Quality Engineering
PPAP Guide for Quality Engineers
PPAP is the evidence package a supplier gives the customer to show that a part can be produced consistently to specification, at the quoted rate, using the real production process. This guide explains how Quality Engineers prepare it in practice.
By Career Plus Academy — manufacturing career development for Production and Quality professionals in India.
What it means
The Production Part Approval Process (PPAP) is a standard approach, widely used in the automotive industry, for getting customer approval of a new or changed part. The package collects design records, process documents, measurement results and capability studies, and ends with the Part Submission Warrant (PSW) signed by the supplier.
Why it matters in manufacturing
PPAP protects both sides. The customer gets confidence before series production begins, and the supplier is forced to confirm that drawings, process, gauges and people are ready. A weak PPAP usually shows up later as field complaints, sorting activity and lost trust.
Step-by-step PPAP preparation
- 1
Confirm the requirement
Check the customer's required submission level, customer-specific requirements and the trigger (new part, engineering change, tool transfer, new supplier).
- 2
Freeze the design record
Make sure you are working on the latest drawing revision and that all engineering changes are documented.
- 3
Build the process documents
Prepare the process flow diagram, PFMEA and control plan so they describe the same operations in the same sequence.
- 4
Run a significant production run
Produce parts on production tooling, at production rate, with production operators and gauges.
- 5
Measure and study
Complete dimensional results (ballooned drawing), material and performance tests, MSA and initial process capability for special characteristics.
- 6
Compile and review
Add appearance approval if applicable, sample parts, master sample and checking aids. Review the complete file internally before signing the PSW.
Practical shop-floor example
Illustrative learning example — not a client result
Example: machined housing after a tool change
A supplier replaces a worn boring tool with a new tool design. The customer requires a PPAP for the process change. The team updates the PFMEA for the new tool wear mode, adds a tool-life counter to the control plan, collects dimensional and capability evidence using the applicable manual and agreed customer sample requirements, confirms the bore gauge through MSA and submits with a PSW referencing the change. The sample size is not prescribed by this introductory example.
Common mistakes
- Process flow, PFMEA and control plan that do not match each other.
- Measuring parts from a trial run instead of a real production run.
- Missing drawing characteristics in the dimensional results.
- Running capability studies before the gauge has passed MSA.
- Treating PPAP as paperwork after production has already started.
Practical checklist
- Latest drawing revision and change documents attached
- Process flow, PFMEA and control plan aligned
- All drawing characteristics measured and ballooned
- MSA completed for gauges used on special characteristics
- Capability results available for special characteristics
- Material and performance test reports included
- PSW completed and signed
Frequently asked questions
What is the default PPAP submission level?
Level 3 is commonly used as the default in automotive supply chains, but the customer decides the level. Always confirm it before preparing the file.
Is PPAP only for new parts?
No. Engineering changes, tooling changes or transfers, new material sources and process changes can also require a PPAP.
What is the PSW?
The Part Submission Warrant is the summary document in which the supplier declares that the parts meet all requirements. It is signed by the supplier and approved by the customer.
References and further reading
This introductory guide does not replace applicable manuals, customer requirements or approved safety and operating procedures.
Want to check how well you know this topic?
Take the Skill AssessmentPreparing for interviews too?
Check Interview Guide & Kit Availability