A part can pass every internal check and still fail once the customer starts a production run. Automotive and aerospace buyers need evidence that a supplier's process will deliver the right part every time, not only on the day of the first sample. The Production Part Approval Process exists to supply that evidence.

What is PPAP?

Production Part Approval Process (PPAP) is the Automotive Industry Action Group (AIAG) standard that “defines generic requirements for production part approval, including production and bulk materials.”

AIAG states the purpose of PPAP as follows: “The purpose of PPAP is to determine if all customer engineering design record and specification requirements are properly understood by the organization and that the manufacturing process has the potential to produce product consistently meeting these requirements during an actual production run at the quoted production rate.”

PPAP is a key procedure within aerospace and automotive manufacturing to ensure that parts manufactured by suppliers are created consistently. It’s a comprehensive process which consists of 18 requirements which ensure that each part meets expectations and is produced to high quality each time. PPAP has been used more widely throughout manufacturing to support key activities and ease collaboration between suppliers and customers.

The process is also a part of APQP (Advanced Product Quality Planning) - specifically stage four which is the product and process validation stage. The full Production Part Approval Process (PPAP) guidelines themselves are published by and can be purchased from the Automotive Industry Action Group (AIAG).

Why PPAP reduces corrective action and keeps supplier expectations clear

In short, production part approval process (PPAP) is important because it ensures quality and minimizes the risk of corrective actions needed in the future. It is essential that each part that is needed for a vehicle or piece of machinery is made to the correct specifications each time, therefore PPAP lays out clear guidelines so that suppliers know exactly what is expected of them, improving the process of communication.

For the manufacturer, it enables quality output and assurance that their requirements are going to be met during the production run. It minimizes the risk of things going wrong and corrective actions having to be implemented, making for a smoother overall process.

The 18 PPAP requirements and which ones a customer asks for

There are 18 elements of PPAP, not all of these are always going to be necessary - it will depend on customer requirements and the complexity of the part being manufactured.

The 18 elements in AIAG order

  • Design Record: this includes the technical drawings alongside the purchase order to ensure everything aligns and meets the requirements.
  • Authorized Engineering Change Documents: this would be present if the request is for amendments to be made to an existing part.
  • Customer Engineering Approval: there needs to be evidence of approval from the customer’s engineering department.
  • Design Failure Mode and Effects Analysis (DFMEA): a comprehensive risk assessment which maps out all possible failures within the design.
  • Process Flow Diagram: this lays out every step in creating the part from start to finish.
  • Process Failure Mode and Effects Analysis (PFMEA): this looks at all the possible failures within the manufacturing process itself.
  • Control Plan: these are the preventative measures designed to mitigate the possibilities outlined in the PFMEA.
  • Measurement System Analysis Studies: studies of the measurement systems used to check the part.
  • Dimensional Results: this is a validation check to ensure the measurements on the drawing are correct in relation to the end result.
  • Records of Material and Performance Test Results: these are validation records of each test performed on the part, including all relevant certifications for materials.
  • Initial Process Studies: process capability studies that include the Cpk and Ppk indices.
  • Qualified Laboratory Documentation: this is made up of certifications from any lab testing that took place.
  • Appearance Approval Report (AAR): verification that the customer has approved the appearance of the product.
  • Sample Production Parts: a sample part is given to the customer for their approval.
  • Master Sample: an example of the final version of the product which requires sign off from the customer.
  • Checking Aids: a list of all required checks to be done during production, including calibration of tools.
  • Customer-Specific Requirements: this element holds any specific requests made by the customer.
  • Part Submission Warrant (PSW): this summarizes everything included in the PPAP submission and declaration signatures.

Planning every element before production starts reduces errors and waste

It’s a long list but the PPAP process ensures that everything is planned for and considered before and during the production to minimize errors and waste and deliver a high-quality product.