The Production Part Approval Process (PPAP) is a standardized framework in manufacturing. This process formally demonstrates that a supplier’s production system can consistently manufacture parts that meet all of the customer’s defined engineering design specifications and quality requirements. Successful completion provides evidence that the supplier understands the requirements and can produce the product at the quoted production rate.
Defining the Production Part Approval Process (PPAP)
The Production Part Approval Process is a comprehensive quality methodology developed primarily by the Automotive Industry Action Group (AIAG). This standardized approach mitigates the risk associated with product and process changes before the start of mass production. It provides formal validation that both the product design and the manufacturing process are robust and capable of sustained, high-quality output. This methodology is a component of Advanced Product Quality Planning (APQP) and is governed by the AIAG PPAP Manual. The process requires the supplier to gather and submit a detailed collection of documents and samples to the customer for review and approval.
Triggers for a Required PPAP Submission
A new PPAP submission is required anytime a change occurs that could affect a part’s fit, form, function, performance, or quality. The most obvious trigger is the introduction of a completely new part or product. Submission is also mandatory for any engineering change to an existing part, including changes to the design record, materials, or specifications. Significant changes to the manufacturing process also necessitate a new approval. This includes the use of new or modified tooling, such as replacement or refurbishment, or the addition of new cavities or molds. Moving the manufacturing location to a different plant or a new physical address requires a resubmission. Resuming production after a prolonged period of inactivity, typically one year or more, also acts as a trigger.
Understanding the PPAP Submission Levels
The level of documentation a supplier must prepare and submit is determined by one of five PPAP submission levels. The customer specifies the required level, based on the part’s complexity, the supplier’s history, and the risk associated with the component. All five levels require the supplier to complete all 18 elements of the PPAP package, but they differ in how much documentation is physically submitted versus how much is retained.
The five submission levels are:
- Level 1: Submit only the Part Submission Warrant (PSW) and retain all other supporting data.
- Level 2: Submit the PSW, product samples, and limited supporting data, such as dimensional results and material test reports.
- Level 3: The most common default, requiring submission of the PSW, product samples, and the complete set of supporting PPAP documentation.
- Level 4: Submission includes the PSW along with other requirements specifically defined by the customer.
- Level 5: Requires the supplier to retain the PSW, product samples, and complete documentation for an on-site review by the customer’s representative.
The 18 Elements of the PPAP Package
Design Records
Design Records represent the official documentation of the part’s design, including a copy of the customer’s drawing, specifications, and the purchase order. This element ensures the supplier is working from the correct and most current revision level, and the drawing must be marked to identify all dimensions subject to inspection.
Engineering Change Documents
This element is required when the PPAP is for a revised part and includes documents detailing changes from the previous part level. The documentation, often called an Engineering Change Notice (ECN), must provide a clear description of the change and be formally authorized by the customer’s engineering department.
Customer Engineering Approval
Evidence of Customer Engineering Approval confirms that the customer has reviewed and signed off on the part design and the proposed manufacturing plan. This is often a temporary or conditional approval obtained during a trial run of the part at the customer’s facility.
Design Failure Mode and Effects Analysis (D-FMEA)
The D-FMEA is a systematic tool used to analyze the part’s design for potential failure modes before the part is produced. It assesses the design’s ability to meet performance requirements and helps the supplier identify high-risk areas to prevent product failure.
Process Flow Diagram
This diagram provides a visual representation of all steps involved in the part’s manufacturing process, from receiving raw materials to final shipment. It illustrates the sequence of operations and establishes a baseline for the production process used to develop the subsequent Process FMEA and Control Plan.
Process Failure Mode and Effects Analysis (P-FMEA)
The P-FMEA focuses on potential failures within the manufacturing process itself, examining how a process step could fail to produce a conforming part. This analysis evaluates the severity, occurrence, and detection of potential process failures to implement controls, directly influencing the Control Plan.
Control Plan
The Control Plan is a detailed document that outlines the methods used to control the manufacturing process and ensure product quality is maintained. It lists all process characteristics that need to be monitored and specifies the methods, sampling size, and frequency for control.
Measurement System Analysis Studies (MSA)
Measurement System Analysis Studies (MSA) assess the quality and reliability of the measurement systems employed during the manufacturing process. These studies, including gauge repeatability and reproducibility (GR&R), ensure that the measurement devices are accurate and precise, confirming variation is due to the process, not equipment flaws.
Dimensional Results
This element contains the actual measurement data taken from the required number of initial production parts. The results must show that every dimension and feature specified on the design records falls within the specified tolerance limits, verifying the supplier’s ability to meet geometric requirements.
Material and Performance Test Results
This documentation provides evidence that the part meets all specified material composition and functional performance requirements. Material tests confirm the chemical and physical properties, while performance tests verify that the part functions as intended under specified operating conditions.
Initial Process Studies
Initial Process Studies are statistical analyses used to determine if the manufacturing process is stable and capable of consistently producing parts that meet specifications. This element includes calculations for process capability indices, such as $C_{pk}$ and $P_{pk}$, providing a quantitative measure of the process’s ability to stay within tolerance limits.
Qualified Laboratory Documentation
This documentation provides proof that any testing performed for the PPAP submission was conducted by a qualified laboratory. The supplier must provide evidence of the laboratory’s certifications, such as ISO/IEC 17025 accreditation, ensuring the integrity and reliability of all test results.
Appearance Approval Report (AAR)
The AAR is a formal document required for any part that has color, grain, surface finish, or other aesthetic specifications. This report confirms that the customer has reviewed and formally approved the part’s appearance against the standards or master sample.
Sample Parts
The Sample Parts are a specified number of components taken from the production run used to create the PPAP documentation. These parts are submitted to the customer along with the documentation package for verification, representing the actual product intended for mass production.
Master Sample
A Master Sample is a single approved part, signed off by both the supplier and the customer, which is retained at the supplier’s location. This sample serves as a physical benchmark for future production runs and must be preserved for the duration of the part’s active production life.
Checking Aids
Checking Aids include any specialized tools, fixtures, gauges, or templates used to inspect, measure, or test the production parts. The supplier must provide a detailed list of these aids, along with documentation showing their calibration records and measurement system analysis data.
Customer Specific Requirements
This element accounts for any unique quality requirements or procedures mandated by the individual customer not covered by the standard AIAG PPAP manual. These requirements are documented in the customer’s specific quality manuals or purchase agreements, and the supplier must provide evidence of compliance.
Part Submission Warrant (PSW)
The PSW is the summary document that formalizes the entire PPAP submission and acts as the final sign-off. By signing the PSW, the supplier warrants that the production parts meet all customer engineering specifications and that the supporting documentation is on file.
The Final PPAP Review and Approval Statuses
After the supplier submits the PPAP package, the customer reviews the documentation and samples to determine the final approval status.
Full Approval
Full Approval confirms that the supplier has met all requirements and is authorized to begin shipping production quantities. This status grants the supplier permission to proceed with mass production at the quoted rate.
Interim Approval
Interim Approval is granted when minor non-conformances exist that do not significantly impact the part’s function. This status allows the supplier to ship a limited quantity of parts for a specified time while corrective actions are completed. The supplier must agree to an action plan and a timeline for resubmitting the corrected documents or samples.
Rejected
The final status is Rejected, meaning the submission fails to meet customer requirements and the supplier is not authorized to ship any production parts. Rejection requires the supplier to stop production, implement corrective actions, and prepare a complete new submission package for review.