Now that you’ve assessed risks using Severity (S), Occurrence (O), and Detection (D) ratings and identified the Action Priorities (AP) in Step 5, it’s time to do something about it.
That’s the role of Step 6 – Optimization.
“What design actions can reduce the risk of failure, and how do we track and close them effectively?”
This step helps drive continuous improvement, making your product safer, more reliable, and launch-ready.
🎯 Objective of Step 6 #
“Define and implement recommended actions that reduce risk, re-evaluate the design, and close all necessary actions before production release.”
🔁 Optimization Workflow Overview #
- Identify High and Medium AP items
- Propose Recommended Actions
- Assign Owners & Due Dates
- Implement actions
- Re-evaluate O/D ratings (S stays constant)
- Update AP status
- Record final residual risk and rationale
🚗 Case Study: Optimization for Electric Water Pump (EWP) #
Let’s take a few High/Medium AP failure chains from our EWP DFMEA and walk through optimization.
🛠️ 1. Failure: “No coolant flow”
AP: High → Must take action
| Element | Optimization |
|---|---|
| Cause | Impeller slip on shaft |
| Recommended Action | Add mechanical spline feature to shaft, increase interference fit, add press-fit simulation |
| Owner | Design Engineer |
| Due Date | 15 Sept 2025 |
| Expected Outcome | Reduce O from 6 → 3 |
🛠️ 2. Failure: “Coolant leakage at seal”
AP: High
| Element | Optimization |
|---|---|
| Cause | Seal wear and shaft runout |
| Recommended Action | Upgrade to FKM seal material, improve shaft surface finish (Ra < 0.3), add alignment check in design |
| Owner | Mechanical Engineer |
| Due Date | 20 Sept 2025 |
| Expected Outcome | Reduce O from 5 → 3, D from 5 → 3 (with additional leak test @ DV phase) |
🛠️ 3. Failure: “EMC radiated emissions too high”
AP: Medium
| Element | Optimization |
|---|---|
| Cause | Missing shielding & bad layout |
| Recommended Action | Add common-mode choke, ground stitch vias, reroute PCB traces, and re-test in pre-compliance lab |
| Owner | Electrical Engineer |
| Due Date | 30 Sept 2025 |
| Expected Outcome | Reduce O from 3 → 2, D from 4 → 2 |
🧾 After Action Implementation – Re-evaluate O/D Ratings #
| Failure | O (Before) | D (Before) | O (After) | D (After) | AP (New) |
|---|---|---|---|---|---|
| No flow | 6 | 5 | 3 | 5 | Medium |
| Leakage | 5 | 5 | 3 | 3 | Low |
| EMC | 3 | 4 | 2 | 2 | Low |
✅ Once actions are effective, update the ratings and track residual risk.
📋 Action Tracker Table (Template) #
| DFMEA Row ID | Action | Owner | Due Date | Status | Revised O | Revised D | New AP |
|---|---|---|---|---|---|---|---|
| R1 | Add spline on shaft | Design Engg | 15 Sep | Done | 3 | 5 | M |
| R2 | Upgrade seal material | Mech Engg | 20 Sep | In Progress | 3 | 3 | L |
| R3 | Add EMC shielding | Elec Engg | 30 Sep | Planned | 2 | 2 | L |
📥 Include this table in downloadable Excel template for tracking
💬 Residual Risk Acceptance #
Once action is complete, if the risk is still:
- Medium or High, you must:
- Justify why further action is not feasible (design limits, cost, timing)
- Document management or customer risk acceptance
- Low, no further action required
✅ This decision is documented in the residual risk column of the DFMEA.
🎯 Best Practices for Optimization #
| Tip | Why It Matters |
|---|---|
| Prioritize AP = H first | These are the most critical risks |
| Include cross-functional owners | Ensure action feasibility |
| Define measurable outcome | Avoid vague actions like “improve design” |
| Link to test plans (DVP&R) | Detection improvements need validation |
| Track and close actions | Show continuous improvement in audits |
✅ Outputs of Step 6 #
By the end of Optimization, you will have:
- ✅ Defined recommended actions for high-risk failures
- ✅ Assigned owners and deadlines
- ✅ Re-evaluated and updated O/D/AP ratings
- ✅ Documented residual risk acceptance or sign-offs
- ✅ Demonstrated a reduction in product design risk
🔗 Internal Linking Suggestions #
- Step 7: Results Documentation – Summary Table and Lessons Learned
- Download: DFMEA Optimization Tracker Template (Excel)
- Guide: Writing Effective Recommended Actions in DFMEA
🧠 Pro Tip #
“The goal isn’t to reduce all risks to zero. It’s to show deliberate action, document decisions, and ensure that critical risks are controlled.”
🏁 Conclusion #
Optimization is the “action” in the Action Priority. It ensures that high-risk issues are not only identified but resolved or mitigated with real improvements.
This is where your DFMEA becomes a living document of engineering problem-solving.
Next, we’ll finalize everything in Step 7 – Results Documentation, where we summarize the DFMEA and prepare for handoff, reviews, and lessons learned.
