Production Part Approval Process (PPAP) Guide: How It Works?

What is PPAP?

We will begin by explaining the PPAP meaning. Its pronunciation is Pee-Pap, by the way!

PPAP is a structured method that suppliers and manufacturers follow to demonstrate their capability to produce a product consistently while meeting all customer requirements. The PPAP procedure builds rapport with the customer by showing that the supplier has developed a production process fully equipped to handle the project.

The PPAP process originally came from the automotive industry owing to its heavy reliance on complex supply chains and OEMs. Resultingly, the central governing body developing industry standards for PPAP is the Automotive Industry Action Group (AIAG), which recognizes PPAP as part of the wider system of the Advanced Production Quality Planning (APQP).

Objectives of PPAP

The PPAP production process serves a critical purpose in industrial settings. Let us briefly discuss its core objectives.

The main objective of the PPAP process, as we know by now, is to ensure that the supplier understands the customer’s requirements and has a system in place to meet them within the correct timeframe and constraints.

Another way to look at this is that the PPAP procedure is a prerequisite to be fulfilled before full-scale production begins. The supplier/manufacturer provides the necessary PPAP documents to prove the readiness of their production strategy for mass-scale production.

Additionally, following the PPAP manufacturing process is also an effective way to catch potential issues early on. PPAP requires suppliers to document and analyze risks that can jeopardize the project, giving them an opportunity to identify and rectify problems, contributing to the overall success of their business deal.

When is PPAP Required?

The PPAP process is not limited to new products only. There are a number of situations where the customer may require the supplier to prepare a new PPAP file. These situations are as follows:

• New Part/Product Launch: The first time a product moves to production, a thorough PPAP approval process is required for validation of the supplier’s capability.
• Engineering Design Change: A significant change in the part design, drawing, or specifications also warrants a renewal of the PPAP elements as it affects the production floor procedures.
• Material or Supplier Change: Switching to a new material or a supplier is also a critical change that requires PPAP updating.
• Change in Production Process: If there is a change in the manufacturing method, equipment, or production location, a new PPAP file is often necessary.
• Corrective Actions: In some cases, major quality problems are identified that require changing the part or process, and the supplier needs to redemonstrate their readiness via the PPAP procedure.
• Customer Request: Customers from highly sensitive industries like medical devices or military may require a new PPAP for quality assurance, even if none of the above events occur.

To summarize, anything that can potentially impact the quality or consistency of the production process requires a PPAP process.

5 Levels of PPAP

The PPAP process has five submission levels. Each PPAP level defines how much documentation and evidence a supplier is required to collect and submit to the client.
The utility of these levels is seen in different situations. Some situations require a full-scale PPAP procedure, while in other cases, a partial submission of specific PPAP documents may suffice.

The upcoming sections provide a breakdown of the five PPAP levels.

Level 1: Part Submission Warrant (PSW) Only

PPAP level 1 only requires the supplier to submit the Part Submission Warrant (PSW). The PSW is an official document that formally certifies that the parts meet all the design and specification requirements.

Level 1 is generally suitable for low-risk PPAP parts having minimal quality concerns. For example, standard parts like washers or fasteners that do not require any special machinery/procedures or advanced analysis, like design for manufacturing. The customer directly trusts the supplier on the basis of the PSW.

Level 2: PSW with Product Samples and Limited Supporting Data

PPAP level 2 comprises a few additional documents, like material tests and dimensional results. Some clients also demand a few product samples for physical verification.

Level 2 PPAP production, like level 1, is a somewhat formal-informal process due to the moderate risk levels of the project. Usually, it involves parts with mostly standard features or dealings between trusted business partners.

Level 3: PSW with Product Samples and Complete Supporting Documentation

PPAP level 3 comprises all the required PPAP elements. These include design records, control plans, and performance results.

Level 3 is the industry standard in most contexts. Its documentation requirement is comprehensive and satisfactory for customers with new part launches, major design alterations, or supplier changes.

Level 4: PSW and Other Requirements as Defined by Customer

PPAP level 4 includes customized requirements by the customer. This is for cases where the standard PPAP file is insufficient for the customer, and they require additional validation from the supplier’s end.

A case in point may be a custom manufacturing project or a high-mix low-volume production setup. Such types of projects often require extra preparedness from the supplier to accommodate quick changes in the production process.

Level 5: PSW with Full Documentation and On-Site Review

PPAP level 5 is an advanced PPAP procedure where not only does the supplier prepare all (and extra) documentation, but the customer also reviews it on-site at the production facility.

Level 5 PPAP approval is generally applicable to high-risk projects where the parts have complex features or have critical safety requirements. For example, components like automotive airbags or high-precision aviation parts.

The 18 Elements of a PPAP Submission

The PPAP file comprises 18 PPAP elements. Each of these serves a different purpose in the PPAP process, and not all of them are mandatory to include in every situation, as the previous section highlights.

The following sections explain the contents and purpose of these 18 PPAP documents. The figure below summarizes which of these 18 PPAP elements go into each PPAP level.

1. Design Records

The design record is the official version of the engineering drawing defining the part’s dimensions, tolerancing, material selection, and other technical specifications.
It is the baseline document that guides everything else in the PPAP procedure.

2. Authorized Engineering Change Documents

This document is an approved record of any changes in the original design of the PPAP parts. These changes can be in dimensions, materials, features, or tolerances. After the supplier records all changes in a consolidated file, the customer reviews and formally authorizes it.

3. Engineering Approval

Certain technical parts require the customer’s engineering team’s inspection and approval before they move to production. This is common in automotive parts with safety risks, for example.

A written approval (Engineering Approval) confirms that the prototype meets its functional and quality requirements.

4. Design Failure Mode and Effect Analysis (DFMEA)

The DFMEA is among the core PPAP elements, where a technical team analyzes the potential ways the part could fail under real operating conditions. This includes identifying failure modes and their cause-effect analysis, their severity, and the probability of their occurrence during service.

The DFMEA report helps the supplier and customer in understanding and evaluating potential risks.

5. Process Flow Diagram

The process flow diagram in the PPAP package is a visual mapping of the supplier’s production setup. It illustrates the flow of material from receiving to manufacturing to inspection and dispatch. The operations, machines, and tests performed at each step are also documented in a detailed way.

The process flow diagram demonstrates that the supplier’s processes are well-defined, controlled, and repeatable.

6. Process Failure Mode and Effect Analysis (PFMEA)

PFMEA is the process version of DFMEA analysis. Having a robust production process is the main reason to conduct the PPAP quality procedures. Thus, PFMEA is a critical element in a PPAP file.

It enlists the potential failures and their impacts, as well as detection/prevention controls, for each process in the production line. This helps the supplier anticipate issues and mitigate them if they should occur.

7. Control Plan

The Control Plan outlines what procedures the supplier has in place to maintain quality throughout production. This includes details like quality checkpoints, checking procedures, frequencies, and corrective actions.

A solid control plan demonstrates the supplier’s ability to stay consistent in terms of part quality during the project.

8. Measurement System Analysis Studies (MSA)

There are a lot of measurements taken during production and PPAP quality checks. MSA verifies that the instrumentation (gauges, sensors, etc.) used for these measurements is reliable and calibrated.

A Gage R&R (Repeatability and Reproducibility) study is a common method to demonstrate that the measurement systems are stable and trustworthy.

9. Dimensional Results

The Dimensional Results document tabulates dimensional measurements from multiple samples of the part. It verifies that the critical features of the part are according to specification and within the correct tolerance limits. This is important to prove the functionality of PPAP parts.

10. Records of Material / Performance Tests

This section in the PPAP file includes reports and certifications confirming the material characteristics of the material procured by the supplier. These can include chemical composition, strength, hardness, or electrical conductivity.

11. Initial Process Studies

This PPAP element includes Statistical Process Control (SPC) analyses for critical production processes, ensuring that they are free of major variations. The target processes are usually high-risk features.

12. Qualified Laboratory Documentation

A standard PPAP process requires that all material or performance testing be done at a qualified laboratory. This document includes official certifications proving the credibility and competence of the labs used by the supplier.

Having a Qualified Laboratory Documentation gives confidence to the customer by improving transparency and traceability of test results.

13. Appearance Approval Report

The appearance of some parts impacts their functionality and aesthetics. Interior automotive panels, for instance. For such PPAP parts, the customer generally signs off on the Appearance Approval Report (AAR) after physical inspection, confirming that visual features like texture and color are up to the mark.

14. Sample Production Parts

A customer may ask for sample parts before giving the go-ahead for mass production runs. These sample parts give the customer an opportunity to verify their performance and functionality.

15. Master Sample

The Master Sample, as the name suggests, is the final, approved part signed off by both the customer and supplier. This part becomes the baseline standard for all PPAP parts during production.

16. Checking Aids

Checking Aids include any custom fixtures, gauges, or templates used for measuring or inspecting the part during production. This document contains information on how to use these checking aids, their calibration records, and any other relevant information.

17. Customer-Specific Requirements

The PPAP process is customer-centric. Its main purpose is to satisfy the customer. Thus, some customers may include special PPAP requirements in addition to the standard PPAP documents.

Customer-specific PPAP requirements can include extra test data (multiple runs), specific documentation formats, or custom quality checkpoints.

18. Part Submission Warrant (PSW)

The Part Submission Warrant is the representative document that certifies that the entire PPAP package is complete and consistent with customer requirements. A signed PSW is an official statement from the supplier requesting production approval from the customer.

PPAP Workflow

The PPAP process generally follows a standard-form workflow adapted by most businesses. In most cases, suppliers develop a process flowchart to define the flow of data/documents and the personnel responsible at each stage.

Generally, it documents the inputs coming from the customer, the processing done by the supplier to meet the customer’s requirements, and then the outputs are routed back to the customer for approval. Thus, a zoomed-out overview of the PPAP workflow looks something like customer-supplier-customer.

Having such a flowchart on hand helps suppliers arrange the PPAP documents in an efficient and timely manner and demonstrate their management capabilities.
A breakdown of a typical PPAP workflow is as follows:

1. Kick-off & Requirement Overview

The customer places an order with the supplier and provides all the necessary information, such as drawings, specifications, timeline, production volume, and any other customer-specific PPAP requirements.

2. Pre-Production

Before moving into production, the supplier performs all the prerequisite checks to minimize the risks of failure. These steps may include devising the Control Plan or conducting a PFMEA.

3. Prototyping

Then comes the prototyping phase. The supplier builds all the necessary tooling and process methods for manufacturing the PPAP parts. This is an important step in a customized project like on-demand manufacturing owing to the part novelty.

4. Data Collection & Testing

The supplier analyzes all data collected during and after the test production runs. This data may include dimensional results, material certificates, and performance test results.

5. Compile the PPAP File

With all the necessary PPAP elements in hand, the supplier then prepares the PPAP file to submit to the customer. This includes the PSW certifying that the supplier is ready to move ahead with the project.

6. Customer Review & Feedback

The customer then checks the PPAP documents as per their criteria and provides feedback to the supplier. If all is well, the production run can begin without additional documentation.

Common Challenges in PPAP

The PPAP process is far from simple. It may be straightforward, but the value it holds for all stakeholders warrants extra care and vigilance. As a result, it is common to face different challenges during the PPAP process.

The list below highlights some of the common challenges in a PPAP procedure.

• Incomplete/Missing Documentation: The PPAP file is quite structured. Although uncommon, mistakes are possible while putting together a large number of PPAP documents, leading to revisions or rejections.
• Time-Taking: The PPAP process is quite extensive. While its procedures are in place to protect both parties, going through it from beginning to end can be time-consuming owing to its various formalities and levels of approval.
• Resource Dependency: Executing a PPAP procedure before full-scale production requires investment in tooling, testing, and personnel training. While the long-term benefits of PPAP are clear, the process itself can be demanding.
• Noncompliance: PPAP is highly standardized. There are specific PPAP requirements from the AIAG, the customer, lean requirements, and regulatory bodies (environment, safety) to be met. Managing all these simultaneously leaves little room for error and can sometimes cause delays/rejections.