Reducing Rework in Plastic Extrusion Process in Pipe Manufacturing using DMAIC

In the highly competitive field of plastic pipe manufacturing, minimizing defects and rework is critical to improving product quality, operational efficiency, and overall profitability. Rework in the plastic extrusion process not only leads to material wastage and increased labor costs but also affects delivery schedules and customer satisfaction. This study explores the application of the Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) methodology to identify and analyze the causes of rework in PVC pipe extrusion. Key quality issues such as dimensional variation, surface defects, and improper die settings were identified as major contributors to rework. Data analysis and quality tools like control charts, fishbone diagrams, and Pareto analysis were used to identify root causes related to material handling, machine conditions, and operator practices. Improvements were implemented through optimized die settings, standardized procedures, enhanced operator training, and better material management. These interventions led to an increase in yield from 75% toward the 95% target for grade A products. Alongside a significant reduction in scrap and rework-related costs. The study highlights how structured problem-solving approaches using Six Sigma can enhance product consistency, reduce waste, and support long-term process control in plastic extrusion manufacturing.This study illustrates how a Six Sigma approach, deals with manufacturing-specific challenges, can lead to operational gains. It not only increases quality and reduces waste but also supports sustainability goals and enhances manufacturers’ competitive advantage to survive in the global plastic pipe market.