Function & performance
Design & Manufacture · National 5 · mrkellydt.co.uk
What you're learning in this topic
Learning intention WALT
We are learning about function & performance, specifically to understand:
- how function influences the design of a product
- primary and secondary functions with examples
- how performance and fitness for purpose influence design
- maintenance issues associated with products
- how life expectancy affects design, manufacture and the environment
Success criteria WILF
- I can describe how function influences the design of a product
- I can explain primary and secondary functions with examples
- I can describe how performance and fitness for purpose influence design
- I can describe maintenance issues associated with products
- I can explain how life expectancy affects design, manufacture and the environment
Function
Function is what a product has to do. Features such as controls, handles and grips are included to improve it, and function influences the choice of materials, manufacture and assembly.
- Primary function: the main job (a kettle boils water).
- Secondary function: extra jobs that add value (water level window, cord storage).
Form follows function: the shape of a product should come from what it has to do (e.g. a funnel's cone, a handle shaped to the grip). Efficient products do their job with the least effort, energy and material.
Performance
How well the product performs its function. Designers consider ease of use, maintenance, life expectancy, fitness for purpose and safety.
- Fitness for purpose: does it do what it should, for its user, where it will be used, for as long as expected?
- Maintenance: who will maintain it, what tasks (charge, fill, empty, adjust, replace parts) and how easy access is. Easy-to-maintain products last longer, but can reduce repeat sales.
- Life expectancy: a disposable razor lasts days; one with a replaceable head lasts years. Longer life usually means better materials and assembly, higher cost and less waste.
Key terms
| Primary function | The main job a product is designed to do. |
|---|---|
| Secondary function | Additional jobs that add value to the product. |
| Fitness for purpose | How well a product meets its intended use, user, environment and life expectancy. |
| Maintenance consideration | Who maintains it, what tasks are needed, and how easily parts can be accessed or replaced. |
Quick check
1. A torch that also works as a bottle opener. The bottle opener is…
- Secondary function
- Primary function
- Performance
- Aesthetics
Show answer
2. Making a phone battery hard to replace mainly affects which factor?
- Aesthetics
- Maintenance
- Target market
- Anthropometrics
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3. A razor with replaceable heads compared with a disposable razor has…
- Longer life expectancy
- Shorter life expectancy
- No maintenance
- No secondary function
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Exam-style questions
1. Describe how the life expectancy of a product can influence its design, manufacture and impact on the environment. (3 marks)
Show marking guidance
- Long-life products use more durable materials/finishes (1)
- Assembled so parts can be accessed/replaced, e.g. screws not adhesive (1)
- Throwaway products use cheaper materials/processes, creating more waste (1)
Printable worksheet
An I do, we do, you do worksheet for this topic, with a separate answer sheet.