AQA GCSE Design and Technology Core Principles & Practice Study Notes

Core Technical Principles: Technologies, Energy & Materials

  • New & Emerging Technologies:

    • Industry & Automation: Evolution from localized workshops to factory mass production using automated lines, Computer Numerically Controlled (CNC) machinery, Flexible Manufacturing Systems (FMS), Just-In-Time (JIT) stock delivery, and lean manufacturing.

    • Enterprise & Funding: Financing through crowdfunding (donations, equity, or debt). Virtual marketing and virtual reality retailing adapt to shopping trends such as showrooming (e.g., Tesco subway app purchasing).

    • Business Models: Co-operatives are self-managed worker-owned entities. The Fair trade movement provides fair trading conditions and higher export prices for developing nations.

    • Design Drivers: Technology push occurs when new tech drives product design without prior consumer demand (e.g., Apple iPad). Market pull occurs when consumer demand redesigns existing products (e.g., Volkswagen Beetle, BMW Mini, Fiat 500).

    • Sustainability & Waste: Product lifecycle planning includes avoiding planned obsolescence, designing for maintenance, and managing end-of-life disposal (landfill, resource/energy recovery, incineration).

  • Energy Generation & Storage:

    • Fossil Fuels: Non-renewable resources (coal, natural gas, crude oil) burned to produce steam that turns electricity-generating turbines; releases carbon dioxide (CO2\text{CO}_2).

    • Nuclear Power: Uses nuclear fission of uranium atoms to superheat steam for turbines; does not release greenhouse gases, but produces hazardous long-term nuclear waste.

    • Renewable Energy: Naturally replenished sources including wind (wind turbines), solar (passive design and active photovoltaic cells), tidal (estuary barrages), hydroelectric (dams/reservoirs), and biomass.

    • Energy Storage: Includes kinetic pumped storage (two-reservoir top-up hydroelectric systems), flywheels, clockwork springs, capacitors / supercapacitors, and electrochemical batteries (primary single-use vs. secondary rechargeable).

  • Developments in New Materials:

    • Modern Materials: Graphene (strong, light, flexible carbon layer), metal foam (porous, high compressive strength), titanium (high corrosion resistance and strength-to-density ratio), coated metals (anodised aluminium, nickel-plated steel, polymer-dipped/powder-coated metals), LCD (liquid crystal display), nanomaterials (<100 nm<100\,\text{nm} particles), Teflon (non-stick PTFE), and corn starch polymers (degradable PLA plastics).

    • Smart Materials: Change properties reversibly in response to external stimuli: thermochromic (temperature), shape memory alloys (SMAs return to shape when heated), and photochromic (light intensity).

    • Composite Materials: Combine properties of constituent materials: concrete (reinforced with steel), Glass-Fibre Reinforced Polymer (GRP), and Carbon-Fibre Reinforced Plastic (CRP).

    • Technical Textiles: Performance-engineered textiles: conductive fabrics (e-textiles), Nomex (fire-resistant meta-aramid), Kevlar (high tensile strength), Gore-Tex (waterproof, breathable PTFE membrane), and microfibres (incorporating microencapsulation).

Mechanical Devices & Systems Approach

  • Systems Approach to Designing:

    • System Architecture: Comprises Input →\rightarrow Process →\rightarrow Output.

    • Input Devices: Sensors converting environmental signals into electrical signals: Light Dependent Resistors (LDRs), Thermistors (PTC and NTC temperature sensors), microswitches, and pressure pads.

    • Process Devices: Microcontrollers (integrated circuits containing processor cores and flash memory, e.g., PIC chips) programmed via flowcharts or code.

    • Output Devices: Convert electrical signals into light, sound, or motion: lamps, Light Emitting Diodes (LEDs), buzzers (electromechanical or piezoelectric), and loudspeakers.

  • Mechanical Movements & Devices:

    • Motion Types: Linear (straight line), Reciprocating (back and forth line), Rotary (circular), and Oscillating (swinging side-to-side).

    • Levers: Pivot on a fulcrum to convert effort into output load:

      • First-Order: Fulcrum situated between effort and load (e.g., seesaws, scissors).

      • Second-Order: Load situated between fulcrum and effort (e.g., wheelbarrows).

      • Third-Order: Effort situated between fulcrum and load (e.g., barbeque tongs, tweezers).

    • Linkages: Assemblies of levers that transfer force and alter motion direction (e.g., bell-crank turns motion by 90∘90^\circ; parallel motion/push-pull linkages).

    • Rotary Systems:

      • Cams & Followers: Convert rotary to reciprocating motion using rise, fall, and dwell profile angles (eccentric, egg-shaped, snail, pear, hexagon).

      • Gear Trains: Interlocking toothed wheels transmitting turning force (torque) and rotational speed (Velocity Ratio=Teeth on Driven GearTeeth on Driver Gear\text{Velocity Ratio} = \frac{\text{Teeth on Driven Gear}}{\text{Teeth on Driver Gear}}).

      • Rack & Pinion: Converts rotary motion to linear motion or vice versa.

      • Crank & Slider: Converts rotary motion to reciprocating motion (e.g., engine pistons).

      • Chain & Sprocket / Pulleys & Belts: Transmit rotary motion over distance (Velocity Ratio=Diameter of Driven PulleyDiameter of Driver Pulley\text{Velocity Ratio} = \frac{\text{Diameter of Driven Pulley}}{\text{Diameter of Driver Pulley}}).

Material Categories & Working Properties

  • Papers & Boards: Measured in grams per square metre (gsm\text{gsm}; paper is <200 gsm<200\,\text{gsm}, board is >200 gsm>200\,\text{gsm}).

    • Paper Types: Bleed proof, cartridge, grid/isometric, layout, tracing.

    • Board Types: Corrugated card, duplex board, foil-lined board, foam core board, inkjet card, solid white board.

  • Timbers:

    • Hardwoods (Deciduous): Broad-leaved, slow-growing. Examples: Ash, beech, mahogany, oak, balsa (softwood characteristics, but botanically classified as hardwood).

    • Softwoods (Coniferous): Evergreen, fast-growing. Examples: Larch, pine, spruce.

    • Manufactured Boards: Medium-Density Fibreboard (MDF), plywood (cross-laminated veneers), chipboard/particle board.

  • Metals & Alloys:

    • Ferrous (contains iron, magnetic, prone to rust): Cast iron, low carbon steel (mild steel), high carbon steel (tool steel).

    • Non-Ferrous (no iron, non-magnetic, corrosion-resistant): Aluminium, copper, zinc, tin.

    • Alloys: Brass (copper + zinc), stainless steel (steel + chromium + nickel), duralumin (aluminium + copper + magnesium + manganese).

  • Polymers:

    • Thermoforming (re-heatable, re-mouldable, recyclable): Acrylic (PMMA), High-Impact Polystyrene (HIPS), High-Density Polythene (HDPE), Polypropylene (PP), Polyvinyl Chloride (PVC), Polyethylene Terephthalate (PET).

    • Thermosetting (permanently heat-set, non-recyclable): Epoxy resin, Melamine Formaldehyde (MF), Phenol Formaldehyde (PF), Polyester resin, Urea Formaldehyde (UF).

  • Textiles:

    • Natural Fibres: Plant/animal sources (Cotton, Wool, Silk).

    • Synthetic Fibres: Petrochemical sources (Polyester, Polyamide/Nylon, Elastane/Lycra).

    • Fabric Constructions: Woven (plain, twill, satin weaves featuring warp, weft, and selvedge), Non-woven (bonded, felted), Knitted (weft knit, warp knit).

  • Physical & Mechanical Properties:

    • Physical Properties: Fusibility, electrical conductivity, thermal conductivity, moisture resistance, absorbency, density.

    • Mechanical Properties: Tensile/compressive/shear/torsional strength, hardness, toughness, malleability, ductility, elasticity.

Specialist Principles: Manufacturing, Forces & Sustainability

  • Forces, Stresses & Enhancement:

    • Structures must withstand tension, compression, shear, bending, and torsion.

    • Enhancements: Steel reinforcement in concrete, synthetic fiber webbing in seatbelts, interfacings in garment collars, cross-lamination in plywood, and high-tensile fiber reinforcing (e.g., Kevlar/fibreglass in engine timing belts).

  • Ecological, Social & Ethical Footprints:

    • Environmental impacts include mining (deforestation, toxic chemical run-off), drilling (oil spills, gas flaring), farming (habitat loss, soil erosion), and ocean plastic pollution.

    • The 6 Rs: Reduce, Reuse, Recycle, Rethink, Refuse, Repair.

    • Ethical Standards: Forest Stewardship Council (FSC) certified timber, Fairtrade premium standards, and anti-exploitation employment guidelines (no child labor, fair living wage).

  • Material Extraction & Conversion:

    • Paper: Cellulose wood pulp bleached and dried on Fourdrinier machines.

    • Timber: Trees felled →\rightarrow converted (baulk, through-and-through, tangential, or quarter cut) →\rightarrow seasoned (air or kiln drying).

    • Polymers: Crude oil extracted →\rightarrow fractional distillation (yielding naphtha) →\rightarrow cracking into monomers →\rightarrow polymerisation into polymer chains.

    • Metals: Ores extracted via mining →\rightarrow smelted in blast furnaces/reduction cells →\rightarrow refined.

  • Specialist Manufacturing Techniques:

    • Cutting & Shaping: Saws (tenon, coping, scroll, jigsaw), chiselling/paring, planing (jack, smoothing), disc/belt sanders, laser cutters, routers, 3D routers, CNC lathes/milling machines, plasma cutters.

    • Forming: Steam bending, laminating, kerfing, line bending, vacuum forming, press forming, injection moulding, extrusion, blow moulding, 3D printing/rapid prototyping.

    • Finishes: Stains, preservatives (tanalising), varnishes, oils, paints, anodising, electroplating, galvanising, powder coating, polishing, screen printing, encapsulation.

  • Production Scales & Stock Forms:

    • Scales: Prototype/One-off (bespoke), Batch (utilizing jigs, templates, and formers), Mass (assembly lines with standardized components), Continuous (24/7 automated production).

    • Materials Management: Tessellation and nesting to minimize scrap, datum points/coordinates ((x,y,z)(x, y, z)), and accounting for seam allowances or joint overlaps.

Designing and Making Principles & Influential Designers

  • Research & Specification:

    • Primary research (surveys, interviews, focus groups) vs. Secondary research (books, internet, articles).

    • Anthropometrics (body dimensions across 5th, 50th, and 95th percentiles) and Ergonomics (human-product interaction across physiological, psychological, and sociological factors).

    • Key Documents: Design Brief (problem statement), Design Specification (testable criteria), Manufacturing Specification (production instructions).

  • Design Movements & Influential Figures:

    • Arts & Crafts (1853–1907): Handcrafted, natural motifs, simple forms (William Morris).

    • Art Nouveau (1880–1910): Organic, sinuous whiplash lines, natural forms (Louis Comfort Tiffany, Charles Rennie Mackintosh).

    • Art Deco (1908–1935): Geometric, symmetrical, stepped profiles, bold contrast (Raymond Templier).

    • De Stijl (1917–1931): Primary colors, vertical/horizontal grid lines, abstract geometry (Gerrit Rietveld).

    • Bauhaus (1919–1933): Form follows function, mass production suitability, tubular steel, geometric simplicity (Marcel Breuer, Walter Gropius).

    • Postmodernism / Memphis (1970s–1990s): Controversial, vibrant colors, clashing patterns, humor (Ettore Sottsass, Aldo Rossi, Philippe Starck, Alessi).

    • Prominent Designers & Brands: Harry Beck (London Underground map), Coco Chanel & Mary Quant & Vivienne Westwood & Alexander McQueen (fashion design), Sir Alec Issigonis (Morris Minor, Mini), Norman Foster (high-tech architecture), Braun (Dieter Rams), Dyson (James Dyson), Apple (Steve Jobs, Jonathan Ive).

  • Design Strategies & Representation:

    • Strategies: User-centred design, biomimicry, iterative design (prototype-test-refine loop), system boundary diagrams, flowcharts.

    • Communication Techniques: Freehand 2D/3D sketching, line weight, thick and thin line work, rendering, isometric projection, 1-point/2-point perspective, orthographic projection (third-angle), exploded diagrams, schematic flats, and physical/virtual prototypes (toiles, breadboards, card/foam models).