Implementation of the Six Sigma Method Using the Taguchi Approach to Reduce Defect Rates in the Indoor Air Conditioner (AC) Production Process at PT Changhong Electric Indonesia

Abstract

Product quality is one of the primary factors determining the competitiveness of
manufacturing companies. A high defect rate increases production costs, reduces productivity,
and decreases customer satisfaction. PT Changhong Electric Indonesia continues to experience
a defect rate in the Air Conditioner (AC) Indoor production process that exceeds the
company's quality standard of 2%. This study aims to identify the major causes of product
defects, evaluate process capability using the Six Sigma methodology, and determine the
optimal process parameter combination through the Taguchi approach. This research
employed a quantitative approach by integrating the Define, Measure, Analyze, Improve, and
Control (DMAIC) cycle with the Taguchi method. Research data were collected from production reports covering the period from June 2025 to January 2026, direct observations,
interviews, and company documentation. The analytical techniques included Critical to
Quality (CTQ), Defects Per Million Opportunities (DPMO), sigma level analysis, Pareto
diagram, Fishbone diagram, Analysis of Variance (ANOVA), Orthogonal Array, and Signalto-
Noise Ratio (SNR). The results revealed seven major defect categories, with foreign
material defects accounting for 26.0%, unfastened components for 20.7%, and missing spare
parts for 14.6% of total defects. The average DPMO was 22,758, with a process capability of
3.50 sigma, indicating that the manufacturing process remains at the average industrial
performance level. The Taguchi optimization successfully identified the optimal process
parameter combination, leading to reduced process variation and improved product quality.
The integration of Six Sigma and Taguchi proved effective in reducing product defects and
enhancing process stability in