1.5 the use of finishes

3 main terms associated with finishing

Self finished

Self coloured

Applied finish

Self finish

A material that has an acceptable finish after processing

Self coloured

A material that has an acceptable colour after processing

Applied finish

A substance applied to the material after processing

Laminating via encapsulation

Desktop laminator - paper encapsulated by a polymer pouch. Fed through and sealed leaving a boarder around the edges

Laminating via surface coating

Liquid lamination: applied by roller or spray - used for signs to protect from dirt, moisture and uv

Film lamination: usually made of PP with an adhesive to make the laminate stick to the paper

Embossing

The process of creating raised images or text on paper or card by placing the paper or card between two dies under pressure

Debossing

Opposite of embossing - creates imprints or depression on card or paper

Foil blocking

application of heat and pressure to a metallic paper (foil) to create areas of depth and texture to add aesthetic impact to a product

varnish

clear, non-pigmented ink used on pre-coated papers and boards to enhance the colour as well as offer protection against dirt, fingerprints and water. it is available in gloss, matt, satin and tinted.

uv varnishing

finishing that protects against UV. specific machinery is required to cure the varnish leaving a high gloss or matt finish which is abrasion and chemical resistant

spot varnishing

varnish which is applied in specific areas or spots rather than the whole surface area

screen printing

a printing process in which ink is forced onto the surface of a material through a mesh screen to create a picture or pattern

flexographic printing

high speed, relief printing process that used flexible plates to transfer ink to a substrate widely used for packaging, labels and flexible materials

flexographic printing advantages

• high print speed

• ideally suited for long runs

• prints on a wide variety of substrate materials, both porous and non-porous

• low cost of equipment and consumables

• low maintenance

flexographic printing disadvantages

• 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

offset lithographic printing

ink is transferred from a plate to a blanket or rollers which then transfers the image to paper

offset lithographic printing advantages

• 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 the substrate

offset lithographic printing disadvantages

• expensive setup and running cost for small quantities. only suitable for porous substrate materials

digital printing

apply colour in a similar way to laser printers which the ink sits on top of the paper and is allowed to dry or be laminated

polymer finishing

considered to be self finishing as they require no additional finishing process

acrylic spray paints

provides improved aesthetics and additional protection against UV. allows for mass customisation in the automotive industry

overmouldings

using two injection moulding moulds e.g. toothbrush one for products and one for grip areas

twin shot injection moulding → injection moulding machine with a mould designed to produce the product in one cycle. mould has two separate component cavities and can be rotated 180 degrees

metal finishing

most metals have an oxide layer to provide barrier to the effects of the environment e.g. copper is reddish tint but overtime and oxide layer or patina forms to protect from corrosion and environmental attack turning it green

steel is the exception→ oxide layer allows moisture → rusting = layers crumbing rust

electroplating

using a metal to coat a usually cheaper base metal to provide both a protective layer and to giver a greater aesthetic appeal

polymer dip coating

metal product is heated to approx 230. the hot product / component part is dipped into a tank of fine polymer powder which has air blowing through it. this provides an even coating

metal dip coating

metals coated with other metals by dipping the product into a tank of molten plating metal

Powder coating

Thermoset polymer powder positively charged and attracted to the negatively charged product. It is then baked to melt the powder and given an even coating

Varnishing

Method that provides a clear finish to protect the metal and allow the colour of the base metal to show through

Sealants

Tough polymer based sealant coating that protects polished surfaces from decay and tarnishing

Preservants

Temporary in process or final post processing, medium to long term protection for metal surfaces. Often used for moulds to prevent fingerprints from showing

Anodising

Commonly used for aluminium to enhance the natural oxide layer resulting in increased hardness and toughness

Catholic protection

Method used to control control the rate of corrosion by making the metal the cathode of an electrochemical cell; the anode is a sacrificial metal which is more easily corroded; the anode corrodes while the base metal is protected. Main use is to protect steel

Polyurethane varnish acrylic varnish

Provides a hard, tough, heatproof, waterproof finish. Clear → allows for grain of wood to be seen

Water-based paints

Provides both protection and colour. Paint can be applied for both indoor and outdoor use and is predominantly used for softwoods.

Makes surfaces more aesthetically pleasing, tougher, harder and resistant to moisture

Stains

Help colour and enhance the grain.

Colour wash

Help to colour the wood while allowing the grain to show through

Wax

Buffed to provide a high gloss finish. Increases the surface hardness and toughness

Pressure treating

Helps protect wood for up to 50 years from rot, insect and fungal attack and weathering

Yacht varnish

Suitable for woods that are outside all year round. Increases toughness, hardness and weather resistance

Danish oil

Maintains the natural appearance of the timber, soaks into the wood and enhances the grain. Not hard wearing but regular applications can build a matt, water resistant finish

Teak oil

Used for outdoor woods to improve weather resistance and resistance to insect and fungal attack. Aesthetically pleasing as grain is enhanced