Silkscreen
Screen printing is one of the most versatile printing processes. It can be used to print on a wide variety of substrates, including paper, board, plastics, vinyl, glass, metal, fabrics, and many other materials. Some common products from the screen printing industry include posters, labels, decals, signage, all types of textiles and electronic circuit boards.
Screen printing consists of three elements: the screen which is the image carrier, the squeegee and ink. The screen printing process uses a porous mesh stretched tightly over metal frame. A stencil is produced on the screen either manually or photo chemically.
Screen printing ink is applied to the substrate by placing the screen over the material. Ink is placed onto screen and then forced through the fine mesh openings using a squeegee that is drawn across the screen, applying pressure thereby forcing the ink through the open areas of the screen. Ink will pass through only in areas where the stencil is open, thus forming an image on the printing substrate.
Pad Printing
Pad Printing is where an inked image is transferred from a photo-etched plate to a thick, soft silicone pad. The pad is then pressed against the object. The pad can wrap itself as much as 180° around a small object, and ink coverage is excellent. One color is done at a time, but registration between colors is good enough to allow four-color process printing. Pad printing is mostly used for printing onto corporate gifts like pens, golf balls, mugs etc.
Pad Printing - Step by Step
Pad printing is used in the decoration or marking of a wide variety of items using an etched nylon or steel plate that will transfer an image via a silicone pad onto a variety of substrates. This is an ideal add-on service for screen and signage businesses.
Why Choose Pad Printing?
It allows for indirect transfer of ink onto flat or irregular shaped surfaces for example golf balls, pens, keyboards, appliances, etc. The process allows for the transfer of concentrated inks with high pigmentation onto substrates irrespective of the base colour or shape of the substrate.
Pad printing can also run at high speeds, between 600 - 2000 prints per hour, irrespective of the number of colours printed. There are one to six colour machines available.
The size of the print may vary from as small as 5mm to 800x200mm - basically from as small as a microchip to full panels used on appliances such as dishwashers.
The process is used vastly in industry, and encompasses the industrial, promotional and cosmetic industries. It is used for branding items such as industrial and home use appliances, electrical and automotive components in the industrial sector. All items that need to be branded where high volume, multi-coloured prints are required in the promotional and corporate gift sectors. In the cosmetic sector it is used for high factor sun lotion tubes, nail polish and perfume bottles.
Etching Plates
The plates are made from nylon or steel. The desired depth of etch is achieved so the best quality image can be transferred by means of a silicone pad onto a variety of substrates.
The exposing process of nylon plates involves fluorescent UV lights to expose an emulsion down positive onto a photo sensitive plate which will require a developing process using water or developing alcohol.
The processing of steel plates is a more complex process involving an acid etching process.
There are many different types of substrates that can be printed onto. The first step is to determine the type of substrate you are printing onto and the process to be used so as to achieve the best adhesion characteristics possible.
Questions you need to ask are: What are the characteristics of the substrates? Which ink will be suitable and will we need any extra process to improve adhesion to the substrate?
The substrates need to be listed, and where necessary broken down into segments:
- Paper and board - coated or uncoated
- Wood - coated or uncoated
- Plastic – thermoplastic
- Metal & Glass - coated or uncoated
- Textile fabric
- Rubber & similar materials
- Leather and PU materials
Overview
There are many different types of materials that will need to be printed. Even from one batch to another changes may take place in the material being used.
Heat Transfers
Heat transfer is the most effective way to transfer a full colour image onto a white t-shirt. The image is printed onto a special paper, which is then transferred to the t-shirt with a heat process. The transferred image is full colour photo finish. If we can print it onto paper, it can be transferred onto a t-shirt. This process is mostly used for low quantity printed shirts. We can print as little as 1 t-shirt.
