Please revise these areas

1. Aluminium sheet
Stock form
Origin of material:
Aluminium ore
BAUXITE
Process: Mining.
The bauxite is washed
& purified to yield a
white powder –
aluminium oxide
Primary processing:
Electrolysis
Aluminium oxide is
dissolved in molten
cryolite – an
aluminium compound
with a lower melting
point than aluminium
oxide. An electric
current is passed
through the solution
forming aluminium
atoms which sink to
the bottom and can
be tapped off.
Secondary process:
Casting and rolling.
Aluminium ingots are
cast and rolled hot
into sheets.
They are then rolled
cold to the required
thickness.
No of children
and material
Calculate the
percentage:
170 use paper
30 use wood
55 use metal
85 use plastic
Percentages
Origins of materials and processing
MDF Sheet
Stock form
Origin of material:
Trees, timber. Softwood pine
trees are grown for timber in a
managed forest.
They are felled with a chain saw
or machine
Primary processing:
De barking & cutting into planks
using a power saw. The waste
wood is chipped and put into a
machine called a defibrator. This
turns the waste wood into wood
fibres.
Secondary process:
Resin urea formaldehyde is
added to the fibres.
A machine is used to form the
MDF with heat and pressure
into a sheet.
The sheets are then cut and
sanded.
Heat &
pressure
Presses
fibre &
resin
How to do it.
Total No of children =
340
Divide by 100 = 3.4 = I
%
Then divide each
group by 3.4
170/3.4 = 50 or 50%
30/3.4 = 8.82%
etc

2. Alloys are mixtures of 2 or more metals to
get the best of their properties. For
example: Stainless steel is an alloy that is
hard wearing like regular steel but does not
rust or corrode.
Material Key info Examples
Brass
Malleable and easy
to cast
Musical
instruments,
plumbing
Stainless
Steel
Doesn’t rust, hard
and smooth
Cutlery,
medical
tools, etc
Alloys and their properties
Reinforced
Materials
Description of reinforcement
Plywood Thin sheets of wood are glued
together to produce a stronger
and thicker sheet.
The thin sheets are laid at 90
degree angles so the grains are
not all pointing in the same
direction. This gives the
plywood added strength
Concrete Steel or glass fibres are put
into the concrete before
pouring to give the concrete
added strength and durability.
cardboard Corrugated cardboard is made
using layers of cardboard with
a corrugated middle layer. This
strengthens the material.
A composite material is produced when two or
more materials are combined. This gives you a
material with improved properties.
GRP (glass-reinforced plastic) GRP consists of strands of
glass fibres that have been coated in polyester resin. It is
used in the manufacture of boat hulls and 'kit cars’.
Carbon Fibre reinforced Plastic Carbon Fibre reinforced
Plastic is a similar material to GRP. It consists of strands of
carbon that have been coated in polyester resin. It is used
in the manufacture of high-performance products such as
racing bikes and tennis rackets.
. Kevlar is a similar material to
carbon fibre matting. It consists of
strands of a very strong plastic
material that is woven to form a
mat. It is used for body armour,
such as the bullet-proof vests and
face masks that are used by the
army and the knife-proof vests
that are used by the police
Composites
Anthropometrics is the study of the sizes of people
in relation to products. For example, chairs used in
schools need to be suitable for the average size of
pupils in the schools. *Used to determine the size
Ergonomics is the practice of making a work space
and working habits healthier for the body. This
should prevent degradation in posture and reduce
wear and tear from repetitive use of hands and
wrists. Using Anthropometric measurements to
improve the products use
Look at this camera.
• Identify the anthropometric features of the
camera.
• Identify the Ergonomic features of the camera.
• Identify the user
• Identify the aesthetic (how it looks)
• Now redesign it for a child.
• What changes would you make – how would it
look,, how would it function. Practice redesigning
it and explaining all the changes you would make.
Designing
OUTPUT
Alarm buzzer
Creates loud alarm
PROCESS
Microcontroller
If smoke detected - sends
signal
INPUT
Smoke Sensor
Smoke alarm system diagram
Heating system diagram
Systems
Reinforced Materials