PPAP originated in the automotive industry and is now governed by the AIAG (Automotive Industry Action Group) standard of the same name. Any supplier to Ford, GM, Stellantis, or their Tier 1 suppliers will encounter PPAP. But the underlying logic — prove before you produce — has spread into aerospace, medical devices, and general manufacturing.
The core question PPAP answers is: Can your production process consistently make this part to our drawing and specifications? Not your prototype line. Not your engineering lab. Your actual production tooling, at production rate, with your production workforce.
What Triggers a PPAP Submission?
A new PPAP submission is required whenever something significant changes — not just for brand-new parts. The AIAG standard lists the triggers precisely:
A new part or product. A correction to a previous discrepancy. A design change to the part. A change in production location. A change in tooling (new, replacement, or refurbished). A change in supplier sub-components. A production interruption exceeding 12 months for automotive, or customer-defined periods for other industries. A change in material specification.
This exhaustive trigger list reflects the automotive industry's hard-won experience: small changes upstream create large quality problems downstream, often months later and deep inside an assembled vehicle.
新規部品の量産開始前、または工程変更時に実施する正式な承認プロセス。サプライヤーは18の要素からなる文書一式と実際の量産条件で生産した試作品を顧客に提出し、承認を得てから量産を開始する。IATF16949の重要構成要素のひとつ。
The 18 PPAP Elements
A full PPAP submission consists of 18 elements. Not every element is required for every submission — the required elements depend on the submission level (explained below) — but understanding all 18 tells you what evidence the system demands.
Elements 4 through 7 form the core process documentation package: DFMEA, process flow, PFMEA, and control plan. Together they describe what can go wrong (FMEA), how the process is designed to run (flow diagram), and what controls prevent escapes (control plan). Element 11 — initial process capability — is where the numbers prove the process is actually capable, not just well-documented.
PPAPで最重要な要素のひとつ。量産条件での試作品（通常300個以上）から工程能力指数（Cpk）を算出し、1.67以上（一部顧客は1.33以上）であることを証明する。能力不足の場合は偏差書（Deviation）を提出し顧客と協議する必要がある。
The 5 Submission Levels
PPAP does not always require submitting all 18 elements to the customer. The submission level — specified by the customer — determines which elements must be physically submitted versus retained at the supplier's facility.
| Level | What Is Submitted | Typical Use |
|---|---|---|
| Level 1 | PSW only (Part Submission Warrant) | Minor changes; low-risk parts with long supplier history |
| Level 2 | PSW + limited supporting data + sample parts | Standard submissions for established suppliers |
| Level 3 | PSW + full supporting data + sample parts | Default level for new parts and new suppliers (most common) |
| Level 4 | PSW + other requirements as specified by customer | Customer-defined; varies by OEM |
| Level 5 | Full submission reviewed at supplier's facility | Critical parts; new suppliers; on-site audit required |
Level 3 is the most common default. When in doubt, a supplier should assume Level 3 unless the customer specifies otherwise in writing. Submitting less than required is a common — and costly — mistake that delays approval and erodes customer trust.
"The PPAP process is not about paperwork. It is about proving, with data from real production conditions, that the process is in control before the customer's assembly line depends on it." — AIAG PPAP Reference Manual, 4th Edition
The Part Submission Warrant (PSW)
The PSW is the cover sheet and legal declaration of the PPAP package. It is Element 18 — but functionally it is the gateway. Without a signed PSW, there is no approved PPAP. The PSW declares:
The part number, revision level, and drawing date. The production location and tooling number. The declaration that all elements have been completed and conform to requirements. The initial process capability results summary (Cpk values). The submission level. The authorized signature of the supplier's quality representative.
PPAPパッケージの表紙であり、最終的な承認文書。サプライヤーの品質代表者が署名し、「全18要素が完結しており、量産品が図面・仕様書に適合する」ことを正式に宣言する。顧客がPSWに承認印を押すことで量産開始が正式に許可される。
The customer responds with one of three dispositions on the PSW: Approved (全面承認 — production may begin), Interim Approval (暫定承認 — limited production allowed while identified issues are resolved, with a deadline), or Rejected (不合格 — the submission is returned with documented reasons, and a revised submission is required before any production).
Initial Process Capability: The Numbers That Matter
Element 11 is where many PPAP submissions fail. The standard requires that all critical and significant characteristics achieve an initial Cpk of 1.67 or higher when measured from a production run of at least 300 consecutive pieces. Some customers accept 1.33, and some require even higher thresholds for safety-critical dimensions.
The 300-piece requirement exists because a short run does not reveal the true process variation. A run of 30 pieces may look capable by chance. At 300 pieces, the tool wear, shift changes, and raw material variation begin to appear in the data. That is the point.
When Cpk falls below the threshold, the supplier must submit a deviation request (偏差書) explaining the gap, the containment actions, and the timeline to reach full capability. Production may be allowed on interim approval, but the deviation does not go away — it is tracked until resolved.
PPAP要件（特に工程能力）を満たせない場合に顧客に提出する書類。暫定的に量産を継続しつつ、改善計画と期限を明示する。「特採（特別採用）」とも呼ばれ、日本の現場では頻繁に使われる用語。偏差書が積み重なるほど顧客との信頼関係が損なわれる点に注意が必要。
Common PPAP Mistakes
Submitting prototype data instead of production data. PPAP requires samples made from production tooling, at production speed, by production operators. Samples machined by engineers in the tool room do not qualify. This mistake is surprisingly common and immediately disqualifies a submission.
Incomplete dimensional balloons. Every characteristic on the drawing must be numbered (ballooned), measured, and reported. Missing a single GD&T callout — even a general tolerance — is grounds for rejection. A balloon check against the drawing is the first thing many customer quality engineers look for.
MSA skipped or faked. Measurement System Analysis (Element 8) requires a genuine GR&R study on the measuring instruments used for PPAP. A %GR&R above 30% indicates the measurement system itself is unreliable — and measuring unreliable data with unreliable gauges means the capability numbers are meaningless.
Wrong revision level on the PSW. The design record revision and the PSW must match. A single character difference in the revision code creates a traceability gap that auditors will flag instantly. Verify the drawing revision the day before submission, not the day the PPAP was started.
Treating PPAP as a one-time event. PPAP approval is tied to the specific conditions documented in the submission. Any change to those conditions — new tooling, new sub-supplier, relocated machine — requires a new or updated submission. Suppliers who proceed without re-submitting put their customer approvals and their quality system certification at risk.