What APQP and PPAP are
APQP and PPAP are two halves of the same automotive process. APQP (Advanced Product Quality Planning) is the planning framework that takes a new product from concept to series production. PPAP (Production Part Approval Process) is the proof: the evidence package a supplier submits to show that its process makes conforming parts at production rate.
Both manuals are published by AIAG and used by OEMs and Tier 1 suppliers that follow IATF 16949. In short, APQP tells you what to do in each phase, and PPAP tells you what to show at the end to be released for production.
APQP and PPAP visual map
The map shows the 5 APQP phases, the 18 PPAP elements, the submission levels and the Ppk example from this article.
The 5 phases of APQP
| Phase | Name | Key outputs |
|---|---|---|
| 1 | Plan and define the program | Quality and reliability goals, preliminary bill of materials, preliminary process flow, preliminary special characteristics |
| 2 | Product design and development | Design FMEA, drawings and specifications, prototype control plan, team feasibility commitment |
| 3 | Process design and development | Process flow chart, floor plan, process FMEA, pre-launch control plan, process instructions, MSA plan |
| 4 | Product and process validation | Significant production run, MSA evaluation, capability study, PPAP, production control plan |
| 5 | Feedback, assessment and corrective action | Reduced variation, lessons learned, continual improvement and customer satisfaction |
The phases overlap on purpose: process planning starts before the product design is frozen. That is how you avoid learning in phase 4 that the part cannot be built. A cross-functional team (quality, engineering, production, purchasing, logistics) works from one timing plan with formal phase reviews.
The core tools run through every phase: FMEA, MSA and Gauge R&R, statistical process control, the control plan and PPAP itself. To map the process end to end, a SIPOC diagram helps build the preliminary flow.
The 18 PPAP elements
The 4th edition of the manual lists 18 elements. Not every customer asks for all of them: the submission level and customer-specific requirements decide what goes in the package.
- Design records (part drawing)
- Authorized engineering change documents
- Customer engineering approval
- Design FMEA (DFMEA)
- Process flow diagrams
- Process FMEA (PFMEA)
- Control plan
- Measurement system analysis studies (MSA)
- Dimensional results
- Records of material and performance test results
- Initial process studies
- Qualified laboratory documentation
- Appearance approval report (AAR)
- Sample product
- Master sample
- Checking aids
- Customer-specific requirements records
- Part submission warrant (PSW)
The PSW is the cover sheet of the package: it identifies the part, the reason for submission, the level, the measurement results and the supplier's declaration that the parts were made with production tooling and processes.
Submission levels and approval status
| Level | What the supplier submits |
|---|---|
| 1 | PSW only (and AAR where applicable) |
| 2 | PSW, product samples and limited supporting data |
| 3 | PSW, samples and complete supporting data (default if the customer sets none) |
| 4 | PSW and other items defined by the customer |
| 5 | PSW, samples and complete data, reviewed at the supplier's site |
The customer's decision is approved, interim approval (with a deadline and defined actions) or rejected. PPAP must also be resubmitted after events such as a design, tooling, process, manufacturing site or sub-supplier change, as the manual and the customer specify.
Example: initial process study with Ppk
Element 11 asks for evidence that the process is capable. For dimensional characteristics, PPAP uses Ppk (process performance, based on long-term standard deviation) from a significant production run, typically 300 consecutive parts. Fictional example: a 10.00 ± 0.10 mm dimension (LSL = 9.90; USL = 10.10), with a mean of 10.01 mm and a standard deviation of 0.020 mm.
Ppk = min[(USL − mean) ÷ 3s ; (mean − LSL) ÷ 3s]
| Side | Calculation | Result |
|---|---|---|
| Upper | (10.10 − 10.01) ÷ (3 × 0.020) = 0.09 ÷ 0.06 | 1.50 |
| Lower | (10.01 − 9.90) ÷ (3 × 0.020) = 0.11 ÷ 0.06 | 1.83 |
| Ppk | the smaller of the two | 1.50 |
Under the usual manual criteria (above 1.67 acceptable; 1.33 to 1.67 may be acceptable, contact the customer; below 1.33 not acceptable), a Ppk of 1.50 sits in the middle band. If the process is centered at 10.00, Ppk rises to 0.10 ÷ 0.06 = 1.67 without changing the spread. To get above 1.67 with the mean at 10.01, the standard deviation would have to drop to about 0.018 mm. The calculation is detailed in Cp and Cpk.
Common mistakes
- Treating PPAP as a last-minute document. Building the package only in phase 4 exposes gaps in FMEA, MSA and the control plan too late.
- Documents that disagree. The flow chart, PFMEA and control plan must share the same steps and special characteristics.
- Measuring with an unevaluated gauge. Dimensional results without an accepted MSA do not support the capability study.
- Bench-built samples. The significant run must use production tooling, operators, rate and methods.
- Ignoring customer-specific requirements. Each OEM has its own forms and deadlines.
- Not resubmitting after changes. A process or site change without a new submission is a nonconformity.
For the certification that requires these methods, see IATF 16949 requirements and preparation; the general quality base is in ISO 9001.
Frequently asked questions
What is the difference between APQP and PPAP?
APQP is quality planning in 5 phases; PPAP is the set of evidence, with 18 elements, that the supplier gives the customer to get the production part approved.
When is PPAP required?
For a new part, and after a design, tooling, process, site or sub-supplier change, plus other cases the customer defines.
What is the PSW?
The Part Submission Warrant, element 18, which summarizes the submission and carries the supplier's declaration of conformity.
What Ppk does the customer require?
The manual treats above 1.67 as acceptable on stable processes. Many customers set their own values, so check the customer-specific requirements.
Are all 18 elements mandatory?
Not necessarily. The submission level and the customer decide what to send, but the supplier must keep all applicable records.
Do APQP and PPAP apply outside automotive?
Yes. Aerospace, electronics and other sectors use adapted versions, but the origin and most common use are in automotive.
Sources
- AIAG. Advanced Product Quality Planning (APQP) and Control Plan. 2nd ed. Southfield: AIAG, 2008.
- AIAG. Production Part Approval Process (PPAP). 4th ed. Southfield: AIAG, 2006.
- AIAG; VDA. FMEA Handbook. Southfield: AIAG, 2019.
- AIAG. Measurement Systems Analysis (MSA). 4th ed. Southfield: AIAG, 2010.
- IATF. IATF 16949:2016 - Quality management system requirements for automotive production and relevant service parts organizations.
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About the author
Lean Manufacturing & Behavioral Management Specialist
Over 20 years in the automotive and metalworking industries (GM and Dana), Lean Manufacturing practitioner since 2006. SENAI instructor and mentor in Brazil’s Brasil Mais Produtivo program, delivering consulting, training and audits for 50+ companies, combining quality, productivity and people development.
