Four families of process

Manufacturing processes are grouped by what they do to the material:

• Wasting — removing material to leave the shape (sawing, drilling, milling, turning, laser cutting).
• Addition/fabrication — joining parts together (welding, adhesives, mechanical fixings).
• Deforming — changing shape without changing state (bending, pressing, vacuum forming).
• Reforming — melting and reshaping (casting, injection moulding, blow moulding).

Watch the state change: deforming keeps the material solid; reforming turns it liquid first, then sets it in a new shape.

Which family?

Wasting processes

Wasting removes unwanted material. Common techniques:

• Sawing / drilling — basic cutting and holes.
• Milling — a rotating cutter removes material from a workpiece fed beneath it.
• Turning (lathe) — the workpiece spins while a fixed tool cuts, producing round parts.
• Routing — a spinning bit profiles and cuts sheet material.
• Laser / plasma cutting — a focused beam vaporises or melts a narrow line for precise 2D profiles.
• Die cutting — a shaped blade stamps out card/board packaging nets.

Waste and cost: wasting always produces offcuts, so parts are nested efficiently on the stock to cut material cost.

Shaping polymers

Key volume processes for thermoplastics:

• Injection moulding — melt injected into a mould; complex 3D parts at high volume (bottle caps, casings).
• Blow moulding — a hot tube (parison) is inflated inside a mould to make hollow items (bottles).
• Vacuum forming — a heated sheet is sucked over a mould to make open, shallow shapes (trays, packaging).
• Extrusion — melt forced through a die to make a continuous profile (pipe, curtain track).
• Rotational moulding — powder tumbled in a heated hollow mould (large hollow items such as water tanks).

Making a hollow bottle

Sort the processes

Tap a process, then the family it belongs to.

Casting and joining

Casting pours molten metal into a mould:

• Sand casting — cheap moulds for one-off/low volumes and large parts.
• Die casting — reusable metal moulds for high-volume, accurate parts (e.g. aluminium fittings).

Joining can be permanent or temporary:

• Permanent — welding (fuses metals), brazing/soldering (lower-melting filler), and adhesives.
• Temporary — nuts and bolts, screws and clips, which allow disassembly for repair or recycling.

Permanent or temporary?

Match each process to a typical product

Tap an item on the left, then its match on the right.

Your turn — material efficiency

The big ideas to know

You have covered how products are cut, joined, formed and cast, and how to judge material efficiency.