Abstract
Acceptance sampling system plays an important role in quality control to make sure consumers to accept products with good quality, it contains two or more acceptance sampling plans and provides more flexible acceptance sampling procedure than existing acceptance sampling plans. Most existing acceptance sampling plans were developed mainly based on the product defective rate or process yield. However, the yield management does not distinguish among the product that fall inside of the specification limits. The process loss index was proposed for measuring process performance by considering the concept of quality loss function introduced by Dr. Genichi Taguchi. This thesis based on process loss index developed an acceptance sampling system contains two acceptance sampling plans: tightened inspection and normal inspection. The first sampling procedure needs to begin from tightened inspection, and switch to normal inspection if lots in a raw are all accepted. If there is an additional lot is rejected in the next lots after a rejection under normal inspection, it needs to switch to tightened inspection. The acceptance sampling system observes the switching condition from tightened inspection to normal inspection and switch back to tightened inspection, so it is also called “Tightened-Normal-Tightened Sampling System （TNT Sampling System）”. The behavior of the proposed three types sampling system: TNT-(nT=mnN,nN;k), TNT-(nT,nN;k) and TNT-(n;kT,kN) are investigated and discussed in this paper. The results for sampling systems indicate that the proposed sampling system gives the desired protection with smaller sample size than traditional variables single sample plan. Lastly, we analyzed a practical case to assist users to learn more from the proposed sampling system.