Effect of Filler Type and Gate Design on EMI Shielding Performance of PA6 and PC-Based Polymer Composites

With the growing demand for electromagnetic interference (EMI) shielding in automotive and electronic applications, lightweight and moldable polymer composites have emerged as promising alternatives to traditional metallic materials. This study investigates the EMI shielding effectiveness (SE) of various PA6- and PC-based composites reinforced with carbon filler, and steel filler, with a particular focus on the effect of injection gate design (tunnel vs. direct). Experimental results show that direct gate configurations significantly enhance EMI SE -especially for steel filler- reinforced composites, which achieved values exceeding 100 dB. Statistical analysis via ANOVA and Pareto charts further emphasized the gate type and filler composition as dominant factors influencing shielding performance. These findings offer a scalable, cost-effective solution for EMI shielding, with several formulations meeting the 30 dB industrial threshold. The findings underscore the importance of injection gate design and material selection in tailoring composite behavior for EMI-sensitive applications.