PPAP: Production Part Approval Process Explained

The Production Part Approval Process (PPAP) is the automotive industry's standard way for a supplier to prove, with documented evidence, that it understands every customer engineering requirement and that its production process can make conforming parts consistently at the quoted rate. It is a package of records and sample parts submitted for customer sign-off before a part is allowed into mass production.

PPAP was created by the Automotive Industry Action Group (AIAG) and has spread well beyond cars into aerospace, medical, and heavy industry because it answers a simple question every buyer has: can this supplier actually make what the drawing says, run after run, not just once for the sample? This guide covers what PPAP is, the standard 18 elements, when a submission is triggered, and how a run actually goes from kickoff to approved warrant.

What is PPAP, in plain terms?

PPAP is a gate. It sits at the end of new-part development and controls whether a supplier is allowed to ship production parts. The supplier runs a small batch of parts on production tooling, at the production location, with the production process, and then hands the customer a stack of evidence showing that the parts measured good and that the process behind them is under control. The customer reviews it, and either approves the part, grants interim approval, or rejects it.

The key word is consistently. A machine shop can hand-fit one perfect prototype. PPAP asks for proof the process will keep making good parts at rate. That is why PPAP leans on production tooling and a real production run rather than a lab sample, and why it carries capability data, a control plan, and measurement studies instead of just an inspection report. PPAP is the deliverable that closes out Advanced Product Quality Planning (APQP): APQP is the plan, PPAP is the proof the plan worked.

What are the 18 PPAP elements?

A full PPAP package is built from 18 standard elements defined in the AIAG PPAP manual. They fall into a few natural groups: design evidence, process planning, measurement and results, sample parts, and the warrant that ties it together. Not every element is physically submitted every time (that depends on the submission level), but every element must be completed and kept on file.

Two elements do a lot of the heavy lifting. Element 11, the initial process study is where capability data lives and where a shaky process shows up. Element 7, the control plan, is the promise about how the process will be held in control after approval. If either is weak, the parts may measure fine today and drift out of spec next month, which is exactly what PPAP exists to prevent.

When is a PPAP required?

A PPAP is required before the first production shipment of a new part, and again whenever something changes that could affect whether the process still makes conforming parts. Customers spell out their own triggers, but the common ones are consistent across the industry:

• A new part or product never supplied before.
• An engineering change to the design, specification, or material.
• New, modified, refurbished, or relocated tooling, including moving a line to a new building.
• A change in the manufacturing process, method, or sub-supplier of a component or material.
• A production gap: tooling that has been inactive for 12 months or more.
• Correction of a discrepancy on a previously submitted part.

When in doubt, notify the customer and let them decide the level. Skipping a PPAP that was required is one of the fastest ways to trigger a containment action and a supplier scorecard hit, which feeds straight into your supplier quality management standing and your supplier scorecard.

How do you run a PPAP submission?

The mechanics are the same whether you are a stamping plant or a resin molder. The sequence below is the path from kickoff to an approved warrant.

1. Confirm the requirements and level. Get the latest design records, customer-specific requirements, and the submission level in writing before you cut a chip. The level decides what you submit versus retain.
2. Finish the planning elements. Process flow, PFMEA, and control plan should already exist from APQP. Reconcile them so every special characteristic on the drawing has a matching control on the plan.
3. Prove the gauges before the parts. Run measurement system analysis on the gauges you will use. If the gauge cannot repeat, every dimensional result and capability number after it is suspect.
4. Run the significant production run. Make the parts on production tooling at the production site. AIAG's default is a run of one to eight hours producing a minimum of 300 consecutive parts unless the customer specifies otherwise.
5. Measure everything and study capability. Record full dimensional results, run material and performance tests, and compute initial process capability on the special characteristics. This is the same math as a full process capability study.
6. Assemble the package and sign the warrant. Collect the elements the level requires, fill out the Part Submission Warrant, and submit. Retain the full file regardless of what you ship.
7. Close out the disposition. Act on the customer's response: full approval releases production, interim approval releases with a time or quantity limit and an action plan, rejection sends you back to fix the root cause.

What is the Part Submission Warrant (PSW)?

The PSW is the one-page cover sheet that summarizes the whole submission and carries the supplier's signed declaration that the parts meet all requirements. It records the part number, change level, reason for submission, results summary, and declared submission level. The customer signs the same form to grant the disposition. Because the PSW is the single element submitted at every level, it is effectively the face of the PPAP.

How does PPAP connect to APQP, IATF 16949, and supplier quality?

PPAP is not a standalone form. It is one of the automotive core tools and the formal output of the APQP process. It is also a requirement of the IATF 16949 quality management standard, which obliges automotive suppliers to conform to a customer-referenced PPAP process. In practice, a customer's APQP timing plan schedules the PPAP, the control plan and PFMEA feed straight into the submission, and the approved PPAP becomes the baseline that any future change is measured against. Miss a PPAP trigger, and you have also breached your IATF 16949 obligations.

The standard behind the process

PPAP is defined by an industry standard, not a supplier preference, which is why the requirements are consistent across customers.

• PPAP is one of the AIAG automotive core tools; the reference manual defines the 18 elements, the five submission levels, and the acceptance criteria (AIAG, Production Part Approval Process).
• The AIAG default significant production run is one to eight hours of production and a minimum of 300 consecutive parts unless the customer specifies otherwise.
• Initial process studies are commonly judged on Ppk, with the AIAG default treating an index of 1.67 or higher as acceptable for a stable process; the underlying capability math is standardized in resources like ASQ's statistical process control materials.

Why PPAP files rot in a binder

The most common PPAP failure is not a bad submission; it is a good submission that nobody keeps alive. The package gets approved, printed, and filed, and then tooling wears, an operator changes a setting, or a sub-supplier swaps a resin, and none of it triggers the re-submission it should. The control plan says one thing; the floor does another. When measurements and line checks are captured digitally at the station instead of on clipboards, the control plan stops being a document in a binder and becomes something the floor actually runs against, and a change that should trigger a new PPAP is visible the day it happens. That live link between the plan and the floor is what Harmony's quality intelligence and paperwork digitization is built for. It is the difference between PPAP as a one-time certificate and PPAP as a standard the process is actually held to, run after run. For the next layer of detail, see the five PPAP submission levels and how each decides what you submit versus retain, or see how the same discipline shows up in first article inspection and the wider work of QMS software. Real proof of that discipline in a running plant is in our CLS case study.