Reducing Waste in the Plastic Bottle Cap Production Process by Applying the DMAIC Principle: A Case Study of XXX Co., Ltd.

Abstract

This research aims to identify the causes of waste in the plastic bottle cap production process and reduce the waste ratio by applying the DMAIC principle along with quality control tools such as Pareto charts and fishbone diagrams. These tools are used to systematically analyze these problems, identify their root causes, and determine clear solutions. The analysis finds that the main causes of waste during setup after machine maintenance are: (1) Machinery: lack of proper maintenance, resulting in frequent breakdowns. and (2) Procedures: absence of standardized work instructions and insufficient in-process quality checks by employees. To address these issues, corrective measures are proposed, including the implementation of a pre-operation readiness checklist and the development of a preventive maintenance plan. The results show a significant reduction in waste caused by setup after machine maintenance. The combined defective output from Machines A and B decreases from 13,366 kilograms (5.16% of total production) to 1.8%, representing a 3.36% reduction. This study demonstrates that the DMAIC principle can serve as a model for addressing waste issues in other plastic manufacturing processes within the company. It helps to further reduce waste and lower production costs for the company.