FMEA Implementation Procedure for Manufacturing: Step-by-Step Practical Guide with AIAG-VDA Method

Types and Purpose of FMEA

DFMEA (Design FMEA) identifies potential failure modes during the product design phase. For example, when designing automotive brake pads, it analyzes material selection or thickness design errors in advance.

PFMEA (Process FMEA) analyzes defects that may occur in manufacturing processes. It addresses process-induced defects such as dimensional defects in CNC machining or insufficient strength in welding processes.

Team Formation and Preparation

Effective FMEA requires cross-functional team composition:

• Team Leader: Quality/Production Engineering Manager
• Core Members: Design, Production, Quality, Maintenance, Customer Service Representatives
• Support Members: Procurement, Logistics Representatives

Preparation Items: Product/process drawings, process flow diagrams (PFD), historical defect data, customer complaint records

Analysis Procedure (AIAG-VDA 7 Steps)

Step 1: Project Planning

Define product/process scope, set objectives, establish timeline

Step 2: Structure Analysis

Decompose the system into components. Example: Electric screwdriver → Motor, Gearbox, Battery, Control circuit

Step 3: Function Analysis

Define functions and requirements for each component. Example: Motor → "Rotate at 1,500 RPM"

Step 4: Failure Analysis

Identify Failure Modes:

• DFMEA example: Insufficient bearing durability
• PFMEA example: Improper torque wrench tightening

Step 5: Risk Assessment

The new AIAG-VDA method is based on Action Priority (AP):

Traditional RPN Method (for reference):

• RPN = Severity (S) × Occurrence (O) × Detection (D)
• Each item rated 1-10 points
• Priority improvement for RPN ≥ 125

AIAG-VDA AP Method (recommended):

• Severity: 1-10 points, 9-10 points require mandatory improvement
• Occurrence: Based on actual process data
• Detection: Effectiveness of current control methods

Practical Example: Battery welding process

• Failure Mode: Insufficient weld strength
• S=8 (safety issue), O=4 (occurs twice monthly), D=6 (difficult to detect before shipment)
• AP: High → Immediate improvement required

Step 6: Improvement Activities

Priority Decision Criteria:

1. Severity 9-10 items (safety/regulatory)
2. AP High items
3. High customer impact items

Improvement Action Examples:

• Design changes: Material replacement, structural improvement
• Process enhancement: Adding Poka-Yoke devices, increasing inspection frequency
• Management methods: Implementing SPC, revising work standards

Step 7: Documentation and Tracking

Conduct reassessment after improvement, manage change history

Form Completion Guidelines

AIAG-VDA Integrated Form Essentials:

• 5-Column Method: Connect Structure → Function → Failure → Effect → Cause
• AP Matrix: Visual priority display through S-O-D combination
• Deliverables: FMEA worksheet, AP table, improvement tracking sheet

Completion Tips:

• Describe failure modes clearly as "insufficient~" or "excessive~"
• Analyze causes to root cause using 5-Why technique
• Categorize current control methods as prevention/detection
• Set target AP to Low or Medium

Practical Operation Points:

• Update DFMEA immediately upon design changes
• Complete PFMEA before introducing new processes
• Review quarterly as Living Document
• Integrate with ERP/MES for automatic defect data reflection