Contents
Section 1
Product Design............................................. 6
1·1 Getting started........................................................8
1·2 Design ideas and techniques.......................... 20
1·3 Making..................................................................... 36
1·4 Evaluation............................................................... 48
1·5 Health and safety................................................. 55
1·6 Use of technology............................................... 63
1·7 Design and Technology in society................. 72
1·8 Product design application.............................. 78
1·9 Environment and sustainability...................101
Section 2
Graphic Products..................................... 108
2·1 Formal drawing techniques...........................110
2·2 Sectional views, exploded drawings and
assembly drawings...........................................115
2·3 Freehand drawing.............................................120
2·4 Drawing basic shapes......................................122
2·5 Developments....................................................127
2·6 Enlarging and reducing...................................130
2·7 Instruments and drafting aids......................134
2·8 Layout and planning........................................136
2·9 Presentation........................................................139
2·10 Data graphics...................................................144
2·11 Reprographics..................................................148
2·12 Materials and modelling..............................150
2·13 ICT.........................................................................156
2·14 Manufacture of graphic products.............159
Section 3
Resistant Materials.................................. 164
Section 4
Systems and Control.............................. 228
4·1 Systems.................................................................230
4·2 Structures.............................................................233
4·2·1 Basic concepts.........................................233
4·2·2 Types of frame structure members....237
4·2·3 Strengthening frame structures.......240
4·2·4 Nature of structural members...........242
4·2·5 Applied loads and reactions..............245
4·2·6 Moments...................................................248
4·2·7 Materials....................................................251
4·2·8 Testing........................................................253
4·2·9 Joints in structures................................255
4·2·10 Forces.......................................................258
4·3 Mechanisms.........................................................265
4·3·1 Basic concepts.........................................265
4·3·2 Conversion of motion...........................273
4·3·3 Transmission of motion.......................281
4·3·4 Energy........................................................292
4·3·5 Bearings and lubrication.....................295
4·4 Electronics............................................................299
4·4·1 Basic concepts.........................................299
4·4·2 Circuit building techniques................305
4·4·3 Switches....................................................311
4·4·4 Resistors....................................................316
4·4·5 Transistors.................................................320
4·4·6 Diodes........................................................323
4·4·7 Transducers..............................................326
4·4·8 Capacitors.................................................328
4·4·9 Time delay circuits.................................330
4·4·10 L ogic gates and operational
amplifiers................................................335
Section 5
The Project................................................ 344
Glossary........................................................................359
Index..............................................................................366
Acknowledgements.................................................373
3
3·1 Types of materials..............................................166
3·2 Smart and modern materials........................170
3·3 Plastics...................................................................173
3·4 Wood......................................................................177
3·5 Composites .........................................................184
3·6 Metals....................................................................188
3·7 Preparation of materials .................................195
3·8 Setting and marking out.................................199
3·9 Shaping.................................................................204
3·10 Joining and assembly....................................210
3·11 Finishes...............................................................222
Contents
Introduction.....................................................................4
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This section will help you to develop a broad understanding of the
materials, techniques, tools, equipment, methods and processes used
with resistant materials. Specifically, it aims to support you as you
develop your understanding of both the physical and working properties
of a range of woods, metals and plastics.
This section is designed to help you to relate your understanding
directly to the processes associated with designing and making, so that
you are able to apply relevant skills, knowledge and understanding
effectively. This is so that following analysis, based on evidence, you
can make sound judgements and decisions in relation to material and
process choices, in order to plan and carry out work safely and
effectively.
You will develop your awareness of the different types of material,
including smart and modern materials, and their associated physical
working properties. You will learn key terms and understand the
processes involved to accurately set and mark out material. You will also
learn the correct techniques and be aware of the manufacturing
processes involved in shaping, joining and finishing different materials.
startIng poInts
• What materials are available?
• What are composite materials?
• How do you decide which type
of material is best to use?
• Which tools and equipment are
available to cut, shape and join
different types of material?
• Which tools and equipment do
you use to mark and set out
material?
• How do you decide which tools
and equipment to use to cut and
shape material?
• How do you decide which is the
best type of finish to use?
• What is PPE equipment and
why is it important to know how
to use it?
seCtIon Contents
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
Types of materials
Smart and modern materials
Plastics
Wood
Composites
Metals
Preparation of materials
Setting and marking out
Shaping
Joining and assembly
Finishes
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3
Resistant
Materials
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3·1 Types of materials
LEARNING OBJECTIVES
By the end of this section you should:
✓✓understand the common physical and working properties of materials
✓✓understand the common factors that should be considered when selecting materials
that are fit for purpose.
Why do I need to know about the properties of
materials?
Designers, technologists and engineers need to know the properties of
materials to inform their selection of suitable materials in order to meet
the requirements of a product design specification. Two key concepts
are critical in relation to your knowledge of materials:
• how materials are classified, so that you have knowledge of a broad
range of materials to choose from when designing, and are not
restricted to the materials that you have used
• what the properties of materials are, how they add functionality or
make a product aesthetically pleasing, and how they can be worked.
Categories of materials
A basic understanding of categories or types of materials can help you
classify and select the materials most appropriate for your design
needs. This can help you to take a methodical approach to materials
and help when interacting with materials databases. The most common
materials are woods, metals and plastics, and composites. The terms
smart or modern materials are often used to describe manufactured
materials with particular properties, which often react to environmental
conditions. These are described in detail in unit 3.2. It is also worth
noting that textiles are a classification of materials and, while these
might be labelled as ‘compliant’ rather than ‘resistant’ materials, some
materials can be produced in both a textiles (or fabric) and a solid
form, such as the polymer nylon which may be used for garments and
engineered mechanical components.
Woods
Natural
Manufactured
Metals
Ferrous
Plastics
Non-ferrous
Composites
Thermoforming
Smart and
Modern
Thermosetting
∆∆A classification table of materials
166
Resistant Materials
Materials
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167
Working properties
Each working property has a technical definition describing how a
material behaves when being worked or shaped (see unit 3.9). The
most common working properties are:
• strength: the ability to withstand a constant external force without
failing
• hardness: the ability to resist wear-and-tear, scratching and dents;
usually related to surfaces
• toughness: the ability to withstand blows or momentary shocks (live
forces)
• durability: the ability to resist wear, such as weathering, over time
• elasticity: the ability to bend and then to return to its original shape/
size
• plasticity: the ability to permanently change shape or form, which
applies to materials other than polymers
• malleability: the ability to permanently change shape, in all
directions, while retaining integrity
• ductility: the ability to change shape by stretching along its length
without snapping.
3·1 Types of materials
Physical Properties
Physical properties are a major factor when selecting materials for
specific users, purposes and conditions. Each physical property
describes how a material behaves under specific conditions. Common
physical properties are:
• mechanical: how a material will react to physical forces, such as
how some materials become brittle when repeatedly bent or flexed
• electrical: a material’s conductive properties including insulation and
resistance, such as how a screwdriver’s polymer handle (insulator)
protects the user from electic shocks through the tip (conductor)
• chemical: how a material reacts to other chemicals, such as how
metals oxidise when exposed (for example, ferrous metals rusting)
• thermal: how a material responds at different temperatures, such as
freezing/melting and boiling points, such as the temperature ranges
where thermoforming plastics can be shaped
• magnetic: most ferrous (containing iron) materials are attracted to
magnets or can be magnetised, such as the use of magnetic catches
for keeping doors closed
• permeability: the degree to which liquids or gases can pass through
a material, such as woods that have been varnished having low
permeability to liquids and water resistance
• aesthetic: the visual sensory properties of the surface/form of a
material, such as colour and shine
• tactile: the touch or sensory properties of a material, such as texture.
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Selecting materials
When selecting appropriate materials for a product it is important to
get the design specification right. It is essential to identify the
requirements for the user, function or conditions that a product will be
exposed to. Once a specification has been drafted, the required
physical and working properties can be identified and used to search a
materials database or table. For example, a specification for a garden
chair might state that the product must be durable for use outdoors in
all seasons, with minimum maintenance.
TOP tip
A common mistake is to rely only on materials that you know and have used before.
Understanding how materials are classified, what their properties are, and how to select
them will lead to more functional and appealing products. When making a prototype
(working model/product to test a concept) you might use the materials that are most
readily available. However, when writing a manufacturing specification for production,
alternative materials should be selected to optimise the efficiency of a commercially
viable product, in relation to the cost of manufacture, marketability or functionality.
SKILLS ACTIVITY
Choose a product that you use often and sketch or photograph it. List
the materials that you can see. If you are unsure what materials have
been used, look in units 3.3 to 3.7 of this book, or go online and
investigate the product. Manufacturers’ websites often list the materials
used. Now select one of the materials that you have identified and list
the properties for which it was selected. Give reasons why you think
this was the case, including functional, aesthetic, financial and
manufacturing factors.
Modern mobile phones and devices are designed around touch screens.
Currently most of these devices use special screens that sense electronic
charge. Therefore, the glass used needs to have specific properties that enable input
from your finger to be picked up by the sensors built into the screen, alongside the
visual display. In addition to this the material used needs to be highly transparent,
avoid glare and be tough enough to resist normal day-to-day use. The glass used in
these devices is designed by material scientists to have particular properties and
differs from that used, for example, in windows or spectacles. This is a good example
of how important it is that designers, technologists and engineers have a sound
knowledge of the properties of materials, so that they can select the most appropriate
materials to meet the functional, aesthetic, financial and manufacturing requirements
of a product.
168
Resistant Materials
DESIGN
IN
ACTION
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KNOWLEDGE CHECK
Design a folding worksurface that could be used by a teenager when doing homework.
1. Communicate your idea using an annotated sketch.
(4)
2. Identify all materials used in your design and list the specific physical and working
properties which make them suitable.
(6)
Reflective
Log
Think of a product that you have made recently. Write a brief evaluation
of the product, focusing on the properties of materials, using these
prompt questions:
• What materials did you use?
• Why did you use these materials?
• Would alternative materials be more appropriate if you were to batch or mass manufacture
the product? Why do you think this? Make reference to properties of materials.
Key
Terms
force: a power that produces strain on a material and that changes its shape, or has the
potential to change its shape. There are five forces that act on materials:
compression, tension, torsion, sheer and bending.
physical property: an observable or measurable characteristic of a material, for instance strength or
density
prototype: a working model, in the early stages of development, which, through testing against the
specification, is used to help refine the product before beginning final or larger scale
production
stiffness: resistance to forces of bending or torsion
stress or strain: a force created by pressure on an object or material, that has the potential to
damage it by changing its shape
working property: the way a material behaves when being worked or shaped or while being used
169
3·1 Types of materials
within a product. Working properties determine the tools or processes that will
be used when making or manufacturing and how a product will function.
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3·2 Smart and modern materials
LEARNING OBJECTIVES
By the end of this section you should:
✓✓be aware of a range of ‘smart and modern materials’, including thermochromic
materials; polymorph; shape memory alloy (SMA); shape memory polymer
✓✓understand the key properties of common ‘smart and modern materials’.
What are smart and modern materials?
‘Smart and modern materials’ is an umbrella term for a wide variety of
materials whose properties alter depending on environmental
conditions, such as light, temperature or movement. These materials
are designed and manufactured through scientific discoveries, where
materials are engineered or altered so that they perform a particular
function. They react independently, which is why they are known as
‘smart’, and some appear to have a ‘memory’: for example, deforming
and returning to their original shape/structure under certain conditions,
such as heat from an electrical current (shape memory alloys and the
effect of heat on shape memory polymers).
Modern materials also include those manufactured by making changes to
the structure at molecular level or using nanoparticles, such as the super
strong graphene or hydrophobic surfaces that repel water. Some smart and
modern materials are inspired by nature; this is called biomimicry.
Smart and modern materials have numerous
applications in health and medicine. A ‘stent’ is
a small mesh tube, made from a shape memory alloy,
which is inserted into damaged blood vessels to
strengthen or keep them from collapsing. The stent is
inserted cold and expands into the desired size with
the patient’s body heat.
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Resistant Materials
DESIGN
IN
ACTION
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Properties
Uses
Shape Memory
Alloy (SMA) or
nitinol
An alloy composed of nickel and
titanium, which will (a) when
deformed (bent), return to its
original shape when heated
beyond 90°C and (b) contract
when an electric current is
passed through it.
SMAs are used in stents, which
are tubes inserted into damaged
blood vessels. They are inserted
cold and expand to the correct
size in response to the patient’s
body temperature, strengthening
the blood vessel. SMAs are also
used in some spectacle frames or
in dentures.
Shape Memory
Polymer (SMP)
A variety of polymer (plastics),
which deform in response to an
external stimulus, such as when
an electric voltage is applied or
there is a change in temperature.
Potential uses for SMPs are
valves or pumps for liquids where
mechanical components are not
desirable.
Thermochromic
inks
Materials with these properties
change colour in response to
changes in temperature.
Commonly used in forehead
thermometer strips and in the
food industry to indicate the
temperature of a packaged food
product.
Photochromic
inks
Materials with these properties
change colour in response to
changes in light level, including
ultraviolet (UV) or infrared (IR).
Light reacting sunglasses or
spectacles, which darken in
response to UV light.
Lenticular
sheet
An embossed polymer sheet with
optical properties which make a
surface appear deeper. There are
different kinds of lenticular
patterns, which can be used to
make images appear to flicker or
move.
Can be used to provide visual/
aesthetic interest to a surface,
such as the illusion of depth, and
3D effects.
Polymorph
Polymorph is available in small
pellets which fuse when heated
to 62°C and can be moulded,
resulting in a tough polymer.
Can be used by designers and
engineers to prototype difficult
shapes, such as components, joints
and handles.
Smart grease
A viscous gel which will
uniformly control the movement
between two friction surfaces.
Can be used to dampen
movement on volume control
knobs, slowing down and
smoothing the rotation.
171
Name
3·2 Smart and modern materials
Examples of Smart and modern materials
There are many different materials that can be classed as being smart
or modern. Some common examples are shown in the table below.
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SKILLS ACTIVITY
Investigate different kinds of smart and modern materials and create a
table containing the following information.
• Find out more about the properties of some of these materials and
their potential uses and applications.
•Find and give details of a product on the market that utilises smart
materials.
KNOWLEDGE CHECK
1. Explain how a smart and modern material differs from a natural material. 2. Describe the properties of a smart and modern material and give
examples of how these could be used to add functionality to a product. Key
Terms
(2)
(4)
biomimicry: an approach to innovation and design that takes inspiration from how nature
solves problems. Materials developed using biomimicry include polymers
with adhesive properties inspired by a gecko’s feet and fabrics with
streamlining properties inspired by shark skin.
memory: the property by which a material returns to its original shape under specific environmental
conditions, such as ambient temperature or heat from an electrical current
nanoparticles: nanoparticles are between 1 and 1000 nanometers (10–9) m, and materials where the
structure has been engineered at the nanoscale can have unique properties. For
example, graphene (comprised of carbon sheets with the thickness of a single atom)
has over 200 times the strength of steel, gram for gram. Nanomaterials is the name
given to materials manufactured at the molecular level to provide specific properties.
polymer: a substance comprised of large molecules made up of simple molecules of the same kind.
172
Resistant Materials
Plastics such as acrylic and polythene are the most commonly recognised polymers, but
polymers exist in nature; for example silk, wool and cellulose.
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