Mr Ridley's Design and Technology Revision Lecture

Overview

• Duration: 1 hour
• Suitable for all exam boards
• 6 episodes
  1. Plastics
  2. Hand tools
  3. Joining Metals
  4. Sustainability
  5. Sustainability question
  6. Health and Safety

Episode 1: Plastics

Origin of Plastic

• Made from oil (finite resource)
• Oil formation: sea creatures/plants → sea floor → layers → oil (millions of years)
• Not sustainable, non-biodegradable

Types of Plastics

Thermoplastics

• Melts and reshapes, easily recyclable
• Examples:
  • Acrylic: Good impact strength, lightweight, polished, colorful
  • Polythene: Tough, chemical resistant, shampoo bottles, hard to recycle
  • PET: Excellent waterproof, easy to recycle, used for bottles
  • PVC: Durable, chemical resistant, used for pipes
  • HIPS: Tough, high impact strength, used for toys
  • ABS: High quality, glossy, used for Lego, expensive
• PLA: Biodegradable, made from plants, used in 3D printing

Thermosetting Plastics

• Retains form after heating/cooling, difficult to recycle
• Examples:
  • Urea Formaldehyde: Used for electrical casings, brittle, stain-resistant
  • Polyester Resin: Waterproof, good chemical/heat resistance, used for glues

Key Terms

• Plasticity: Ability to change shape
• Durability: Withstand weathering

Episode 2: Hand Tools

Measuring Tools

• Vernier Caliper: Accurate to 0.1 mm
• Steel Ruler: Accurate to ~0.5 mm
• Measuring Tape: Accurate to ~1 mm

Wood Tools

• Coping Saw: Curved cuts
• Tenon Saw: Straight cuts
• Try Square: Draw 90° lines
• Bench Hook/Wood Vise: Secure wood for cutting
• Wood Plane: Smooth wood, shape edges
• Screwdrivers: Plain head and posi-drive
• Mallet: Hit chisels
• Pin Hammer: Small nails
• Marking Gauge: Marks lines on wood
• Wood Chisels: Remove wood
• Rasp & Surform: Shape wood
• Abrasive Paper: Smooth wood

Metal Tools

• Hacksaw: Cut metal
• Scriber: Mark metal
• Ball Peen Hammer: Hammer metal
• Files: Remove material (different shapes)
• Center Punch: Marks for drilling
• Tin Snips: Cuts thin steel

Episode 3: Joining Metals

Categories

• Permanent Joining: Welding, Brazing, Soldering
• Non-permanent Joining: Nuts, Bolts, Screws

Techniques

Soldering

• Weak join, low melting point
• Uses solder and soldering iron

Brazing

• Stronger than soldering
• Uses brass filler metal, gas torch

Welding

• Strongest joining method
• Types: Gas Welding, Arc Welding, MIG Welding
• Arc & MIG Welding: Uses electrical current
• Spot Welding: Sheet steel, mechanized welding

Temporary Methods

• Set Screws/Nuts and Bolts: Variety of head types
• Spring Washers & Nylon Lock Nuts: Prevent loosening
• Countersinking: Achieves flush finish
• Pop Riveting: Joins sheet metal, one sided access
• Thread Cutting: Internal/external threads using Taps and Dies

Episode 4: Sustainability

Key Concepts

• Reducing environmental impact of products
• Managed forestry and biodegradable materials
• Biopolymers: Plastics not from oil (PLA)

The 6 R's

1. Reduce: Minimize material use
2. Rethink: Better problem-solving methods
3. Refuse: Avoid unnecessary products
4. Recycle: Convert materials into new products
5. Reuse: Extend product life
6. Repair: Fix before disposal

Importance of Trees

• Absorb CO2, combat global warming

Sustainability Question

• Example: Comparing glass vs plastic bottles on sustainability
• Discuss finite resources, recyclability, production energy

Episode 6: Health and Safety

Safety Signs

• Prohibitive (Red): Do not do
• Mandatory (Blue): Must do
• Warning (Yellow): Alert to danger

Safety Equipment

• Goggles: Protect eyes
• Ear Defenders: Protect hearing
• Dust Masks: Protect lungs
• Gloves: Handling hot metal
• Face Shield: Full face protection
• Welding Mask: UV protection

Safety Precautions

• Tie back long hair
• Wear an apron

COSHH Regulations

• Control of Substances Hazardous to Health
• Examples: Paints, glues, dusts

Practice Questions

• Apply safety rules and precautions in examples
• Explain symbols and regulations related to workshop safety

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Remember to pay attention to the details of each episode for potential exam questions. Keep revisiting these notes to reinforce understanding and retention. Enjoy your revision!