A Control Plan is a required element of the PPAP submission and defines how the manufacturing process will be monitored, controlled, and verified to ensure consistent product quality.
The Control Plan documents the controls applied at each step of the process and must directly mirror the PFMEA, ensuring that all identified process risks are effectively managed.
Purpose of the Control Plan
The Control Plan translates risk analysis into practical, day-to-day controls on the shop floor. It specifies:
- What characteristics are controlled
- How they are measured or monitored
- How often checks are performed
- What actions are taken when results are out of specification
By doing so, it ensures that nonconforming products are detected early and prevented from reaching the customer.
Alignment with PFMEA
Every control listed in the Control Plan should correspond to a risk identified in the PFMEA. If a failure mode exists in the PFMEA, there must be a defined control in the Control Plan to prevent or detect it.
Any misalignment between these documents is a common reason for PPAP rejection.
Pre-launch and early production containment
For new parts, new processes, or significant changes, the Control Plan may include early production containment measures. This is often referred to as a Pre-Launch Control Plan and typically includes:
- Increased inspection frequency
- Additional verification steps
- Temporary controls to protect the customer during initial production
Once the process has proven stability and capability, these enhanced controls may be reduced and transitioned to a standard production Control Plan.
Approval and maintenance
The Control Plan must be:
- Reviewed and signed by the appropriate responsible parties
- Aligned with the actual production process
- Updated whenever process changes, failures, or improvements occur
A well-defined Control Plan demonstrates that risks identified during planning are actively managed throughout production.