Proposed Quality Control Using the Six Sigma (DMAIC) Method to Reduce Defects in Partially Oriented Yarn Products at PT XYZ

Abstract

The high defect rate of Partially Oriented Yarn (POY) demands systematic Quality Control to maintain the competitiveness of the textile industry. This study aims to propose Quality Improvements to reduce the number of defective products using the Six Sigma Method. The research was conducted at a textile manufacturing company using production data from January-August 2025. The Measured variables include Denier, DTI, Elong, and Uster defects. The process was evaluated through the Define, Measure, Analyze, Improve, Control (DMAIC) phases. The root cause analysis was supported by the P-Chart, DPMO calculation, Pareto Diagram, Fishbone, and Failure Mode and Effect Analysis (FMEA). Initial Measurements showed the process capability was at 3.16 Sigma with a DPMO of 48,851. DTI (61.76%) and Denier (22.29%) defects were identified as the most dominant. The main failures were caused by Machine instability, lack of maintenance, and operator fatigue. The proposed Improvements using the 5W+1H principle projected a 78% reduction in the Risk Priority Number (RPN). The post-Improvement estimation results showed an increase in process capability to 3.80 Sigma and a DPMO reduction to 10,747. The application of Six Sigma (DMAIC) effectively identifies root causes and formulates strategic Improvements capable of significantly reducing defects and increasing process capability.