4.3 Risk Management for EMS Projects

In electronics manufacturing, optimism is a liability. A successful project manager does not hope for the best; they systematically hunt for failure modes before they manifest. Risk management is not a paperwork exercise; it is the engineering discipline of predicting the future. If a risk is identified early, it is a variable to be managed. If it is ignored, it becomes a crisis that halts production.

The following framework maps the six distinct territories where projects fail. Treat this as a scan pattern for every design review.

Supply Chain Risk (The Components)

The Risk: Inability to build due to missing parts.

The most common line-down cause is not a broken robot, but a $0.05 capacitor that is out of stock globally.

• Detection: Scrub the BOM against market databases (e.g., SiliconExpert, IHS) to check "Lifecycle Status" and "Global Inventory."
• If a critical chip is "Sole Source" (only one manufacturer) → Then the project is tied to that vendor's factory stability.
• Mitigation:
  • Design: Validate at least one alternate for every passive component.
  • Procurement: Buy "Safety Stock" for high-risk silicon immediately upon design approval, even before the PCB is finalized.

Design Risk (The Margins)

The Risk: The product works in the lab but fails in the factory.

Lab benches use stable power supplies and "golden" prototypes. Factories use statistical distributions of tolerance.

• Detection: Monte Carlo simulation and "Worst Case Circuit Analysis" (WCCA).
• If the circuit requires components to be within 1% tolerance to function → Then normal manufacturing variation will cause a 10% failure rate.
• Mitigation:
  • Action: Relax tolerances. Design circuits that function even if components drift by 5%.

Process Risk (The Assembly)

The Risk: The design exceeds the capability of the factory equipment.

• Detection: DFM Report and Capability Index ($C_{pk}$) analysis.
• If you place a BGA with 0.3mm pitch on a line calibrated for 0.5mm → Then yield will crash due to bridging.
• Mitigation:
  • Pilot Build: Run a small batch (50 units) specifically to measure process capability ($C_{pk}$) before committing to mass volume.

Test Risk (The Blind Spot)

The Risk: Shipping defective units because the test didn't catch them.

• Detection: Test Coverage Analysis. Map every net on the schematic to a test verification method.
• If a feature is "Untestable" (no test points, no firmware command) → Then you are shipping it on faith.
• Mitigation:
  • Action: Add test points for ICT. Implement "Boundary Scan" (JTAG) for complex digital chips to verify soldering without physical probes.

Compliance Risk (The Legal Wall)

The Risk: Product is seized by customs or banned from sale.

• Detection: Regulatory review (FCC, CE, UL, RoHS).
• If the design uses a pre-certified radio module but places it near a noise source → Then the final system may fail radiated emissions testing, requiring a total board re-spin.
• Mitigation:
  • Action: Pre-scan at a compliance lab during the prototype phase. Do not wait for the final "Golden Unit" to check for EMI (Electromagnetic Interference).

Logistics Risk (The Physical Journey)

The Risk: Damage during transit.

• Detection: Drop testing and vibration profiles.
• If the packaging is designed for a pallet but shipped via courier (UPS/FedEx) → Then single-box drops will shatter the LCDs.
• Mitigation:
  • Action: Perform ISTA-2A shipping tests on the final packaged unit. Define "Shock Watch" stickers on outer boxes to detect rough handling.

Final Checklist: The Pre-Flight Scan