Production Part Approval Process (PPAP)
All you need to know
1) What PPAP Is (and Why It Exists)
Production Part Approval Process (PPAP) is the formal method used to prove to the customer that the supplier can consistently produce parts that meet all requirements at the intended production rate using the intended production process.
PPAP answers one question:
“Can you make this part correctly, every time, under real production conditions?”
PPAP is not paperwork. It is evidence of readiness.
2) Where PPAP Fits in the Quality System
PPAP is the culmination of APQP and Core Tools execution:
Requirements → APQP → DFMEA → PFMEA → Control Plan → MSA → SPC → Capability → PPAP
If any upstream element is weak, PPAP will expose it.
3) When PPAP Is Required
PPAP is typically required for:
new part or product launch
design changes
process changes
tooling changes
supplier changes
material or sub-supplier changes
lapse in production
correction of a quality issue
If the risk changes, PPAP is triggered.
4) PPAP Submission Levels (What They Mean)
PPAP has defined submission levels specifying how much evidence is required:
Level 1: Part warrant only
Level 2: Warrant + limited supporting data
Level 3: Warrant + full supporting data (most common)
Level 4: Customer-defined requirements
Level 5: Warrant + on-site review at supplier
Level 3 is the standard for most automotive launches.
5) The 18 PPAP Elements (What Each Proves)
1. Design Records
Drawings, specifications, and revisions defining the product.
2. Authorized Engineering Change Documents
Proof that all changes are approved and incorporated.
3. Customer Engineering Approval (if required)
Evidence of customer sign-off during development.
4. Design FMEA (DFMEA)
Shows design risks were identified and mitigated.
5. Process Flow Diagram
Maps the real manufacturing process.
6. Process FMEA (PFMEA)
Shows process risks and controls.
7. Control Plan
Defines how the process is controlled in production.
8. Measurement System Analysis (MSA)
Proves measurement systems are reliable.
9. Dimensional Results
Verification that dimensions meet requirements.
10. Material and Performance Test Results
Validation of material properties and functional performance.
11. Initial Process Studies
Capability evidence (Cpk/Ppk) for key characteristics.
12. Qualified Laboratory Documentation
Proof that testing was done by approved labs.
13. Appearance Approval Report (AAR)
Required for appearance-critical parts.
14. Sample Production Parts
Physical evidence from production conditions.
15. Master Sample
Reference sample retained for comparison.
16. Checking Aids
Gages, fixtures, or templates used for inspection.
17. Records of Compliance
Regulatory or customer-specific compliance documents.
18. Part Submission Warrant (PSW)
Formal declaration that all requirements are met.
6) The Part Submission Warrant (PSW)
The PSW is the formal commitment by the supplier.
By signing it, the supplier declares:
parts meet all requirements
process is stable and controlled
all PPAP evidence exists and is accurate
Submitting a PSW without true readiness is high risk.
7) Production Conditions — What Customers Expect
PPAP evidence must come from:
actual production tools
real production operators
normal cycle times
approved materials and suppliers
intended measurement systems
Prototype or temporary conditions invalidate PPAP.
8) PPAP and Capability Requirements
For critical characteristics, customers often expect:
Cpk ≥ 1.67 (initial studies)
Cpk ≥ 1.33 (long-term)
If capability is not met:
containment and improvement plans are required
customer approval may be conditional
Capability without SPC stability is meaningless.
9) PPAP and Control Plans
The Control Plan submitted in PPAP must:
match PFMEA controls
reflect real production practice
include reaction plans
reference validated measurement systems
Any mismatch is a common reason for PPAP rejection.
10) PPAP and Change Management
Changes after PPAP approval must be:
evaluated for risk
communicated to the customer
approved before implementation (when required)
“Silent changes” are one of the fastest ways to lose customer trust.
11) Common PPAP Rejection Reasons
incomplete or outdated DFMEA/PFMEA
weak or missing MSA
capability not demonstrated
Control Plan not aligned with PFMEA
test results from non-approved labs
evidence not matching actual production practice
PPAP exposes reality. It rarely fails by accident.
12) Supplier PPAP (Cascading Requirements)
Tier-1 suppliers are responsible for ensuring:
sub-suppliers also complete appropriate PPAP
supplier risks are reflected in PFMEA
supplier capability and controls are verified
Supplier PPAP is part of your risk, not theirs.
13) PPAP in Non-Automotive Industries
PPAP concepts are used beyond automotive:
aerospace (with adaptations)
industrial equipment
electronics
medical devices (with regulatory overlays)
The principle remains the same: prove readiness with evidence.
14) How to Prepare for PPAP Efficiently
build PPAP evidence progressively during APQP
don’t “collect documents at the end”
keep FMEAs and Control Plans living
validate measurement systems early
run capability studies before deadlines
Good PPAP is the result of good planning, not heroics.
15) What Auditors and Customers Really Look For
They focus on:
consistency across documents
traceability from requirement to evidence
risk-based controls
effectiveness of reaction plans
honesty in capability reporting
They are testing trustworthiness, not formatting.
16) Practical PPAP Readiness Checklist
all changes approved and documented
DFMEA and PFMEA updated and linked
Control Plan reflects reality
MSA completed and acceptable
SPC implemented and stable
capability demonstrated
samples match documentation