1.1.29 Product Manufacture & Industry
D&T 2026 — 1.1(c) Product Design Pathway
The different scales of production
Scale of production — how many of a product are made, and how often. It decides which materials, processes, machinery and labour are used, and how much each product costs.
As the number made goes up:
- Cost per product goes down, because tooling and set-up costs are shared across more items and materials are bought in bulk (economies of scale).
- Set-up cost and investment go up, because specialist machinery, moulds and automated lines are needed.
- Flexibility goes down, because changing the design means retooling.
- Skill moves from the hands of craftspeople into the machines and the people who programme and maintain them.
Job, batch and mass production, and Just in Time
| Scale | What it is | Advantages | Disadvantages | Examples |
|---|---|---|---|---|
| Job (one-off) production | A single product made to a client’s exact requirements, often by hand by skilled workers | Unique, made to measure, high quality; easy to change the design | Slow and labour-intensive; very high cost per item | Bespoke furniture, wedding dresses, prototypes, a made-to-measure kitchen |
| Batch production | A set quantity of identical products is made at one time; the batch may be repeated when needed | Flexible — equipment can switch to a different product between batches; jigs and templates keep parts consistent | Machines stand idle while being reset between batches; stock must be stored | Bread, furniture ranges, seasonal products, school uniforms |
| Mass production | Very large numbers of identical products made on a production line, often over a long period | Low cost per item; consistent quality; semi-skilled workers or automation | Huge set-up cost; inflexible; repetitive work for staff | Cars, phones, kettles, flat-pack furniture |
Just in Time (JIT) — a system in which materials and components arrive from suppliers exactly when they are needed on the production line, rather than being stored in a warehouse.
| Advantages of JIT | Disadvantages of JIT |
|---|---|
| Little money tied up in stock, and less warehouse space needed | Production stops if a delivery is late or a supplier fails |
| Less waste from damaged, out-of-date or unsold stock | Relies on very reliable suppliers and transport |
| Products can respond quickly to changes in demand | Frequent small deliveries can increase transport costs and emissions |
JIT is used widely in mass production, particularly the car industry, where it was developed by Toyota.
Continuous flow production
Continuous flow production — production that runs 24 hours a day, 7 days a week, making very high volumes of identical products on heavily automated lines.
- Used where demand is constant and enormous: drinks cans, plastic bottles, nuts and screws, paper, steel, chemicals and fuels.
- Stopping and restarting the process is expensive (furnaces must stay hot, for example), so the line runs without a break.
- Advantages: the lowest possible cost per item; very consistent quality; few workers needed.
- Disadvantages: extremely high investment; a single breakdown can halt the whole line and be very costly; virtually no flexibility.
The importance of CAM in modern high-volume production
Computer aided manufacture is what makes modern high-volume production possible.
- Consistency — every product is made to the same accuracy, so parts are interchangeable and quality is reliable.
- Speed and continuous running — CNC machines and robots can run day and night with little supervision.
- Complexity — shapes that would be impossible or slow by hand are repeated perfectly every time.
- Flexibility — CNC equipment can be reprogrammed for a new product instead of being replaced, supporting batch production and customisation.
- Less waste — software nests parts efficiently on a sheet and machines cut precisely.
- Safety — robots take over dangerous, dirty and repetitive tasks such as welding and spray painting.
The downsides are the high cost of machinery and maintenance, the need for trained programmers and technicians, and the loss of some manual jobs. See Computer aided manufacture (CAM) in 1.1.1.
Ergonomics and anthropometrics in product development
Ergonomics — designing products so they fit the people who use them and are comfortable, safe and efficient to use.
Anthropometrics — the measurement of the human body, collected as data and used to make ergonomic design decisions.
Anthropometric data is published in tables of percentiles. Designers usually design for the 5th to 95th percentile, which covers 90% of users:
- Reach and clearance — design for the extremes. A shelf must be reachable by a 5th percentile (shorter) user; a doorway must clear a 95th percentile (taller) user.
- Adjustability — where users vary a lot, products are made adjustable, such as office chairs, car seats and bicycle saddles.
- Grip and controls — handle diameters, button sizes and the force needed to operate them are based on hand measurements and strength data.
In development, designers test ergonomics with models and prototypes, user trials, CAD human models and virtual reality, and refine the design before it is manufactured. See Ergonomics and Anthropometrics in 1.1.5.
The role of design organisations such as the Design Council
The Design Council — the UK’s national strategic adviser on design. It is an independent charity, founded in 1944, that promotes the use of design to improve business, public services, the environment and people’s lives.
The Design Council:
- Champions good design and shows businesses and governments how design adds value.
- Created the Double Diamond design process — Discover, Define, Develop, Deliver — which is now used by designers around the world.
- Supports design for sustainability and the move to a low-carbon, circular economy.
- Runs programmes, research and training to help companies and public services use design well.
Organisations like the Design Council matter because they set out good practice, share research and help raise the standard of products, buildings and services across a whole country. Standards bodies such as the BSI play a related role by setting the safety and quality standards products must meet.
How manufacturing systems are organised, and choosing the most appropriate scale
How manufacturing is organised
- Production line (flow line) — the product moves from one work station to the next, each doing one task, as in car assembly.
- Cell production — a team of workers and machines in a cell makes a complete product or component. Workers are multi-skilled and share responsibility for quality.
- Lean manufacturing — removing every kind of waste: stock, waiting time, unnecessary movement, overproduction and defects. JIT is part of lean manufacturing.
- Quality control and quality assurance — products are checked at set points (quality control), and the whole system is organised to prevent faults (quality assurance).
- Automation — robots and CAM carry out repetitive tasks, with people monitoring, programming and maintaining them.
Choosing the most appropriate scale
| Ask | Points towards |
|---|---|
| How many are needed — one, hundreds, or millions? | Job → batch → mass → continuous |
| Is the product unique to one customer? | Job production |
| Is demand seasonal or likely to change? | Batch production |
| Is demand very high and steady? | Mass or continuous production |
| Can the investment in tooling and machinery be recovered? | Only high volumes justify expensive moulds and automated lines |
| How much will customers pay? | Low prices need high volumes |
When recommending a scale of production, justify it with the quantity, the cost and the type of product — for example: “Batch production, because the school needs 200 identical mugs for the event, and the jigs can be reused for the next order.”