Edexcel A-level Design & Technology: Product Design (9DT0) · Further Processes and Techniques
Mini-Lesson
Further Processes and Techniques
This mini-lesson covers Further Processes and Techniques for Edexcel A-level Product Design: additive manufacture, composite forming, and tolerances and quality control.
You will compare FDM, SLA and SLS, follow GRP lay-up, and calculate a tolerance. Press Start to begin.
Advanced making
Further processes overview
At A-level you study higher-level manufacturing and how quality is designed in:
Additive manufacture — building parts layer by layer (FDM, SLA, SLS).
Composite forming — laying up reinforcement and resin (GRP, CFRP).
Precision and inspection — tolerances and measurement to guarantee parts fit.
Additive
Additive manufacture in depth
Three common additive processes:
FDM (fused deposition modelling) — melts and lays down a plastic filament layer by layer; cheap and common.
SLA (stereolithography) — a laser cures liquid resin layer by layer; very fine detail.
SLS (selective laser sintering) — a laser fuses powder (polymer or metal); strong parts needing no support structure.
Why additive? Complex shapes, one-offs and rapid prototypes with little waste, though it is slow for large volumes.
Quick check
Which additive process?
?A designer needs a strong, complex nylon part with internal channels and no supports. Which additive process suits it best?
Composites
Composite forming
Composites are formed by combining reinforcement and resin:
GRP hand lay-up — a gel coat is applied to a mould, then glass fibre matting is wetted out with polyester resin and rolled to remove air.
Vacuum bagging — a bag and vacuum press the layers together, removing excess resin and air for a stronger, lighter part.
CFRP — carbon fibre in an epoxy matrix, often cured under heat and pressure for high strength-to-weight.
Quick check
Why a gel coat?
?In GRP hand lay-up, why is a gel coat applied to the mould first?
Tolerances
Tolerances and quality control
Parts must fit, so sizes are given with a permitted range:
Nominal size — the target dimension (e.g. 50 mm).
Upper and lower limits — the largest and smallest acceptable sizes (e.g. 50.2 and 49.8 mm).
Tolerance = upper limit - lower limit (the total permitted variation).
Quality is checked with go/no-go gauges, vernier calipers/micrometers and, at high precision, a CMM (coordinate measuring machine).
Calculate
Your turn — tolerance
1A shaft is specified as 50 ± 0.2 mm. Tolerance = upper limit - lower limit. Calculate the total tolerance.
mm
Hint: upper = 50.2, lower = 49.8, so 50.2 - 49.8.
Sort it
Sort the techniques
Tap a technique, then the group it belongs to.
🖨️ Additive
🧵 Composite forming
📏 Inspection / QC
Quick check
Reading a tolerance
?A part is dimensioned 50 ± 0.2 mm. What does the tolerance tell the manufacturer?
Match it
Match each term to its meaning
Tap an item on the left, then its match on the right.