Statistical Process Control Transition Rules for Skip Lot Qualification
Transitioning to skip-lot sampling demands a proven Cpk of 1.33 across consecutive lots and contract rules that force instant reversion to full inspection upon any defect.
Line Stop Containment
Meaning
Immediate quality control action halts a manufacturing assembly line and isolates potentially defective materials when a critical non-conformance is detected during production. Implementing line stop containment prevents the further distribution of substandard components throughout the supply chain. This procedure is designed to protect both downstream assembly and final customer assembly from quality failures.
The action is maintained until a corrective strategy is approved and verified.
Operational Execution
Quality engineers initiate the block by physically marking the affected workstations and locking the digital production records. During line stop containment, operators must run a boundary check on all parts produced since the last verified quality gate. Any materials currently on the conveyor or in intermediate storage are routed to a secure quarantine zone.
This quarantine ensures that no suspicious inventory is loaded onto transport vehicles.
Root Action
Cross-functional teams assemble at the factory floor to identify the underlying cause of the process failure. During line stop containment, technicians analyze machine parameters and tool wear to determine the point of deviation. They must prove that the issue was isolated to a specific batch before the production line can be authorized to restart.
If the source of the defect is a raw material batch, the procurement team immediately contacts the sub-tier supplier to suspend incoming shipments.
Closure Protocol
Production resumes only after a formal sign-off from the quality director and the operations manager. The line stop containment is declared complete when the first five units of the restarted run pass a complete laboratory dimension check. These verification results are logged into the enterprise resource planning system to create a permanent audit trail.