📐 GCSE Design & Technology

Materials, manufacturing processes, electronics, sustainability, and the design process revision.

AQA Edexcel OCR

The Design Process

Iterative Design Cycle

Modern design is iterative — it repeats through stages of designing, testing, and refining until the product meets requirements.

  • Explore: research the problem, identify user needs, analyse existing products
  • Create: generate ideas (sketches, CAD), develop chosen concept, prototype
  • Evaluate: test against design criteria, gather user feedback, reflect on improvements

Design Brief & Specification

  • Design brief: a short statement of the problem to be solved
  • Design specification: detailed criteria the product must meet — function, aesthetics, materials, cost, safety, ergonomics, target user
  • Use ACCESS FM to structure a specification: Aesthetics, Cost, Customer, Environment, Safety, Size, Function, Materials

Research Methods

  • Primary research: questionnaires, interviews, user testing — data collected directly
  • Secondary research: internet, books, existing products — data from existing sources
  • Anthropometric data: measurements of the human body used to inform ergonomic design
Exam Tip:

When evaluating a design decision, always link back to the specification criteria and say whether the product meets them — vague answers don't score well.

Material Properties

You must know key mechanical and physical properties of materials:

  • Strength: ability to withstand forces without breaking (tensile, compressive, shear)
  • Hardness: resistance to surface scratching or indentation
  • Toughness: ability to absorb impact without fracturing
  • Malleability: can be shaped by hammering/pressing without cracking
  • Ductility: can be drawn into wire (stretched) without breaking
  • Elasticity: returns to original shape after deforming force is removed
  • Plasticity: permanently deforms without breaking
  • Conductivity: thermal or electrical — how easily heat/electricity passes through
  • Density: mass per unit volume — affects weight of products
  • Absorbency: how much liquid a material can absorb

Manufacturing Processes

Types of Production

  • One-off (bespoke): single item made to order; highly skilled; expensive (e.g. tailor-made suit, handmade chair)
  • Batch production: set quantity made, then machines reset for different product; flexible; medium cost
  • Mass production: continuous large quantities; very efficient; low unit cost; dedicated tooling (e.g. car manufacture)
  • Continuous production: 24/7 automated production; used for products like chemicals, paper, steel
  • Just-in-time (JIT): materials delivered exactly when needed; reduces storage costs; relies on reliable suppliers

Quality Control vs Quality Assurance

  • Quality control: checking finished products against tolerances/standards — reactive
  • Quality assurance: systems and processes to prevent errors during production — proactive
  • Tolerances: acceptable range of variation (e.g. ±0.5mm) — products outside tolerance are rejected

Timber & Manufactured Boards

Hardwoods (from deciduous trees)

  • Oak: strong, heavy, durable, expensive — furniture, flooring
  • Beech: hard, close grain, bends well when steamed — chairs, tool handles
  • Mahogany: attractive reddish grain, easy to work — furniture
  • Balsa: extremely lightweight — model making (technically a hardwood!)

Softwoods (from coniferous/evergreen trees)

  • Pine: cheap, easy to work, lightweight — furniture, joinery
  • Spruce: light and strong — musical instruments, aircraft
  • Softwoods are generally cheaper and grow faster (more sustainable)

Manufactured Boards

  • Plywood: layers of wood glued at right angles — strong in all directions, resists warping
  • MDF (Medium Density Fibreboard): smooth surface, easy to machine/paint; not water resistant
  • Chipboard: wood chips and resin; cheaper; often veneered; used in flat-pack furniture
  • Hardboard: thin, smooth one side; used for back panels and templates

Metals

Ferrous Metals (contain iron)

  • Mild steel: strong, cheap, magnetic, rusts — most commonly used metal; construction, cars, tools
  • Stainless steel: contains chromium — corrosion resistant; cutlery, medical instruments
  • Cast iron: very hard and brittle; engine blocks, manhole covers
  • High speed steel: retains hardness at high temperatures — cutting tools, drill bits

Non-Ferrous Metals

  • Aluminium: light, corrosion resistant, good conductor — aircraft, drink cans, cooking foil
  • Copper: excellent electrical and thermal conductor, ductile — electrical wiring, plumbing
  • Brass (copper + zinc): machinable, corrosion resistant, decorative — taps, instruments
  • Tin: soft, corrosion resistant — used to coat steel (tin cans)

Metal Treatments

  • Annealing: heating then slow cooling — removes hardness, relieves stress
  • Hardening: heating steel then quenching (rapid cooling) — makes it harder but brittle
  • Tempering: reheating hardened steel to lower temperature — reduces brittleness
  • Galvanising: coating steel with zinc — prevents rusting
  • Powder coating, painting, electroplating: surface finishes for protection and aesthetics

Polymers (Plastics)

Thermoplastics (can be reheated and reshaped)

  • Acrylic (PMMA): transparent, brittle, scratches easily — signs, display cases
  • High-density polyethylene (HDPE): stiff, chemical resistant — bottles, pipes
  • Low-density polyethylene (LDPE): flexible, waterproof — bags, film
  • Polypropylene (PP): flexible hinge properties — living hinges, containers
  • ABS (Acrylonitrile butadiene styrene): tough, impact resistant — LEGO, car dashboards, phone cases
  • Nylon (Polyamide): self-lubricating, strong — gears, bearings, clothing

Thermosetting Plastics (set permanently — cannot be remelted)

  • Urea formaldehyde: hard, brittle, heat resistant — electrical fittings, toilet seats
  • Epoxy resin: strong adhesive, good electrical insulator — circuit boards, adhesives
  • Polyester resin: used with fibreglass — boat hulls, car body repairs
  • Melamine formaldehyde: hard, heat/scratch resistant — worktops, crockery

Shaping Processes

  • Injection moulding: melted plastic injected into a mould — mass production, complex shapes
  • Blow moulding: air blown into molten plastic in a mould — hollow objects (bottles)
  • Vacuum forming: plastic sheet heated then sucked over a mould — food packaging, trays
  • Extrusion: plastic forced through a die — pipes, curtain tracks
  • Line bending: heating a strip of acrylic then bending it — single bends

Textiles

Natural Fibres

  • Cotton: absorbent, washable, comfortable — clothing, towels
  • Wool: warm, absorbent, naturally flame-resistant — jumpers, carpets
  • Silk: strong, lustrous, lightweight — luxury clothing
  • Linen (from flax): strong, cool, creases easily — summer clothing, tablecloths

Synthetic Fibres

  • Polyester: crease-resistant, durable, non-absorbent — sportswear, mixed fabrics
  • Nylon: strong, elastic, abrasion-resistant — tights, ropes, sportswear
  • Acrylic: soft, wool-like, cheap — knitted items, blankets
  • Lycra/Elastane: very stretchy — sportswear, swimwear

Fabric Construction

  • Woven: interlaced warp and weft yarns; strong but limited stretch
  • Knitted: interlocked loops; stretchy, comfortable
  • Bonded/non-woven: fibres bonded by heat/chemicals — felt, interfacing

Composites & Smart Materials

Composites

  • Made from two or more materials combined to improve properties
  • Carbon fibre reinforced polymer (CFRP): very strong and light — bicycles, aircraft, F1 cars
  • Glass reinforced polymer (GRP/fibreglass): strong, light, corrosion resistant — boats, car bodies
  • Concrete: cement + aggregate; reinforced with steel rebar — construction

Smart Materials

  • Shape memory alloy (SMA): e.g. nitinol — returns to original shape when heated; dental braces, spectacle frames
  • Thermochromic pigment: changes colour with temperature — mood rings, food packaging, baby spoons
  • Photochromic material: changes with UV light — self-darkening lenses
  • Piezoelectric material: generates electricity when deformed — sensors, energy harvesting

Modern & Technical Materials

  • Graphene: single layer of carbon atoms; strongest known material; excellent conductor
  • Kevlar: stronger than steel by weight; bullet-proof vests, tyres
  • Nanomaterials: tiny particles (<100nm); used in medicine, sun cream, coatings

Electronics & Systems

Systems Approach

  • All electronic systems have: Input → Process → Output
  • Input components: sensors (light, temperature, sound, pressure), switches, potentiometers
  • Process components: microcontrollers, transistors, logic gates, timers (555 IC)
  • Output components: LEDs, buzzers, motors, displays, relays

Common Components

  • Resistor: limits current; value in ohms (Ω); colour coded bands
  • Capacitor: stores charge; used in timing circuits and smoothing
  • LED: emits light when current flows in correct direction; needs series resistor
  • Transistor: acts as a switch or amplifier
  • Diode: allows current in one direction only
  • LDR: resistance decreases as light increases
  • Thermistor: resistance decreases as temperature increases

Microcontrollers & Programming

  • Microcontrollers (e.g. Arduino, Raspberry Pi) can be programmed to control outputs based on inputs
  • Advantages: flexible, reprogrammable, can handle complex logic
  • Used in: smart home devices, robotics, embedded systems

CAD/CAM

  • CAD (Computer Aided Design): designing products digitally using software
  • CAM (Computer Aided Manufacture): using computer-controlled machines to make products

Benefits of CAD

  • Designs can be quickly modified without starting from scratch
  • 3D modelling allows virtual testing (stress analysis, rendering)
  • Easy to share and collaborate on designs
  • Files sent directly to CAM machines — reduces human error

CAM Processes

  • Laser cutter: cuts/engraves sheet materials precisely using laser
  • CNC router/mill: cuts 2D/3D shapes from sheet/block materials
  • 3D printer (additive manufacturing): builds layer by layer from digital file; good for prototypes
  • Vinyl cutter: cuts adhesive vinyl for signs and decals

Sustainability & the Environment

The 6 Rs

  • Refuse: choose not to use materials/products with high environmental impact
  • Reduce: use less material; design for minimal waste
  • Reuse: design products that can be used multiple times
  • Recycle: recover materials at end of product life
  • Rethink: consider whether the product is necessary; design differently
  • Repair: design for easy maintenance and repair to extend product life

Life Cycle Assessment (LCA)

  • Evaluates environmental impact across a product's entire life: extraction → manufacture → use → disposal
  • Considers: energy use, water use, carbon emissions, waste generated

Carbon Footprint

  • Total greenhouse gas emissions from making/using a product
  • Reduced by: local sourcing, renewable energy in manufacture, using recycled materials
  • Fair trade and ethical sourcing: ensuring workers in supply chain are paid fairly and work in safe conditions

Social, Moral & Ethical Issues

  • Planned obsolescence: designing products to fail or go out of fashion quickly — forces consumers to buy replacements; environmentally harmful
  • Inclusive design: designing for all users including those with disabilities
  • Ergonomics: designing for human comfort and usability using anthropometric data
  • Cultural influences: colours, patterns, and forms have different meanings in different cultures
  • Fashion and trends: products designed to appeal to current tastes; fast fashion has high environmental cost
  • Intellectual property: patents, copyright, and design rights protect designers' work
  • Globalisation: manufacturing moved to low-wage countries — lower cost but ethical concerns
Exam Tip:

For "evaluate" questions on social/moral issues, give both sides of the argument and reach a supported conclusion — don't just list points on one side.