The benefits of quality systems to the manufacturer and the consumer.

Cambridge International AS & A Level Design & Technology (9705) – Lecture Notes

1. How to use these notes

• Each numbered heading follows the exact order of the syllabus (AS 1‑12, A 13‑18).
• Key points are in bullet form – ideal for quick revision and exam flash‑cards.
• “AO‑Mapping” tables show which Assessment Objectives (AO1‑AO4) each sub‑topic addresses.
• “Link‑in” boxes highlight connections between topics (e.g., quality systems ↔ sustainable design).
• Diagrams and tables are marked with <figure> tags – copy them into your notebook or print them as revision sheets.

2. Assessment Objectives (AOs) – Quick Reference

AO	What is assessed?
AO1	Knowledge and understanding of theory, terminology and principles.
AO2	Application of knowledge – interpreting diagrams, symbols, standards and calculations.
AO3	Analysis and evaluation – weighing advantages, disadvantages, risks and sustainability.
AO4	Communication – clear presentation of ideas using appropriate technical language, diagrams and tables.

AS‑Level Topics (1‑12)

1 The Design Process – Iterative vs Intuitive Design (AO1‑AO4)

• Stages: Brief → Research → Concept Generation → Development → Realisation → Evaluation → Communication.
• Iterative design: cycles of prototype → test → modify → retest. Example: redesigning a bicycle frame after fatigue testing.
• Intuitive design: relies on designer’s experience; useful for low‑risk, time‑critical projects such as emergency‑use medical tools.

2 Design Principles – Good‑Design Checklist (AO1‑AO3)

• Functionality, ergonomics, aesthetics, sustainability, safety, reliability, manufacturability, cost‑effectiveness.
• Checklist example – handheld power drill
  1. Delivers required torque (function).
  2. Grip fits 5th‑95th percentile hand sizes (ergonomics).
  3. Modern matte‑black finish aligns with brand identity (aesthetics).
  4. Housing made from recycled aluminium (sustainability).
  5. Double‑insulated switch prevents electric shock (safety).
  6. Modular motor assembly for easy replacement (manufacturability).
  7. Target price £45 (cost‑effectiveness).

3 Communication – From Sketches to Technical Drawings (AO2‑AO4)

• Freehand sketching, orthographic projection, isometric & exploded views.
• CAD standards (ISO 128) – layers, line weights, dimensioning.
• Presentation tools: mood boards, storyboards, product portfolios.

4 Society, Culture & Sustainable Design (AO1‑AO3)

• Inclusive ergonomics – design for diverse body sizes, cultural colour meanings.
• Life‑cycle thinking: raw‑material extraction → manufacture → use → end‑of‑life.
• Eco‑design strategies:
  • Material substitution (e.g., bioplastics for packaging).
  • Modular design & design for disassembly.
  • Energy‑efficient manufacturing (heat‑recovery, low‑temperature forming).

5 Health & Safety in Design (AO1‑AO3)

• Risk‑assessment matrix: likelihood × severity → risk rating.
• Key legislation:
  • EU Machinery Directive (2006/42/EC).
  • ISO 45001 – Occupational health & safety management.
• Design controls:
  • Physical guarding, interlocks, safety‑rated switches.
  • Ergonomic risk reduction – adjustable workstations, anti‑vibration handles.

6 Aesthetics & Ergonomics (AO1‑AO3)

• Visual appeal – proportion, balance, rhythm, colour theory.
• Human factors – anthropometric data (5th‑95th percentile), reach envelopes, grip forces.
• Case study: redesign of a kitchen knife reduced wrist extension by 15 % and improved cutting efficiency by 10 %.

7 Materials & Components – Selection Criteria (AO1‑AO2)

• Properties to consider:
  • Mechanical: tensile strength, hardness, impact resistance.
  • Physical: density, thermal conductivity, coefficient of thermal expansion.
  • Chemical: corrosion resistance, UV stability.
  • Environmental: recyclability, embodied energy.
• Selection tools:
  • Material selection charts (Ashby diagrams).
  • CE marking & REACH compliance tables.
• Example: polymer choice for a mobile‑phone case – polycarbonate (high impact, high cost) vs. TPU (moderate impact, low cost).

8 Stages in Processing – From Raw Material to Finished Part (AO1‑AO2)

• Forming: casting, forging, extrusion, roll‑forming.
• Machining: turning, milling, drilling, EDM.
• Joining: welding, brazing, adhesives, mechanical fasteners.
• Finishing: coating, heat‑treatment, surface‑texturing.

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9 Materials Processing – Energy & Control (AO1‑AO2)

• Energy forms: electrical, thermal, hydraulic, pneumatic.
• Conversion devices: electric motors, steam turbines, hydraulic pumps, pneumatic cylinders.
• Control systems:
  • PLCs – programmable logic controllers.
  • CNC – computer‑numerical control for machining.
  • PID control – proportional‑integral‑derivative feedback loops (see Figure 2).
• Impact on quality: stable temperature reduces residual stress; precise speed control improves surface finish.

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10 Emerging Technologies – Digital Fabrication & Smart Materials (AO1‑AO3)

Technology	Key Features	Typical Application
FDM (Fused Deposition Modelling)	Thermoplastic extrusion, layer‑by‑layer	Prototyping of plastic enclosures
SLA (Stereolithography)	UV‑cured resin, high surface finish	Dental models, precision tooling
SLS (Selective Laser Sintering)	Powder bed fusion, no support structures	Functional aerospace brackets
IoT‑enabled products	Embedded sensors, wireless data transmission	Smart thermostats, predictive‑maintenance pumps
Shape‑memory alloys (SMA)	Recover original shape on heating	Actuators in aerospace & medical devices
Piezo‑electric polymers	Generate voltage under strain	Energy‑harvesting floor tiles

• Case study: a SMA‑actuated valve reduces the number of moving parts in a refrigeration system, improving reliability and lowering assembly time.

11 Industrial Practices – Service Sectors & Roles (AO1‑AO4)

• Service sectors: automotive, consumer electronics, medical devices, construction, aerospace.
• Key roles:
  • Designer – concept, specification, GD&T.
  • Manufacturer – process planning, quality assurance, production management.
  • Supplier – material provision, component sub‑assembly.
  • Consumer – feedback, after‑sales service.
• Collaboration models:
  • Concurrent engineering – parallel development of design and manufacturing.
  • Design‑for‑X (DfX) – manufacturability, assembly, cost, reliability.

12 Business & Commercial Practices – Product Life‑Cycle & the 4 Ps (AO1‑AO4)

• Product life‑cycle stages: Introduction, Growth, Maturity, Decline.
• 4 Ps of marketing: Product, Price, Place, Promotion – influence design brief and target market.
• Costing methods:
  • Target costing – set selling price → deduct desired profit → determine allowable cost.
  • Activity‑based costing – allocate overheads based on actual activities.
• Example: a smartwatch project uses target costing to keep retail price under £120 while achieving a 20 % profit margin.

A‑Level Topics (13‑18)

13 Industrial Practices – Quantity Production (AO1‑AO3)

• Production types:
  • Batch production – set‑up for a limited run, then changeover.
  • Continuous flow – steady‑state operation (e.g., steel rolling).
  • Mass‑customisation – modular platforms allowing product variants.
• Key concepts:
  • Takt time = available production time ÷ customer demand.
  • Line balancing – allocate tasks to minimise idle time.
  • Bottleneck analysis – identify and alleviate the slowest operation.
• Quantitative example: Economic Production Quantity (EPQ) for a plastic injection‑moulded component
  Given: demand D = 30 000 units/yr, set‑up cost S = £800, holding cost H = £0.15/unit/yr, production rate P = 10 000 units/yr.
  EPQ = √[ (2DS) / (H(1‑D/P)) ] = √[ (2×30 000×800) / (0.15×(1‑30 000/10 000)) ] ≈ 7 746 units.
  Interpretation: produce ~7 800 units per batch to minimise total cost.

14 Business & Commercial Practices – Global Supply Chains (AO1‑AO3)

• Out‑sourcing, off‑shoring, near‑shoring – compare cost, lead‑time, risk.
• Incoterms (2020):
  • EXW – buyer bears all transport risk.
  • FOB – seller loads on board vessel; risk passes at port.
  • CIF – seller pays cost, insurance, freight; risk passes at destination port.
• Risk mitigation strategies:
  • Dual‑sourcing – two approved suppliers for critical components.
  • Inventory buffers – safety stock calculated via service‑level factor.
  • Supplier audits – ISO 9001 compliance checks, on‑site inspections.
• Impact of certifications (e.g., ISO 14001, ISO 45001) on market access and contract eligibility.

15 Quantity Production – Industrial Materials Processing (AO1‑AO2)

• High‑speed stamping – rapid punch‑press cycles, die wear considerations.
• Roll‑forming – continuous bending of sheet metal; ideal for long sections (e.g., roof purlins).
• Extrusion – profile shaping of aluminium, PVC, and composites.
• Continuous casting – solidification of molten metal into slabs or billets.
• Process control:
  • Statistical Process Control (SPC) – control charts, process capability (Cp, Cpk).
  • Real‑time monitoring – temperature, force, speed sensors linked to MES.
• Environmental considerations:
  • Waste‑heat recovery – using exhaust heat to pre‑heat feedstock.
  • Closed‑loop water systems – filtration and reuse to minimise discharge.

16 Quantity Production – Digital Technology (AO1‑AO4)

• Computer‑Integrated Manufacturing (CIM) – seamless flow from CAD → CAM → CNC → inspection.
• Industry 4.0:
  • Cyber‑physical systems – machines equipped with sensors and actuators that communicate autonomously.
  • Digital twins – virtual replica of a production line for scenario testing.
  • Predictive analytics – machine‑learning models forecast downtime.
• Data standards:
  • STEP (ISO 10303) – neutral file format for product data exchange.
  • MTConnect – open protocol for machine tool data.
• Example: a factory uses MTConnect to stream spindle speed data to a cloud dashboard; an alert is generated when vibration exceeds the control limit, prompting a preventive maintenance ticket.

17 Quality Systems – Detailed Coverage (AO1‑AO4)

17.1 Definition and Scope

A quality system is a coordinated set of policies, procedures, processes and resources required to implement quality management throughout the product life‑cycle. It includes:

• Quality Assurance (QA) – planned activities (audits, process design) that give confidence requirements will be met.
• Quality Control (QC) – operational techniques (inspection, testing) used to fulfil quality requirements.
• Total Quality Management (TQM) – organisation‑wide philosophy of continuous improvement through employee involvement.
• Six Sigma – data‑driven methodology targeting ≤3.4 defects per million opportunities (DMO).
• ISO 9001:2015 – internationally recognised standard based on the Plan‑Do‑Check‑Act (PDCA) cycle.

17.2 ISO 9001 Structure – The PDCA Cycle

1. Plan – set quality objectives, define processes, allocate resources.
2. Do – implement processes, produce the product.
3. Check – monitor performance (internal audits, control charts).
4. Act – take corrective action, drive continual improvement.

17.3 Core Quality Tools (AO2)

Tool	Purpose	Typical Output
Process Flow Diagram	Visualise each production step	Sequential block diagram (see Figure 3)
Check Sheet	Record frequency of defects in real time	Tabular count of defect types per shift
Control Chart (X̄ & R)	Monitor process stability and variability	Centre line, Upper/Lower Control Limits
Pareto Analysis	Identify the “vital few” causes of problems	Bar chart with cumulative % line
Cause‑and‑Effect (Fishbone) Diagram	Explore root causes across categories (Man, Machine, Method, Material, Measurement, Environment)	Spine‑and‑rib diagram

17.4 Quantitative Example – Evaluating a Quality System (AO3)

Scenario: An electric‑kettle manufacturer implements ISO 9001. Defect data for four weeks are shown below.

Week	Units Produced	Defective Units	Defect Rate (%)
1	5 000	150	3.0
2	5 200	104	2.0
3	5 100	77	1.5
4	5 300	53	1.0

• Defect rate fell from 3 % to 1 % – a 66 % reduction.
• Warranty cost assumed £20 per defective unit:
  • Week 1 cost = 150 × £20 = £3 000.
  • Week 4 cost = 53 × £20 = £1 060.
• Pay‑back period for the ISO 9001 implementation (£25 000 consultancy fee):
  £25 000 ÷ (£3 000 − £1 060) ≈ 13 weeks – a rapid ROI.
• Non‑quantitative benefits: stronger brand reputation, smoother regulatory audits, higher employee morale.

17.5 Benefits to the Manufacturer (AO4 – Communication)

• Reduced waste & re‑work – early defect detection can cut scrap by up to 40 % (see example above).
• Improved efficiency – standardised work instructions lower set‑up time by 15‑20 %.
• Enhanced reputation – ISO‑certified logo on packaging builds market confidence and can be a tender requirement.
• Compliance & risk management – audit trails satisfy legal, customer and insurance requirements.
• Data‑driven decision making – SPC data feed into Kaizen projects, reducing cycle time.

17.6 Benefits to the Consumer (AO4)

• Reliability & safety – lower defect rates mean fewer recalls and fewer injuries.
• Value for money – longer product life reduces total cost of ownership.
• Confidence & trust – visible quality marks (ISO 9001, CE) reassure buyers.
• Consistent performance – each unit meets the same specifications, simplifying use and maintenance.
• Environmental benefits – less waste and lower energy consumption during manufacture → smaller carbon footprint.

17.7 Link‑ins (Cross‑topic relevance) (AO4)

• Sustainable Design (AS 4) – quality systems reduce material waste and energy use, supporting eco‑design goals.
• Quantity Production (A 13) – ISO 9001 is often a prerequisite for large‑scale contracts and helps achieve takt‑time targets.
• Digital Technology (A 16) – real‑time SPC data are captured via PLCs and visualised in dashboards or digital twins.
• Business Practices (A 14) – certifications act as market differentiators in global supply chains.

18 Digital Technology – Integration with Quality Systems (AO1‑AO4)

• CAD → design verification (DFM/DFA) → automatic export of GD&T data to CNC machines.
• Manufacturing Execution Systems (MES) collect process data for SPC and feed back to the QMS database.
• IoT sensors on production lines provide real‑time alerts when control limits are breached; data stored in cloud‑based QMS platforms.
• Cloud‑based quality management software (e.g., QMS, SAP QM) stores audit records, corrective‑action reports and training logs, accessible to all stakeholders.

Electronic Symbols (p. 34 of the syllabus) – Printable Table

Symbol	Name	Typical Use
⚡	Power Supply	Battery, mains connection
⏚	Ground	Reference point for circuits
—|—	Resistor	Limits current
—⏚—	Capacitor	Stores charge
—▶	Diode	Allows current in one direction
≈	Inductor	Stores magnetic energy
⊕	Switch (normally open)	Opens/closes circuit
⊗	Switch (normally closed)	Breaks circuit when actuated
⧖	Transformer	Voltage step‑up/step‑down
⎓	Motor	Converts electrical to mechanical energy