Acceptance Quality Limit Sampling Plans for Lithium Cell Receiving Facilities
Enforce ANSI ASQ Z1.4 Level II sampling with AQL 0.010 for critical safety flaws and Kelvin OCV IR screening to reject defective lithium cells at receiving dock.
Normal Inspection
Meaning
Standard quality control sampling plans determine the baseline level of inspection for batches of incoming materials or finished products. Operating under normal inspection, a factory inspects a moderate number of samples from each batch according to international standards. This level of checking is applied when there is no reason to suspect that the product quality has drifted below the specified limits.
Sample Size
Selected quantities of cells are tested based on batch size and the specified quality level. During normal inspection, the sampling rate is lower than that used in tightened testing, reducing the time and cost of quality control. This approach optimizes laboratory throughput while still providing statistical confidence.
Decision Boundary
Predefined acceptance and rejection numbers guide the quality engineers in deciding the fate of the batch. If the number of defective cells found during normal inspection does not exceed the acceptance limit, the entire batch is accepted. A higher count of defects triggers a transition to a more stringent inspection regime for subsequent batches.
Quality Level
The acceptable quality limit is defined in the purchasing contract to establish the maximum tolerable defect rate. Through normal inspection, the supplier and the buyer agree on a statistical baseline that protects both parties from excess risk. If the historical data shows that the defect rate remains low, the plant can transition to a reduced testing protocol.
This helps lower overall operating costs while maintaining quality. In contrast, if multiple batches fail in a row, the plant immediately escalates to a tightened inspection scheme to capture defective parts before they can reach the assembly lines.