What materials are used to make commercial products, and how do their properties decide the choice?
Materials used in the commercial manufacture of products: the properties and uses of thermoplastics, thermosetting plastics, elastomers, bio-based plastics, ferrous and non-ferrous metals and alloys, timbers, boards and composites, and the issues that influence material selection.
An SQA Advanced Higher Design and Manufacture answer on the materials used in commercial manufacture, covering the properties and uses of thermoplastics, thermosetting plastics, elastomers, bio-based plastics, ferrous and non-ferrous metals and alloys, timbers, boards and composites, and the issues that influence selection.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this key area is asking
The SQA wants you to know the materials used in commercial manufacture, their properties and their appropriate uses, and the issues that influence material selection. Advanced Higher widens the list well beyond Higher to include elastomers, bio-based plastics and composites. You must reason from properties (link a property to the product), which is what Section 2 and product-analysis questions reward.
Polymers: thermoplastics, thermosets, elastomers and bioplastics
- Thermoplastics: ABS (tough, good finish, casings), acrylic (clear, weather-resistant, signs and lenses), nylon (tough, low-friction, gears and bearings), polypropylene (tough, fatigue-resistant, living hinges), polycarbonate (very impact-resistant, safety guards), polystyrene (cheap, rigid or expanded for packaging), polythene (flexible, bottles and bags), PVC (durable, pipes and cladding).
- Thermosetting plastics: melamine formaldehyde (hard, heat-resistant surfaces and tableware), urea formaldehyde (rigid, electrical fittings).
- Elastomers: natural rubber (latex); synthetic rubbers - styrene-butadiene (tyres), neoprene (seals, wetsuits), silicone (heat-resistant seals and bakeware).
- Bio-based plastics: bio-based polymers (from renewable feedstock) and biodegradable polymers (break down to reduce waste).
Metals: ferrous and non-ferrous
- Ferrous metals and alloys (contain iron): iron (cast, brittle, bases and machine beds), mild steel (tough, easily worked, general use), high-speed steel (very hard, cutting tools), stainless steel (corrosion-resistant, cutlery and medical parts).
- Non-ferrous metals and alloys (no iron): aluminium (light, corrosion-resistant, easily cast and extruded), brass (corrosion-resistant, good conductor, fittings and contacts), copper (excellent conductor, wiring and pipes), tin (corrosion-resistant coating), zinc (galvanising and die casting).
Reason from the property: stainless steel for a wet environment because it resists corrosion; aluminium for a portable product because it is light; high-speed steel for a cutting edge because it stays hard.
Timbers, boards, composites and additives
- Timbers and manufactured boards: hardwoods (dense, durable), softwoods (cheaper, faster-grown, construction), and boards (MDF, plywood, chipboard) that are stable, large and cheap.
- Composites: carbon-fibre-reinforced plastic (very stiff and light, high cost, performance products) and glass-reinforced plastic (strong, light, mouldable, boats and panels). A composite combines materials to get properties neither has alone.
- Additives and fillers: added to polymers to change properties (plasticisers for flexibility, fillers to cut cost and add bulk, stabilisers, pigments).
Issues that influence material selection
The issues that influence the choice include: the properties needed (strength, weight, corrosion resistance, finish); manufacture (does it suit the chosen process?); cost and the scale of production; aesthetics; sustainability and recyclability; and current developments in materials (new composites and bioplastics that may change a product). Advanced Higher expects you to weigh these, not just name a property.
Where this fits in the course
Materials underpin the whole Manufacture area: the material must suit the commercial process and the designing-for-manufacture rules, and material choice is justified in product analysis and in sustainability.
Try this
Q1. Justify a thermoplastic for the casing of a power tool. [3 marks]
- Cue. ABS or polycarbonate because it is tough and impact-resistant, takes a good finish and is cheaply injection moulded for high volume.
Q2. Explain why aluminium is often chosen for portable products. [3 marks]
- Cue. It is light, corrosion-resistant and easily cast or extruded, so it suits products that must be carried and resist weathering.
Q3. Explain what a composite material is, with an example. [3 marks]
- Cue. A composite combines two or more materials to get properties neither has alone, such as carbon-fibre-reinforced plastic, which is very stiff and light.
Exam-style practice questions
Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
SQA Advanced Higher6 marksJustify the choice of three different materials for the parts of a commercial product such as a cordless kettle.Show worked answer →
Worth about 6 marks, so the marker wants three materials each justified
from a property linked to the part, not just named.
Body polymer. The outer body is polypropylene because it is tough,
food-safe, heat-resistant enough for the wall, and cheaply injection
moulded, suiting a high-volume kitchen product.
Element and contacts metal. The heating element sheath is stainless steel
because it resists corrosion in water and conducts heat well, and brass is
used for electrical contacts because it conducts and resists corrosion.
Handle insert. A thermosetting plastic or a heat-resistant grip is used
where the part is near heat, because thermosets do not soften when warm.
Conclude. A top answer links each property to the part and the use and
notes the choices suit mass production, which is what the marker rewards.
SQA Advanced Higher4 marksExplain the difference between a thermoplastic and a thermosetting plastic, with an example of each.Show worked answer →
Worth about 4 marks. The markers want the behaviour on heating, the
reason, and an example of each.
Thermoplastic. It softens when heated and can be reshaped again and again
because its long chains are not permanently linked, so it can be moulded
repeatedly and recycled, for example polypropylene or ABS.
Thermosetting plastic. It sets permanently on first heating and curing as
its chains cross-link, so it cannot be remelted but resists heat well, for
example melamine formaldehyde or urea formaldehyde.
Why it matters. A strong answer notes that the choice depends on the use:
thermoplastics for mouldable, recyclable parts, thermosets for
heat-resistant electrical fittings and surfaces.
Related dot points
- Processes used in the commercial manufacture of products: the appropriate uses and features of moulding, casting, forging, forming and digital processes, and the issues that influence the selection of a process.
An SQA Advanced Higher Design and Manufacture answer on the processes used in commercial manufacture, covering the uses and features of injection, blow, compression, rotational and gas-assisted moulding, die casting, drop forging, press forming, thermoforming, 3D printing, laser cutting and CNC machining, and how a process is selected.
- Designing for manufacture: mould and pattern design, wall thicknesses, split lines, injection and ejector points, draft angles, location pins, fillets and radius corners, undercuts, shrinkage and thinning, integrated assembly features, and the purpose of bosses, ribs and webs.
An SQA Advanced Higher Design and Manufacture answer on designing for manufacture, covering mould and pattern design, wall thickness, split lines, draft angles, fillets and radii, undercuts, shrinkage and thinning, integrated assembly features, and the purpose of bosses, ribs and webs in moulded parts.
- Product analysis: the information gathered from analysing commercial products, including identifying influences on performance, evaluating performance, analysing manufacture and assembly, and judging impact on society and the environment, as referenced in question 1 of the question paper.
An SQA Advanced Higher Design and Manufacture answer on product analysis, covering the information gathered from analysing commercial products: identifying and evaluating influences on performance, analysing manufacture and assembly, and judging impact on society and the environment, as needed for question 1 of the question paper.
- The impact of design and manufacturing technologies on society, the environment and the workforce: methods to limit a product's environmental impact, the effects of traditional and new technologies, and the economic and environmental sustainability of products.
An SQA Advanced Higher Design and Manufacture answer on the impact of design and manufacturing technologies, covering the methods designers and manufacturers use to limit a product's environmental impact, the effects of traditional and new technologies on society and the workforce, and the economic and environmental sustainability of products.
- Assembly methods used in the commercial manufacture of products: methods used to join materials, the issues that influence assembly, and simplifying assembly by limiting handling and operations, standardising parts and operations, limiting the number of parts, and using jigs.
An SQA Advanced Higher Design and Manufacture answer on assembly methods in commercial manufacture, covering the methods used to join materials, the issues that influence assembly, and how assembly is simplified by limiting handling and operations, standardising and limiting parts, and using jigs.