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AQL Inspection Manual Double Sampling Plan Find the Sample Size Code Letter Set the range covering the Batch or Lot Size being inspected in the window at the top right corner on the front of the AQL Inspector's Rule. Then read the Sample Size Code Letter, in the box, directly to the left of the Inspection Level. Find the Sampling Plan The Double Sampling Plan consists of two sets of Acceptance Numbers, Rejection Numbers and Sample Sizes. Normal inspection is used until such time as the results of inspection dictate the Tightened or Reduced inspection should be employed as outlined in Switching Procedures on page 10. Double sampling plans are found on the back of the AQL Inspector's Rule. Set the required AQL level in the window above the Double Sampling Plans. Locate the Sample Size Code Letter previously selected in step 1. If an arrow show in the window directly below the Code Letter, follow the direction of the arrow until a set of acceptance-rejection numbers are reached. Then read the first Acceptance (in black) and Rejection (in color) Number in the window on the '"1st" row. The Acceptance and Rejection number pairs and the Sample Sizes directly below them make up the Sample Plan. Perform the First Inspection Randomly select a group of "Sample Size" items from the lot and inspect them. If the sample size equals or exceeds the lot size do 100% inspection. If the number of defective items is equal to or less than the Acceptance Number accept the lot. If the number of defective items is equal to or greater than the "Rejection Number" reject the lot. Perform The Second Inspection If the lot was the accepted or rejected from the first inspection the second sample inspection is not required, skip this step. Read the Acceptance and Rejection Numbers and Sample size from the "2nd" row under those used for the first inspection. Randomly select a second group of "Sample Size" items from the lot and inspection them. Combine the total number of defective items from the first and second samples. If the total number of defective items is equal to or less than the Acceptance Number accept the lot. If the total number of defective items is equal to or greater than the "Rejection Number" reject the lot. MIL-STD-105E and ISO 2859-1 (1999) When an asterisk (*) is found in place of the acceptance-rejection levels either use the corresponding single sampling plan on the front side of the AQL Inspector's Rule or use the double sampling plan to the right. ANSI/ASQ Z1.4-2003 When an asterisk (*) is found in place of the acceptance-rejection levels use the corresponding single sampling plan on the front side of the AQL Inspector's Rule. | |||||||||||||
