ltchandran

Hi Ramesh, How I understand it is, AQL is not something to be calculated. It is your objective, something that you want. The limit of failure that you are ready to accept is the AQL. Once you have decided this, then you can chose your sampling plan based on various standards which gives the number of samples for a given batch size, to meet the AQL, within acceptable risk. What do you do with the samples? You inspect them to check whether they meet your specs. Based on the failures within the sample, you look back at the standard and decided the fate of the lot from which the sample was drawn. Now, zero defect is desirable. But that does not necessarily mean 100% inspection. There are some inspection processes which are destructive. Then, in the process of confirming zero defect by 100% inspection, we would have no product left for the customer. Here we have to look at confidence level. This is based on past experience and inspection. Here again, to achieve 100% confidence, we have to test the product at different stages. The new mantra is to ensure the process is perfect, resulting in defect free product. But then here, the process has to be tested for correctness at every stage, and that is inspection of the process. Regards