The six material groups

A-level Product Design works across six broad material groups. For each you must know a working definition, key examples, typical properties and where each is used.

• Papers & boards — from graphics stock to rigid packaging.
• Timbers — hardwoods, softwoods and manufactured boards.
• Metals — ferrous, non-ferrous and alloys.
• Polymers — thermoforming and thermosetting plastics.
• Textiles — natural and synthetic fibres.
• Composites, smart & modern materials — engineered and responsive materials.

Selection is a trade-off. Designers choose materials by weighing function, aesthetics, cost, availability, ease of working and environmental impact — rarely is one material best on every count.

Papers and boards

Paper and board are sold by weight per unit area, measured in gsm (grams per square metre). By convention, stock above about 200 gsm is called board (its thickness is often quoted in microns, µm).

• Layout / bleedproof paper (~50 gsm) — thin, for marker rendering.
• Cartridge paper (~120–150 gsm) — general drawing.
• Corrugated board — fluted core between liners; strong yet light packaging.
• Foamboard & solid white board — rigid modelling and premium packaging.

Your turn — paper weight (gsm)

Timbers: hardwood, softwood, manufactured

Natural timber is classified by the tree it comes from — not by how hard it feels.

• Hardwoods come from broad-leaved (deciduous) trees. They generally grow slowly, are denser and cost more — e.g. oak, ash, beech, mahogany, balsa (balsa is a hardwood despite being soft).
• Softwoods come from coniferous (needle-leaved, evergreen) trees. They grow faster and are cheaper — e.g. pine, spruce, larch, cedar.
• Manufactured boards are made from timber fibres, veneers or particles bonded with adhesive — MDF, plywood, chipboard. They are stable (resist warping) and come in large sheets.

Hardwood or softwood?

Metals: ferrous, non-ferrous, alloys

Metals split into three groups:

• Ferrous metals contain iron, so most are magnetic and will rust (oxidise) unless protected — e.g. mild steel, cast iron.
• Non-ferrous metals contain no iron, so they resist rust and are usually non-magnetic — e.g. aluminium, copper, zinc, tin.
• Alloys are mixtures of two or more metals (or a metal and another element) engineered for better properties — e.g. brass (copper + zinc), bronze (copper + tin), stainless steel (iron + chromium), pewter (tin-based).

Sort the metals

Tap a metal, then tap its group.

Why does mild steel rust?

Polymers: thermoforming vs thermosetting

The key division is what happens when you reheat the polymer.

• Thermoforming (thermoplastic) polymers soften when heated and can be reshaped repeatedly — so they are recyclable. Examples: HDPE, LDPE, PP, PS, PET, PVC, acrylic (PMMA).
• Thermosetting polymers undergo an irreversible chemical cross-linking when first set. They cannot be re-melted and resist heat — Examples: epoxy resin, polyester resin, urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde (Bakelite).

Design consequence: thermoplastics suit injection/blow/vacuum forming and recycling; thermosets suit heat-resistant handles, electrical fittings and resin composites.

Which polymer will not re-melt?

Textiles: natural and synthetic

Fibres are spun into yarns and then woven, knitted or bonded into fabric.

• Natural fibres come from plants or animals — cotton (plant, absorbent, cool), wool (animal, warm, resilient), silk (animal, strong, lustrous), linen (plant, strong).
• Synthetic fibres are polymer-based — polyester (strong, crease-resistant), nylon/polyamide (tough, elastic), elastane/Lycra (very stretchy).
• Blends (e.g. polyester-cotton) combine properties — comfort of cotton with the durability and easy-care of polyester.

Composites

A composite combines two or more materials so the result has properties better than either alone — usually a strong reinforcement held in a matrix.

• GRP (glass-reinforced plastic / fibreglass) — glass fibres in polyester resin; used for boat hulls and body panels.
• CFRP (carbon-fibre reinforced polymer) — very high strength-to-weight; used in bikes, F1 and aerospace.
• Concrete and reinforced concrete (with steel bars) — compression + tension.
• Plywood & MDF are also composite manufactured boards.

What makes a composite?

Smart and modern materials

Smart materials respond reversibly to a change in their environment:

• Shape-memory alloy (SMA, e.g. Nitinol) — returns to a remembered shape when heated.
• Thermochromic pigment — changes colour with temperature (mood spoons, battery testers).
• Photochromic — changes colour with light (self-tinting lenses).
• Piezoelectric — generates a voltage when squeezed (sensors, igniters).

Modern materials are newly developed rather than responsive — e.g. graphene, Kevlar (aramid), PLA/corn-starch polymers (bio-based), precious metal clay.

Identify the smart material

Match material to application

Tap a material, then its typical product application.

The big ideas to know

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