The Production Part Approval Process (PPAP) is a framework of requirements used in the automotive supply chain to establish confidence in suppliers and their manufacturing processes.
PPAP was initially created by the Automotive Industry Action Group (AIAG), and has been adopted in other industries to improve communication and provide quality products.
There are 18 documents that comprise the PPAP:
Most customers will specify a PPAP Submission Level, which will dictate what elements you need to submit to your customer.
According to the AIAG PPAP manual, all elements should be completed. The PPAP levels indicate which documents need to be submitted to the customer, and which can simply be retained by the manufacturer.
Level 1 - Part Submission Warrant (PSW) only
Level 2 - PSW with product samples and limited supporting data
Level 3 - PSW with product samples and complete supporting data
Level 4 - PSW and other requirements as defined by the customer
Level 5 - PSW with product samples and complete supporting data available for review at the supplier's manufacturing location
PPAP is listed as a customer specific requirement (CSR) by FCA US, Ford Motor Company, and General Motors. If you are producing for any of these supply chains it is likely you'll be required to conduct PPAP. We've also heard of more industries adopting PPAP to ensure that suppliers understand all customer engineering design specifications and requirements.