Design technology

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Design Technology is an IB course focusing on design, materials, and manufacturing processes. It is one of the Group 4 sciences.

IB Design Technology is given elective subject offered in all IB schools globally. Design Technology is also offered in the IBMYP program as a compulsory subject for the first four years of the MYP (grades 6-9). DT, as it is commonly known, is very similar in content to Design Technology which is widely offered in the English, Australian, Canadian, New Zealand and many African Nation’s national curriculums.

Contents 1 The IB design and technology course of 2005 1.1 Topic 1: Designer and the Design Cycle 1.2 Topic 2: The Responsibility of the Designer 1.3 Topic 3: Materials 1.4 Topic 4: Manufacturing Processes and Techniques 1.5 Topic 5: Production Systems 1.6 Topic 6: Clean Technology and Green Design 1.7 Topic 7: Raw Material to Final Product 1.8 Topic 8: Microstructures and Macrostructures 1.9 Topic 9: Appropriate Technologies

[edit] The IB design and technology course of 2005

[edit] Topic 1: Designer and the Design Cycle

Introduction: Each element of the design cycle represents how designers progress through the design process with the design solution becoming progressively more refined. This topic focuses on the strategies designers employ to arrive at a solution to a problem and the varied nature of the skills needed to carry out their activities successfully.

The Design Process (1.1)

• Brief: starting point for the design of a new product. It is a statement of what the product is expected to do and is a statement of the design problem. It sets the; design goal, target market, major constraints, criteria by which a good design proposal may be achieved.
• Specification: a set of precise limits for the complete range of performance requirements for the design of a product. (PDS – product design specification)
• The designer’s role varies depending on the complexity of the process and the intended outcome
• Designers often work as members of a team. Priorities will vary depending on the nature of the activity
• Incremental Design: small changes to the design of a product. Eg. Pen with lid -> click pen
• Radical Design: a completely new product is devised by going back to the roots of a problem and thinking about a solution in a different way

The Design cycle Model; DCM (1.2)

• Simple Design Cycle
  • Identifying the Problem and the Brief
  • Researching and Specifications
  • Generating ideas
  • Developing the chosen solution
  • Planning and realising the chosen solution
  • Testing and evaluation the chosen solution.
• the cycle is always an ongoing process

Application of the DCM (1.3)

• three limitations of the simple design cycle
  • model suggests that one activity starts only after the previous activity has finished
  • does not allow integration of the different stages
  • does not imply that the DCM is an ongoing process (refer Fig 1)

Generating Ideas (1.4)

• Constructive Discontent: analysing a situation, which would benefit from re-design, and working out a strategy for improving it.
• Adaptation: an existing technology or solution to a problem in one field is used to provide a new idea for a solution in another.
• Analogy: drawing on a similar situation for solutions, eg. Ultrasonic focusing system for cameras was based on how bats navigate in the dark
• Brainstorming: generating random and divergent ideas to try to solve a problem.
• Divergent Thinking: being creative to produce a wide range of possible solutions.
• Convergent Thinking: ability to analyse information in order to select an answer from alternatives.

Design Communication (1.5)

• 2D and 3D drawing techniques are used for the purpose of achieving an alternative view to a product or design. Designers use a range of freehand drawings in the early stages of developing ideas to explore shape and form (3D) and constructional details (2D).
• Freehand drawing: spontaneous representation of ideas on paper without the use of technical aid. The importance of annotating freehand drawings is to explain the thinking behind the image.
• Orthographic Drawing: a series of flat views of an object showing it exactly as it is in shape and size. Are used in the final solution stage of the DCM and in the working drawings for the realisation stage.
• Exploded Isometric Drawing: an isometric drawing of an object with more than one component, which depicts how the parts of assemblies fit together.
• Perspective Drawing: 3D drawing which realistically represents an object, using such effects as foreshortening and vanishing points.
• Physical models are made from raw materials and can be handled. Mathematical models use symbols that can be manipulated numerically.
• Algorithm: a sequence of instruction to describe a set of actions. Correct sequencing is important with input, output and feed back. Remember the flow chart symbols.
• Computer-Aided Design (CAD): use of computers to aid design process. Adv / Disadv; skills required, storage, complexity, styles of drawings, time, cost, purpose of drawings,

[edit] Topic 2: The Responsibility of the Designer

Introduction: This topic focuses on the designer’s responsibilities to the consumer / user, the client or manufacturer and society, and how these responsibilities can sometimes cause conflict. It is imperative to understand the constraints and opportunities that exist for optimising the exploitation of resources and renewable energy sources. Be aware of the need to conserve non-renewable resources and to meet human, environmental and industrial requirements. Ethical, moral and legal issues must also be considered.

Ergonomics (2.1)

• Ergonomics: application of scientific information concerning the relationship of human beings to the design of objects, systems and environments.
• Anthropometrics: the aspect of ergonomics that deals with body measurements, particularly those of size, strength, and physical capacity.
• Percentile Range: the proportion of a population with a dimension at or less than a given value. I.e. 5th-95th percentile range: greater proportion of population, 90%, eg clothes. 50th percentile range: average, standardised, eg washing machines. Designers tend not to use the 1st-99th percentile range as it is uneconomical to design for people outside the 5th-95th percentile range.
• Manikin: 2D physical anthropometric model based on a specific percentile, considers the relationship between the size of an object and people.
• Ergonome: 3D physical scaled model based on a specific percentile with moving parts. Establishes spatial ergonomic considerations between people and products or environments.
• Psychological factors to ergonomics; smell, light, sound, taste, texture and temperature. Consider how different people react to differently to sensory stimuli.

Product Evaluation (2.2)

• Cost-effectiveness: the most efficient way of designing and producing a product from the manufacturers point of view.
• Value for Money: the relation between what something is worth and the cash amount spent on it
• Criteria use to evaluate products; performance, reliability, ease-of-use, safety, aesthetics, materials, construction and cost.
• The purpose of evaluation must be clearly defined as it determines the criteria to be used and the methodology for gathering information.
• Literature Search: use of consumer reports and newspaper items to follow historical development. Eg. CDs, encyclopaedia’s, Internet, Books, etc. Also use of information and communication technology (ICT).
• User Trial: the observation and analysis of comments made by people who have used a particular product. Anyone, ie average Joe, who has trialled a product and reports back on it. They are non-specialist, cost-effective and more readily available.
• Expert Appraisal: reliance on the knowledge and skills of an expert in the operation of the product. ‘Specialist’. Gain of expert knowledge and advice, however may be biased.
• Performance Test: observations and their record of users. Provides data about how the product will perform, eg car crash, yet, may be time consuming and costly to perform.
• User Research: obtaining users’ responses. Data is relatively easy and cheap to obtain but it is largely qualitative.

The Designer and Society (2.3)

• designers need to be aware of legislation that affects their roe, eg safety standards. Local and national requirements should be considered.
• Style is often the main selling point for a product, eg, car.
• Changes in values (attitudes to waste and pollution) affect designers’ activities
• Conflict between form and function. Tension between aesthetic characteristics and functionality,
• Planned Obsolescence: a conscience act either to ensure a continuing market or to ensure that safety factors and new technologies can be incorporated into later versions of the product.

Adv for consumer – more choice, increased innovation, more competition. Disadv for consumer – less intrinsic value to products, need to replace products more often. For manufacturer – increased wealth from sales, but increased research and development requirements.

• Fashion: a style or trend. Consider whether ‘designer’ products are better quality than cheaper brands of the same product. Consider the values of a “throw away society”.

[edit] Topic 3: Materials

Introduction: This topic aims to ensure understanding of the relationships between materials choice, manufacturing processes and the concepts of designers. Essentially it evaluates the way in which material properties and manufacturing processes can be integrated.

Introducing and Classifying Materials (3.1)

• materials can be classified into groups according to similarities in their microstructures and properties. However, no single classification is perfect.
• The classification includes; timber, metals, ceramics, plastics, textile fibres, food and composites. However these groups have subdivisions. Eg. Timber; natural wood / composite. Metals; ferrous / nonferrous. Ceramics; earthenware / porcelain / stoneware. Plastics; thermoplastics / thermosets. Textile Fibres: natural / synthetic. Food; vegetable / animal origin.

Properties of Materials (3.2) Physical Properties

• the properties that are actual. They are always there
• density: the mass per unit volume of a material
• electrical resistivity: the measure of a material’s ability to conduct electricity. A material with a low resistivity will conduct electricity well.
• Thermal conductivity: the measure of how fast heat is conducted through a slab of material with a given temperature difference across the slab.
• Thermal Expansion: measure of the degree of increase in dimensions when an object is heated. Eg. Increase in length, area or volume.
• Hardness: resistance a material offers to penetration or scratching.

Mechanical Properties

• properties which occur through an external being, ie a force. For example…
• tensile strength: ability of a material to withstand pulling forces
• stiffness: difficult to bend, rigid
• toughness: ability of a material to resist propagation of cracks.
• Ductility: ability of a material to be drawn or extruded into a wire or other extended shape.

Aesthetic Characteristics

• taste: how appealing a substance is to the taster, flavour. Consider taste buds, as well as after taste etc.
• smell: scent, odour.
• Appearance: appealing, colour, how it looks
• Texture: how it feels

The IB Properties / Materials Matrix (3.3)

[edit] Topic 4: Manufacturing Processes and Techniques

Introduction: Designers need to understand a wide range of manufacturing processes and techniques to match their knowledge of materials. This includes how different processes link together in the manufacture of a product.

Manufacturing Processes and Techniques (4.1)

• manufacturing process: making of products. A finished product may be required in any one of an innumerable number of shapes and sizes, and there are many different techniques by which to produce the final article. The three major groups are; shaping, joining and wasting.
• Manufacturing technique: the technique by which products are made.
• Shaping: materials are formed into shape by particular techniques. Consider other techniques / methods of shaping; bending, moulding, casting and weaving
• Joining: putting together of two or more components or materials. Consider other techniques / methods of joining; fasteners, adhesives, fusing, stitching,
• Wasting: process by which hand tools and machines are used to fabricate materials by the removal of waste. Consider other techniques / methods of wasting; machining, cutting or abrading

Selecting Materials and Techniques (4.2)

• Selection of materials takes into account economic processing and service requirements. Products should be evaluated in terms of efficiency and economy of manufacture.
• Injection Moulding: The direct introduction of molten plastic under pressure into a die, which then cools allowing the forming object to be released from the mould.

Adv – no finishing, volume production, Disadv – set up costs, limitations to size, shape etc.

• Lamination: building up a thick layer of material using thin layers of the material joined with adhesives.

Adv – no finishing, able to form complex shapes and surfaces, Disadv – labour intensive, limitations to the glue, size, clamping, shape and angles of curvature.

• Sintering: The fusing of solid particles together by heat and pressure without completely liquefying the particles.

Adv – no surface machining required to casting, suitable for high melting-point materials Disadv – high-energy requirements, limitations to the sizes and shapes that can be produced and the materials that can be used.

• Extrusion: forcing material through a shaped die to produce a shaped rod or tube of material, eg, wire, pasta

Adv – no finishing require, volume production, hollow shapes Disadv – limitation to size, shape and detail of extruded products.

• Cutting and Machining: cutting a material into shape and finishing it by machines

Adv – versatility and flexibility, range of material suitability Disadv – assembly requirements Limitations – size, joining process

[edit] Topic 5: Production Systems

Introduction: This topic is concerned with the commercial aspects of design and manufacture: the management, economics and politics of assimilating products into the market. It explores how the scale and type of production affects the nature, quality and cost of a product.

Designers and the Product Cycle (5.1)

• Product cycle: a product’s introduction, growth, maturity and decline and to its general pattern of production and profitability.
• The cycle is complicated by distribution and retailing, accountants, production engineers, all of whom have an influence over the cycle. Cycle; a need is generated, a product is designed, made and sold, eventually becoming obsolete.
• Cradle to Grave theory: early stages many changes to the product may take place until it develops to the mature stage where it is diffused into the market, gains acceptance and sells well. In the late stage the product begins to decline in need and therefore in sales.

Scale of Production (5.2)

• one-off production: an individual article or a prototype for larger scale production. (Usually expensive. Examples include; painting, wedding dress, engagement ring)
• Batch Production: limited volume production. (a set number of items to be produced. Eg. School clothes; blazers, ties)
• Volume Production: continuous flow, large-scale production
• Craft Production: a small-scale production process centred on manual skills
• Mechanisation: a volume production process involving machines controlled by humans.
• Automation: a volume production process involving machines controlled by computers.
• Assembly Line Production: mass production of a product via a flow line based on the interchangeability of parts, pre-processing of materials, standardisation and work division.
• Consider Industrial Revolution, Technological Revolution.
• CAD: computer aided design
• CAM: computer aided manufacture
• CNC: computer numerical control. It contains a dedicated, stored program computer which is used to preform some or all of the basic numerical control function. Example; machine at school.
• Robot: a mechanical device controlled by computer that can perform human-like tasks.
• Automated Guided Vehicle (AGV): a robot vehicle that moves over s “shop floor” guided by means, of painted lines, IR rays or cables laid beneath the surface.
• Adv & Disadv; consider; cost, flexibility, skills, effect of the workforce, quality, complexity of product and process, type of market, traditions, training and management structures.

Economic Considerations (5.3)

• Fixed Costs: costs that must be paid out before production starts, eg machinery. These costs do not change with the level of production.
• Variable Costs: costs that vary with output, eg fuel or raw materials.
• Some costs are more relevant than others eg raw materials and labour costs will be a significant part of the final cost of an individually crafted mahogany table but for an injection moulded plastic component these costs would be low and the capital cost of machinery high.

[edit] Topic 6: Clean Technology and Green Design

Introduction: This topic explores the impact of manufacturing processes and products on the environment. Clean technologies have emerged as a result of greater pressure for environmental protection and are supported by legislative frameworks. Take into consideration green design principles such as “cradle to grave”. Strategies for green design include designing products so that they can be repaired, reused, reduced or recycled.

Clean Technology (6.1)

• Clean Technology: an approach to manufacturing or production which uses less resources and causes less environmental damage. Eg reducing the exploitation of natural resources, minimising waste and preventing pollution.
• Technologies impact on the environment
  • Climatic changes; greenhouse gases – carbon dioxide from burning fossil fuels
  • Acid Rain; sulphur dioxide from power stations damaging forests.
  • Destruction of the ozone layer; chlorofluorocarbon’s (CFCs) – reduces the protection of the earth from ultraviolet radiation.
• Clean technology emerged as a result of greater pressure for environmental protection. They generate less pollution and waste and adopt more efficient use of energy and materials.
• Consider conservation of natural resources, reducing pollution and use of energy, and wastage of energy resources.
• The addition of clean-up technologies to the end of the manufacturing process is termed “end-of-pipe” approach
• Note: carbon credits – companies buy trees to counter their emissions of carbon.
• More radical approaches require a rethink of the whole system and may result in significant product modification
• Legislation is needed to help protect the environment. Eg Kyoto Protocol (Greenhouse emissions), consider the power of the United Nations and the framework of protection it holds
• Major companies have realised that using energy and materials more efficiently can save money and have adopted pro-active environmental policies to avoid problems

Green Design (6.2)

• green design: designing in a way that takes account of the environmental impact of the product through its life. Taking into account “cradle to grave” approach, considering the adverse impacts of the product on the environment at all stages of its life
• Potential environmental impact of the product is assessed with the specific objective of reducing this impact and minimising it over the longer term.
• Catastrophic incident; Chernobyl – nuclear meltdown, inexperienced workers. Increased public awareness has put pressure on corporations and gvts through purchasing power and voting power.
• Objectives for green products
  • Increasing efficiency in the use of materials, energy and other resources
  • Minimising damage or pollution
  • Reducing long-term harm caused by use of the product.
  • Ensuring that the planned life of the product is most appropriate and that the product functions efficiently for its full life
  • Effects of the end of disposal of the product

Strategies for Green Design (6.3)

• Designers modify the environmental impact of the production, use and disposal of their product through careful consideration at the design stage.
• REUSE, REPAIR, RECYCLING, RECONDITIONING: strategies for optimising resource utilisation
• Eg of materials that can be easily and economically recycled; plastic, glass, aluminium, paper

Life Cycle Analysis (6.4)

• life cycle analysis: the assessment of the effect a product has on the environment from the initial concept to disposal.
  • It provides a framework within which clean production technologies and green design can be evaluated holistically for a specific product.
  • Stages of the life cycle include:
    • Pre-production
    • Production
    • Distribution
    • Packaging
    • Utilisation
    • Disposal
  • life cycle analysis of the environmental considerations include; water, soil pollution and degradation, air contamination, noise, energy consumption of natural resources, pollution and effect on ecosystems

[edit] Topic 7: Raw Material to Final Product

Introduction: This option considers the conversion of some important raw materials (timber, ceramic (glass), metal, textile fibre, plastic and new materials such mycroprotein and superconductor) to final products.

Timber (7.1)

• timber can be classified according to the conditions needed for tree growth, namely temperate and tropical conditions
• conifer trees are referred to as softwoods and that these grow only in temperate regions and have features in common.
• Deciduous trees are referred to as hardwoods and that these grow in both temperate and tropical regions and have features in common. Harwood trees, they drop their leaves
• Particle board and plywood are examples of composite timbers
• Seasoning: the process of drying out timber after conversion
• Reasons for treating or finishing wood include reducing attack by organisms and chemicals, enhancing aesthetic properties and modifying other properties.

Ceramic – glass (7.2)

• glass is composed primarily of silicon dioxide (SiO2), together with some sodium oxide (Na2O) and calcium oxide (CaO) and small quantities of a few other chemicals. The raw materials come from sand (SiO2), limestone (CaCO3 for making CaO) and sodium carbonate (Na2CO3 for making Na2O).
• large quantities of energy is required for the manufacture of glass and scrap glass is added to new raw materials to make the process economic. Note: very high melting points of raw materials and the strength of chemical bonds.
• Characteristics of glass; brittleness, transparency, hardness, un-reactivity aesthetic properties. The desired characteristics of glass can be accurately determined by altering its composition.
• Toughened glass is made by heating glass almost to the melting point. The surfaces are then cooled while the centre remains hot and plastic. It will shatter into tiny fragments when broken (eg windscreens). Laminated glass has a thin later of material, usually plastic, between the layers. This prevents cracks from growing and it can even be made bullet proof.

Metal (7.3)

• iron is a relatively reactive element and so is never found “free”. Also iron from its ore requires some chemistry and energy to extract it from its oxide (ore), and needs treatment to prevent the iron reacting with air (oxygen and water) and reverting back to its oxide.
• Chemical changes that take place in a blast furnace; Carbon monoxide (CO) from the carbon (C) is used to reduce the iron oxide to iron metal via the reaction:

3CO (g) + Fe2O3 (s) à 2Fe (l) + 3 CO2 (g)

• wrought iron has a lower carbon content (,0.03%) and is formed by heating, rolling and laminating hots slabs together. This toughened alloy is a better engineering material than pig iron.
• Iron is converted into steel in a furnace where the carbon level in the molten iron is reduced by blowing oxygen through the liquid metal. The carbon forms carbon dioxide which bubbles off. The resulting steel has a higher tensile strength and is tough compared with high-carbon alloys.
• Iron is an extremely versatile metal since the desired properties can be accurately determined by altering its composition.
• Consider such effects on metals as, corrosion, rust, treating metal, different types of metal and their specific uses.

Textile Fibre and Plastic (7.4)

• cotton is a natural fibre, a cellulose polymer, obtained from the bud of cotton plants that grow in several sub-tropical regions. Nylon is a synthetic polyamide fibre, obtained by the polymerisation of adipic acid and a diamine.
• Polymer: chain structure, ability to make a long chain.
• Cotton balls are converted into threads:
  • Grow cotton à harvest crop à stored in modules à module feeders clean gin, dirt and excess from cotton à pressed into big bales à bales opened by machinesàmixed and cleaned further blowing and heating à spinning à machine called Loom; weaves cotton à woven fabrics sent to finishing plant à bleached, pre-shrunk, printed, special finish à made into clothing or products for home
• nylon threads are manufactured from petroleum
• cotton is very absorbent and increases in strength when wet because the degree of alignment of long polymers increases, leading to the strengthening of bonds. Cotton is relatively inelastic, so it wrinkles and creases easily. It is a good conductor of heat and so is little effected by heat and chars rather than melts when exposed to high temperatures
• by treating cotton it; enhances aesthetic properties, reduces flammability and the need for waterproofing. However cotton is degraded by ultraviolet rays, moisture and air pollutants.
• Cotton, nylon or polyester may be incorporated into a composite fabric and the composition of this fabric determines its characteristics. Eg socks, short and waterproof garments.

New Materials (7.5) Mycoprotein – a new food

• mycoprotein is a food product made from a fungus grown on grain and paper flour wastes and harvested as a mass of threads. Eg Quorn.
• Adv: nutritional value, ability to form into chunks (that can simulate beef or chicken), high protein and fibre content, low salt and cholesterol levels. Is virtually tasteless but can be given any flavour, safe to eat, easily processed into acceptable food product, no toxicological effects and no residues or contaminants from substrates.
• However for such a new product as mycoprotein the importance of public acceptability is fundamental.

Superconductor

• superconductors are ceramic alloys made from various metal oxides, non-metal oxides and metals, and that they are sintered so there is no need for treatment or finish.
• Resistivity of superconductors becomes nearly zero at temperatures below about 140 K due to pairs of electrons weakly bonded together, which can move freely at these temperatures.
• Adv: superconductors are currently of rather limited use, they are utilised in NMR brain scans and levitating trains. Adv include energy savings and less raw material needed since cables can be smaller

[edit] Topic 8: Microstructures and Macrostructures

Introduction: This topic provides the concepts used to explain that properties of materials. These concepts also allow a designer to choose the type of microstructure needed. This allows the designer to specify a type of material and specific treatment, such as annealing, quenching or case –hardening.

Structure of Matter (8.1)

• all matter is composed of particles
• atom: the smallest part of an element that can exist chemically
• molecule: two or more atoms which are normally bonded together convalently
• ion: positively or negatively charged atom or molecule caused by the loss or gain of electrons from an atom or atoms.
• Bond is a force of attraction between particles
• Element: a substance that cannot be decomposed into simpler substances.
• Compound: a substance formed by the combination of elements in fixed proportions. They may be bonded ionically or covalently
• Pure substance: a substance made of only one element or compound
• Mixture: a substance made of two or more substances that can be separated by physical means, ie not chemically bonded together.
• Alloy: a mixture that contains at least one metal. This can be a mixture of metals or a mixture of metals and non-metals
• Composite: a mixture composed of two or more substances (materials) with one substance acting as the matrix or glue

Bonding (8.2)

• ionic bonds, covalent bonds, metallic bonds. Ionic and covalent bonds are non conductive.
• Secondary bonds are weak forces of attraction between molecules.
• Eg, in a diamond each carbon is covalently bonded to four other carbon atoms, tetrahedrally arranged. The carbons at the edges are attached to hydrogen atoms. This is specifically why diamonds are so hard.
• Amorphous material: don’t have regular structures or crystal patterns. General appearance is glossy and they can occur in ceramics, polymers and metals.
• Fibres have a length-to-thickness ratio of at least 80 but are generally much longer. Textile fibres and food are made up of polymers

The IB Properties / Bonding Matrix (8.3)

The Properties of Metals and Alloys (8.4)

• metals (pure or alloyed) exist as crystals
• grain size can be controlled and modified by the rate of cooling of the molten metal, or by heat treatment after solidification. Reheating a solid metal or alloy allows material to diffuse between neighbouring grain structure to change. Slow cooling allows larger grains to form; rapid cooling produces smaller grains. Directional properties in the structure may be achieved by selectively cooling one area of the solid.
• Plastic deformation: the permanent deformation of a solid subjected to a stress.
• The tensile strength of a metal is increased by alloying
• The movement of free electrons makes metals very good electrical and thermal conductors.

The Properties of Thermoplastic and Thermosets (8.5)

• Thermoplastics are linear chain molecules, sometimes with side bonding of the molecules, but with weak, secondary bonding between the chains.
• Deformation occurs in two ways: elastic in which initially coiled chains are stretched and plastic at higher loads, where secondary bonds weaken and allow the molecular chains to slide over each other. Creep and flow are important.
• Thermosets are formed by making primary (covalent) bonds which form strong, primary cross-links between adjacent polymer chains. This gives the thermosets a rigid-dimensional structure/
• Heating increases the number of permanent cross links and so burdens the plastic.

The Properties of Composite Materials (8.6)

• composites are a combination of two or more materials which are bonded together to improve their mechanical, physical, chemical or electrical properties
• cellulose fibres in a lignin matrix – the tensile strength is greater along the grain (fibre) than across the grain (matrix)
• Kevlar (aramid) fibre: aramid fibre comprises linear chains of hydrocarbon rings. Aramid chains behave like rigid rods and they are aligned along the length of the fibre during the manufacturing process. They have a very high tensile structure. Kevlar fibres do not absorb water, have a high tensile strength and are non-stretch

Young’s Modulus – Stress and Strain (8.7)

• stress (load) is force per unit area acting on a body or system.
• Strain is the ratio of a change in dimension to the original value of the dimension. Strain in a material is a measure
• Yield stress: the stress at which plastic deformation begins. The importance of this is the stress at the yield point. Many materials undergo plastic as well as elastic deformation.
• Young’s Modulus: the stiffness of a material
• Young’s modulus =

Forces (8.8)

• an external load acting as a structure involves loads where physical contact is made
• body load is a load without physical contact, eg a structure’s own weight
• Mass is a measure of how much matter an object has. Weight is a measure of how strongly gravity pulls on that matter. Thus if you were to travel to the moon your weight would change because the pull of gravity is weaker there than on Earth but, your mass would stay the same because you are still made up of the same amount of matter.
• A structure “works” by interpreting how external loads give rise to internal forces within the structural members. A static structure is in quilibrium, otherwise it would move, ie the forces acting upon it are equal in size and opposite in direction
• Tensile laods tend to extend or stretch a structural member. Compressive loads to to compress or shorten a structural member. Tensile and compressive forces must balance if the structure is to maintain quilibrium. Only forces that are parallel or perpendicular need to be considered.
• Stress =
• Strain =

The Strength and Stiffness of Structures (8.9)

• if an external load is applied to some part of a structure, that part will be deflected to some extent, depending on the size of the load and the stiffness of the structure.
• Stiffness =
• The load multiplied by distance from the pivot is called the “moment” about the pivot. The distance between the load and the pivot is called the “moment arm”
• Factor of safety =
• A factor of safety is simply a ratio of the quantitative value of a design divided by the normal maximum expected value, eg stiffness, fuel tank volumes, electrical resistance, engine acceleration

[edit] Topic 9: Appropriate Technologies

Introduction: Understanding the constraints and opportunities that exist for optimising the exploitation of resources and renewable energy sources. The aim of this topic is to promote an awareness of the need to conserve non-renewable resources while meeting human, environmental and industrial requirements.

Resources and Reserves (9.1)

• Resources can be classified as renewable and non-renewable
• renewable resources: resources that are naturally replenished in a short time
• non-renewable resources: resources that take too long (say more than one human lifetime?) for natural processes to replenish them.

The Technologies (9.1)

• appropriate technology: technology appropriate to the context in which it is applied. Appropriate technologies are low in capital cost, use local materials wherever possible, create jobs using local skills and labour, involve decentralised renewable energy sources, make technology understandable to the people who use it, are flexible and not detrimental to quality of life or the environment.
• Alternative technology: a technology that involves new types of equipment or organisational forms, and which represents a viable alternative to the existing mainstream technologies of today.
• Intermediate technology: a relative term that stands between traditional and modern technology

Exploitation of Energy Resources (9.3)

• Renewable energy sources; include wind, wave, solar, biomass, hydroelectric, tidal and geothermal, energy sources.
• Non-renewable energy sources; include coal, oil, timber, gas and nuclear.

Exploitation of Material Resources (9.4)

• Reference to “developing versus developed” countries; renewable / non-renewable versus economic considerations; built-in obsolescence versus longevity; aesthetics versus function; and considerations of culture, values and attitudes.
• Barriers to recycling include manufacturing capacity, technical factors, economics, product specifications and consumer resistance to using waste-based products. Using the example of paper – features that favours recycling are not using glossy surfaces, ones that cannot be processed by machines or plastic components since they make recycling expensive. More recycled materials can be reintroduced into the industry since recycling reduces the need for purchasing more virgin raw materials. More public subsidies would help to persuade firms to introduce recycled materials. Large paper manufacturers could be encouraged to sell off their stakes in forests in order to encourage their use of recyclable materials.

Strategies for Sustainable Development (9.5)

• Sustainable development: development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
• Global conferences: The Earth Summit in Rio de Janeiro, provides a platform for the development of global strategies for sustainable development. Discussed such issues as promoting sustainable energy development; safe and environmentally sound transport systems; industrial development that does not adversely impact the atmosphere.
• Sustainable development requires system-level changes in industry and society. Eg the development of a sustainable transport system is likely to involve much more than the green design of cars. Ie it should also consider the fundamental role of transport in human life.
• Sustainable development requires close cooperation between manufacturers and gvt. Regulations by gvt from which manufacturers are incorporated.
• It is difficult for gvts to introduce legislation to cover all aspect of sustainability. Consider globalisation; can not control the product overseas.
• Weightless Economy: economic activity whose value does not lie in a physical end-product. Eg intellectual property, ideas and designs, computer software, entertainment products, telecommunications , etc. Success in such a weightless economy comes from being able to organise and manipulate information in ways that generate extra value and is closely linked to success in applying information technology.
• Anticipating sources of pollution and eliminating them at the design stage can lead to savings on raw materials and waste treatment.
• Cost-savings can be achieved by introducing more energy-efficient and less wasteful manufacturing processes.
• Market Pull – attraction to certain products
• Market Push – give into propaganda, consumer advertising.
• Product characteristics can be consistent with sustainable development. A product should be considered for its long-term characteristics. It should help and liberate human beings. Should not demand exceptional user skill and should be controlled by human beings. Value of a product should be more important than its exchange value. A product should be regarded as part of culture and as such should meet the cultural. Designed for high durability and reparability. Designed for disassembly.

Option E: Computer-aided Design, Manufacture and Production

Introduction: This topic is concerned with understanding how computer-based technologies have transformed the nature of the design and manufacture of products. The impact of the application of such technologies on the role of the designer and manufacturer.

The Impact of CAD on the Design Process (E.1)

• many CAD software packages exist, each of which offer particular facilities and advantages. Such as the range of packages for different design applications, eg for architecture where the software package can calculate the building costs or for engineering and product design applications.
• Advantages of these packages for designers
  • Able to conceptualise final product before construction
  • Greater precision and detail, therefore minimal mistakes
  • Gives ability to manipulate and change
• disadvantages of the packages for designers
  • often these packages are very expensive
  • doesn’t provide a physical object
  • can be complicated to operate and function and integrate with other programmes.
• different computer modelling techniques. Eg Spreadsheet – Microsoft Excel. Pro desktop. Cordis. Cressanda. (latter two are random programmes add better ones if you know of them) packages can be used for numeric modelling, 2D and 3D modelling techniques, and exploded views.
• Criteria designers use to select an appropriate computer modelling technique/programme.
  • Certain programmes/tools are designed for particular jobs. i.e. architecture, bridge building etc
  • Ease-of-use
• Animation: the ability to link graphic screen together in such a way as to simulate motion or a process.
• Virtual reality: the ability to simulate a real situation on the screen and interact with it in a near natural way.
• Aeroplane simulator for learner pilots – is a design context where the use of virtual reality helps to conserve resources. Such as; time, materials, energy, money.
• Various input devices can be used by a CAD system including a scanner, digital camera, graphics tablet, video camera.
• Various output devices can be used by a CAD system including a printer and plotter.

Impact of CAD/CAM on Manufacturing (E.2)

• NC machines aid manufacturing with reference to the quality of reproduction, the reduction in the need for operators, and speed. Also reduces long term investment costs, greater flexibility, reprogram-ability and multi-machine control.
• CAD & CNC can be interfaced to produce a CAD//CAM system.
  • Graphics produced on a CAD system are translated to a set of programming coordinates which instruct the CNC machines how to manufacture the design seen on the screen.
  • Eg. sewing machines, knitting machines and looms can be interfaced to produce textile products.
  • Eg. lathes, milling machines or shapers can be interfaced to produce metal, plastic or wood products.
    • ref. x, y, z axis and management of materials.
  • Eg. engraver interfaced to produce printed circuit boards.
    • ref. x, y, z axis, interface, accuracy, detail and size.
• CIM: computer integrated manufacturing; integration of CAD, CNC, robotics, etc. All components of the system will share the same database and have instant access to it.
  • Eg. Car production manufacturer, such as Toyota, Subaru.
• Adv of CIM to consumers and manufacturers.
  • More choice, design in own requirements, more consistent quality, fewer errors and waste, improvements in productivity and quality control, better machine utilisation.
• Dis of CIM to consumers and manufacturers.
  • High initial investment and personnel, training cost, job losses, lack of individuality.

The Impact on Industry (E.3)

• Just-in-time (JIT): a business does not allocate space to the storage of components but instead orders/manufactures them when required.
  • Adv: save on storage space, increased efficiency, reduced capital investment, fewer unsold items.
  • Dis: possible stoppages due to non-delivery of external components, communication breakdown, distribution and transport breakdown.
• Just-in-case (JIC): company keeps small stock of rare components that take a long time to make, just in case of a rush order.
  • Adv: acts like a “buffer”, goods-in-stock in case of unforseen circumstances
  • Dis: unsold stock, space needed for storage and capital investment.
• Impact of CAD/CAM on working conditions and the work force is such that it will take out unnecessary employees, different skills will be required by employees, health and safety will change inherent to CAM/CAM
• Adv of CAD/CAM
  • Quality control greater consistency, fewer errors, reduction of waste, higher quality of finish, greater variety of choice,
• Dis of CAD/CAM
  • High initial investment. Training personnel, job losses, lack of individuality,
• Patent: an agreement from a gvt office to give someone the right to make or sell a new invention for a certain number of years.
• Copyright: the right in law to be the only producer (or seller) of a book, play, film, design, etc.
• The implications of computerised manufacture on the infringement of copyright and patent laws are primarily the ease of copying and changing designs.
• Product which can be manufactured either by CAD/CAM: flat pack or self-assembly furniture. Compared to. Traditional cabinet making techniques, children’s toys,
  • Comparison = diff skills involved, efficiency of production, quality control, precision and wastage, ability to change the product during manufacture, variety, quantity, complexity, individuality.

The Impact on the Consumer (E.4)

• CAD/CAM improved the type and range of products available to the consumer.
  • Replication of ancient artefacts would be impossible without CAD/CAM
• CAD/CAM affected consumer choice.
  • Eg. having kitchen showrooms and car showrooms which allow consumer to have input options such as colour and certain preferences.
• CAD/CAM designed to allow for the needs of individual consumers
  • Consumer culture and society, obsolescence, energy, individual needs, waste, lifestyle and recycling.
• Impact of CAD/CAM on consumerism.
  • Recycling wastage, energy, individual needs and cultural aspects.

Mass Customisation (E.5)

• Mass customisation: sophisticated CIM system which manufactures products to individual customer orders. Benefits of economy of scale are gained whether the order is for a single item or for thousands.
  • Transforming the relationship between the manufacturer and the consumer.
    • In mass customisation the manufacturer produces products in response to customer orders.
  • Adv for consumers and manufacturers: (help)
  • Dis for consumers and manufacturers: (help)

Global Communication Systems (E.6)

• information is a commodity which is handled by computers
• Optical Fibre: cable that can transmit huge quantities of digital info at very high speed in both directions by means of light waves.
• Analogue Signal: signal that may change continuously to represent a physical property.
• Digital Signal: encoded signal, simplest being binary. Converted from analogue signals into discrete values – high, low or on, off.
• Satellite Communication: telecommunication whereby radio waves are transmiteed from one part of the globe to a satellite in space which amplifies the signal and retransmits it to a receiver in another part of the globe.
• Internet: global network connecting millions of computers.
• Effectiveness of information transfer in optical fibres and copper wires – fibre optics use light pulses to transmit info down fibre lines instead of using electronic pulses to transmit info
• Fibre optic technology allows for a wide variety of input and output devices
  • Eg. video conferencing, televisions and computers.
• Internet assisting designers with market research
  • Computer Aided Market Analysis (CAMA)
  • Designers can gain info without need to carry out research themselves.

Global Production Systems (E.7)

• Flexible Manufacturing System (FMS): any computer-controlled manufacturing system which is capable of dealing with several different products and offers users an opportunity to obtain the benefits of economies of scale in small batch production.
  • Benefits of FMS to manufacturers
    • Reduces labour, shortens lead times, improves productivity and quality, reduces costs
• Design for Manufacture (DfM): designers design specifically for optimum use of this capability.
  • Can be a dominating constraint on the design brief and can conveniently be split into design for materials, design for process and design for assembly.
    • Design for materials – designing in relation to materials during processing, rather than design for the final desired properties of the end product in use
    • Design for process – this is designing to match an existing manufacturing process, eg injection moulding.
    • Design for assembly – designing to take account of assembly at various levels eg, component to component, parts into sub-assemblies.
  • Strategies Designers could employ for DfM
    • Minimising number of parts, using standard components, designing multi-functional parts, designing parts for ease of fabrication.
• Design for Disassembly: designing a product so that when it becomes obsolete it can easily and economically be taken apart, the components reused or repaired and the materials recycled.
  • Strategies designers could employ to design for disassembly.
    • Designing components made from one material, using adhesives that lose their properties easily when reheated, designing snap-fittings.
• Lean Production: combining the advantages of craft and mass production while avoiding the high cost of the former and the inflexibility of the latter.
  • Implications for the workforce – workers need to be professionally skilled and must be able to diagnose problems, repair equipment and undertake quality control.

The Global Manufacturer (E.8)

• importance of lean production to the global car manufacturer – 1990 Toyota became third largest car manufacturer
• global manufacturer’s from the west have found it difficult to adapt to lean production – constraints of traditional working practices, views of the workforce, training, costs of new machinery
• Multi-national company: company, which not only trades internationally but has manufacturing outlets in a number of countries.
  • Growth of multi-national companies = mobility of capital; increased foreign investment, expansion of international trade, worldwide markets, global manufacturing outlets reduction in trade boundaries, advertising, rapid communication systems,
  • Global manufacturers establish production units in different part of the world to; gain greater market, greater source of income, could benefit from currency rates (cheaper workforce), could make it easier for product distribution and selling.
• Adv/dis for countries hosting production units of global manufacturers
  • Import expertise and technologies, employment image, effects on the local and national economy, influence of multi-national companies, effect on environment, culture and working practices.

Option F: Invention, Innovation and Design

Introduction: Technological development is always accelerating. Many interesting inventions fail to become innovations due to unfavourable social, economic, and political conditions.

Invention and Innovation (F.1)

• Invention: process of discovering a principle. A technical advance in a particular field often resulting in a novel product.
• Innovation: the business of putting an invention in the marketplace and making it a success.
• Importance of science to invention - scientific research uncovers new possibilities for a product or process
• Majority of inventions fail to become innovations coz: marketability, financial support, marketing, need for the invention and price.
• Stages of innovation: for continued innovation (re-innovation), products and processes are constantly updated (re-designed) to make them more commercially viable and to give consumers choice and improved products.
• Dominant design: design containing those implicit features of a product which are recognised as essential by a majority of manufacturers and purchases.
• Diffusion into the market place: wide acceptance of a product.
• Market Pull: initial impetus for the development of a new product is generated by a demand from the market.
• Technology push: where the impetus for a new design emanates from a technological development.

Invention (F.2)

• lone inventor: individual working outside or inside an organisation who is committed to the invention of a novel product and often becomes isolated being engrossed with ideas.
  • Difficult to become a successful lone inventor because; most products are now quite complex and rely on expertise from various disciplines. Investment required is often too much.
  • Find it difficult to work in design departments of large companies because they are often used to setting their own targets rather than working as a member of a team.
• Product Champion: influential individual, usually working within an organisation, who develops an enthusiasm for a particular idea.
• Product champion and lone inventor are opposites.
• Entrepreneur: individual committed to the development of a particular new product or process, and prepared to provide or persuade others to provide the necessary finance to turn the invention into an innovation.
  • Have difficulty in obtaining financial support for an invention as most people with money to invest will be inclined to wait until it is clearer whether or not an invention is going to be successful before investing.
  • Thomas Edison: entrepreneur, inventor, created phonograph, electric light bulb 1879, carbon telephone transmitter. Est. Menlo Park. Institution set up with the specific purpose of producing constant technological innovation and improvement. Also
    • Eg of an incremental design based on Edison’s incandescent lamp: the fluorescent lamp / halogen lamp

Innovation in Practice – the Bicycle (F.3)

• scientific inventions were important in the development of the bicycle, such as; wheels, gearing, brake systems, steering and chain systems.
• Technological developments: materials; iron – carbon fibre, processes and production system – individually hand made – mechanised production line.
  • Technological developments provided designers with the opportunity to re-arrange components, devise new forms of assembly and use new materials. Eg. tires, frames, suspension, alloys, carbon fibres, manufacturing technique, mass production, automation
• Social and economic demands in the development of the bicycle; ergonomics, aesthetics, environmental considerations, fashion, planned obsolescence, health and lifestyle influences.
  • Only a minority of inventions become innovations, success depends on the economic and social conditions
  • Many innovations fail because they are inconsistent with existing values of customers

Market and Innovations (F.4)

• technophile: someone who immediately welcomes a technological change.
• technocautious: someone who needs some convincing before embracing technological change.
• Technophobe: someone who resists all technological change.
  • These above classifications refer to issues of morality or ethics, security and privacy, and economic circumstances.
• There is often resistance to innovation by companies as research and development is expensive. Innovation involves disturbance and change and so tends to be resisted by organisations.
• Corporate Strategy: long-term aims and objectives of a company and ways of achieving them by a collection of resources.
  • Large companies develop a corporate strategy for innovation
  • Corporate strategy –
    • “pioneering”: Being ahead of the competitors by introducing a new product first. Most risky (costly) strategy, has potential for large gains.

· Eg. can – flush toilet, loose leaf tea leaves – tea bag, Morse code – radio, walkman

• • • “imitative”: aims to develop a product similar to the “pioneered” product as quickly as possible. Takes advantage of research and development invested by other companies and is less risky.

Invention, Innovation and the Environment (F.5)

• technological innovation can make a major contribution to safeguarding the environment by replacing damaging processes and products with environmentally more benign ones.
• Companies have decided to adopt pro-active environmental policies to avoid problems and regulations that may emerge in the future.

The Designer in the Global Marketplace (F.6)

• market research important for establishing the design need in the global marketplace.
  • With such a large market the risks of being unsuccessful are great. Different cultures and attitudes from different parts of the world would also impact.
• Conditions that allow for sustainability of innovation in a global society
  • Easy and fast travel, rapid communication system, economic and trading arrangements
• Responsibility of designers in the global marketplace; environment, quality control, safety, people’s needs.
• As the pace of innovation increases, the product life cycle decreases.