Papers and Boards Flashcards
Forming Paper Pulp
Paper pulp slurry is sprayed onto a fine wire mesh mould in the shape of the upper/exposed surface of the product to be created.
The water passes through the mesh, leaving the paper pulp on the mould.
A secondary mould presses down onto the pulp, forcing out more water and ensuring accuracy of the form.
The pulp is dried under heaters and then the completed product is removed from the mould.
Screen Printing Properties/uses
Low set up cost.
Small runs.
Posters, Clothing and Display Boards.
Flexographic Printing properties/ uses
Cyan, Yellow magenta and black (key) (CYMK) printed on top of each other in different quantities.
Least Expensive - simple operation.
Fast.
News papers, comics, packaging, carrier bags and wallpaper.
Screen Printing Process
The image to be printed is created on a mesh screen, blocking off the mesh where ink is not required.
The open areas allow the ink to pass through.
The material to be printed sits on the bed, the screen is placed on top of the substrate and locked in place.
Coloured ink is placed onto the screen and a squeegee is used to force the ink through the mesh onto the substrate.
The ink is then dried or cured. A different screen is required for each colour, which makes the process slow and can increase production costs.
Flexographic Printing Process
Flexible printing plates are wrapped around rotating cylinders.
Ink is fed from the fountain roller onto the anilox roller, which makes the ink a uniform thickness, and then transferred to the plate cylinder.
The substrate moves between the plate cylinder and the impression cylinder, which applies pressure to transfer the image.
The substrate is then fed past dryers to ensure the ink is dried before moving to the next colour print unit.
Offset Lithographic Printing Properties/ uses
Versatile.
Single or multicoloured prints.
CYMK and other metallic inks can be printed. Print on both sides.
Medium and long print runs for books, forms, magazines, posters and packaging.
Offset Lithographic Printing process
Lithographic printing is based on the principle that oil and water do not mix. Lithographic plates are chemically treated to make the image area absorb oils (oleophollic) and therefore receptive to oil-based inks. The non-image area is treated to absorb water easily (hydrophollic) and therefore repel the ink. During printing, water is applied to the plate cylinder and is attracted to the hydrophollic, non-image areas. Ink is then applied to the oleophilic image areas. The water ensures that the ink does not bleed into the non-image areas. The ink is transferred to the offset cylinder and then the substrate. The substrate is either sheet or roll fed into the machinery
Digital Printing properties/ uses
Widely Used.
Quick, efficient.
Full colour, highly detailed images on both side of the substrate.
Suitable for low and high volume prints.
Promotional Materials as well as packaging.
Ways of Forming Paper and Boards
Die cutting and creasing.
Bending.
laser Cutting.
Ways of finishing paper and boards
Laminating (encapsulation and surface coating)
Embossing.
Debossing.
Foil blocking.
Varnishing.
UV Varnishing.
Spot Varnishing.
