Communication in Design & Technology (Cambridge 9705)
Purpose of this section
Develop the ability to convey design intent clearly and accurately using a range of visual and digital tools. This supports:
- Collaboration with teammates, manufacturers and clients
- Accurate cost and resource estimation
- Realistic project planning and risk management
What the Cambridge syllabus expects
Design communication is a combination of hand‑drawn, digital and planning tools. Students must be able to produce each of the following for Paper 1/3 (hand‑drawn) and for coursework (digital where appropriate).
- Free‑hand sketching – exploded views, sectional views, isometric, perspective & planometric drawings. Include a scale and, where required, BS 308/BS 8888 symbols.
- Orthographic drawings – first‑angle or third‑angle projection, correct scale, dimensioning, BS 308/BS 8888 symbols, and clear view labels (Front, Top, Side, etc.).
- Development of 3‑D forms – nets, pattern development, sheet‑metal unfolding. Remember to indicate grain direction on sheet‑metal nets.
- Enhancement techniques – tone, colour, shading and hatching to indicate material, finish or texture. Use visual cues to communicate sustainability (e.g., green hatch for biodegradable material) or ergonomics.
- Planning drawings – flowcharts, Gantt charts, materials/cutting lists.
- Digital communication tools – Word/PowerPoint for reports, Excel for data, Adobe Acrobat for PDFs, Teams/Miro for collaboration, CAD packages for detailed drawings (coursework only).
Planning Drawings
1. Flowcharts
A flowchart shows the logical sequence of operations, decisions and information flow. Use recognised ISO 5807 symbols and keep the layout simple.
| Symbol | Meaning | Standard shape |
|---|
| Start / End | Entry or exit point of the process | Oval |
| Process | Operation or action | Rectangle |
| Decision | Yes/No or multiple‑choice test | Diamond |
| Input / Output | Data entry, material receipt, report | Parallelogram |
| Connector | Jump to another part of the chart | Circle |
| Document | Reference to a drawing, spec or sheet | Rounded rectangle |
Guidelines for a clear flowchart
- One clearly marked start and one end.
- Flow direction top‑to‑bottom or left‑to‑right; avoid crossing lines.
- Use consistent line thickness and arrowheads.
- Label each step with a verb phrase (e.g., “Cut timber to 200 mm”).
- Number steps (e.g., 1, 2, 3…) – these numbers will be used in the Gantt chart and cutting list.
- Test the logic by tracing every possible path.
- Cross‑reference: write the corresponding cutting‑list item number in the process box if a material is taken from stock.
Mini‑example (flowchart fragment)
+-----------+ +----------------+ +-----------+
| Start |---►[1]---| Cut timber |---►[2]---| Drill |
+-----------+ +----------------+ +-----------+
| |
▼ ▼
(Item 1 – Pine) (Item 2 – Steel)
2. Gantt Charts
A Gantt chart visualises the project schedule, task durations, dependencies and key milestones.
- Vertical axis: task list – use the same numbers as the flowchart.
- Horizontal axis: time scale (days, weeks or months).
- Bars: duration of each task.
- Precedence arrows: show which tasks must finish before another can start.
- Milestones: diamond symbols marking key events (e.g., “Prototype approved”).
- Critical path: the longest sequence of dependent tasks; highlight in a contrasting colour.
Duration calculation (including contingency)
\[
\text{Duration (days)} = \frac{\text{Total work (hours)}}{\text{Crew size} \times \text{Hours per day}} \times (1 + \text{Contingency})
\]
Example: Cutting operation requires 24 h, crew of 2, 6 h day⁻¹, 10 % contingency.
\[
\frac{24}{2 \times 6} \times 1.10 = 2.2 \text{ days} \;\approx\; 3 \text{ days (rounded up)}
\]
Mini‑example (Gantt fragment)
| Task No. |
Task description |
Start |
Duration |
Predecessor |
| 1 |
Cut timber (Item 1) |
Day 1 |
3 days |
– |
| 2 |
Drill holes (Item 2) |
Day 4 |
2 days |
1 |
3. Materials & Cutting Lists
A cutting list records every raw material needed, its size, quantity and any special handling instructions. It is the basis for cost estimation, waste control and cross‑referencing with the Gantt chart.
| Item No. |
Material |
Dimensions (mm) |
Quantity |
Units |
Tolerance |
Grain / Finish |
Remarks (waste % / notes) |
| 1 |
Pine timber |
2000 × 100 × 20 |
4 |
pcs |
±0.5 mm |
Long grain parallel to load |
0 % waste – cut from one board |
| 2 |
Plywood |
1200 × 800 × 12 |
2 |
pcs |
±0.2 mm |
Face grain outward, matte finish |
Include 5 % off‑cut for errors |
| 3 |
Steel rod |
Ø 10 × 1500 |
6 |
pcs |
±0.1 mm |
Cold‑drawn, polished |
Cut to length on site |
Integrating the Planning Tools
- Flowchart – explains the logical order of operations, assigns a step number, and notes any material taken from stock.
- Gantt chart – converts each numbered step into a timed schedule, shows dependencies, milestones and the critical path.
- Cutting list – supplies the exact material requirements for every scheduled task.
Cross‑reference numbers throughout (e.g., “Task 3 – Cut timber” in the Gantt chart matches step 3 in the flowchart and Item 1 in the cutting list).
Digital Communication Tools (syllabus requirement)
- Word / PowerPoint – written reports, presentation of design rationale, annotated images.
- Excel – calculations for task durations, cost tables, material take‑offs.
- Adobe Acrobat – assembling PDFs for submission, adding hyperlinks to drawings.
- Microsoft Teams / Miro – real‑time collaboration, sharing sketches, voting on design options.
- CAD software (e.g., AutoCAD, Fusion 360) – permitted for coursework to produce detailed orthographic and 3‑D drawings; hand‑drawn versions remain essential for exam papers.
Common Pitfalls & How to Avoid Them
- Over‑crowded diagrams – keep ample spacing, use consistent symbol size, and break complex processes into sub‑flowcharts.
- Unrealistic time estimates – apply the duration formula, add a 5‑10 % contingency, and verify against resource availability.
- Missing material details – always record tolerance, grain direction, surface finish and an estimated waste percentage.
- Ignoring dependencies – ensure every task that must precede another is linked with a clear arrow; identify the critical path.
- Inconsistent terminology – use specialist vocabulary (e.g., “machining”, “deburring”, “lamination”) and standard symbols from BS 308/BS 8888.
- Sketches without scale or symbols – always include a scale bar and, where required, BS 308/BS 8888 symbols on free‑hand drawings.
Orthographic Drawing Checklist (hand‑drawn)
- Projection type: first‑angle or third‑angle (state which one is used).
- Scale indicated (e.g., 1 : 20) and a scale bar drawn.
- All three principal views shown (Front, Top, Side) and correctly labelled.
- Dimensions placed according to BS 308/BS 8888 conventions (clear, non‑overlapping, appropriate precision).
- Relevant symbols (section, hidden line, centre line, etc.) from BS 308/BS 8888 used.
- Material grain direction or fibre orientation indicated where relevant.
Summary Checklist for Exam & Coursework
- Flowchart uses ISO 5807 symbols, has a single start/end, numbered steps, clear verb‑phrase labels, and cross‑references cutting‑list items.
- Gantt chart lists all major tasks, shows correct durations (using the formula), includes precedence arrows, milestones, and highlights the critical path.
- Cutting list records dimensions, quantity, tolerance, grain/final finish, waste % and any special notes.
- All three documents are cross‑referenced (task numbers match flowchart steps and cutting‑list items).
- Free‑hand sketches (exploded, isometric, orthographic) are produced to the required scale, include BS 308/BS 8888 symbols, and indicate material grain where appropriate.
- Enhancement techniques (tone, colour, hatching) are used to convey material, finish, and sustainability information.
- Digital tools are mentioned where appropriate and used to support, not replace, the hand‑drawn evidence.