Specifications
Design & Manufacture · Higher · mrkellydt.co.uk
What you're learning in this topic
Learning intention WALT
We are learning about specifications, specifically to:
understand
- the role of a specification in the design process
- the purpose and contents of a product design specification
- the purpose and contents of a performance specification
- the purpose and contents of a technical specification
be able to
- write specific specification points from a brief and research
Success criteria WILF
- I can explain the role of a specification in the design process
- I can write specific specification points from a brief and research
- I can describe the purpose and contents of a product design specification
- I can describe the purpose and contents of a performance specification
- I can describe the purpose and contents of a technical specification
What a specification is
A list of everything the product must do, be and have. It sets clear boundaries for the designer and covers every design factor: function, aesthetics, market, performance, ergonomics and safety.
It is used to evaluate ideas throughout the design process, so designs keep meeting the client's and user's needs.
Writing good specification points HIGHER
At Higher the product is commercially manufactured, so points also cover volume, cost, materials and processes, standards and environment. Points must come from the brief and research, and be specific and measurable.
| Weak | Strong |
|---|---|
| Must hold a standard bulb. | Must hold a 28 W bulb with a standard E14 screw fitting. |
| Must be easy to maintain. | Must leave at least 20 mm clearance around the bulb so it is easy to replace. |
| Must be low cost. | Must retail for no more than £20, with manufacturing cost about 30% of retail. |
| Must be environmentally friendly. | All plastic parts must be labelled for recycling and separable without tools. |
Three types of specification HIGHER
- Product design specification (PDS): written before the product is designed. Gives direction to the design team, defines parameters, used to evaluate decisions. Contains function, aesthetics, performance, safety, ergonomics, cost, quantity, target market, where it will be used, environmental impact.
- Performance specification: summarises the performance the product must achieve without saying how. Covers legislation, standards and regulations, sustainability, guarantee requirements, ease of use, durability.
- Technical specification: written after the product is designed and tested. Gives the technical details needed to manufacture it: materials, processes, assembly methods, dimensions, weight, production costs, power supply, maintenance cycles, safety standards.
In the Higher assignment, use at most 3 points from the brief plus at least 8 from your research.
Key terms
| Where does specification information come from? | The design brief and the results of research. |
|---|---|
| Why is a specification important to a designer? | It sets clear boundaries, gives direction, and is used to evaluate ideas against the client and user needs. |
| Product design specification | Written before designing. Sets parameters and direction; includes function, aesthetics, cost, target market, quantity, environment of use. |
| Performance specification | States the performance the product must meet without saying how: standards, legislation, sustainability, guarantees. |
| Technical specification | Written after designing. Technical detail to manufacture it: materials, processes, assembly, dimensions, costs. |
Quick check
1. Which is the strongest specification point?
- It must be safe for everyone to use
- It should look attractive to the target market
- It must be durable enough to last a long time
- It must fit a 40 mm diameter water bottle
Show answer
2. Which two sources provide information for a specification?
- Brief and research
- Sketches and models
- Working drawing and cutting list
- Marketing and retail
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3. Which specification is produced AFTER the product has been designed and tested?
- Product design
- Technical
- Performance
- Design brief
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4. "Must comply with BS EN 71 toy safety standards" belongs mainly in which specification?
- Technical
- Brief
- Performance
- Cutting list
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5. Which is most likely in a technical specification?
- Target market profile of 13–16 year olds
- It must appeal strongly to teenagers
- A retail price of under £20 in the shops
- Wall thickness of 2.5 mm in ABS
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Exam-style questions
1. Explain why a specification is an important tool for a designer. (2 marks)
Show marking guidance
- It clarifies what the solution must do/be/have (1)
- Designer can evaluate ideas and decisions against it to make sure they meet the client/user needs (1)
2. Describe the purpose of a product design specification and a technical specification, giving an example of the information found in each. (4 marks)
Show marking guidance
- PDS purpose: defines parameters, gives direction, used to evaluate decisions (1)
- PDS example: target market, cost, quantity, dimensions, environment of use (1)
- Technical purpose: gives technical detail required to manufacture, produced after design and testing (1)
- Technical example: materials, processes, assembly, dimensions, production costs (1)
Printable worksheet
An I do, we do, you do worksheet for this topic, with a separate answer sheet.