Precision and efficiency in the manufacturing of medical-grade tubing are critical factors that directly influence both production costs and product safety. This research addresses the persistent challenges of high material waste and prolonged setup times in a medical tube extrusion process. The study identifies that the traditional die centering mechanism, which relies heavily on operator skill and visual judgment for alignment, is the primary cause of significant wall thickness inconsistency and frequent machine downtime. To mitigate these issues, a systematic improvement was implemented through the Plan-Do-Check-Act (PDCA) cycle, integrating Lean manufacturing principles with advanced engineering design. Key interventions included the transition to SUS420J2 stainless steel for die components to minimize surface oxidation and the development of a specialized Center Die Gauge to standardize measurements. The culmination of this study was the engineering of a self-centering die (Die Model 2), which eliminates the need for manual bolt adjustments. Experimental results demonstrate a substantial improvement in operational performance: the setup procedure was streamlined from 23 to 15 steps, and the average setup duration was reduced by 9.33 minutes per lot. Furthermore, total plastic waste decreased by 7.88 kg per lot. Quality analysis showed that wall thickness deviation was minimized from 4.13% to 2.08%, surpassing the industrial standard requirement. These enhancements collectively resulted in a productivity increase of 3.1% and a monthly cost reduction of 11,300.65 THB, proving the effectiveness of the proposed design in high-precision manufacturing environments.

Keywords

Medical Tube Extrusion, Die Design Optimization, Waste Reduction, Self-centering Die, Setup Time Improvement.