How do designers select a material and its stock form for a product, and what factors drive that decision?
The selection of materials and standard stock forms (sheet, bar, rod, tube, extrusion, granules, pre-formed sections) for a product, weighing functional, aesthetic, economic, manufacturing, availability and environmental factors.
A focused answer to OCR A-Level Product Design on selecting materials and stock forms: the functional, aesthetic, cost, availability, manufacturing and environmental factors, the standard stock forms (sheet, bar, rod, tube, extrusion, section, granules), and how a designer justifies a material choice for a product.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
OCR wants you to explain how a designer chooses a material and the stock form it is bought in, weighing the competing factors, and to justify a choice for a named product. Selection is where the materials content meets the design content: the right material balances function, cost, manufacture, appearance and environmental impact.
The factors that drive material selection
These factors map onto the ACCESSFM specification headings (Aesthetics, Cost, Customer, Environment, Size, Safety, Function, Materials), which is why material selection is examined alongside the design process.
Standard stock forms
Buying the right stock form matters: choosing a tube rather than a solid bar for a frame saves weight and material; choosing a near-net extrusion or section reduces the machining needed and the waste produced.
Why stock form affects cost and waste
Matching material to product: a worked judgement
A designer rarely has one perfect material; they choose the best compromise and justify it. The justification names the property that matters most, checks the material can be manufactured at the right scale, and considers cost and end-of-life.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20204 marksName four standard stock forms in which materials are supplied to manufacturers, and for each give a product or component that is typically made from that stock form.Show worked answer →
A Component 01 recall question. One mark for each correctly paired stock form and product.
Award marks for any four of: sheet (metal or polymer panels, vacuum-formed packaging, a laptop lid); bar or rod (machined shafts, handles, axles); tube (bicycle and furniture frames, scaffolding); extrusion or pre-formed section (aluminium window frames, curtain track, plastic guttering); granules or pellets (the feedstock for injection moulding a kettle body); plank or board (timber furniture, MDF flat-pack panels); wire (springs, fasteners, electrical conductors); powder (rotational moulding, sintered parts).
A common dropped mark is naming a process (injection moulding) instead of a stock form (granules). The stock form is the shape the material is bought in before it is processed.
OCR 20228 marksEvaluate the factors a designer must consider when selecting the material for the body of a cordless kettle. Justify which material you would choose.Show worked answer →
A Component 01 levels-of-response question (AO2 application plus AO3 evaluation), marked by levels.
A top-level answer weighs several factors against the product, then concludes. Function: the body must resist boiling water and heat, be food-safe, electrically insulating and rigid, which favours a polymer such as polypropylene or, for a premium look, stainless steel with an inner liner. Aesthetics: a polymer can be coloured and moulded into smooth ergonomic forms, while brushed stainless steel signals quality. Manufacture and scale: a kettle is mass-produced, so injection-moulded polypropylene (from granules) gives low unit cost and complex shapes, while stainless steel needs pressing and more assembly. Cost and availability: polypropylene is cheap and widely available; stainless steel costs more. Environment: polypropylene is recyclable but oil-based; stainless steel is durable and highly recyclable. A justified conclusion might be polypropylene for a budget mass-market kettle (cheap, mouldable, insulating) but stainless steel for a premium model where durability and appearance justify the cost.
Markers reward weighing more than one factor and reaching a justified decision, not listing properties.
Related dot points
- The classification of materials used in product design: papers and boards, natural and manufactured timbers, ferrous and non-ferrous metals and alloys, thermoplastic and thermosetting polymers, and composites, with the defining features of each category.
A focused answer to OCR A-Level Product Design on the classification of materials: ferrous, non-ferrous metals and alloys, thermoplastic and thermosetting polymers, hardwoods, softwoods and manufactured boards, papers and boards, and composites, with the defining feature and a named example of each category.
- The physical and mechanical properties of materials (strength, hardness, toughness, ductility, malleability, elasticity, plasticity, density, conductivity, durability) and how they govern the suitability of a material for a product.
A focused answer to OCR A-Level Product Design on the physical and mechanical properties of materials: tensile and compressive strength, hardness, toughness, ductility, malleability, elasticity, plasticity, density and conductivity, with definitions, the calculation of density, and how each property governs material choice.
- Smart materials that change a property in response to an external stimulus (shape memory alloys, thermochromic and photochromic pigments, piezoelectric and electroluminescent materials) and modern materials developed by research (Kevlar, graphene, nanomaterials, polymorph), and their use in products.
A focused answer to OCR A-Level Product Design on smart and modern materials: shape memory alloys, thermochromic, photochromic, piezoelectric and electroluminescent materials, and modern materials such as Kevlar, graphene, nanomaterials and polymorph, with the stimulus, the response and a product application for each.
- The scales of production (one-off or bespoke, batch, mass and continuous), their use of jigs, fixtures and automation, the relationship between fixed cost, volume and unit cost, and Just in Time (JIT) stock control.
A focused answer to OCR A-Level Product Design on the scales of production: one-off (bespoke), batch, mass and continuous production, the use of jigs, fixtures and automation, the calculation of unit cost from fixed and variable costs, and Just in Time stock control.
- Design briefs and design specifications: the difference between them, writing measurable and justified specification criteria (using a framework such as ACCESSFM), and the role of the specification in evaluating a design and judging its viability.
A focused answer to OCR A-Level Product Design on design briefs and specifications: the difference between a broad brief and a measurable specification, writing justified design criteria using the ACCESSFM framework, and using the specification to evaluate a design and judge its viability.
Sources & how we know this
- OCR A Level Design and Technology (H404-H406) specification — OCR (2017)