A Master Sample is a required element of the PPAP submission and represents an approved reference part that fully meets all design, specification, and customer-specific requirements.
The Master Sample must be formally reviewed and signed by both the customer and the supplier, confirming that the part is acceptable in every respect. Once approved, it serves as a benchmark standard for future production and inspection activities.
Purpose of the Master Sample
The Master Sample is used to:
- Provide a physical reference for acceptable product quality
- Support operator training and visual inspection
- Aid in resolving disputes related to part conformity
- Ensure consistency across production runs
By comparing production parts against the Master Sample, operators and inspectors can quickly identify deviations from approved standards.
Approval and identification
The Master Sample must:
- Be clearly identified as a “Master Sample”
- Show the customer approval date
- Reference the correct part number and revision level
- Reflect production-intent materials, tooling, and processes
Both supplier and customer approval is required before the sample can be used as a reference.
Retention requirements
According to PPAP requirements:
“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.”
Additionally:
- A Master Sample must be retained for each cavity, mould, tool, die, or production process, unless otherwise specified by the customer
- The sample must remain available for audit, reference, or revalidation purposes
Key considerations
- The Master Sample must always reflect the current approved design
- Any design or process change requires review of the Master Sample status
- Storage conditions should protect the sample from damage or degradation
- The Master Sample must align with the Control Plan and inspection criteria
The Master Sample is a critical link between documented approval and real-world production, helping ensure ongoing consistency, quality, and compliance.