Designing variables sampling plans based on the yield index Spk

Abstract

Abstract The acceptance sampling plan is extensively used as a tool to determine whether the submitted lot should be accepted or rejected. In addition, the index establishes the relationship between manufacturing specification and the actual process performance providing a precise measure on the process yield. In this paper, we develop two variables sampling plans based on the index At first, the procedure of a modified double sampling plan by variables is presented for evaluating the lot or process fraction nonconforming. Then, the modified variables repetitive group sampling (VRGS) plan based on the yield index is implemented. The required parameters of proposed sampling plans are specified by minimizing the average sample number (ASN) and tabulated based on miscellaneous combinations of quality levels and producer s and consumer s risks. In order to specify an appropriate sampling plan based on the smallest value of ASN, proposed VDSP and modified VRGS plan are compared with SSP, RGS plan, SSP based on EWMA yield index, and MDS sampling plan. The comparison of sampling plans indicates that SSP based on EWMA yield index reduces ASN values significantly.