SAMPLING PLANS FOR MONITORING QUALITY CONTROL PROCESS AT A PLASTIC MANUFACTURING FIRM IN NIGERIA: A CASE STUDY

Abstract

This paper explores the problem of high quality cost at a medium –sized firm manufacturing various types and sizes of plastic container, using a real life data. In pursuance of their quality objectives, the company established a policy that dictates and expensive and time-consuming post-manufacturing process. While the problem of the company’s process control system was being studied, management considered other options that include sampling plans. The sampling plans were evaluated by considering the competing goals of decreasing the shipment of substandard goods, decreasing the percentage of acceptable lot that are erroneously labeled defective, and decreasing the sampling costs. The three sampling plans considered were the current sampling plan, minimum average total inspection (ATI) fixed average outgoing quality level (AOQL) plans, and a compromise plan.  Comparison of the plans on a relative basis shows that the compromise plan is the best choice in term of cost.