

The nylon or silk to mesh is supported o railed on the square frame for printing.

(3) SCREEN MESH

This is made of fine nylon threads.

The term mesh indicates the gap between two adjustcent threads.

(4) SQUEEGER

The sqeeger is to squeeger the ink on the mesh to get impression on the substrate.

There are two types of squeeger materials used they are

1. Rubber Squeeger

2. Nylon squeeger

PROCESS

The viscous is poured on the inner side ink the screen of and when pressure is frame from applied sqeeger.

The ink passed over screen through unlocked printed areas and finally we get impression on the substrates which we are using.

No other printing process offers the depth, reach ness and spectrum of colour obtainable with the screen printing.

SCREEN PRINTING INKS

Ultraviolet Inks

Solvent inks

Reactive Inks

ADVANTAGES

Versatile use of process for printing on paper, board, fabric, plastics, wood, glass etc

Also used suitable for multi-colours, light colours and fluorescent ink widely used.

DISADVANTAGES

Printing speed is comparatively slow.