Complete Guide to PPAP (Production Part Approval Process)

Complete Guide to PPAP (Production Part Approval Process) — In-Depth for 2025

What is PPAP?

PPAP stands for Production Part Approval Process — a formal and structured approach used in manufacturing (mainly in the automotive and aerospace industries) to ensure that suppliers deliver parts that consistently meet customer engineering design and quality requirements.

Originally developed by the AIAG (Automotive Industry Action Group), PPAP is a cornerstone of APQP (Advanced Product Quality Planning) and is closely linked to IATF 16949, the automotive quality management standard.

Why is PPAP Important?

PPAP acts as a formal communication between the customer and supplier to verify that:

• All design and specification requirements are understood.

• The manufacturing process is capable and controlled.

• Quality is built into the process, not just inspected at the end.

• The supplier is ready for mass production with no surprises.

PPAP helps eliminate trial-and-error in production by replacing it with a data-driven validation approach.

When is PPAP Required?

PPAP submission is required by most OEMs and Tier-1 suppliers under various scenarios:

• Introduction of a new part or product.

• Engineering change to design, material, or dimensions.

• Change in manufacturing process, method, equipment, or location.

• Change of supplier for subcomponents or raw materials.

• Tooling replacement, refurbishment, or transfer.

• Corrective action request (CAR) due to a nonconformance.

• As part of annual revalidation in some contracts.

The Foundation: 5 Core APQP Elements Behind PPAP

PPAP doesn’t work in isolation. It is deeply tied to the 5 Core APQP Tools:

1. DFMEA (Design Failure Mode and Effects Analysis) – Proactive risk assessment of potential design failures.

2. PFMEA (Process Failure Mode and Effects Analysis) – Risk analysis of process-based issues (e.g., missed steps, human error).

3. Process Flow Diagram – Blueprint of the production flow.

4. Control Plan – Specifies how quality is ensured at each process step.

5. MSA (Measurement System Analysis) – Validates that inspection and testing methods are reliable.

The 18 Mandatory PPAP Elements (Explained in Detail)

Let’s go beyond the checklist and understand what each of the 18 PPAP elements really means:

1. Design Records
   Final engineering drawings or CAD models with all revisions and part numbers.

2. Authorized Engineering Change Documents
   Evidence of any approved changes (ECNs) to the drawing or specifications.

3. Customer Engineering Approval
   If required, a test or validation conducted by the customer (e.g., fitment or performance check).

4. Design-FMEA (DFMEA)
   Team-based risk analysis on how the product design could fail and how to prevent it.

5. Process Flow Diagram
   Detailed diagram showing steps from raw material to final shipment, including inspection points.

6. Process-FMEA (PFMEA)
   Risk assessment of how the manufacturing process could go wrong (e.g., equipment failure, operator error).

7. Control Plan
   A document specifying what to measure, how to measure, and what reaction plan is in place if there’s a deviation.

8. Measurement System Analysis (MSA)
   Typically includes Gage R&R studies to validate measurement repeatability and reproducibility.

9. Dimensional Results
   Actual inspection results of all dimensions on the drawing from at least 5-10 parts.

10. Material and Performance Test Results
    Mechanical, chemical, and physical test reports with traceability to testing labs and batch numbers.

11. Initial Process Studies (Cp, Cpk)
    Process capability study done using trial production data — ensures the process can meet spec consistently.

12. Qualified Laboratory Documentation
    Certifications and accreditation details of labs used (e.g., ISO 17025).

13. Appearance Approval Report (AAR)
    Required for visual parts (like dashboards) — verifies surface finish, texture, color, etc.

14. Sample Production Parts
    Physical parts submitted to the customer along with the documentation for validation.

15. Master Sample
    The standard reference sample, signed off by customer and supplier, kept for future comparison.

16. Checking Aids
    Details about fixtures, templates, or gages used to measure or inspect the part.

17. Customer-Specific Requirements
    Any additional documents or tests demanded by the customer (e.g., special torque tests, traceability reports).

18. Part Submission Warrant (PSW)
    The final summary sheet that confirms compliance with all 17 other elements, signed by an authorized quality representative.

Best Practices for Preparing a Strong PPAP File

1. Use real production equipment and team — not lab or trial lines.

2. Perform at least 300 pieces for capability studies (30 for dimensional).

3. Cross-check each FMEA control with Control Plan entries — they must link.

4. Keep revision control on every document — no uncontrolled changes.

5. Validate all gages and tools — with proper calibration records.

6. Include traceability tags — like batch numbers, heat numbers, or barcodes in test reports.

PPAP Process Flow: Step-by-Step

1. Receive engineering specs and purchase order.

2. Form a cross-functional APQP team.

3. Prepare DFMEA, PFMEA, Process Flow.

4. Create MSA, Control Plan, and trial samples.

5. Produce pilot lot, collect data, and test parts.

6. Compile 18 PPAP documents.

7. Submit the PSW with selected PPAP Level.

8. Address customer feedback (if any).

9. Receive PPAP approval (or conditional approval).

10. Start production and maintain continuous improvement.

Certainly! Here's the explanation of the PPAP Submission Levels (1 to 5) in a clear, paragraph format without using a table:

Understanding PPAP Submission Levels (Explained)

The Production Part Approval Process (PPAP) includes five defined levels of submission. Each level represents the depth and detail of documentation that a supplier must provide to the customer during the approval phase. The appropriate level is typically specified by the customer (often an OEM or Tier 1 supplier). Here's a breakdown of each level:

🔹 Level 1 – PSW Only:
At this level, only the Part Submission Warrant (PSW) is submitted. This is the most basic form of PPAP, typically used for prototype parts or when only minor changes have been made to an existing part. It assumes a high level of trust and prior validation between supplier and customer.

🔹 Level 2 – PSW with Limited Supporting Data:
This level requires submission of the PSW along with limited additional data, such as dimensional results and material or performance test results. It is used when the part is simple, the risk is low, or the customer has enough historical confidence in the supplier’s processes.

🔹 Level 3 – Full PPAP Submission:
This is the most commonly required level and is considered the default level unless otherwise specified. It includes the PSW plus all 18 supporting documents such as DFMEA, PFMEA, Control Plan, MSA studies, dimensional results, and test reports. This level provides a comprehensive validation of both product and process quality.

🔹 Level 4 – PPAP Customized to Customer Requirements:
In this level, the customer defines what specific documents are to be submitted. It could be a combination of documents from Levels 1, 2, or 3, depending on the customer's internal risk assessments or policies. This level is often used when the customer has unique requirements or documentation formats.

🔹 Level 5 – Full Documentation with On-Site Review:
Level 5 requires the supplier to retain all PPAP documents on-site and make them available for customer review during an on-site audit or visit. It’s typically used for high-risk parts, new suppliers, or critical safety components. This level involves maximum scrutiny and requires the supplier to have a well-organized and ready-to-audit quality system.

Real-Time PPAP Example: CNC Machined Shaft for Automotive Transmission

A) Part Description:

A precision CNC-machined steel shaft used in an automotive transmission system. The shaft has critical dimensions, such as a ±0.01 mm tolerance diameter, a surface finish of Ra < 0.8 µm, and hardened zones for bearing seating.

B) Scenario Context:

• The OEM has released a new gearbox model.

• They outsource machining of this transmission shaft to a Tier-2 CNC supplier.

• The drawing specifies heat treatment, tight tolerances, and surface roughness.

• The supplier uses CNC turning, induction hardening, and centerless grinding.

C) Let’s look at how PPAP Levels apply in real terms:

✅ Level 1: PSW Only

Example Use Case:
During prototype development, the OEM only needs proof that the shaft is being manufactured.
The supplier submits only the Part Submission Warrant (PSW) confirming part number, revision, and process intent.

Why this is OK:
The OEM is still testing performance and not requiring full documentation yet.

✅ Level 2: PSW + Limited Data

Example Use Case:
After minor process changes, such as switching from one inspection micrometer to another, the supplier resubmits a PSW along with dimensional reports and material hardness test results.

Why this is OK:
The risk is low. No changes to design or process flow. The change doesn’t affect function or fit.

✅ Level 3: Full PPAP Submission

Example Use Case:
The supplier sets up a new production line for this CNC part using different lathes and grinding equipment.
The OEM demands full Level 3 PPAP, including:

• DFMEA – Identifies shaft bending risk, warping during heat treatment.

• PFMEA – Highlights process risks like tool wear, improper clamping.

• Process Flow – Shows steps from steel bar cutting → CNC turning → heat treatment → grinding → inspection → packing.

• Control Plan – Specifies controls like in-process diameter checks every 10 pieces, 100% surface finish checks.

• MSA – Shows gage R&R results for OD micrometer and roughness tester.

• Dimensional Results – From 5 sample shafts.

• Material Test Reports – Confirm hardness and microstructure.

Why this is Required:
This is a new product line with critical dimensions, requiring full validation of both product and process.

✅ Level 4: Customized Submission

Example Use Case:
The OEM uses an internal format for PFMEA and Control Plan.
They request only those documents plus PSW and test results – skipping others like AAR or MSA.
Supplier adapts PPAP file accordingly.

Why this is Used:
The OEM has specific documentation expectations that don’t align exactly with AIAG's format.

✅ Level 5: On-Site Review

Example Use Case:
The shaft is a safety-critical component (connected to braking system or high-speed rotation).
The OEM quality team conducts an on-site audit at the CNC supplier’s facility. They inspect:

• In-process checks and measurement records.

• Gage calibration certificates.

• Heat treatment furnace traceability.

• Actual samples and inspection setup.

Why this is Done:
The part has high risk and tight tolerances, so the customer demands total transparency and real-time verification.

D) Final Summary

Part	CNC Machined Shaft for Transmission
Material	EN8 steel (with case hardening)
Key Features	OD tolerance ±0.01 mm, Ra < 0.8 µm, chamfered edges
Risk Level	Medium to High
Typical PPAP Level	Level 3 (Full Submission)

If you're preparing PPAP for such a part, remember:

• Use actual production equipment during sample run.

• Document tooling, CNC program revisions, and operator training.

• Trace heat treatment batch numbers to material certificates.

• Validate CMM programs and surface testers with MSA.

Sample PPAP Document Checklist Format

Element	Status	Reviewer Comment
DFMEA	✅	RPNs below 100
PFMEA	✅	Linked with Control Plan
MSA (Gage R&R)	✅	<10% variation
Dimensional Report	✅	Within ±0.05 mm
Control Plan	✅	Included reaction plans
PSW	✅	Signed by QA Manager

Where to Learn PPAP – Trusted Resources

YouTube Training Videos:

• PPAP for Beginners – Quality HUB India
  https://www.youtube.com/watch?v=cN-fBAe-Bqo

• AIAG – Official PPAP Training Introduction
  https://www.youtube.com/watch?v=FWp3wAU45EM

• QHSE – Control Plan & FMEA Simplified
  https://www.youtube.com/watch?v=1a1UQIBowL8

Study Websites:

• AIAG Official – https://www.aiag.org

• IATF Global Oversight – https://www.iatfglobaloversight.org

• QualityTrainingPortal.com – PPAP Course – https://qualitytrainingportal.com

• ASQ (American Society for Quality) – https://asq.org

Conclusion

PPAP is not just a customer requirement — it’s a strategic quality tool that promotes defect prevention, robust process control, and continuous improvement. While the 18 elements may seem complex, they collectively ensure your process is stable, repeatable, and capable of producing quality parts consistently.

If you’re starting with PPAP:

• Begin with Level 3 as a baseline.

• Use templates and AIAG formats.

• Engage a cross-functional team early.

• Audit your PPAP file before submission.

By mastering PPAP, you ensure customer satisfaction, regulatory compliance, and long-term business growth in competitive industries like automotive, aerospace, electronics, and metallurgy.