Average outgoing quality of calibration Lab facilities

Abstract

Quality assurance is an integrated part of any calibration facility. The calibration facility as well as its customers are interested in the facility production outgoing quality. In most calibration labs the inspection of calibrated items is performed according to a suitable sampling inspection policy. Some of these policies are very good in assuring the quality of the calibration services they offer, but do not provide a clear assessment of the outgoing quality of the entire production of the facility. This paper has developed two methods of calculating the average outgoing quality (AOQ) of a calibration lab that uses a multistage sampling inspection policy. The policy structure is presented first along with the exact procedure of how to perform it by the inspectors and the methods to calculate the AOQ. The two methods differ from each another in the type of data required to calculate the AOQ. The first method requires the technicians’ production, the number of items subject to inspections and the number of failing items found. The second method requires only the number of technicians at each level of the multistage inspection policy. The verifications of the performances of two methods are accomplished by building a simulation model on an Excel worksheet. The model simulates the calibration facility with the right parameters, and then compares the two methods with the actual AOQ. The paper further discusses the advantages and disadvantages of each method in a broader context of quality assurance.