Materials, Manufacturing and Technical Feasibility
This domain tests whether a concept can be made at the required volume, cost and quality. You should be able to select materials by function, choose a process, apply design-for-manufacture rules and calculate whether tooling pays back.
Material and process selection
Use property requirements first: strength, stiffness, toughness, density, thermal resistance, chemical resistance, electrical behaviour and recyclability. Ashby-style property charts and performance indices help compare families rather than single brands. Then screen processes by volume, tolerance, surface finish and tooling. Common rules:
- Injection moulding: high tooling cost, low variable cost, requires draft, controlled wall thickness and generous radii.
- Sheet metal: bend radius at least material thickness, account for bend allowance, avoid holes too close to a bend.
- CNC machining: no tooling, higher variable cost, good for low volume and tight tolerance.
- Extrusion: constant cross-section only.
- Additive manufacturing: design freedom, but anisotropic properties and higher unit cost at volume.
Feasibility and cost
Part cost = material + processing + tooling amortisation + yield loss + logistics. DFM/DFA reduce part count, fasteners and handling. Tolerance stack-up must be calculated rather than guessed; over-tolerancing inflates cost. Technical feasibility also includes test capability, supply chain and technology readiness.
Worked example
An enclosure is needed at 50,000 units per year. CNC variants cost €18 per part with no tooling. Injection moulding costs €45,000 for tooling and €4.50 per part. At 50,000 units, CNC totals €900,000; moulding totals €225,000 + €45,000 = €270,000. Break-even volume is €45,000 ÷ (€18 − €4.50) = 3,333 units. Moulding is therefore justified, but only if the design has draft, a feasible wall thickness and a two-week tool build is acceptable. The reasoning combines economics with process constraints; the cheaper unit price alone is not the answer.
Traps that cost marks
- Comparing unit prices without tooling amortisation or yield.
- Specifying tolerances tighter than the function requires.
- Assuming the prototype process will be the production process.
- Ignoring draft, wall thickness or bend radius until the design is frozen.
- Omitting supply-chain and test-capability constraints from feasibility.
Sustainability, Safety, Quality and Regulatory Compliance
This domain combines environmental performance, product safety, quality systems and market-access law. The exam expects you to connect design decisions to evidence that a product is sustainable, safe and legally placeable on the market.
Sustainability
Use life-cycle assessment (LCA) across raw material, manufacture, distribution, use and end-of-life. Define the functional unit and system boundary; results are not comparable without them. Circular strategies rank roughly as refuse, reduce, repair, remanufacture, recycle, recover. Material choice, fasteners, monolithic construction and disassembly time affect recyclability. Regulatory drivers include RoHS (restricted substances), REACH (chemical safety), WEEE (e-waste take-back) and the EU ecodesign framework, including digital product passports for many product groups.
Safety and quality
ISO 12100 risk assessment follows hazard identification, risk estimation, risk evaluation and mitigation by inherently safe design, then safeguarding, then information. FMEA prioritises failure modes using severity, occurrence and detection; RPN = S × O × D. Quality systems such as ISO 9001 provide process control, CAPA and traceability. QFD links customer needs to design characteristics; SPC monitors process stability.
Regulatory compliance
CE marking is a declaration supported by a technical file, risk assessment, applicable harmonised standards and conformity assessment. Relevant legislation may include Machinery Regulation, EMC, Low Voltage, Medical Device Regulation or the General Product Safety Regulation. The technical file must exist before the declaration, not after launch.
Worked example
A charger overheating failure has S=9, O=4, D=3, giving RPN 108. Adding a thermal cut-off reduces occurrence to 1 and detection to 2, giving RPN 18. However, severity remains 9 because a fire is still possible. The stronger action is to remove the flammable housing and use a flame-retardant material, which reduces severity, then add the cut-off. The reasoning: RPN reduction can hide unchanged severity; mitigation should follow the hierarchy and address the most severe outcome first.
Traps that cost marks
- Claiming recyclability without an end-of-life route or disassembly evidence.
- Comparing LCAs with different functional units or boundaries.
- Treating CE marking as a self-certification formality without a technical file.
- Using an RPN threshold as the only risk criterion while ignoring severity.
- Confusing quality control with regulatory conformity.
Project Management, Teamwork and Communication
This domain tests whether you can plan and control a development project, manage risk and dependencies, and communicate decisions to stakeholders without hiding bad news.
Planning and control
Break scope into a work breakdown system (WBS) with deliverable owners. Sequence activities, identify the critical path (longest dependency chain, zero float), and track progress against baselines. Earned value compares planned value (PV), earned value (EV) and actual cost (AC): SPI = EV/PV and CPI = EV/AC. A risk register records cause, event, impact, probability, owner and response. A RACI matrix must have one accountable person per deliverable; two accountable people means no accountability.
Teams and communication
Tuckman’s forming, storming, norming and performing describes team development, not a fixed timetable. Psychological safety supports challenge and early bad-news reporting. Stakeholder mapping identifies influence and interest, and the communication plan sets audience, message, channel and cadence. Gate reviews, sprint reviews and design reviews are communication controls, not reporting theatre.
Worked example
A project has tasks A (4 days), B (6 days), C (3 days) and D (2 days). A precedes B and D; B and D precede C. Paths are A–B–C = 13 days and A–D–C = 9 days. The critical path is A–B–C, and D has 4 days of float. If B slips by 2 days, the project slips by 2 days; if D slips by 2 days, the project does not slip unless the delay exceeds 4 days. Separately, PV is €100,000, EV is €80,000 and AC is €90,000, so SPI = 0.80 and CPI = 0.89. The project is behind schedule and over budget; the response should address the critical path and cost drivers, not demand more reporting.
Traps that cost marks
- Confusing the longest task with the critical path.
- Reporting percent complete without earned value or a baseline.
- Assigning two accountable owners to one deliverable.
- Treating a risk register as a list without owners or trigger dates.
- Suppressing bad news until a gate, when options are already expensive.