UNIT 3UNIT 3TECHNICAL MATERIALSTECHNICAL MATERIALS

WOODSWOODS

CLASSIFICATIONCLASSIFICATIONWOODS

NATURAL MANMADE

SOFTWOODS HARDWOODS

They come from coniferous trees. They are ever green, and

have got NEEDLE shaped leaves

They come from decicious trees(they lost their FLAT leaves in autumm)

BOARDS

SOFTWOODS - PROPERTIESSOFTWOODS - PROPERTIES

CONIFEROUS ARE CONIFEROUS ARE FAST GROWING FAST GROWING (20-30 years to mature)

TIMBER THAT COMES FROM TIMBER THAT COMES FROM CONIFEROUS TREES IS CONIFEROUS TREES IS OPEN GRAINEDOPEN GRAINED

IT IT SPLITSSPLITS EASILY EASILY IT IS IT IS WEAKWEAK IT IS IT IS CHEAPCHEAP

HARDWOODS - PROPERTIESHARDWOODS - PROPERTIES

DECICIOUS TREES ARE DECICIOUS TREES ARE LOW GROWINGLOW GROWING (100 years to mature)(100 years to mature)

TIMBER THAT COMES FROM TIMBER THAT COMES FROM DECIDIOUS TREES IS DECIDIOUS TREES IS CLOSE GRAINEDCLOSE GRAINED

IT IT DOES NOT SPLITDOES NOT SPLIT EASILY EASILY IT IS IT IS STRONGSTRONG IT IS IT IS EXPENSIVEEXPENSIVE

SOFTWOODSEXAMPLES

HARDWOODSEXAMPLES

HARDWOODSEXAMPLES

HARDWOODSEXAMPLES

BLOCKBOARDBLOCKBOARD

IT IS MADE FROM IT IS MADE FROM SOFTWOOD STRIPSSOFTWOOD STRIPS

BONDED WITH AN BONDED WITH AN ADHESIVE.ADHESIVE.

IT IS USED FOR IT IS USED FOR FURNITURE FURNITURE MANUFACTURINGMANUFACTURING

(internal parts)(internal parts)

CHIPBOARDCHIPBOARD

IT IS MADE FROM IT IS MADE FROM SMALL CHIPS OF SMALL CHIPS OF WOOD BONDED WOOD BONDED WITH A RESINEWITH A RESINE

IT IS USED IN IT IS USED IN FURNITURE FURNITURE MANUFACTURING.MANUFACTURING.

IT IS CHEAPIT IS CHEAP

MEDIUM DENSITY FIBRE MEDIUM DENSITY FIBRE BOARD MDF = DMBOARD MDF = DM

IT IS MADE FROM IT IS MADE FROM WOOD DUST AND WOOD DUST AND RESIN, AND THEN RESIN, AND THEN PRESSURED INTO A PRESSURED INTO A BOARD.BOARD.

IT IS EASY TO WORK IT IS EASY TO WORK (machine, cut, paint...)(machine, cut, paint...)

IT IS USED IN CHEAP IT IS USED IN CHEAP FURNITURE (internal FURNITURE (internal parts)parts)

PLYWOODPLYWOOD

IT IS MADE FROM IT IS MADE FROM VENEERS OF VENEERS OF TIMBER BONDED BY TIMBER BONDED BY A RESIN.A RESIN.

THE GRAINS OF THE THE GRAINS OF THE VENEERS ARE VENEERS ARE PERPENDICULAR PERPENDICULAR EACH OTHER. EACH OTHER.

WORKING WITH WOODSWORKING WITH WOODS

TO MEASURE & DRAW, WE USE...TO MEASURE & DRAW, WE USE...

TO CUT, WE USE ...TO CUT, WE USE ...

TO HOLD, WE USE ...TO HOLD, WE USE ...

TO HOLE, WE USE ...TO HOLE, WE USE ...

TO SAND & RASP, WE USE ...TO SAND & RASP, WE USE ...

TO JOIN, WE USE...TO JOIN, WE USE...

PHSICAL PROPERTIESPHSICAL PROPERTIES

The relationship The relationship between between

MASSMASS and and VOLUMEVOLUMEDENSITY

The ABILITY The ABILITY of being of being

sratched by sratched by other materialother material

HARDNESS

The property The property of resisting of resisting PULLING PULLING

forcesforces

The property The property of resisting of resisting PUSHING PUSHING

forces forces

TENSILESTRESS

PULL

PUSH

COMPRESSIONSTRESS

The property ofThe property ofbeingbeing

BENT...BENT...

The ability ofThe ability ofresisting the actionresisting the actionof living organisms,of living organisms,

moisture ...moisture ...

DURABILITY

FLEXIBILITY

The abilityThe abilityto to

TRANSFER HEATTRANSFER HEAT

ELECTRICCONDUCTIVITY

THERMALCONDUCTIVITY

The ability to allow The ability to allow the the FLOWFLOW

OF ELECTRONSOF ELECTRONS

WOODS ARE GOOD THERMAL & ELECTRICITY INSULATORSINSULATORS