This study aims to analyze the product failure of the type of pin post insulator product, as well as to find the main cause and to propose improvements at PT XYZ using the Six Sigma method. This research was conducted only in parts of the production process that have a high failure rate such as in natural dryingsections. This study uses a Six Sigma methodology approach with tools such as Fishbone diagrams and Pareto diagrams. This research is a quantitative descriptive exploratory method. The results of this study were the type of cracked lip crack caused by the vaccum is unstable in finishing section, with the improvement of cleaning the vaccum duct and routine maintenance vaccum duct in finishing machine. For the type of cracked middle skirt crack caused by the auger on pugmill machine being worn, between the dimensions of Honggote (HG) in the forming and Sita in finishing are not matching, with corrective actions: repairing pugmill machine, vaccum duct in finishing section, repairing sita so that HG and sita are matched and conducting routine test and periodic maintenance. The conclusion of this research is that quality control using the six sigma method can reduce the rejection level and increase the six sigma level.

Keywords : Six Sigma, Quality Improvement, Fishbone Diagram, and Ceramic Insulator.