IGCSE DT Booklet (1)

Materials:


Metals

  • ferrous (contain iron)

    • Mild steel

    • stainless steel

    • wrought iron

  • non ferrous

    • Copper

    • brass

    • aluminum

woods

  • manmade

    • Plywood

    • chipboard

    • MDF

  • natural

    • Pine

    • mahogany 

    • oak

textiles

  • cotton

  • wool

  • silk

  • dyes

  • fabric

  • threads

finishes

  • natural

  • varnish

  • paint

environment

  • Recycling

  • sustainable

  • renewable

  • non toxic

  • toxic

plastics

  • thermoplastic 

    • Acrylic

    • polythene

    • PVC

  • thermosetting

    • Polyester resin

    • melamine formaldehyde 

    • polyurethane

Properties of Materials

Key Properties

  • Strength: Ability to withstand applied forces.

  • Elasticity: Flexibility of material under force.

  • Plasticity: Permanent shape change under stress.

  • Ductility: Ability to stretch without breaking.

  • Tensile Strength: Resistance to pulling forces.

  • Compressive Strength: Resistance to squeezing forces.

  • Malleability: Ability to be reshaped without cracking.

  • Toughness: Durability under sudden shock.

  • Hardness: Resistance to surface deformation.

  • Thermal and Electrical Conductivity: Ability to conduct heat and electricity.

  • Stability: Resistance to dimensional changes.

Wood Growth Process

  • Roots: Absorb water and nutrients.

  • Sapwood: Transports sap; living part of the tree.

  • Heartwood: Stronger, durable part used commercially.

  • Bark: Protective covering.

  • Annual Rings: Indicate growth patterns.

Wood Types

Hardwoods

  • Deciduous trees: Lose leaves; slow-growing and often more expensive (e.g., Oak, Ash).

  • Evergreen hardwoods: Grow faster; softer and easier to work (e.g., Mahogany, Teak).

Softwoods

  • Conifers: Needle-like leaves; faster growth; cheaper and softer (e.g., Pine, Fir).

Wood Properties and Workability

  • Preparation: Knowledge of cutting methods and tools.

  • Marking: Accurate measurement and marking procedures are fundamental for success.

Tool Safety and Usage

  • Workshop environment requires adherence to strict safety protocols to prevent accidents.

Joining Processes

Ferrous and Non-Ferrous Metals

  • Ferrous metals: Mainly iron (e.g., mild steel).

  • Non-Ferrous metals: Do not contain iron (e.g., aluminum, copper).

Heat Treatment Techniques

  • Annealing, Hardening, and Tempering adjust the properties of metals according to their intended use.

Chemical Joining

  • Techniques like Soldering and Welding are employed for joining metals, being mindful of safety and preparation.

Plastic Manufacturing Processes

Types of Plastics

  • Thermoplastics: Can be reshaped with heat (e.g., PVC).

  • Thermosetting Plastics: Permanent shape once set.

Moulding Processes

  • Injection Moulding: Produces complex shapes, ideal for mass production.

  • Vacuum Forming: Simple forming process for creating products from thin plastic sheets.

Metalworking Processes

Cutting Techniques

  • Machining, Sawing, Drilling: Different tools and techniques for processing metals and plastics.

Conclusion

  • Understanding materials and their properties is critical for successful design and technology projects.