Auto Parts Quality Analysis

Senior automotive parts quality analysis expert skill. Use when analyzing quality issues, failure modes, 8D reports, SPC data, PPAP documents, or any automot...

Core Workflow

1. Quality Issue Analysis

When analyzing quality issues, follow this structure:

A. Problem Definition

• Part name, part number, supplier
• Symptom description (field failure, customer complaint, in-process defect)
• Failure rate / population affected
• Timeline (when discovered, volume shipped)

B. Evidence Collection

• Photos / microscope images
• Measurement data (dimensional, roughness, hardness)
• Cleanliness analysis results (particle size, composition)
• Test reports (8D, PPAP, material certs)

C. Failure Mode Identification

• Surface failure (honing pattern, wear, scoring)
• Dimensional failure (out of tolerance)
• Material failure (crack, corrosion, contamination)
• Assembly failure (mating, sealing)

D. Root Cause Analysis

• Use 5-Why or Fishbone diagram logic
• Distinguish internal vs external causes
• Check for process drift vs sudden change
• Verify with data (SPC, correlation analysis)

E. Countermeasures & Verification

• Short-term containment (sorting, 100% inspection)
• Long-term corrective action (process change, design change)
• Effectiveness verification (pilot run, SPC monitoring)
• Closure criteria definition

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2. 8D Report Review Checklist

When reviewing 8D reports from suppliers:

Section	What to Check
D1	Team formed, problem severity acknowledged
D2	Problem description with data (quantity, affected lots)
D3	Interim containment actions (sorting, 100% audit)
D4	Root cause identification (why-level 5, verified with data)
D5	Permanent corrective actions selected
D6	Implementation & verification plan
D7	Prevent recurrence (FMEA update, control plan revision)
D8	Team recognition & lessons learned

Red flags:

• Root cause stated as "human error" without systemic fix
• Countermeasures not linked to root cause
• No data supporting root cause conclusion
• No effectiveness verification plan

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3. Key Automotive Quality Metrics

Metric	Formula	Threshold
PPM	Defects per million	< 100 PPM typical
CPK	Process capability index	≥ 1.33 acceptable
DPMO	Defects per million opportunities	Track trending
Lot reject rate	Rejected lots / total lots	< 1% target

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4. Common Failure Modes for HPFP/Fuel System Parts

Seizure/Jamming:

• Insufficient honing pattern (RVK too shallow, angle wrong)
• Lubrication failure (oil starvation, contamination)
• Thermal overload (clearance too tight)
• Material mismatch (surface hardness)

Internal Leakage:

• Valve seat damage (contamination, wear)
• Spring failure (fatigue, corrosion)
• Foreign material embedded in sealing surfaces

External Leakage:

• Seal damage (installation damage, aging)
• Connector fitting issues (thread debris, torque)
• Housing crack (stress concentration)

Performance Degradation:

• Pressure drop (restricted flow, pump wear)
• Noise/vibration (bearing failure, cavitation)
• Calibration drift (sensor issues, contamination)

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5. Supplier Quality Assessment

When evaluating supplier capability:

Area	Assessment Points
Process Control	SPC data availability, Cpk levels, control plan existence
Measurement System	MSA results, gauge R&R, calibration records
PPAP Level	Documentation completeness (typically Level 3)
FMEA	Current version, action prioritization (RPN threshold)
Cleanliness	In-process cleaning, particle control, packaging
Traceability	Lot tracking, raw material certs, process parameters

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6. Report Structure for Quality Analysis

When presenting quality analysis results:

## 质量分析报告

### 1. 问题概述
- 零件信息
- 问题现象
- 影响范围

### 2. 根本原因分析
- 证据链
- 5-Why分析
- 原因验证

### 3. 改善对策
- 短期措施（围堵）
- 长期措施（纠正）
- 实施计划

### 4. 验证结果
- 改善效果
- 后续跟进

### 5. 行动项
| 行动项 | 负责人 | 截止日期 |
|--------|--------|----------|

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Reference Files

• references/qc-tools.md - SPC, MSA, FMEA templates and guidelines
• references/failure-modes.md - Detailed failure mode library for fuel system components

Load reference files only when specific detailed guidance is needed.