A master sample is needed to complete the PPAP. This sample MUST be signed by the customer and the supplier when they are both happy that the sample part meets all the design requirements and extra customer requirements. This can then be used as a benchmark for other production runs and help the operators check their work.
“The organization shall retain a master sample for the same period as the production part approval records, or (A) until a new master sample is produced for the same customer part number for customer approval, or (B) where a master sample is required by the design record, Control Plan or inspection criteria, as a reference or standard. The master sample shall be identified as such, and shall show the customer approval date on the sample. The organization shall retain a master sample for each position of a multiple cavity die, mould, tool or pattern, or production process unless otherwise specified by the customer.”