Technology - Design and Technology up to mdf

up to mdf

mass production

high-scale production of a standardised product

batch production

products are made in smaller batches and production line can be adapted to allow variation between batches

one-off production

one-off products made to a client specification

electrical conductivity

the measure of a material’s ability to allow the transport of an electrical charge.

thermal conductivity

the property of a material to conduct heat

density

the quantity of mass per unit volume of a substance

tensile strength

the ability to resist pulling forces

compressive strength

the ability to withstand push forces that try to crush or shorten a material

bending strength

the ability of a material to resist forces which attempt to bend it

shear strength

the ability of a material to resist shear forces

what is a shear force

unaligned forces pushing one part of a body in one specific direction and another part of the body in the opposite direction

torsional strength

the ability of a material to resist torsional forces

what is a torsional force

a force that attempts to twist an object

elasticity

the ability of a material to flex bend and be deformed and return to its original shape once the forces are removed

plasticity

the ability of an object or material to permanently change shape as a result of forces applied to it without cracking or breaking

malleability

the degree to which a material can be deformed in all directions as a compressive force caused by impact such as hammering, pressing or rolling is applied, without cracking or breaking the material

ductility

the ability of a material to be drawn to be longer and thinner into a wire

toughness

the ability of a material to withstand sudden shocks or blows

hardness

the ability to resist indentation or scratching

indentation tests

brinell, vickers, rockwell

what doe the brinell test use

hard steel ball

what does the vickers test use

small pyramid-shaped diamond tool

what does the rockwell test use

steel ball or diamond cone

durability

the ability to withstand wear and tear and deterioration as a result of weathering

brittleness

tends to break or shatter before they deform

what trees do hardwoods come from

deciduous or angiosperms

what are the hardwoods

beech oak mahogany ash birch teak walnut

what trees do softwoods come from

evergreen or coniferous or gymnosperms

what are the softwoods

pine cedar cypress fir spruce redwood

working characteristics of pine

easy to work with, readily available, prone to shrinking and twisting

uses of pine

construction work, joinery, shelving, cupboards

properties of pine

knotty, straight fine grained

working characteristics of ash

easy to work with, finishes well

properties of ash

strong and durable, flexible ,open-grained

uses of ash

furniture, tool handles, sporting goods, ladders

working characteristics of beech

easy to work with, finishes well, can warp

properties of beech

close grained, strong hard and tough

uses of beech

furniture, kitchen utensils, toys, tool handles, chairs

working characteristics of oak

easy to finish

properties of oak

hard tough durable and very strong, open grained, expensive

uses of oak

high quality furniture, boat building, garden furniture, flooring

working characteristics of mahogany

available in long wide boards, difficult to finish, prone to warping, easy to work with

properties of mahogany

quite strong hard and durable

PAR

planed all round

forms woods can be bought in

rough sawn timber, planed timber, moulds, dowel rod,

what are the manufactured boards

plywood, blockboard, chipboard, hardboard, MDF

properties of plywood

thin layers of wood called laminates are glued together with adhesive and pressure with their grains running at 90 to each other.

advantages of plywood

strong, resistant to warping, cost effective

disadvantages of plywood

porous, will splinter badly when cut

uses of plywood

chests and cabinets, roof construction, flooring, sheds and building cladding, chairs

properties of blockboard

numerous strips of softwood sandwiched between 2 sheets of hardwood and glued together under high pressure

advantages of blockboard

fairly strong, cheap, resistant to splitting, light, good stability, does not shrink

disadvantages of blockboard

retains moisture, not as strong as the original wood, needs veneer on the edges

uses of blockboard

high quality furniture, bedroom units, shelves, table tops, kitchen worktops

properties of chipboard

made up of wood particles glued together with heat and pressure

advantages of chipboard

easy to use, relatively cheap, can be aesthetically presented

disadvantages of chipboard

likely to crack and fall apart over time, retains moisture and swell, rough edges when cut, needs veneer to cover it when used as a furniture item

uses of chipboard

kitchen tops, fire doors, furniture, flooring, shelving

properties of hardboard

wood chips and pulped wood waste is put under pressure until the fibres bond to produce tough board with one smooth side and one rough side.

advantages of hardboard

cheap, has a smooth surface which can be easily painted, oil tempered board is resistant to being dented and scratched

disadvantages of hardboard

poor water resistance, weak

uses of hardboard

bottoms of drawers, general purpose backing, doors, packing for transport

properties of MDF

fine wood dust and resin pressed into a board

advantages of MDF

fairly strong and durable, easily made in industry, easily cut shaped and drilled, can be manufactured in many forms, can be fire and water resistant if particular resins are used

disadvantages of MDF

easily split and damaged, high density, contains a lot of glue which can damage tools, can be harmful to health when being cut, will absorb water and swell without additive

uses of MDF

kitchen cabinets, flooring, furniture, panel moulding, exterior cladding, joinery