S1/S2
DATA BOOK
Design and Technology
Contents
The symbols opposite will help you to identify the topics
• Health and Safety Rules
• Designing
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Data on Timber
Man-made Boards
Methods of Joining Timber
Woodworking Hand Tools
Machine Tools
Methods Of Fixing Timber
Wood Finishes
Contents
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Metals and their Properties
Metalworking Hand Tools
Permanent Methods of Joining Metal
Metal Finishes
• Data on Plastics
• Plastics and their Properties
• Shaping and Forming Plastics
Input
• Systems
• Sub-Systems
Process
Output
Contents
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Graphic Symbols and Signs
Charts and Graphs
Free Hand Sketching
Measurement
Orthographic Drawing - 3 rd Angle Projection
Lines and Symbols
Perspective Drawing
Isometric Projection
Oblique Projection
Colour Theory
The Colour Wheel
Shading and Rendering
Health and Safety Rules
Attention to safety is the most important thing in any
workshop and everyone, teachers and pupils alike, must
learn the following simple safety rules before beginning
any practical work.
1. Always dress safely:
• The best way to prepare for a practical lesson is to take
off your jacket and put on an apron.
• Long sleeves are dangerous so they should be rolled up.
• Long hair is also dangerous and should be tied back so
that it cannot fall forward.
• Jewellery should be removed and ties safely tucked in.
Contents
Health and Safety Rules
2. Always wear the correct safety equipment:
• Take special care to protect hands, eyes and feet. If there is
the slightest risk of eye injury safety goggles should be worn.
• When handling hot materials gauntlet style protective gloves
should be worn.
• In order to avoid any foot injuries, strong shoes should be
worn in the workshop.
3. Never run or play in the workshop and do not play tricks
on people:
• Accidents in the craft rooms usually result from silly
behaviour.
• Never act in a foolish manner in the craft room or encourage
anyone else to act in a foolish manner. Remember someone
else's foolish behaviour could result in your injury.
• Always carry tools and materials safely.
• Sharp tools must be held so that they cannot cut anybody.
Contents
Health and Safety Rules
4. Never use a machine without permission and correct
training:
• Only ONE person at a time can use a machine.
• Do not distract or stand talking to anyone who is operating a
machine.
• You must wear safety goggles when operating machinery.
• Make sure all machine safety guards are in place and that the
work to be machined is held securely.
5. Keep yourself and the workshop clean and tidy:
• To avoid the danger of skin disease, always wash your hands
thoroughly at the end of each lesson.
• Care should be taken to avoid spilling paint, varnish etc. onto
your clothes.
• Do not allow tools, materials or waste to litter the benches,
machines or floor.
Never break a safety rule.
If in doubt ask.
Contents
Designing
THE DESIGN PROCESS – is the steps that you go through to get
from a problem to the solution.
Problem
Analysis
Required Specification
Investigation
Solution
Manufacture
Evaluation
Contents
Designing
PROBLEM – States what your problem is but not how it
should be solved.
e.g. I keep mixing my keys up with my brother, and
need to be able to identify my own keys.
REQUIRED SPECIFICATION – This is a list that describes
what the solution has to be able to do, and be like. It will
describe such features as size, shape, safety, function
etc.
e.g. The pencil has to:
1.
2.
3.
4.
Be a suitable size to fit into your pocket
Be easy to hold
Cost 15p or less
Be brightly coloured to appeal to children.
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Designing
INVESTIGATION – This is where you investigate
1. the types of material that are available for you to
use
2. designs that you want to try
3. colour that you would like to use
4. Finish that you could use
5. environment that it will be used in
6. maximum cost
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Designing
SOLUTION – This should contain a sketch of what you
intent to make.
The solution usually contains a set of Working
Drawings. These drawing show all the parts, their
shapes, and their sizes, and how they fit together. this
allows you to plan for your manufacture
4
4
PLAN
5
60
5
40
END
ELEVATION
ELEVATION
END
ELEVATION
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Designing
MANUFACTURE – This will contain a cutting list that
will help you to collect the correct material.
PART No.
REQUIRED
LENGTH
BREADTH
THICKNESS
MATERIAL
The manufacture contains a Sequence of
Operations; this is a set of instructions that
describes how to make the product. All steps
must be in the correct order and the tools that
will be used named. Sketches should be used
to help make the sequence clearer.
Contents
Designing
EVALUATION – Testing a finished product.
• ‘How well does it do the job?’
• ‘Does it look good?’
• The best way to evaluate something is to test it
against the Required Specifications. The
evaluation also includes
•
‘Problems met during manufacture’
•
‘Things I’d do better next time’
•
‘Good and bad points.’.
Contents
Data on Timber
There are 2 types of timber: SOFTWOOD and
HARDWOODS. It has nothing to do with how hard the
wood is.
SOFTWOODS come from trees that have needles and
cones (coniferous trees). The needles remain all year
round, except for one or two species. The grain is
usually very noticeable.
Examples:
Pine, Larch, and Spruce.
They grow in cool countries like the UK, Scandinavia,
Canada, and Russia.
HARDWOODS come from trees that have broad
leaves. (Broadleaf trees). They are common in cool
countries also, and the leaves fall off in winter.
Examples:
Oak, Ash, and Elm.
Contents
Data on Timber
There are 2 types of timber: SOFTWOOD and HARDWOODS. It
has nothing to do with how hard the wood is.
SOFTWOODS come from trees that have needles and cones
(coniferous trees). The needles remain all year round, except for
one or two species. The grain is usually very noticeable.
Examples: Pine, Larch, and Spruce.
They grow in cool countries like the UK, Scandinavia, Canada, and
Russia.
HARDWOODS come from trees that have broad leaves.
(Broadleaf trees). They are common in cool countries also, and the
leaves fall off in winter.
Examples: Oak, Ash, and Elm. HARDWOODS also grow in
tropical countries where it is hot and wet. There is no winter so the
leaves are there all year round.
Examples of Tropical Hardwoods: Mahogany. Jelutong, Balsa.
Contents
Data on Timber
The Importance Of Timber
Timber has been an important material all over the world for
thousands of years.
Britain’s natural forests have almost completely disappeared, due
to the increase in need for land for development and for home
building.
The remaining world forests are ecologically important as they
change carbon dioxide into oxygen and this helps prevent global
warming.
Timber can be a renewable resource if it is harvested and planted
properly.
How We Get Our Wood
Growing
Tree
Felled
Log
Sawn
Log
Plank
Contents
Softwoods and Their Properties
(Coniferous trees)
Name
Advantages
Disadvantages
Uses
Red Pine
Cheap, Straight grain.
Fairly strong. Easy to
work. Finishes well.
Fairly durable.
Knotty.
Sometimes stains
from fungus.
Most used softwood
in the UK. Suitable
for interior work and
exterior work with a
preservative.
Spruce
Fairly strong, easy to
work, very resistant to
splitting
Not durable, has small
hard knots and lots of
resin.
General inside work.
Cedar
Very durable, easy to
work, knot free and
attractive.
Most expensive than
the two above. Not
very strong.
Exterior joinery,
cladding for
buildings and sheds
etc.
Knot free, straight
grain, slightly resinous,
fairly strong and
durable.
Splits easily.
General outside
work, ladders and
plywood.
Douglas Fir
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Hardwoods and Their Properties
(Broadleaf trees)
Name
Advantages
Disadvantages
Uses
Oak
Very strong, very durable,
works well with sharp
tools, finishes well and
attractive.
Heavy, expensive,
contains acid which
corrodes steel screws,
use brass.
Boat building, highclass furniture and
floors.
Beech
Hard, tough, very strong
and straight. Close grain,
polishes well and is hard
wearing.
Not suitable for outdoors,
heavy and difficult to
work.
Most used hardwood in
the UK. Furniture,
floors, wooden tools
and toys.
Walnut
Works fairly well and is
attractive.
Cross grain can make
planing difficult.
High-class interior and
exterior joinery and
furniture.
Hard, strong, very durable,
attractive straight grain and
works fairly easily.
Difficult to glue because
of oil in wood. Very
expensive.
High-class furniture,
laboratory benches and
ships decking.
Teak
Contents
Man-made Boards
Wide boards of hardwood or softwood are expensive
and can warp. Man-made boards are available in large
boards which do not warp (twist).
ROTARY CUT VENEERS – the log is fitted
to a lathe and is then slowly rotated
against a knife that cuts a continuous
sheet of wood.
PLYWOOD – is made from layers or piles
of wood glued together. The grain of each
ply is laid at right angles to the next. This
makes the ply strong in both directions.
Plywood is ideal for lightweight box
construction, cabinet backs and drawer
bottoms.
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Man-made Boards
BLOCKBOARD and LAMINBOARD –
these boards are made by sandwiching
strips of softwood between two piles. The
strips are narrower for laminboard. The
outer faces of veneer have the grain
running at right angles to the strips. It is
usually less expensive to make laminboard
rather than plywood that is over 12mm
thick.
CHIPBOARD – is made by gluing chips of
wood together under heat and pressure.
Veneer and plastic laminate-faced
chipboard is widely used for worktops,
shelves and furniture making.
Contents
Man-made Boards
MEDIUM DENSITY FIBREBOARD (MDF)
– is usually manufactured in a similar way
to hardboard but is compressed under
greater pressure and is therefore much
stronger. MDF is cheap, strong and is
easily shaped and finished. It is ideal for all
types of furniture making.
Contents
Methods of Joining Timber
There are many different methods used to join timber
together. Here we will look at some of the most common
used.
THE HOUSING JOINT – is used in the
carcass construction of cabinets to support
shelves and in box construction for
partitions.
THE REBATE – is used in carcass
construction to join sides to the top and
likewise in box construction.
THE DOWELLED JOINT – is used in
similar situations as the rebate. A jig is very
useful to help make sure that the dowel
holes line up.
Contents
Methods of Joining Timber
THE DOVETAIL JOINT – is very strong
because of the way the ‘tails’ and ‘pins’ are
shaped. This makes it difficult to pull the
joint apart and virtually impossible when
glue is added. This type of joint is used in
box constructions such as drawers,
jewellery boxes, cabinets and other pieces
of furniture where strength is required.
KNOCKDOWN FITTINGS – There is a
wide range of knockdown fittings available.
These devices are commonly used to fit
flat packed furniture together, particularly
chip board flat packed kitchens
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Woodworking Hand Tools
There are a vast range of hand tools available to the wood worker
but here we will only look at the tools that you will be using in first
and second year.
Tool
Name
Uses
Saw Board
Or
Bench Hook
The sawing board is used to aid
cutting of timber battens. The
board is gripped in the vice and
the timber held against the
bench hook while being cut.
Try-square
This tool has two uses.
1.To test the squareness of the
material.
2.To mark out lines at right
angles to a given surface.
Marking Gauge
This tool is used to mark lines
parallel to an edge or side.
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Woodworking Hand Tools
Tool
Name
Uses
Coping Saw
The coping saw has a very fine
blade which can be used to cut
thin wood or plastic. This saw is
suited to cutting curves and
intricate shapes.
Firmer Chisel
The firmer chisel is a generalpurpose chisel used for cutting
and parting wood. E.g. For
cutting waste wood in a
housing joint.
Bradawl
This tool is used to mark
centres and prepare pilot holes
for screws.
Tenon Saw
The Tenon Saw has a rigid
back and is designed to be
used for straight cutting of
small timber sections.
Contents
Woodworking Hand Tools
Tool
Name
Uses
Nail Punch
The nail punch is used to drive
nail heads below the surface of
the wood. Nail punches are
made from high carbon steel,
hardened and tempered.
Jack-plane
This plane is used for a wide
variety of work. It is used to
remove marks left on the timber
by the saw, to bring the down to
size, to make the timber flat and
square, etc.
Smoothingplane
The smoothing plane is used to
remove slight irregularities by
taking thin shavings from the
surface. It is used to prepare
surfaces for finishing.
Bevel-edge
Chisel
The bevel-edge chisel is a more
specialised chisel for lighter
work. The bevel edge allows the
chisel to be used in tight
corners. E.g. when trimming
corners.
Contents
Woodworking Hand Tools
Tool
Name
Uses
Wood Mallet
The wood mallet is designed for
striking chisel handles when
heavy cutting is required. The
head and the shaft are made
from beech. The handle is a
wedge to fit into the head.
Cross Pein
Hammer
Or
Warrington
Hammer
This hammer is a lightweight
general-purpose hammer. The
cross pein is used to start
driving in short nails. The handle
is made from ash or hickory.
Claw Hammer
The claw hammer is the joiner’s
choice of hammers. The claw of
the hammer is used to withdraw
nails.
Contents
Machine Tools
While there is a large range of machine tools
available to the wood worker and the
metalworker it will only be necessary to look at
one of these machines for now.
The Pedestal or Pillar Drill
This machine is designed to drill holes. The
pedestal drill will hold both parallel and tapered
shank twist drills. Unlike the drills you may have
seen at home or in Do it Yourself shops the drill
is mounted on a stand which supports it weight
and makes it easy to use.
Although the drill is fixed the drill table is
adjustable both for height and from side to side
(some tables can also be tilted so that angled
drilling can be done). This is to allow different
shapes and sizes of objects to be drilled.
To allow the user to drill accurately there is a
depth stop on the side of the drill. The depth stop
is very useful if the user wishes to drill a series of
holes al the same depth.
The pedestal drill is not a dangerous machine
to use provided all the health and safety rules
are strictly followed.
Contents
Methods Of Fixing Timber
As well as fixing timber with glue it is often necessary to use mechanical
methods as well. Normally this is done either to hold the joint together while
the glue dries or to allow the joint to be taken apart later.
NAILS AND NAILING – there is a vast range of nails
available. Each nail type is designed to be used for a
special purpose. As well as having different types of
nails they are also available in different lengths.
The types of nails that you will generally use in first
and second year are panel pins. Panel Pins are very
thin nails with small heads and are used to hold
panels in place while the glue dries. So that the head
of the nail is not visible it can be driven below the
surface of the wood with a nail punch.
WOOD SCREWS – are a much more secure method
of mechanically joining timber together. It is also
possible to undo a screwed joint to dismantle the
construction. Screws are also available in different
types, sizes and lengths.
Contents
Wood Finishes
There are two main reasons for giving wood a finish.
1. To protect it from dirt and the wet.
2. To make it look good.
Examples of wood finishes: Gloss paint. Varnish. Sanding Sealer.
Stain. Vegetable Oil.
How to get a good finish.
1. Plane it smooth
2. Sand it along the grain with abrasive paper. (e.g. Glass paper,
garnet paper)
3. Remove the dust
4. Apply the 1st coat of varnish. Do not overload the brush.
5. When dry, rub down with glass paper.
6. Apply the 2nd coat of varnish. Do not overload the brush.
7. Repeat this 3 or 4 times.
Contents
Wood Finishes
VARNISH – is probably the most frequently used finish applied to
timber. This is because it brings out the natural colour and grain of
the timber. Generally varnishes are clear (uncoloured) and are
available in gloss, silk and matt finish.
SILK FINISH gives a more natural sheen to the wood and does not
show up the imperfections like gloss varnish. The two most
common types of varnish available today are polyurethane and
acrylic.
POLYURETHANE varnish gives a very hard wearing waterproof,
smooth finish after only one or two coats but the brush has to be
very carefully cleaned in white spirit afterwards. Polyurethane
varnish is the best finish for exterior work.
ACRYLIC varnish requires more coats, is perhaps not a durable,
but he brush can easily be cleaned under the tap.
Contents
Wood Finishes
PAINT FINISHES – there are a number of types of paint suitable
for application on wood.
There are:
Emulsion
Oil based paints
Polyurethane
Emulsion paint is water based and is not very durable. A wide
range of colours is available. Being water based the brush is easily
cleaned under the tap. Emulsion paints are available in matt or silk
finish.
Oil based paints are much more durable than emulsion and are
suitable for both interior and exterior use. These paints come in a
wide range of colours which are usually a gloss finish. The brush
must be cleaned in white spirit.
Polyurethane paints are very durable and hardwearing. They are
ideal for exterior use and are available in a wide range of colours.
The brush must be cleaned in white spirit.
Contents
Metals and their Properties
Metal
Composition
Properties
Forms
Uses
Copper
Pure Metal
Conducts heat and electricity.
Can be bent easily.
Sheet
Bar
Tube
Plumbing
Wire Core
Brass
Alloy of Copper and
Zinc
Stronger than copper.
Casts well.
Sheet
Bar
Woodscrews,
castings, valves
and propellers.
Tool Steel
Iron and Carbon
Very hard and brittle but can
be hardened and
tempered.
Bar
Screwdrivers,
scribers, centre
punches, saw
blades.
Easily bent. Will rust if the tin
surface is broken.
Sheet
Tin cans and light
sheet
metalwork.
Engine blocks, vice
bodies,
blacksmith’s
anvil.
Tin Plate
Sheet Steel with a
coating of tin on
both sides
Cast Iron
Iron with 3.5% carbon.
Hard wearing and brittle.
Castings
Black Bar
Almost pure iron
Can be forged easily.
Can be easily bent without
fracture.
Bar
Aluminium
Pure Metal
Light and strong and can be
easily bent.
Does not corrode after initial
corrosion has made a
protective coating.
Bar
Tube
Sheet
Gates, stands and
other decorative
work.
Window frame and
greenhouse
frames.
Contents
Metals and their Properties
Aluminium is a very important metal. It comes from the
ore called Bauxite. The Bauxite is heated in an electric
furnace. The metal produced is very pure
Pure aluminium is soft and easy to work. It can be made
stronger and harder by mixing other metals with it. (This
is called and alloy).
Aluminium is lightweight, easy to recycle and it is a good
conductor of heat and electricity.
It is a non-ferrous metal. (It contains no iron). It does not
rust as iron does. Instead a skin of oxide forms on the
surface so it looks dull. The skin prevents further
oxidation.
Contents
Metalworking Hand Tools
Tool
Name
Uses
Scriber
For marking out lines on metal.
Engineers
Square
For testing internal and external
right angles.
For marking out lines at right
angles to an edge.
Centre Punch
For punching a small indent to
locate twist drills and spring
divider points.
Straight Edge
For marking straight lines or
checking straightness.
Spring Dividers
Ball-pein
hammer
Or
Engineers
hammer
Marking out tool used to scribe
circles and arcs on metal and
wood.
Metalwork hammer. Small sizes
are used for centre punching,
riveting, bending and large sizes
are used for forging.
Contents
Metalworking Hand Tools
Tool
Name
Uses
Rawhide mallet
A soft mallet used to shape
sheet metal without damaging
the surface.
Hacksaw
The hacksaw is used to cut
metal bars, plates and tubes.
There are a variety of blades
available for different types of
work.
The junior hacksaw is smaller
and designed to cut thin
material and for lighter work.
Junior hacksaw
Odd leg
callipers
Or
Jenny callipers
This marking out tool is used to
scribe lines parallel to an edge.
Inside
And
Outside
callipers
These are used to measure the
inside and outside diameters of
objects. The size is then read
from the edge of a steel rule.
Contents
Metalworking Hand Tools
Tool
Name
Flat File
Uses
General filing of straight edges
on plastic and metal.
Half round file
General filing of straight edges
and curves on plastic and metal.
Tin snips –
straight and
curved
For cutting thin sheet metal. The
curved cutters are for cutting
radius cuts.
Vice – engineer
and hand
Engineers vice used to grip
large sections of bar and tube
when drilling.
The hand vice should be used
to grip thin sheet metal when
drilling.
Contents
Permanent Methods of Joining Metals
WELDING – Steel parts can be
joined together by using an electric
current to melt a steel rod onto the
joint. There is a danger of flashes to
the eyes. A weld is very strong but
not very neat.
Example: Metal chairs and benches.
BRAZING – This is very similar to welding, except that a
brass rod is used and a hot flame is used to heat up the
metal. A brazed joint is not as strong as a weld, but it is
neater.
Example:
Bicycle frames.
Contents
Permanent Methods of Joining Metals
RIVETING – A rivet is a sort of metal rod with a head. It can be
hammered into shape.
Example:
Pot lids and handles.
Flat head rivet
for thin metal.
Snap head rivet
for strength.
Countersunk head
Rivet for a flat joint
POP RIVETING – hollow rivets are
put in with a ‘gun’. Used for joining
thin metal. The work can be done
from one side.
Example:
Ventilation Ducts.
Contents
Permanent Methods of Joining Metals
SPOT WELDING – For joining thin sheets. The spot
welder melts the metal at a single ‘spot’. It works by
passing an electric current through the metal at the
spot. The spot gets so hot that it melts the plates
together.
Example:
Car bodies
Contents
Metal Finishes
As with timber, the finish of metal is very important.
Before applying any finish to metal the surface must be
carefully prepared. If the article is to be painted the
surface of the metal should be prepared in the
following way.
1.
2.
3.
Prepare the metal by making sure that all major
blemishes are removed. This should be first with a file
and then with emery cloth.
Any major imperfections can be repaired with plastic
car body filler.
Once the surface has been thoroughly prepared and
sanded down it should be wiped clean with a cloth
dipped in white spirit to remove all traces of oil and
grease.
Contents
Metal Finishes
4. The metal should now be painted with a
suitable primer – in the care of ferrous metals
a rust preventative primer.
5. When the primer is dry it should be lightly
rubbed down with fine grade wet or dry paper
and then cleaned with a cloth in preparation for
the topcoat.
6. If the finish achieved in 5 is acceptable then
the topcoat should be applied. If not, the
stages 4 and 5 should be repeated.
Contents
Metal Finishes
The above procedures apples to a variety of
different paint materials.
1. Oil based paints – cover well and are ideal for
both indoor and outdoor use.
2. Emulsion paints – are available in a wide
variety of colours. They are not very durable
and are best suited to indoor use.
3. Cellulose paints - are available in a wide
variety of colours. These paints, available in
spray cans, are used to paint car bodies.
Contents
Metal Finishes
DIP COATING – gives protection to metals by coating with a
coloured plastic. The work should first be cleaned and then
heated. When hot, the metal is then dipped into the nylon or
acrylic powder, which is contained in a fluidiser. A fluidiser tank
contains the plastic powder which has compressed air blown in at
the base. This renders the powder ‘fluid’ and
ensures even coating of the hot metal.
Fluidiser
The coated article is then removed from the tank and allowed to
cool. The hot metal first melts the plastic powder attached to its
surface and as it cools the plastic hardens leaving a thin coating
of plastic on the metal surface. The metal can be heated using an
oven at approximately 150oC
Contents
Data on Plastics
Compared with wood and
metal, plastics are very new
materials. They have only
been manufactured during the
last 40 years or so.
There are many kinds of
plastic and we use them for
many different jobs. This is
because they can be made to
behave in almost any way that
is needed.
You have probably come
across plastics that are hard,
soft, brittle, flexible,
transparent, coloured and so
on. The list is almost endless.
Contents
Data on Plastics
Most plastics are made from oil; a natural material which will run out
quite soon if we do not use it sensibly. Disposing of waste plastic
without causing pollution can also be a problem, so perhaps we
should now stop thinking of plastic as such a disposable material.
There are two main types of plastic:
THERMOSETTING PLASTICS – are generally strong and resistant
to heat. Once formed into a shape they cannot be re-shaped. These
plastics are used in situations where resistance to heat is important.
Although they are quite hard, they can be chipped or cracked if they
are dropped or banged.
THERMOPLASTICS – when thermoplastics are heated, they
become soft and can be moulded into shapes. When cooled, they
keep their shape. If these plastics are heated again they become
soft and can be re-moulded into other shapes. This process can be
repeated over and over again as long as the plastic has not been
stretched too far.
Contents
Plastics and their Properties
Thermosetting
Properties
Forms
Uses
Hard, heat
resistant
Hard, heat
resistant
Hard, heat
resistant &
brittle
Powder,
granules
Liquid, paste
Liquid, paste
Electrical
appliances,
saucepan
handles
Bonding, gluing
GRP boats, car
bodies,
embedding.
Phenolic Resin
Epoxy Resin
Polyester Resin
Contents
Plastics and their Properties
Thermoplastics
Properties
Stiff, hard, clear.
Easily cut,
glued &
polished.
Scratches
easily
Stiff, hard, wide
range of
colours. OR
Very light &
buoyant.
Hard, tough.
Good bearing
surface. Wear &
friction resistant.
Good colour
range. Stiff, hard.
OR
Soft &
flexible.
Forms
Rod, tube &
sheet in a wide
range of colours
Powders,
granules &
sheet. OR
Slabs & beads.
White powder,
granules &
chips. Rod, tube
& sheet.
Powders, pastes
& sheets.
Car light units,
shop signs,
watch lenses
Model kits,
disposable
cups.
OR
Insulation &
floats.
Gear wheels,
bearings,
clothing &
combs.
Pipes & guttering.
OR
Dip
coating, floor tiles.
Acrylic
Polystyrene
Nylon
PVC
Uses
Contents
Shaping and Forming Plastics
Plastics such as acrylic can be easily cut, shaped, drilled and
formed. These processes in general will use equipment that is also
used for metal and/or wood. The main difference with plastic is that
it need to be treated very carefully as it can be scratched, chipped or
broken easily. Materials such as acrylic come with a protective
coating of paper or film, this should be left on to protect the material
while it is being worked.
CUTTING AND SHAPING ACRYLIC – before cutting the material
should be carefully marked out with a felt tipped pen. Once marked
out the acrylic should be cut with either a junior hacksaw or a coping
saw. The material should be cut near to the line but not on it and
then the plastic can be filed up to the line.
DRILLING ACRYLIC – acrylic and be drilled with ordinary twist drills,
hole saws and flat bits. However, as the acrylic is quite brittle it
should be drilled with great care. The cutter should be brought down
on the plastic very slowly.
Contents
Shaping and Forming Plastics
1.
2.
FORMING ACRYLIC – there are two main methods of forming
acrylic used in schools. These are:
Strip heater – bending
Press forming
THE STRIP HEATER – is designed to heat a narrow strip across
a sheet of plastic so that it can be bent. The heater has a single
element enclosed in a box which has a slot above the element.
The plastic sheet should be heated on both sides to ensure even
heating. To make bends at particular angles the sheet can be
bent against a protractor and the correct angle maintained while
the plastic cools.
Contents
Shaping and Forming Plastics
HEATING PLASTIC IN AN OVEN – when a large radius curve or
double bend is required it is best to heat the whole sheet in an
oven and then form the sheet around a suitable former. Even
heating of the sheet is important. Bending should not be
attempted until the whole sheet is heated right through and is
completely flexible.
Heating times are: 3mm acrylic heated to 160oC for 20 minutes.
6mm acrylic heated to 160oC for 30 minutes.
Contents
Shaping and Forming Plastics
PRESS FORMER – If you require to make a simple shaped object
then the best process to use is press forming. Press forming uses
a two-part mould, the female former and the male former. The
male former will consist of a ‘replica’ of the shape to be formed –
the surface finish of this former must be good if a good quality
shape is required. The female former consists of a ring, which fits
around the perimeter of the male former (allowing for a gap equal
to the thickness of the plastic all around).
Contents
Technological Studies – Systems
In order to use the system we do not
need to know how it works, but simply
what it does. The Scot-rail Transport
System is a complicated railway system
consisting of many railway stations
connected together by railway track.
The human body is made up of systems, the
circulation system, the nervous system and
the respiratory system.
Input
Process
Contents
Output
Technological Studies – Systems
A System, then, is something complicated, made up from lots of
parts, but which we think of as a single thing. We may not know how
it works but we know how to use it.
Lets look at another system, the ‘Coca-Cola’ drinks machine in the
school canteen. This is a system for converting money into drinks.
We do not know how it works, but we all know what it does and how
to use it.
We put money IN and the machine gives OUT a drink
Money
Coke
Machine
Can of Coke
An electric kettle may also be described as a system. We put IN
cold water, switch IN electricity and later pour OUT hot water.
Cold Water
Electricity
Kettle
Hot Water
Input
Process
Contents
Output
Technological Studies – Systems
A washing machine is another system.
We put IN dirty clothes, soap powder, water
and electricity, and we get OUT clean clothes
and dirty water.
Electricity
Dirty Clothes
Soap Powder
Clean Water
Washing
Machine
Clean Clothes
Dirty Water
Input
Process
Contents
Output
Technological Studies – Systems
On the diagrams we have shown a box with arrows
attached at the sides. Some of the arrows are entering
the box and some are leaving the box.
The arrows entering the box represent INPUTS to the
system.
The arrows leaving the box represent OUTPUTS from
the system.
The box represents the PROCESS (or change) that
takes place in the system.
Thus a system is made up of INPUTS, PROCESS and
OUTPUTS.
Input
Process
Output
Input
Process
Contents
Output
Sub-Systems
Some systems are made up from other smaller
systems called SUB-SYSTEMS.
Lets take another look at the ‘Coca-Cola’ machine. This
machine (or system) is made up of the following
sub-systems: the money counting sub-system
the can selecting sub-system
the can dispensing sub-system
System
Boundary
Money
Money
Counter
Can
Correct
Amount Selector
Can
Can
Dispenser
Selected
Can
Input
Process
Contents
Output
Sub-Systems
The money counting sub-system counts the
value of the coins as they are put into the
machine. When the correct amount has been
entered, a signal is sent to activate the can
selection sub-system. Once a button is
pressed to select the required drink, a signal is
sent to the can dispensing sub-system and a
can drops down. The machine is then reset to
await more money.
No matter how complicated the system might
be, block diagrams can represent it.
Input
Process
Contents
Output
Graphic Communication
A busy street is full of signs and signals, which give information to passers by.
For example, a shop sign tells shoppers what goods are for sale inside a
building; road signs tell drivers what lies ahead as they drive; traffic lights give
instructions to pedestrians and drivers to prevent accidents and create an
even traffic flow.
This giving of information is called communication.
A collection of objects or connected parts can be grouped
together to form a system. There are many different kinds
of systems. The solar system consists of the Sun and
the planets, which revolve around it. The railway system
in Scotland includes all the track, stations, engines, and
carriages, which are run by Rail Track. The telephone
system conveys sound between connected houses by
electrical pulses. The transmission system of a car
passes power from the engine to the axle, which turns
the wheels.
Contents
Graphic Communication
All types of communication use a code or language to represent
information in a convenient form.
This may be made up of shapes, sounds, hand-signals, lights, and
other signs. Together, these symbols or tokens can form a code.
For example, C-A-T are letter symbols
strung together in a particular order to
convey the idea of an animal.
Would this drawing not do as well?
To communicate effectively, only information which is necessary
should be included: the message may be lost if too much information
is given.
Contents
Graphic Symbols and Signs
Graphic Symbols and Signs are used to form visual
languages for all to understand. Wherever groups of
people with different speaking and written languages
meet communication can be assisted with symbols.
Chemist
Musician
Tourist
It is important that the message is clear and is easily
interpreted. Many of the symbol signs that you will see
are without text. There are some that are text only and
these are generally used in conjunction with the symbol
signs.
Contents
Symbols
Warning Signs
(Caution)
Risk of danger
Prohibition Signs
(Prohibit)
Do Not Do
Yellow triangle /Black Border
Yellow most easily seen even
in poor light.
Black provides a striking
contrast.
Green Square/
Rectangle
Green is associated
with safety
Safe Condition Signs
The Safe Way
White Circle/ Red Border/
Red Cross Bar
Red is associated with
danger.
Red Square/
Rectangle
Red is associated
with fire.
Fire Fighting Signs
Blue Circle
Easily seen
Good contrast with white.
Mandatory Signs
(Protection)
Must Do
Contents
Charts and Graphs
There are many different types of graphs that are used. Each type of graph
is used to show different information.
Line Graphs - are used to show the
variations between two quantities,
such as time/distance, current/voltage
Bar Charts - are a simple way of
comparing information.
Pie Charts - are a useful way of showing numerical information in the form
of a picture.
Contents
Free Hand Sketching
There are an number of way that an object can be drawn in order
to allow the shape and form of the object to be understood by
someone who is looking at the drawing.
You may know of some already. The methods that we are going
to look at are ISOMETRIC and OBLIQUE.
For this you will need:
1. A pencil
2. A blank piece of paper
3. An eraser
When you are free hand sketching you NEVER use a rule to draw
your lines. Each line that you draw should be as light a possible
at first and then they can be darkened in if there are no mistakes.
Contents
Practice
Practice by first of all sketching some lines. Begin
sketching some horizontal lines and then some vertical
lines or if you prefer diagonal lines.
If you find that horizontal lines are easier then turn your
paper until you are comfortable.
If you find that vertical lines are easier then turn your paper
until you are comfortable.
If you find that diagonal lines are easier then turn your
paper until you are comfortable.
You should continue to practice these lines at home.
Contents
Sketching Oblique Cubes
1. Start off with a square
made up of 4 straight
lines.
2. Sketch three parallel
lines from the corners at
approximately a 45°
angle.
3. Now join up the lines as
shown.
4. Darken in the outside
lines only, as shown.
Contents
Sketching Isometric Cubes
1.
Start of with a vertical line. Then
draw 2 pairs of parallel line that
are at approximately a 30° angle,
as shown.
2. Now join up the lines as
shown above.
3. Darken in the outside lines only, as shown below.
Contents
Sketching Circles
1. Sketch a square.
2. Sketch in a vertical line, a
horizontal line and two diagonal
lines from corner to corner as
shown.
3. Select the points as shown by
splitting the diagonals into three
equal parts.
4. Sketch the circle as shown.
Contents
Sketching an Ellipse
Sketching an ellipse is very similar to sketching a circle.
Instead of sketching a square you should sketch a
rectangle and then select the points in the exact same
way as for a circle.
Contents
Measurement
In both Graphic Communication and in Craft and Design
it is very important to be able to measure and mark out
accurately.
In both these subjects all your measuring and marking
out will always be in millimetres (mm). e.g. 1 cm = 10
mm, 50 cm = 500 mm etc.
In Graphic Communication you will use a variety of
measuring instruments that have to be handled
carefully, rule with chips out of them do not measure
accurately, compasses with damaged points cannot
draw accurate circles.
Contents
Scale Drawing
Scale drawing is used when something large, e.g. a building or some thing
small, e.g. a microchip, has to be drawn on to a sheet of paper.
Some people who use scales are:
Architects designing buildings
Geographers drawing maps
Electronic engineers designing printed circuit boards
Reading scale drawings and making scale drawings is usually done in one
of three ways or as a combination of these three ways.
1. Using the written scale as a multiplier for each scale size.
e.g. Measured or scale length = 32 mm
Scale is 1:10
Actual or real length = 32 x 10 = 320 mm
2. By measuring a distance on a drawing using a pair of compasses and
comparing the distance lifted to a scale printed for that purpose.
3. By using or making a scale rule to suit the drawing
Note It is not difficult to decide which method to use, in fact the decision
is likely to be made for you by the problem involved.
Contents
Orthographic Drawing
3 rd Angle Projection
PLAN
Ortho comes from a Greek word meaning
‘straight’, ‘right’, or ‘square’.
Graphic comes from a Greek word meaning ‘to
draw’.
So orthographic means ‘to draw by projecting
straight and parallel lines’.
END ELEVATION
ELEVATION
Orthographic drawing is a drawing technique commonly used in industrial
areas as a method of communicating detailed information. The type of
orthographic drawing that you will be using is called 3 rd angle projection and
the views observed from the positions shown above would be presented in the
way shown below.
PLAN
ELEVATION
END ELEVATION
Contents
Lines and symbols
Full Line
Continuous thick line
used to indicate the OUTLINE of
objects
Faint Line
used in the CONSTRUCTION of
objects
Broken Line
used to indicate HIDDEN edges
Chain Line
used to indicate lines of SYMMETRY in
objects
Continuous thin line
Short dashes, thin line
Chain, thin line
Contents
Perspective Drawing
Perspective drawing allows us to draw 3D shapes quickly. A perspective
drawing shows an object in way that resembles the actual appearance
of an object.
When we look at objects we see that:
1. Parallel lines appear to converge. i.e. come closer together until they
disappear to a vanishing point.
2. Equal sizes appear smaller the further they are away. This is known as
foreshortening.
3. Objects of similar size appear to get smaller as they recede from us.
If you look at the drawing of the railway track
you will be able to see this.
The parallel lines converge to a vanishing
point. The equal length sleepers foreshorten
as they recede. (Go into the distance)
HORIZON LINE
Contents
One-point Perspective
To draw a simple box shape in one point perspective:
1. Draw a flat view of one side of the object in light construction lines.
Step 1 – Flat view
2. Draw the horizon line, which represents your eye level as you look at the
object. If you want to see the top of the object then the horizon line is drawn
above the flat view. If you want to see the bottom of the object then the
horizon line should be below the flat view. If you want to show the object
viewed straight on then the horizon line should run through the flat view.
Step 2 – Insert horizon
line and vanishing point
Mark the vanishing point on the horizon line. The position of this point will
determine the side of the view that you will see.
Contents
One-point Perspective
3. Draw feint lines from each corner of the flat view to the vanishing point.
Step 3 – Lines to
the vanishing point
4. Complete the shape by drawing the back of the shape.
Step 4 – Draw in
the back.
Contents
Two-point Perspective
This method is a little more complicated than one point perspective but will give
you a much more realistic view of an object. The horizontal lines of the object
will recede in two directions and converge on two different vanishing points.
The diagrams below show the six simple stages of making a two-point
perspective drawing.
Step 1. Draw the horizontal
line.
Step 2. Mark on the vanishing
points.
Step 3. Draw the corner of
the box that will be closest
to you.
Contents
Two-point Perspective
Step 5. Estimate the
length of the side and the
end of the box and draw
them in.
Step 4. Draw in the
lines to both of the
vanishing points.
Step 6. Connect the corners
of the box to the vanishing
point and draw in the outline.
Contents
Isometric Projection
Height
For this example you will be shown how to construct an isometric crate
ready to hold a more complex form. Always draw the basic crate lightly
first as this will save you time later.
Step 1. front and base edges
Step 1 - front and base edges
a) Make sure you have only the
30°/60° set-square available.
b) Mark the bottom position of the
drawing.
c) Project a vertical line and mark
the height of the crate onto it.
d) Project a line, at an angle of 30°
to the left, and measure the depth
of the crate.
e) Project a line, at an angle of 30°
to the right, and measure the
length of the crate.
Contents
Isometric Projection
Step 2 - front and side surfaces
Step 3 - top surface
Step 2 - front and side surfaces
a) Project a vertical line from the length
marker and a line at 30°, parallel to the
base, from the height marker.
This provides you the front surface.
b) Project a vertical line from the depth
marker and a 30° line, parallel to the base,
from the height marker.
This provides you the side surface.
Step 3 - top surface
a) From the top left hand comer project a 30°
line up to right.
b) From the top right hand comer project a
30° line up to left until it crosses the one
above completing the isometric crate.
Contents
Oblique Projection
For this example you will be shown how to construct an oblique crate ready to
hold a more complex form. Always draw the basic crate lightly first as this will
save you time later.
Height
Length
Step 1 - front surface
Step 2 - side and top surfaces
Step 1 - front surface
a) Draw a construction rectangle with the same
length and height to the crate required.
This will be the front surface of your crate.
Step 2 - side and top surfaces
a) From the bottom right and both the top
corners of the rectangle project lines at an
angle of 45° to the right.
b) Find the depth of the required crate and half
this size. You should always halve sizes
being projected along the 45° lines.
c) Mark this size along one of the 45° lines.
d) Construct the rest of the crate using lines
parallel to those already on the page.
Contents
The Colour Wheel
N
EE W
R
G LL O
YE
YELLOW
YE
O R LL O
AN W
GE
N
GR
BLUE
RED
ORANGE
GR
GE
EE
GE
AN
BLUE
GREEN
AN
EE
N
OR
OR
YELLOW
RED
UE
RE
D
BL
VIOLET
VI O
B L LE T
UE
D
R E LE T
VIO
Blue, Yellow and Red are
called primary colours and
cannot be made by mixing
other colours.
Green, Violet and Orange are
called secondary colours
and can be made by mixing
two of the primary colours.
Blue-green, Blue-violet, Redviolet, Red-orange, Yelloworange and Yellow green are
called tertiary colours and
are made from a mixture of
one primary colour and one
secondary colour.
VIOLET
Contents
Colour Theory
There is no right or wrong in selecting a colour. Colour is only unsuitable if used
inappropriately or in inharmonious combinations.
The choice of colour combinations is highly personal but you should be able to
give a reason for your choice of colour selection using the guidelines below.
Red
Yellow
Blue
Orange
Green
Great power of attraction but too much can be tiring.
Hot, bold, exciting, festive, positive.
Can be associated with rage, aggression, danger, courage,
speed.
Most easily seen, luminous.
Bright, pleasant, happy, sunny, lively, cheerful.
Associated with sunshine and holidays.
More formal than red or yellow.
Cool, sophisticate, aristocratic, serene, passive, elegant,
reliable.
Not used in food, as it is associated with mould.
Sunny, cheerful, warm, happy.
Associate with flavour and energy.
Most restful of the colours.
Fresh, youthful, soothing, natural, informal.
Associated with safety, health and the environment.
Contents
Colour Theory
Purple
Combines the courage of red and the nobility of blue.
Rich, pompous, impressive, regal.
Violet
Cool, negative, retiring, subdued, solemn.
Associated with peacefulness and solitude.
Grey
Neutral, sedate, dignified, inconspicuous.
Associated with old age.
White
Luminous, positive, light, delicate, clean.
Associated with innocence and purity.
Black
Subdued, solemn, profound.
Associated with sorrow, and evil.
Brown
Safe, reliable, natural.
Associated with earth, therefore good.
Yellow/Green
Unpleasant. Associated with sickness.
Contents
Shading and Rendering
Pencil shading can be used to improve the impact of a drawing. If this shading is to look
realistic, the effect of light must be taken into account.
When the light falls on an object, surfaces reflect different amounts of light depending on their
position in relation to the light source. Look at the picture shown below. It shows that when
solid forms are illuminated the side that faces towards the light looks lighter than the face that
faces away from the light. With the cylinder, the part directly facing the light source is the
lightest.
When shading, use a soft lead pencil to give a wide range of tones from light grey to dense
black. It will be difficult to obtain dark enough shading with any grade of pencil harder than
HB. The most suitable grades are 2B, B and HB.
The areas to be shaded can be covered quickly and evenly if the pencil is held, as shown in
the picture below, so that it is nearly horizontal. In this position more lead is in contact with
the paper.
Contents
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