Materials & manufacture · National 5
Manufacturing features
2 cards · 2 quiz · 0 exam
Design & Manufacture · National 5 · mrkellydt.co.uk
What you're learning in this topic
Learning intention WALT
We are learning about manufacturing features, specifically to:
know
- flashing, ejector marks, draft angles and injection points
understand
- how ribs and webs strengthen a moulded part
Success criteria WILF
- I can identify flashing, ejector marks, draft angles and injection points
- I can explain how ribs and webs strengthen a moulded part
Spotting how something was made
- Flashing: thin excess material squeezed out where the mould halves meet.
- Ejector pin marks: small circles where pins pushed the part out.
- Injection point / sprue: where material entered the mould.
- Draft angles: tapered sides for release.
- Wall thickness: even (rotational moulding), thin and varying (vacuum forming).
- Thinning of sheet material at corners (vacuum forming).
- Surface finish: smooth (injection, die casting) or rough (sand casting).
Strengthening and assembly features
- Ribs and webs: thin walls that add strength and rigidity without thick sections, help material flow evenly into the mould, reduce distortion, and hold internal components (circuit boards, wires) in place.
Key terms
| Ribs/webs | Add strength and rigidity, help material flow, locate internal parts. |
|---|---|
| Flashing | Thin excess material where the two halves of a mould meet. |
Quick check
1. Why are ribs added to the inside of a plastic casing?
- To make the casing heavier so it feels solid and expensive
- To give a better grip on the outside of the casing
- Add rigidity without thick walls and hold internal parts
- To use up any extra plastic left in the mould
Show answer
C: Add rigidity without thick walls and hold internal parts. Thin ribs stiffen the part and locate components.
2. Thin excess plastic along the edge of a moulded part is called…
- Draft
- Rib
- Ejector pin mark
- Flashing
Show answer
D: Flashing. Flash forms where the mould halves meet.
Printable worksheet
An I do, we do, you do worksheet for this topic, with a separate answer sheet.