Skill: zxw8309/auto-parts-quality (version 1.0.0)

--- name: auto-parts-quality description: "Senior automotive parts quality analysis expert skill. Use when analyzing quality issues, failure modes, 8D reports, SPC data, PPAP documents, or any automotive quality-related work. Triggers on: quality analysis, failure analysis, 8D report, APQP, PPAP, FMEA, SPC, root cause analysis, supplier quality management, parts inspection, quality metrics, customer complaint handling for automotive components (HPFP, fuel pumps, pistons, valves, etc.)." --- # Auto Parts Quality Analysis ## 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 --- ### 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 --- ### 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 | --- ### 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) --- ### 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 | --- ### 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 | |--------|--------|----------| ``` --- ## 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.

path: references/failure-modes.md
content: # Failure Mode Library - Fuel System Components

## HPFP (High Pressure Fuel Pump)

### 1. Seizure/Jamming

**Symptoms:**
- Pump cannot rotate
- Engine stall
- Unusual noise during operation

**Root Causes:**

| Category | Specific Cause | Evidence |
|----------|---------------|----------|
| **Surface** | Honing pattern insufficient (RVK too shallow, angle wrong) | Microscope: shallow valleys, smooth surface |
| **Surface** | DLC coating damage | Microscope: coating chip-off, exposed substrate |
| **Surface** | Scoring from contamination | SEM: embedded particles, linear scratches |
| **Dimensional** | Clearance too tight (thermal expansion) | Measurement: dimensions at low end of tolerance |
| **Material** | Surface hardness insufficient | Hardness test: below specification |
| **Lubrication** | Oil starvation | Oil passage blockage, low oil pressure |

**Investigation Steps:**
1. Measure RVK, RPK, RZ against OE parts
2. Compare honing angle with specification
3. Check oil passages for blockage
4. Review hardness test results
5. Analyze particle composition from cleanliness test

---

### 2. Internal Leakage

**Symptoms:**
- Pressure drop below specification
- Fuel consumption increase
- Engine performance degradation

**Root Causes:**

| Category | Specific Cause | Evidence |
|----------|---------------|----------|
| **Valve** | Valve seat wear | Microscope: wear pattern on seat |
| **Valve** | Valve spring fatigue | Spring force measurement below spec |
| **Valve** | Foreign material on seat | Microscope: embedded particle |
| **Sealing** | Seal surface damage | Microscope: scratches, deformations |
| **Sealing** | Seal aging/hardening | Visual: cracks, permanent set |

**Investigation Steps:**
1. Disassemble and inspect valve train
2. Measure spring free length and force
3. Check seal surfaces under microscope
4. Review cleaning/particle analysis results

---

### 3. External Leakage

**Symptoms:**
- Fuel odor
- Visible fuel seepage
- Pressure drop over time

**Root Causes:**

| Category | Specific Cause | Evidence |
|----------|---------------|----------|
| **Connector** | Thread damage | Visual: crossed threads, missing thread starts |
| **Connector** | Fitting not torqued properly | Torque verification, witness mark check |
| **Connector** | Debris in thread | Visual: contamination in threads |
| **Seal** | O-ring damage | Visual: cut, deformation, aging |
| **Housing** | Crack (stress or thermal) | Visual: crack, fluorescent dye test |

**Investigation Steps:**
1. Inspect connector threads
2. Check torque specifications
3. Verify O-ring condition
4. Pressure test to locate leak point

---

### 4. Noise/Vibration

**Symptoms:**
- Abnormal noise during operation
- Vibration felt through structure

**Root Causes:**

| Category | Specific Cause | Evidence |
|----------|---------------|----------|
| **Mechanical** | Bearing failure | Noise frequency analysis, visual |
| **Mechanical** | Rattle from loose part | Visual inspection, shake test |
| **Hydraulic** | Cavitation | Noise characteristics, air in system |
| **Mechanical** | Buffer pad broken | Disassembly: fragmented buffer |

**Investigation Steps:**
1. Noise frequency analysis
2. Disassemble and inspect components
3. Check buffer pad condition
4. Verify mounting torque

---

## Fuel Injector

### 1. Nozzle Clogging

**Symptoms:**
- Fuel spray pattern abnormal
- Engine misfire
- Power loss

**Root Causes:**
- Fuel contamination (particles, water)
- Internal corrosion from low-quality fuel
- coking from high temperature operation

---

### 2. Leakage at Fitting

**Symptoms:**
- External fuel leak
- Pressure drop

**Root Causes:**
- Misfit during assembly
- Damaged sealing surfaces
- Incorrect torque sequence

---

## General Guidelines

### Microscope Inspection Checklist

For honing pattern evaluation:
- [ ] Overall pattern visibility (should show clear cross-hatch)
- [ ] Valley depth (RVK should be measurable)
- [ ] Peak height (RPK within spec)
- [ ] Angle consistency (should match specification)
- [ ] Surface randomness (no unidirectional patterns)
- [ ] Embedded particles (indicates contamination source)

### Cleanliness Analysis Interpretation

| Particle Size | Likely Source | Implication |
|---------------|--------------|-------------|
| > 50 μm | Assembly/handling | Major contamination |
| 10-50 μm | Internal wear | Normal or abnormal depending on rate |
| < 10 μm | System-generated | May indicate running-in wear |

**Key indicator:** Particles matching housing/plate material composition suggest internal origin; particles with external composition (dust, debris) suggest contamination.

### Comparison with OE Parts

Always compare suspect parts with OE reference parts using:
1. Microscope at same magnification
2. Roughness profilometer with same measurement settings
3. Visual inspection under same lighting angle

Document differences with photos for reporting.


path: references/qc-tools.md
content: # Quality Control Tools Reference

## SPC (Statistical Process Control)

### Control Chart Interpretation

| Pattern | Meaning | Action |
|---------|---------|--------|
| 7 points one side of center | Process shift | Investigate cause |
| 6 points steadily increasing | Trend | Check for wear |
| 14 points alternating up/down | Over-control | Reduce adjustment |
| 2 of 3 points beyond 2σ | Warning | Monitor closely |
| Any point beyond 3σ | Out of control | Immediate investigation |

### Cpk Assessment Criteria

| Cpk Value | Process Capability | Action |
|-----------|-------------------|--------|
| Cpk ≥ 2.0 | Excellent | Maintain |
| 1.67 ≤ Cpk < 2.0 | Good | Minor improvement |
| 1.33 ≤ Cpk < 1.67 | Acceptable | Monitor |
| 1.0 ≤ Cpk < 1.33 | Barely capable | Improve required |
| Cpk < 1.0 | Not capable | Significant improvement |

---

## MSA (Measurement System Analysis)

### Gauge R&R Acceptance Criteria

| %GRR | Assessment | Action |
|------|------------|--------|
| < 10% | Acceptable | Use measurement system |
| 10-30% | Marginal | Review if acceptable for application |
| > 30% | Unacceptable | Improve measurement system |

### Measurement Linearity

- Compare measurements across expected operating range
- Reference standard vs bias should be consistent
- Bias should be < 10% of tolerance

---

## FMEA (Failure Mode and Effects Analysis)

### RPN Calculation

```
RPN = Severity × Occurrence × Detection
```

### Severity Rating (1-10)

| Rating | Effect | Example |
|--------|--------|---------|
| 10 | Safety/regulatory without warning | Seizure causing stall |
| 9 | Safety/regulatory with warning | Engine warning light |
| 8 | Very high | Vehicle inoperable |
| 7 | High | Performance severely affected |
| 6 | Moderate | Vehicle operable but comfort affected |
| 5 | Low | Minor inconvenience |
| 4 | Very low | Minor fit/finish issue |
| 3 | Minor | Fit/finish noticed by most customers |
| 2 | Very minor | Fit/finish noticed by discriminating customers |
| 1 | None | No discernible effect |

### Occurrence Rating (1-10)

| Rating | Likelihood | Approximate Failure Rate |
|--------|-------------|-------------------------|
| 10 | Very high | ≥ 100 per thousand |
| 9 | High | 50 per thousand |
| 8 | Moderately high | 20 per thousand |
| 7 | Moderate | 10 per thousand |
| 6 | Low | 2 per thousand |
| 5 | Very low | 0.1 per thousand |
| 4 | Remote | 0.01 per thousand |
| 3 | Very remote | ≤ 0.001 per thousand |
| 2 | Nearly impossible | 0.0001 per thousand |
| 1 | Impossible | Failure eliminated |

### Detection Rating (1-10)

| Rating | Detection | Likelihood of Detection |
|--------|-----------|-------------------------|
| 10 | Absolute uncertainty | Cannot detect |
| 9 | Very remote | Very slight chance of detection |
| 8 | Remote | Slight chance |
| 7 | Very low | Low chance |
| 6 | Low | Moderately low chance |
| 5 | Moderate | Moderate chance |
| 4 | Moderately high | Moderately high chance |
| 3 | High | High chance |
| 2 | Very high | Very high chance |
| 1 | Almost certain | Almost certain to detect |

### Action Priority

| Priority | RPN Range | Action |
|----------|-----------|--------|
| Critical | RPN ≥ 100 | Immediate action required |
| High | 50 ≤ RPN < 100 | Action in current cycle |
| Medium | 20 ≤ RPN < 50 | Monitor and improve |
| Low | RPN < 20 | Document and monitor |

---

## 5-Why Analysis Template

```
Problem Statement: [Describe the problem clearly]

Why 1: [First level cause]
  ↓ Why?
Why 2: [Second level cause]
  ↓ Why?
Why 3: [Third level cause]
  ↓ Why?
Why 4: [Fourth level cause]
  ↓ Why?
Why 5: [Root cause - should be controllable]

Verification: [How to confirm root cause]
Countermeasure: [What will fix the root cause]
```

---

## 8D Problem Solving

### D1: Establish Team
- Team leader appointed
- Team members with relevant expertise
- Customer involvement if required

### D2: Problem Description
- What is the problem?
- How many affected?
- What are the symptoms?
- What is the severity?

### D3: Interim Containment Actions
- Sort good/bad parts
- 100% inspection of suspect lots
- Customer notification if required
- Time-bound actions

### D4: Root Cause Identification
- Use 5-Why or Fishbone
- Verify with data
- Test potential causes
- Confirm with experiments

### D5: Permanent Corrective Actions
- Select based on root cause
- Consider cost/benefit
- Verify with small batch
- Validate against similar processes

### D6: Implementation
- Implement on production parts
- Train operators
- Update documentation
- Set up monitoring

### D7: Prevent Recurrence
- Update FMEA
- Update Control Plan
- Update PFMEA if needed
- Set up long-term monitoring

### D8: Team Recognition
- Document lessons learned
- Recognize team contributions
- Share knowledge


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