PPAP (production part approval process) is how a supplier proves to a customer that it understands the requirements and can consistently make conforming parts at the quoted rate. A submission is a package of up to 18 elements, from design records and the PFMEA to measurement results, capability studies and a signed part submission warrant (PSW). The customer sets the submission level, most often Level 3, which decides how much of the package you send. Build it from your real process, and make sure the documents agree with each other.
What PPAP is for
A customer does not want to find out on the first production order that a supplier misread the print or cannot hold the rate. PPAP is the evidence beforehand. It says: we understood the requirements, we made parts from the production tooling and process at production rate, we measured them, and the process is capable.
PPAP comes from the AIAG manual, which is copyrighted. This guide describes the ideas in plain words and does not reproduce the manual. Your customer’s requirements come first, and their supplier manual is where they are written down.
When a PPAP is required
- A new part or product. The usual trigger.
- An engineering change. A revision to the print or specification that affects form, fit or function.
- A change to tooling, process or location. New or refurbished tooling, a different method, or production moved to another site.
- A change of material or sub-supplier. Any change to who supplies what goes into the part.
- Production restarting after a lapse. A long gap in production, or tooling that sat unused. Customers define how long a gap counts.
- Correction of a rejected submission or a discrepancy. Resubmit once the cause is fixed.
Customers can ask for PPAP in other situations too. Their quality requirements will say when.
The 18 elements
Not every element applies to every part, and some customers want you to keep certain records at your plant without sending them. Ask which apply before you start.
| # | Element | What it shows | Group |
|---|---|---|---|
| 1 | Design records | The print or specification, plus your ballooned copy | Design |
| 2 | Authorized engineering change documents | Changes on the part that are not yet on the print | Design |
| 3 | Customer engineering approval | The customer signed off, when they require it | Design |
| 4 | DFMEA | How the design could fail, if you are design responsible | Design |
| 5 | Process flow diagram | Every step from receiving to shipping | Process |
| 6 | PFMEA | How each step could fail and what stops it. See how to write a PFMEA | Process |
| 7 | Control plan | What is checked at each step, how, how often, and what happens when it fails | Process |
| 8 | Measurement system analysis | Your gauges are good enough for the tolerances, usually a Gage R&R | Measurement |
| 9 | Dimensional results | Measured values for every dimension on the print, from parts you built | Measurement |
| 10 | Material and performance test results | Material certifications and any tests the print calls for | Measurement |
| 11 | Initial process studies | Capability on the special characteristics. See Cpk vs Ppk | Measurement |
| 12 | Qualified laboratory documentation | The lab that tested is qualified to do it | Measurement |
| 13 | Appearance approval report | Color, grain and finish, for parts that have appearance requirements | Approval |
| 14 | Sample production parts | Actual parts for the customer | Approval |
| 15 | Master sample | A signed reference sample you keep | Approval |
| 16 | Checking aids | The fixtures, gauges and templates used, with calibration records | Approval |
| 17 | Records of compliance with customer-specific requirements | Proof that you met anything particular to this customer | Approval |
| 18 | Part submission warrant (PSW) | The cover sheet: a signed statement that the package is complete and true | Approval |
The five submission levels
| Level | What you send the customer |
|---|---|
| 1 | The PSW only, plus the appearance report where it applies |
| 2 | The PSW with product samples and limited supporting data |
| 3 | The PSW with product samples and complete supporting data. This is the default when a customer does not say otherwise |
| 4 | The PSW and other items the customer specifies |
| 5 | The PSW with product samples and complete supporting data, reviewed at your site |
Whatever level you submit, keep the complete records at your plant. The customer can ask for them at any time.
How to build the package
Get the requirements first
Ask your customer for the submission level, the due date, their templates or portal and any special characteristics. Do not start from assumptions.
Start from the print
Balloon every dimension and note, and number them. That numbering carries through to the dimensional results.
Write the process documents together
The flow diagram, PFMEA and control plan should be built from one list of steps, with the same step names and numbers. They are three views of one process.
Qualify the gauges
Check calibration and run a Gage R&R before you measure the parts. Measurements taken with a gauge you cannot defend are not evidence.
Make the parts the way you will make them for real
Use production tooling, production operators and production rate. A significant production run is commonly a minimum of 300 pieces unless the customer says otherwise.
Measure, then study capability
Measure the dimensions, run the capability studies and write down what you find, including any shortfall and your plan for it.
Complete the PSW last
Check every item against the package, make sure the revision levels agree and sign it.
Submit, then track the answer
The customer returns a status: approved, interim approval for a limited time or quantity, or rejected. Record it and the date.
Why submissions get rejected
- Documents that disagree. The control plan lists steps the PFMEA does not, or the flow diagram has a different number of operations. Reviewers check this first.
- The wrong revision. The drawing revision on the dimensional report is not the one the customer issued.
- Incomplete dimensional results. Missing characteristics, or measurements taken with a gauge outside its calibration date.
- Capability below the requirement with no plan. A study under the minimum is a conversation. A study under the minimum with nothing in the package is a rejection.
- A weak PSW. Missing signatures, the wrong reason for submission or numbers that do not match the package.
- Samples that did not come from production. Parts made on prototype tooling or at a slow rate do not prove the production process.
- Missing material or lab evidence. A certification without the supporting test, or a lab that is not qualified for the test.
After approval
A PPAP is a snapshot of one day. When a complaint, a change or an audit alters the process, the PFMEA, control plan and work instruction should change with it, and some changes need a new submission. That is one more reason to keep the documents alive instead of filing them. The New part launch path shows the order of work from the first PFMEA through to the control plan.
The PPAP Submission Checklist tracks the elements, owners and due dates. The Process Launch Bundle puts the launch tools together in one purchase.
Questions people ask
What is a PSW?
The part submission warrant is the cover sheet of a PPAP. It identifies the part, the reason for submission and the level, states that the package is complete and true, and carries a signature.
Which PPAP level do I need?
Whatever your customer specifies. Level 3 is the default when they do not say.
Do I need all 18 elements every time?
No. The customer decides which apply to the part and the level, and some records are kept at your plant instead of sent.
What happens after I submit?
The customer reviews it and returns a status: approved, interim approval for a limited time or quantity, or rejected. A rejection means correcting the gaps and submitting again.
Is PPAP the same as a first article inspection?
No. PPAP is the automotive approval process and covers the whole process. First article inspection is a related idea used widely in aerospace and other industries, and it centers on measuring the first parts against the drawing.