This mini-lesson works through manufacturing processes — wasting, forming (vacuum forming, bending), redistribution (injection/blow/rotational moulding, casting) and addition (welding, adhesives, 3D printing), plus CNC.
Work through each screen, answer the questions as you go and collect ⭐ stars. Press Start when you’re ready.
Overview
Four ways to shape a material
Every manufacturing process falls into one of four families depending on what happens to the material:
Wasting — material is removed (cutting, machining).
Forming / deforming — a solid is reshaped without adding or removing material (bending, vacuum forming).
Redistribution / reforming — material is melted and re-set in a mould (casting, injection moulding).
Addition — material is joined or added (welding, adhesives, 3D printing).
Wasting
Wasting processes
Wasting removes unwanted material to leave the required shape:
Sawing, drilling, milling and turning (on a lathe) — traditional machining.
Routing — a spinning cutter follows a profile.
Laser and plasma cutting — accurate, fast cutting of sheet.
Die cutting / punching — a shaped blade stamps out card or sheet in one stroke (batch/mass).
Forming
Forming (deforming) processes
Forming reshapes a solid — usually a softened thermoplastic sheet or a ductile metal — without melting it:
Vacuum forming — a heated thermoplastic sheet is sucked down over a mould (packaging trays, yoghurt pots).
Line bending — an acrylic sheet is heated along a line and folded.
Press forming / drape forming — sheet pressed between a die and former.
Quick check
Which process makes a blister pack?
?A thin thermoplastic sheet is heated until floppy, then pulled down over a mould by removing the air beneath it. Which process is this?
Redistribution
Moulding: redistribution processes
Here the material is melted and re-set to the shape of a mould:
Injection moulding — molten polymer granules are forced into a steel mould. Very high tooling cost, so only economic at high volumes (casings, LEGO bricks).
Blow moulding — air inflates a molten tube (parison) against a mould to make hollow bottles.
Rotational moulding — powder tumbled in a heated hollow mould coats the walls; large hollow parts (water tanks, traffic cones).
Compression moulding — thermosetting powder squeezed and cured in a hot mould (electrical fittings).
Match it
Match moulding process to product
Tap a process, then tap the product it typically makes.
Term
Match
Quick check
When is injection moulding economic?
?Injection moulding needs an expensive precision-machined steel mould. When does it become the right choice?
Calculate
Your turn — production rate
∑An injection-moulding tool is a 4-cavity mould (it makes 4 parts each cycle). One cycle takes 30 seconds. How many parts can it produce in one hour?
parts
Hint: cycles per hour = 3600 ÷ 30, then × 4 cavities.
Casting
Casting metals
Sand casting — molten metal poured into a sand mould made from a pattern; cheap for one-off and batch metal parts, but a rough finish.
Die casting — molten metal forced into a reusable metal die; excellent detail and finish at high volume (e.g. die-cast toy cars, engine parts).
Addition
Addition: joining and fabricating
Addition / fabrication joins parts together. Joints are either permanent or temporary:
SLA / SLS cure or sinter resin/powder with a laser.
It excels at one-off prototypes and complex geometries impossible to machine, with little waste — but is slow and weaker than moulded parts for mass production. It is the opposite of subtractive (wasting) manufacture.
Quick check
Additive vs subtractive
?Which statement correctly contrasts additive with subtractive manufacture?
CNC
CNC — computer numerical control
CNC machines (routers, lathes, mills, laser cutters) are driven by code (typically G-code) generated from CAD/CAM. Benefits: high accuracy, repeatability and the ability to cut complex shapes unattended — the same part made identically thousands of times.