Root Cause Analysis Of Defects In Sfs Comb Products Using Fmea And Fta Methods In Injection Molding

Abstract

Injection molding is a critical process for producing high-precision components, yet it remains vulnerable to quality variations. The production of the SFS Comb using the Sumitomo SG series machine and PC Makrolon resin faces challenges with inconsistent defect rates. This study aims to analyze and minimize these issues by applying an integrated Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA) approach. To ensure a focused and in-depth investigation, this research is limited to analyzing the top three (4) dominant defects identified during the observation period. FMEA is utilized to prioritize these failure modes based on the Risk Priority Number (RPN), while FTA is employed to perform a deductive, top-down analysis that maps the logical relationships between machine parameters, material properties, and environmental factors. The integration of these methods allows for a precise identification of root causes, such as unstable injection pressure or improper drying of the PC resin. The results provide technical recommendations for process parameter optimization, aimed at reducing critical defects, enhancing process stability, and supporting more effective quality control on the SFS Comb production line.