Design and Development of Quality Control System: Case Study of Recycled Plastic Pellet Plant

Abstract

The factory case study is a plastic recycling plant which does not have a quality control system resulting in inefficient production and has a lot of defects. This research aims to design and develop a quality control system for the factory. The procedure is divided into three parts. The first part is to design the check sheets for the main process, which are the receiving and sorting of raw materials process, grinding/milling process, and melting/cutting process. The second part is to design a control chart;  and for controlling the length and diameter of the plastic pellets, and for controlling the shape plastic pellets.  The third part is to design the sampling plans for product acceptance before delivering to customers, which consists of MIL-STD 414 sampling plans for inspection of the length and diameter of plastic pellets, and MIL-STD 105E sampling plans for inspection of the shape of plastic pellets. The designed quality control tools are applied to the factory, resulting in the factory being able to monitor the production process and lead to quality improvement design further.