DT

Woods

Where is hardwood obtained from?

Slow growing deciduous trees

Give qualities of hardwoods

• typically high density ]

• Strong and durable

Give 6 example of hardwoods?

• oak

• Balsa

• Mahogany

• Beech

• Ash

• Ebony

Where do softwoods come from?

Fast growing coniferous trees

Give qualities of softwoods?

• Generally lightweight

• Cheap

• Easy to shape

Give 3 examples of softwoods?

• spruce

• Pine

• Cedar

What’s are all woods made from?

Fibres

What are the fibres they are made up?

Cellulose and lignin

What is the most common defect that could happen in a wood?

A knot which is when a branch forms from within the main trunk

What are man made boards?

Designed and engineered to give specific properties and consistent uniform dimensions and surfaces

They are manufactured from sheets, veneers, chips and fibres using high pressure glues, resins and waxes which are bonded through heat

Give examples of manufactured woods?

OSB

MDF

Plywood

Chip board

Give performance characteristics of chip boards?

• weak

• Absorbs water and swells

• Heavy less durable

What does less durability cause?

Chipping

Give common forming methods?

• sawing

• Sanding

• Drilling

• Screwing

Give common finishes and enhancements?

Melamine lamination

Paint

Varnish

Wood veneer

Give common products made with chipboard?

Flat back furniture

Cabinets

Flooring

What are the common stock forms? (How they are bought)

• sheets

What are the joining methods for chipboard?

• Pva glue

• Dowles, nails

• Resin adhesive

Give performance characteristics of plywood?

• high strength due to the alternating grain directions

• Durable

• Resisting to splitting

• Water resistent

• Lightweight

• Expensive

Give commonly used forming methods?

• laser cutting

• Sawing

• Drilling

• Sanding

Common finishes and enhancements for plywood?

• laminating

• Paint

• Varnish

• Wood veneer

Give common stock forms and adhesive joint methods?

Stock forms- sheets

Joining methods- pva, epoxy resin, screws and bolts and dowels

State the performance characteristics of block board?

• high strength

• Not flexible

• Limited water resistance

• Cheaper

• Lightweight

What are the forming methods?

• sawing

• Drilling

• Sanding

What are the commonly used processes stock forms and the joining methods?

Stock forms- large sheets and boards

Joining methods- pva glue, epoxy resin, bolts, screws and dowels

Polymers

What are the 4 types of polymers?

• thermoplastics

• Thermosetting

• Thermosoftening

• Elastomers

What are the properties of thermoplastics?

• Can be softened and hardened when heated and cooled

• Can be reheated and reshaped repeatedly

• Recyclable

Give examples of thermoplastics?

• Acrylic,

• polypropylene (PP),

• high implant polystyrene (HIPS)

• Polyethlyene (PE)

What are the performance characteristics of polypropylene?

• tough

• Lightweight

• Fatigue resistant

• Chemical resistant

• Waterproof

What are the common forming methods for PP

• vacuum forming

• Blow moulding

• Injection moulding

• Extrusion

What area the common product made from PP

• plastic chairs

• Living hinges

• Plastic storage boxes

What is the melting point of PP

160 - 170 degrees

What are the performance characteristics of HIPS

• tougher than standard polystyrene

• imopact resistent (egg carton)

• Lightweight

• Easy to thermoform

What are the commonly used forming methods for HIPS?

• vacvuum forming

• Injection moulding

• Extrusion

What are common products for HIPS?

• packaging trays

• Fridge lining

• Yoghurt pots

• DVD