PPAP: the 18 elements explained

What PPAP is for

PPAP is a production part approval process. It exists to show that a supplier can make the part to the drawing, at the quoted rate, with the process that will actually run in production. The submission is a pack of evidence, not a single inspection report.

The AIAG manual sets out eighteen elements and five submission levels. The level decides how much of the pack the customer receives. The evidence still has to exist at the supplier, even when the customer asks for less.

The table is the reference list. The sections that follow explain how the groups fit together and where submissions usually fail.

Elements 1 to 4: design and change control

The first four elements fix the design. The design record is the drawing and the specification at the revision being approved. The engineering change documents show that every difference from the previous revision is authorised. The customer engineering approval covers deviations the customer has accepted. The design FMEA records the design risks and the actions taken.

A common failure is a pack built on the wrong revision. The drawing in the pack is current, but the control plan or the inspection report still refers to the previous issue. The mismatch is easy to miss and hard to defend after launch.

Elements 5 to 7: the process on paper

The process flow diagram, the process FMEA and the control plan are one argument in three documents. The flow shows the steps. The FMEA shows what can go wrong at each step. The control plan shows how each risk is prevented or detected.

Read them together. Every step in the flow should appear in the control plan. Every failure mode with a high severity or a special characteristic should have a control. If the FMEA says a step can produce a crack and the control plan only checks appearance, the pack has a gap.

Elements 8 to 10: measurement and test

The measurement system analysis shows that the gauge can separate good parts from bad ones at the tolerance in question. The dimensional results show the actual values on the ballooned drawing. The material and performance tests show that the material and the function meet the specification.

The dimensional results should cover every characteristic, not only the difficult ones. The material tests should name the standard, the method and the laboratory. A certificate that lists a grade without the test results is not the same as a test report.

Elements 11 and 12: capability and laboratories

The initial process study estimates whether the process can hold the tolerance over time. It is normally a Ppk study from the significant production run, and the customer sets the acceptance value. A study from a trial run, or from parts made on a different machine, does not answer the question.

The laboratory documentation shows that the lab that ran the tests is competent for the methods used. That can be an accreditation scope, a customer approval or an internal qualification, depending on the requirement. The scope has to cover the test, not just the lab name.

Elements 13 to 16: physical evidence

The appearance approval report matters where colour, grain or gloss is part of the requirement. The sample parts, the master sample and the checking aids give the programme a physical reference that survives staff changes.

A master sample needs a label, a date, a part number, a revision and a storage condition. If the material ages, the label should say when the sample stops being valid. A checking aid needs its own verification against a known part, or it becomes another source of variation.

Elements 17 and 18: customer rules and the warrant

The customer specific requirements are the rules that sit outside the standard manual. They can add a test, change a sample size or name a document format. The part submission warrant is the final element. It names the part, the drawing, the change level, the weight, the material and the submission level, and the supplier signs it.

The warrant is a declaration, not a substitute for the pack. If the customer receives a warrant at level one, the supplier still holds the eighteen elements and can produce them on request. A warrant signed before the evidence is complete turns a quality problem into a credibility problem.

Submission levels and common gaps

Level one is the warrant only. Level two adds samples and limited supporting data. Level three adds samples and the full supporting data and is the usual default. Level four is defined by the customer. Level five requires the full pack to be reviewed at the supplier site.

Most rejected submissions fail on the same few points: a drawing revision that does not match the pack, a control plan that does not follow the flow, capability data from the wrong run, a master sample with no label, or a warrant signed before the material certificates arrived. None of these needs a new process. They need a checklist and a second pair of eyes.