PPAP Submission Guide: What Automotive Buyers Need from Chinese Suppliers
If you're sourcing castings for automotive applications, PPAP (Production Part Approval Process) compliance is non-negotiable. This guide explains what PPAP is, what to request from Chinese foundries, and how to verify the submission package quality.
The 18 PPAP Elements Explained
| # | Element | What to Check |
|---|---|---|
| 1 | Design Records | PDF/DXF drawings with revision level — must match PSW |
| 2 | Authorized Engineering Change Documents | Any changes not yet on design records |
| 3 | Engineering Approval | Proof of customer engineering sign-off |
| 4 | DFMEA (Design FMEA) | Design failure mode analysis — typically OEM-prepared |
| 5 | Process Flow Diagram | Shows each step in the manufacturing process |
| 6 | PFMEA (Process FMEA) | Process failure mode analysis — foundry's responsibility |
| 7 | Control Plan | Documented quality control steps at each process stage |
| 8 | MSA (Measurement System Analysis) | Gage R&R study — must be <10% for critical dimensions |
| 9 | Dimensional Results | CMM report on sample parts vs. drawing dimensions |
| 10 | Material/Performance Test Results | MTR (chemistry) + tensile test + hardness |
| 11 | Initial Process Study (CpK) | Process capability — must be ≥1.33 for critical characteristics |
| 12 | Qualified Laboratory Documentation | Scope of accreditation for the testing lab |
| 13 | Appearance Approval Report | For appearance parts only |
| 14 | Sample Production Parts | Production representative parts (typically 5–10) |
| 15 | Master Sample | Retained sample for reference — stored per shelf life |
| 16 | Checking Aids | Gages/fixtures used for dimensional verification |
| 17 | Customer-Specific Requirements | Any additional requirements from OEM (specify by OEM) |
| 18 | Part Submission Warrant (PSW) | Formal submission form — must be signed by foundry's quality manager |
Submission Levels
| Level | Required Documents | When Used |
|---|---|---|
| Level 1 | PSW only | Rare — sample parts only |
| Level 2 | PSW + sample + limited data | Standard samples |
| Level 3 | PSW + all 18 elements | Most common — standard requirement |
| Level 4 | PSW + requirements as specified | By agreement |
| Level 5 | PSW + all elements + on-site review | High-risk or new supplier |
Key Documents to Scrutinize
CpK Study (Element 11)
Initial process capability — ask for actual Cpk values, not just "PASS":
- Cpk ≥ 1.33: Capable process
- Cpk 1.00–1.33: Marginally capable — requires improvement plan
- Cpk <1.00: Not capable — unacceptable
For critical safety characteristics (brake, steering), some OEMs require Cpk ≥ 1.67.
MSA / Gage R&R (Element 8)
Measurement system variation must be <10% of process variation. If gage R&R is 10–30%, the results are marginal. Above 30%, the measurement system is inadequate and results are unreliable.
Material Test Report (Element 10)
Verify: heat number traceable to casting, all elements within spec, mechanical properties meet minimum, heat treatment condition specified and confirmed.
What to Request from Your Chinese Foundry
- Request PPAP at least 12 weeks before first shipment
- Specify the submission level clearly (typically Level 3)
- Provide all customer-specific requirements (OEM-specific PPAP supplements)
- Review PFMEA and Control Plan before production — catch issues early
- Conduct PPAP readiness audit before submission
- Reject incomplete submissions — especially missing PSW or CpK data
Frequently Asked Questions
What is PPAP and when is it required?
PPAP is the automotive industry's Production Part Approval Process required for new parts, design changes, location changes, or material/process changes. All Tier 1 and Tier 2 automotive suppliers must comply with IATF 16949 PPAP requirements.
What is a good Cpk value for automotive castings?
Cpk ≥ 1.33 for critical characteristics is standard. Some OEMs require Cpk ≥ 1.67 for safety-critical dimensions (brake, steering). If Cpk is <1.00, the foundry must implement corrective action before PPAP approval.
Sourcing Automotive Castings from China?
We work with IATF 16949-certified foundries experienced in automotive PPAP submissions. Full Level 3 packages, CpK studies, and dimensional reports included as standard.
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