In the world of manufacturing quality—especially within the automotive industry—two documents are at the core of proactive quality management: the Process Failure Mode and Effects Analysis (PFMEA) and the Control Plan.
While they serve different purposes, these two are deeply connected.
✅ FMEA identifies the risks,
✅ Control Plan defines how to control those risks.
In this article, we’ll explore how FMEA drives Control Plans, step-by-step, using real-world examples and aligning with the AIAG-VDA FMEA 7-Step methodology.
What Is a Control Plan? #
A Control Plan is a structured document that outlines how key process steps and product characteristics are monitored and controlled during manufacturing.
It defines:
- What to monitor (process/product characteristics),
- How to monitor (measurement method, tool, sampling),
- How often to monitor (frequency),
- What to do when issues are detected (reaction plan).
What Is PFMEA? #
A Process FMEA (PFMEA) is a structured risk assessment tool that:
- Analyzes potential failure modes in manufacturing processes,
- Identifies causes and effects of those failures,
- Evaluates the risk level using Severity, Occurrence, and Detection,
- Prioritizes failures using Action Priority (AP) or RPN,
- Recommends actions to eliminate or control risk.
How FMEA Drives Control Plans: 5 Key Connections #
Below are the 5 ways FMEA directly drives the development and content of Control Plans:
1. Risk Identification → Becomes Control Requirements
The primary purpose of FMEA is to identify what could go wrong in a process.
These risks include:
- Failure Modes (e.g., “Weak weld joint”),
- Causes (e.g., “Incorrect current setting”),
- Effects (e.g., “Leakage, joint failure”).
Once a risk is identified and prioritized, it must be controlled—this is exactly where the Control Plan comes into play.
✅ The failure causes identified in PFMEA become the characteristics that the Control Plan must monitor.
2. Prevention & Detection Controls → Become Control Methods
In PFMEA:
- Prevention Controls aim to reduce the chance of a failure happening.
- Detection Controls aim to identify the failure before the part leaves the process.
These controls are transferred directly to the Control Plan as:
| PFMEA Control Type | Control Plan Entry |
|---|---|
| Prevention Control | Process control method |
| Detection Control | Inspection or monitoring method |
Example:
If PFMEA has a prevention control like “PLC monitoring of weld current”, then the Control Plan should include:
“Monitor weld current via PLC – Continuous”
3. Special Characteristics → Drive Control Emphasis
During FMEA, you determine special characteristics such as:
- Critical Characteristics (CC)
- Significant Characteristics (SC)
These are based on:
- Severity ratings,
- Customer requirements,
- Regulatory requirements.
In the Control Plan, these are highlighted with symbols (● or ◊) and must have stricter controls, higher sampling frequency, and defined reaction plans.
✅ FMEA flags what needs tight control—Control Plan defines how to do it.
4. Recommended Actions → Become Control Improvements
In Step 6 of PFMEA (Optimization), you define Recommended Actions like:
- Adding Poka-Yoke devices,
- Improving gages,
- Increasing sampling frequency,
- Installing sensors or alarms.
Once these actions are implemented and closed, they must be reflected in the Control Plan as updated control methods.
✅ PFMEA actions → Control Plan improvements.
5. Audit Readiness and Traceability
A common question in IATF 16949 or customer audits:
“Can you show the link between your PFMEA and Control Plan?”
Here’s how to ensure you’re ready:
- Keep process step numbers consistent between PFMEA and Control Plan.
- Ensure control methods align.
- Reference FMEA document number and revision in your Control Plan.
- Update both documents whenever there’s a change.
✅ FMEA is the root document. Control Plan is the execution document.
Practical Example: FMEA to Control Plan Flow #
🔍 PFMEA Example (Welding Operation)
| Step | Function | Failure Mode | Cause | Prevention Control | Detection Control |
|---|---|---|---|---|---|
| 10 | Weld parts A+B | Weak weld joint | Low weld current | PLC checks current | Visual inspection – 100% |
📋 Control Plan Output
| Step | Characteristic | Spec | Control Method | Frequency | Reaction Plan |
|---|---|---|---|---|---|
| 10 | Weld current | 200–250 Amps | PLC Monitoring – Real-time | Continuous | Stop line, adjust setting |
| Weld appearance | Visual Pass | 100% Visual Inspection | 100% | Rework, segregate parts |
✅ See how FMEA drives both what we monitor and how we monitor it.
Summary: From Risk to Control #
Here’s a summary table of how PFMEA drives Control Plans:
| PFMEA Output | Drives Control Plan Entry |
|---|---|
| Failure Mode / Cause | Process or product characteristic |
| Prevention & Detection Controls | Control method |
| Action Priority / Risk Ratings | Frequency / method of inspection |
| Special Characteristics (SC/CC) | Special symbol, higher sampling, stricter control |
| Recommended Actions | Updated control or detection method |
Conclusion #
A Control Plan is not a standalone document. It’s the natural extension of PFMEA. Without linking the two, your risk analysis efforts may never reach the production floor.
By letting your PFMEA drive your Control Plan, you ensure:
- ✅ Better risk control,
- ✅ Higher process consistency,
- ✅ Audit compliance,
- ✅ Customer satisfaction.
💡 Always treat PFMEA as your quality planning engine, and the Control Plan as your execution roadmap.
FAQs: How FMEA Drives Control Plans #
Q1. Can I create a Control Plan without doing PFMEA?
No. PFMEA is the foundation. Control Plans must be based on the risks identified in PFMEA.
Q2. How do I ensure FMEA and Control Plan stay aligned?
- Use the same structure and process flow.
- Update Control Plan whenever FMEA is revised.
- Cross-reference documents in revision logs.
Q3. Are special characteristics mandatory in Control Plans?
Yes. Any SC or CC from FMEA must appear in the Control Plan with proper monitoring and reaction strategies.
