Integrating Weld Line Effects from Molding Processes into Structural FEA

Weld lines can significantly reduce the strength of injection-molded parts. This work introduces a workflow to incorporate weld line effects into structural FEA. For fiber-filled polymers, weld line regions are identified through orientation and meeting angle, while for unfilled polymers, a weld line strength factor (WLSF) is applied to mechanical responses. Demonstration cases show that integrating process-induced weld line data improves predictions of strain localization and failure. The approach bridges molding processes with structural analysis to enhance reliability assessment.