<p>This study explores the application of Six Sigma methodologies within an Electronics Manufacturing Services (EMS) company, focusing on the automation assembly line for electronic shelf labels. Utilizing the DMAIC (Define—Measure—Analyze—Improve—Control) framework alongside root cause analysis tools such as the Fishbone diagram and the 5 Whys, the research identified key factors contributing to high defect rates and scrap costs. Targeted improvements were implemented for the three most critical defects through mechanical design modifications, design of experiments (DOE), and enhanced document control measures such as checklists and standard operating procedures (SOPs). The improvement initiative led to a 50% reduction in scrap cost, a 50% decrease in DPPM, and an increase in the Six Sigma level from 2.6 to 2.9, indicating significant gains in quality and process performance. These results underscore the effectiveness of defect elimination and process control, and highlight the practical value of Lean Six Sigma in improving manufacturing efficiency. This case contributes to the growing body of research on automation and Lean Six Sigma applications in industry.</p>