1.19 use of finishes

Question 1

Paper and Board Finishing

Lamination via encapsulation

Answer 1

A desktop laminator and the sheet of paper is encapsulated by a polymer pouch or film roll

Question 2

Paper and Board Finishing

Lamination via a surface coating

Answer 2

Liquid lamination (for signage) or film lamination (meu cards)

Question 3

Paper and Board Finishing

Embossing

Answer 3

Creates a raised design on the surface of the paper or card to give a visual and tactile effect (greetings cards, chocolate box lettering)

Question 4

Paper and Board Finishing

Debossing

Answer 4

Produces an imprinted depression that sits below the surface of the paper or card

Question 5

Paper and Board Finishing

UV varnishing

Answer 5

Provides a very smooth finish, usually high gloss or matt and chemcial resistant. Applied to a sheet via a set of rollers, then passed under UV light to cure

Question 6

Paper and Board Finishing

Spot varnishing

Answer 6

Applied in specific areas or spots rather than to the whole surface area

Question 7

Paper and Board Finishing

Foil blocking

Answer 7

Heat and pressure applied to a metallic paper (foil) to create areas of depth and texture to add aesthetic impact

Question 8

Paper and Board Printing

Screen Printing

Answer 8

• Can be carried out in a workshop with minimal set-up costs due to the use of basic screens and printing inks
• A different is required for each colour
  -Quite a slow process with a reasonably high cost per product
  -Used for small print runs of items such as posters, display boards and textile T-shirts

Question 9

Q
Paper and Board Printing

Flexographic printing

Answer 9

-Four colours (cyan, magenta, yellow, key (black)) are printed on top of one another in various quanties on to the substrate surface to create the print colour required.
-It is used for newspapers, comics, catalogues, folding packaging cartons, labels, carrier bags and continous pattern products such as wallpaper and gift wrap.

Question 10

Paper and Board Printing

Advantages of flexographic printing

Answer 10

-High print speed
-Ideally suited for the long run
-Prints on a wide variety of substrate materials
-Low cost of equipment and consumables
-Low maintenance

Question 11

Paper and Board Printing

Disadvantages of flexographic printing

Answer 11

-The cost of the printing plates is relatively high, but they last for millions of print runs
-Takes a large amount of substrate to set up the job; excess material may be wasted
-Time consuming to change for any alterations to the print content

Question 12

Paper and Board Printing

Offset lithographic printing

Answer 12

-Extremely versatile printing process of producing one colour, five colours and a ten colours
-Used for printing medium and long print runs of products such as books, business forms and documentation, magazines, posters and packaging.

Question 13

Paper and Board Printing

Advantages of offset lithographic printing

Answer 13

-Consistently high image quality
-Suited to higher-volume print runs of 1000 or more
-Quick and easy production of printing plates
-Long life of printing plates because they only come into contact with the printing blanket, which is softer and less abrasive than substrate

Question 14

Paper and Board Printing

Disadvantage of offset lithographic

Answer 14

Expensive set-up and running costs for small quantities

Question 15

Paper and Board Printing

Digital printing

Answer 15

-Produces full-colour, highly detailed print runs with the option of different designs on each page, both front and reverse sides
-Widely utilised resources for printing products, due to their speed and efficiency
-Can be used for low and high volume print runs
-Used for mass customisation, such as the printing of specific names on drinks cans.

Question 16

Polymer Finishing

Overmoulding

Answer 16

Overmoudling is moulding a second polymer over specific parts of a products

-TPE (thermoplastic elastomer) is often used
-Overmouldings provide areas of grip or texture
-Overmoulding can highlight different colours for different component Polymer Finishing parts on the product

Question 17

Polymer Finishing

Two injection moulding moulds

Answer 17

-One mould for the product and one mould for the grip areas
-Product is injection moulded, then placed into a second mould where the overmoulding polymer is injection-moulded on to the body

Question 18

Polymer Finishing

Twin-shot injection moulding

Answer 18

-The injection moulding machine has a mould designed to produce the product in one cycle
-The mould has two separate component cavities and can be rotated through 180° so that they line up with the twin injection points
-First, the main product part is created in the first mould cavity
-The mould opens slightly and rotates 180° to the secondary position
-The mould closes and the second injection applies the overmould

Question 19

Polymer Finishing

Acrylic spray paints

Answer 19

-Fast-drying
-Water-soluble paint
-Water resistant when dry
-Improves aesthetics and provides additional protection against the effects of UV light and weathering
-Often used for mass customisation, particularly in the automotive industry, such as colour coding bumpers and wing mirrors on cars.

Question 20

Polymer Finishing

Adding pigments

Answer 20

-Provide colour to the polymer
-Smart pigments such as thermochromic or phosphorescent pigments can be added
-Can also be added to gel coats when laying up GRP

Question 21

Metal finishing

Cellulose and acrylic paints

Answer 21

-Provide colour and a textured finish
-Provide a barrier against corrosion
-Specialist paints provide texture or special graphic effects such as pearlescence
-Primarily used on low-cost metals such as steel.

Question 22

Metal finishing

State the method of application of cellulose and acrylic paints

Answer 22

-Paints are primarily used on low-cost metals such as steel. The surface of the metal is cleaned and degreased, which ensures that the primer coat has a sound surface to ‘key’ (or grip) to
-Red oxide primer is often used, followed by an undercoat in a similar colour to the final top coats
-Paints can be applied by brush or spray

Question 23

Metal finishing

Electroplating

Answer 23

-A protective layer, a more hardwearing finish, and enhanced aesthetics
-The product and donor material are placed in a container with an electrolyte solution. As the direct current is applied, the product attracts the donor metal and the product is electroplated.
-Metals for electroplating include sliver, gold, zinc, copper and tin

Question 24

Metal finishing

State the method of application of electroplating

Answer 24

-The product and donor material are placed in a container with an electrolyte solution
-As the direct current is applied, the product attracts the donor metal and the product is electroplated
-Metals used are sliver, gold, zinc, copper and tin

Question 25

Metal finishing

Polymer dip coating

Answer 25

Used on products such as wire coat hangers, kitchen dish drainers, coat hooks, dishwasher racks, and outdoor play equipment frames

Question 26

Metal finishing

State the method of application of polymer dip coating

Answer 26

-The metal product is heated to approximately 230°C
-The hot product is then dipped into a tank of fine polymer powder, which has air blowing through it (fluidisation bath) to provide an even coating on the product.
-The retained head from the product melts the polymer powder over the product, which is then air cooled allowing the coating to set evenly

Question 27

Metal finishing

Metaldip coating

Answer 27

1) Provides a barrier against corrosion
2) Tin plating: often used to provide a non-corrosive coating to food cans
3) Zinc plating: used for many industrial and agricultural applications such as beams, gates, and animal pens. Also, like the first protective layer in car bodies made from low carbon steel.

Question 28

Metal finishing

State the method of application of metaldip coating

Answer 28

-Metals are coated by dipping the product into a tank of molten plating metal (the donor metal)
-The metals must be clean and degreased
Tin plating:
* pass sheets of steel through a tank of molten tin at approximately 320°C
Zinc plating (galvanising):
* dipping steel into molten zinc at approximately 460°C

Question 29

Metal finishing

Powder coating

Answer 29

-Protection from corrosion and aesthetic appeal, more hardwearing than paint
-Used on washing machine bodies, dishwasher bodies and refrigerator bodies, metal gates, fencing, and railings.

Question 30

Metal finishing

State the method of application of powder coating

Answer 30

-The product to be coated is statically charged (negative)
-Thermoset polymer resin (positively charged) is then sprayed through an airgun
-The use of charge results in a strong attraction between the powder and the product
-The product is then baked in a oven; the heat melts the powder over the product to give an even coating