The production part approval process is the automotive supply chain's way of proving that a supplier's process will reliably make the part the drawing describes. It is a package of evidence rather than a test, it is submitted at one of five levels of disclosure, and level 3 is the default that most customers ask for on a new part.
What the package contains
The submission is built from a defined set of elements: design records, any engineering change documents, customer approvals, design and process failure mode analyses, a process flow diagram, a control plan, measurement systems analysis, dimensional results, material and performance test results, initial process studies, qualified laboratory documentation, appearance approval where relevant, sample parts, a master sample, checking aids, customer specific requirements, and the part submission warrant that summarises it.
How the levels differ
The levels do not change what the supplier must have; they change what is sent to the customer. Level 1 sends the warrant alone, plus appearance approval where it applies. Level 3 sends the warrant with product samples and complete supporting data, which is why it is the usual default. Level 5 keeps everything at the supplier's site for review there.
Preparing for it properly
The mistake is treating it as paperwork produced after the parts. Every element derives from work that has to happen anyway: the process flow, the failure mode analysis and the control plan are how the process is designed, and the measurement systems analysis and initial process study are how you find out whether it is capable before the customer does. Doing them in that order makes the submission a by product.
What usually goes wrong
Dimensional results missing a characteristic because the drawing was not fully ballooned. Measurement systems analysis done on a gauge that turns out not to be capable of the tolerance. Initial process studies run on a batch that was not representative. And customer specific requirements overlooked, since they sit outside the standard package and vary by customer.
Questions people ask about ppap level 3
What is PPAP?
The production part approval process: a defined package of evidence that a supplier's process will consistently produce parts to the drawing and specification.
What does level 3 send?
The part submission warrant with product samples and complete supporting data. It is the default level most customers request for a new part.
Do the levels change what I must do?
No. They change what is submitted to the customer. The underlying work and records are required regardless of level.
When is a PPAP resubmission needed?
On engineering changes, process or location changes, tooling changes or transfers, a new source of material, and after a long production suspension. The customer's requirements define the list.