WJEC GCSE Design and Technology Manufacturing and production: scales of production, processes, structures and human factors

What the manufacturing content demands

To turn a design into a real product you must understand how things are made: in what numbers, by what processes, how structures carry loads, and how products fit people. WJEC tests this in Unit 1 with questions that name a scale or process, describe how a process works, or ask you to choose and justify a method. This guide walks through the manufacturing content and links to the dot-point page for each part, where worked exam questions live.

Scales of production

The number of items to be made decides how a product is manufactured. One-off production makes a single unique item, high quality but slow and dear per item. Batch production makes a set number then changes over, flexible but with downtime. Mass production makes large numbers on a line, cheap per item but with a high set-up cost. Continuous production runs nonstop for huge volumes, the cheapest per item but the least flexible. As the scale rises, the cost per item falls but so does flexibility and customisation, so the scale must match the quantity and the variety needed.

Manufacturing and shaping processes

Processes fall into four groups. Cutting and wasting removes material, by sawing, drilling, laser cutting and CNC routing. Forming and moulding shapes material with little waste: vacuum forming (heat a plastic sheet and suck it over a mould), injection moulding (force molten polymer into a mould, ideal for mass production), casting (pour molten metal into a mould) and blow moulding (inflate plastic to make bottles). Joining is temporary (screws, knock-down fittings) or permanent (welding, adhesives, stitching). Finishing protects and improves the surface, by painting, varnishing, anodising or polishing. Each process suits particular materials and quantities.

Structures, forces and stresses

Five forces act on structures: tension (pulling), compression (squashing), bending (tension on one face, compression on the other), shear (sliding past, like scissors) and torsion (twisting). Structures resist them through strong, stiff materials and through shape, such as an I-beam that puts material where bending is greatest. They are made stronger by triangulation (diagonals that keep frames rigid), bracing and webbing, lamination (gluing layers), and folding or corrugating sheet material. The triangle is special because it cannot be pushed out of shape without changing the length of a side.

Ergonomics and anthropometrics

Anthropometrics is the measurement of the human body, giving data such as reach, hand size and seat height. Ergonomics is designing products to fit the body, so they are comfortable, safe and efficient. Because people vary, designers use percentiles: the 5th percentile is a small user, the 95th a large one, and designing for the 5th to 95th range suits the middle 90 percent. Clearance is set for the largest user, reach for the smallest, and adjustability lets one product fit a range, as in an office chair.

Check your knowledge

A mix of recall and application questions across scales, processes, structures and human factors. Attempt them, then check against the solutions.

1. Name the four scales of production. (4 marks)
2. State the most suitable scale for a bespoke wedding dress. (1 mark)
3. Describe the vacuum forming process. (4 marks)
4. Name the four groups of manufacturing process. (4 marks)
5. Name the five forces that act on structures. (5 marks)
6. Explain how triangulation strengthens a frame. (2 marks)
7. State the difference between ergonomics and anthropometrics. (2 marks)
8. State which percentile sets the clearance for a doorway, and why. (2 marks)