Quality Control Analysis of Products Using the Six Sigma Method: A Case Study at PT. XYZ

Abstract

The A.V. Fistula is a critical medical device required to comply with stringent quality standards under ISO 13485, making systematic quality control essential. This study aims to analyze and improve A.V. Fistula product quality at PT. XYZ through the Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) methodology. Production data recorded from April 2023 to March 2024 revealed 148,682 defective units from a total of 49,813,422 units produced, with four primary defect types identified: Scratch, Cannula Loose, Foreign Particle, and Bent Needle Tip. Pareto analysis identified Scratch as the dominant defect category (63,580 units; 42.8% of total defects). Fishbone diagram and FMEA analyses identified the principal root causes: tube dimensions outside tolerance (RPN = 180), improper storage of sharp materials (RPN = 160), operator handling errors (RPN = 140), and raw material contamination (RPN = 128). Corrective measures at the Improve stage included operator retraining, SOP revision, adoption of precision measurement tools, and automated visual inspection systems. Post-improvement monitoring data (January-March 2025) demonstrated a reduction in the average defect rate from 0.31% to 0.20% and an increase in the process sigma level from 4.67 to 4.80. These results confirm that the Six Sigma DMAIC methodology effectively reduces process variability, enhances production stability, and advances the company toward a zero-defect objective. This research provides a replicable framework for continuous improvement in the medical device manufacturing industry.