A manufacturer of extruded HDPE pipes was experiencing excessive scrap rates and high costs associated with product defects. By partnering with us to implement a targeted Lean Six Sigma improvement initiative, the company was able to reduce its defect rate from nearly 60% to just 5%, while cutting the cost of poor quality (COPQ) from 37.5% to 15% of revenue—a transformation that significantly improved operational performance and financial outcomes.
Client Profile & Challenges:
This manufacturer, operating in the plastics industry, produces high-density polyethylene (HDPE) pipes for industrial and commercial applications. They faced several persistent challenges:
- Surface defects, inconsistent wall thickness, and pigmentation flaws leading to high scrap rates
- Variation in pipe weight and density caused by unstable blending processes
- Non-compliance with SOPs during pigment testing and production monitoring
- A COPQ that amounted to 37.5% of total revenue, placing considerable pressure on margins and delivery schedules
Lean Six Sigma Approach:
To address these inefficiencies, we launched a structured Lean Six Sigma project tailored to the client’s operations. Key interventions included:
- Defining pipe weight as a key performance indicator (KPI), incorporating wall thickness, length, and density in a single metric
- Evaluating process capability, which revealed a very low performance level and a defect rate close to 60%, confirming the need for urgent corrective measures
- Applying Pareto analysis and fishbone (Ishikawa) diagrams to identify root causes of variation
- Isolating issues related to inconsistent blending, inadequate SOP compliance, and process drift
- Performing correlation analysis between blend density and melt flow index (MFI) to stabilize extrusion conditions and pigmentation outcomes
Results:
The initiative delivered measurable improvements:
- Defect rate dropped from nearly 60% to just 5%
- COPQ reduced from 37.5% to 15% of revenue
- Achieved greater consistency in pigmentation, viscosity, and wall thickness
- Enhanced production reliability, fewer customer complaints, and improved yield
Conclusion:
This project showcases AM Saxum’s ability to drive measurable quality, cost, and efficiency improvements in the plastics and extrusion manufacturing sector. With over 20 years of cross-industry experience, our consultants guide organizations from problem definition to sustainable value creation—improving EBITDA, cash flow, and long-term competitiveness through hands-on, client-centric Lean Six Sigma solutions.
