The big idea: Six factors decide a manufacturing technique.
The six factors
- The type of part
- The material
- The scale of production
- The production system
- Cost constraints
- Environmental considerations
A checklist, not a list: They are not a list to recite. They are a checklist, and the answer is usually decided by two of them fighting each other.
Scale is the factor that decides most often — but it is never the only one.
Interactive diagram
Explore the labelled diagram, charts and maps for this topic in full study mode.
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
| Factor | What it rules in or out | An example of it deciding |
|---|---|---|
| Type of part | The shape: hollow, thin-walled, constant section, an internal cavity, a tight tolerance | A constant cross-section means extrusion; a seamless hollow means rotational moulding |
| Material | Whether the material can be melted, cast, bent, welded or machined at all | Timber cannot be moulded; a thermoset cannot be remelted; titanium machines slowly and expensively |
| Scale of production | Whether the tooling can be paid for | 300 parts rules out injection moulding; 300,000 rules out machining |
| Production system | What the factory already has and what its people can do | A workshop with a CNC router and no moulding machine will machine a part that a moulder would mould |
| Cost constraints | The total budget, including tooling, and the price the product must sell at | A tool costing more than the whole product's first-year revenue is not an option, whatever the per-part cost |
| Environmental considerations | Waste, energy, transport, and whether the part can be recycled afterwards | Subtractive turns bought material into swarf; forming wastes almost none; a glued assembly cannot be separated |
Stop wasting time on topics you know
Our AI identifies your weak areas and focuses your study time where it matters. No more overstudying easy topics.
| Conflict | How it is usually resolved |
|---|---|
| Scale says mould it; cost says the tool is unaffordable | Start with a cheaper process at a lower volume, prove the market, then tool up — accepting a higher cost per unit for the first year |
| Material says machine it; environment says the waste is unacceptable | Near-net-shape forming or additive manufacturing first, with machining only where the tolerance demands it |
| Part type says one moulding; production system says the factory cannot mould | Buy the moulded part in and assemble it, rather than choosing a worse process to keep the work in house |
| Cost says glue it; environment says it must come apart | Screws or released snap-fits, accepting slightly slower assembly for a product that can be repaired and recycled |
The strongest answers name the conflict: "Scale points to injection moulding, but the tooling costs more than the first year's revenue, so the trial run is vacuum formed and the moulding tool is ordered once 10,000 units have sold."
That is a manufacturing decision. A list of six factors is not.
Reading a process selection chart
Find the material
Each process bar or row is marked with the material families it can shape: metals, polymers, ceramics, composites, glass.
Find the size
A second scale gives the mass (or size) range each process can handle, e.g. 0.01 kg to 100 kg.
Keep only the overlap
The suitable processes are the ones that cover BOTH the material and the mass. List them exactly as the chart names them.
Then judge
The chart narrows the list; scale, cost and environment then pick the winner from what is left.
How this is tested — discussing factors that influence the choice of manufacturing technique. It comes up two ways:
Paper 1 — multiple choice
- Identify the factor that rules out a stated process.
- Choose the dominant factor in a described situation.
Paper 2 — analysing a product
- Analyse the factors influencing a technique for a product.
- Explain how two factors conflict and how you would resolve it.
The trap: Listing all six factors with equal weight. Say which one DECIDES, and what it is fighting against.
A start-up needs 2,000 aluminium brackets a year for an outdoor product. Analyse the factors and recommend a technique.
Model answer plan
See the answer broken into clear points, with guidance on how each point earns marks.