PPAP: How Suppliers Prove a Production Process Is Ready

A part can pass inspection and still raise questions about whether the process can repeatedly produce the same part.

That is what PPAP answers. It combines design records, process controls, measurements, testing, and other evidence to show that a supplier is ready to produce the part to the customer's requirements.

Much of that evidence starts as quality data on the shop floor, which FlowFuse captures directly from machines and gauges.

This article covers what PPAP is, its 18 elements, the submission level requirements, and the approval process, including what goes into the Part Submission Warrant (PSW).

What Is PPAP?

PPAP is the Production Part Approval Process, a structured process that shows a supplier's production process can meet the customer's engineering and quality requirements on each run, not just on a single sample.

The Automotive Industry Action Group publishes PPAP as one of its Quality Core Tools, alongside APQP, FMEA, MSA, and SPC.

PPAP is most associated with automotive manufacturing, though other industries use similar part approval processes with different requirements.

The 18 Elements Of The Production Part Approval Process

PPAP is made up of 18 elements covering the product and process, measurement systems, testing, samples, and approval. The table below puts them into four areas to show how they are related. The groups are not part of the PPAP requirements.

The elements are interconnected, not 18 separate documents. The Design Record defines what the customer requires. The Process Flow Diagram, PFMEA, and Control Plan define how the supplier will manufacture and control the part. MSA, dimensional results, testing, and initial process studies then show that the process and its controls are working as intended, and the Part Submission Warrant brings the submission together for customer review.

PPAP Levels Explained

PPAP defines five submission levels, each setting how much of the 18-element package the supplier submits to the customer. The customer defines the level, usually in the PPAP request, supplier manual, or purchase order. Anything not submitted is maintained by the supplier and made available if requested.

PPAP Level 1

Only the Part Submission Warrant (PSW) is submitted.

PPAP Level 2

The PSW, product samples, and limited supporting data are submitted.

PPAP Level 3

The PSW, product samples, and the complete supporting data package are submitted. Level 3 is commonly requested for new part introductions because it gives the customer the complete supporting data package without an on-site review.

PPAP Level 4

The PSW is submitted along with whatever other requirements the customer defines, so the contents vary from customer to customer.

PPAP Level 5

The PSW, product samples, and complete supporting data are reviewed at the supplier's manufacturing location.

The Significant Production Run

The sample parts and data in a PPAP are pulled from a significant production run. Unless the customer specifies otherwise, the AIAG PPAP manual defines this as one to eight hours of production totaling at least 300 consecutive parts, made at the production site with the production tooling, gauging, materials, process, and operators.

Initial process studies are typically calculated from this run. Customer-specific requirements determine the acceptance criteria for these studies. Common capability criteria use thresholds such as a Cpk or Ppk of 1.33 or 1.67, depending on the characteristic and the customer.

What The Part Submission Warrant Includes

The PSW is the summary document the customer signs off on, and a separate PSW is generally completed for each part number unless the customer agrees otherwise. Typically, it records:

• Part number, part name, drawing number, and engineering change level
• Part weight
• The supplier's manufacturing site
• The reason for submission, such as a new part, engineering change, or tooling change
• The requested submission level
• Whether dimensional, material and performance, appearance, and statistical results meet requirements
• A declaration signed by an authorized supplier representative, including the production rate from the significant production run
• A customer disposition field recording the approval decision

PPAP Approval Status

After the submission is reviewed, the customer records one of three dispositions defined in the AIAG PPAP manual:

• Approved: The part and process meet the customer's requirements, and the supplier is authorized to ship production quantities.
• Interim approval: Shipment is permitted for a limited time or quantity while open issues are resolved, typically under an action plan agreed with the customer. Full approval is still required.
• Rejected: The submission does not meet requirements. The supplier must correct the issues and resubmit before production shipments are authorized.

When Is PPAP Required?

PPAP may be required when a change could affect how a part is made or how it performs. Each customer defines its specific submission triggers in its supplier manual, but most fall under a few categories.

The most common trigger is a new part, meaning a part number the supplier has never produced for that customer. An engineering or design change, such as a new drawing revision, tolerance, or material specification, also requires approval before the changed part ships.

Changes to how or where the part is made are treated the same way. These include a new manufacturing method or process sequence; new, replacement, or refurbished tooling; moving production to another line or plant; and switching to a new source for material or an outsourced operation. Many customers also require PPAP when production resumes on tooling that has been inactive for a long period, often 12 months or more.

A process correction after a significant quality problem can also trigger a new submission, typically as part of a corrective action.

The supplier is expected to notify the customer before making any of these changes. The customer then decides whether a complete PPAP, a partial resubmission covering only the affected elements, or another form of approval is required.

Final Thoughts

PPAP boils down to documented evidence that a production process can consistently meet requirements at production rates. Approval is commonly followed by a safe launch period, where the customer checks that proof against full production.

For manufacturers running several plants, most of the work goes into gathering that evidence. Dimensional results, test data, and capability studies sit in gauges, inspection systems, and MES platforms, and are typically copied into spreadsheets by hand before each submission. With FlowFuse, teams capture those measurements during production, tied to each part. Once the pipeline is established, FlowFuse lets them roll it out to other plants and secure and manage every deployment from one place.