Real-time monitoring and quantitative analysis of residual stress in thin-walled injection-molded components

Abstract

Residual stress represents a significant quality concern in injection molding processes. While traditionally quantified through photoelasticity techniques, offline measurements fail to support real-time process monitoring and control. This study introduces a residual stress intensity indicator that quantifies residual stress from qualitative images of injection-molded parts captured under a stress viewer while utilizing quality metrics derived from pressure profiles to monitor residual stress variations during the molding process. Results demonstrate that hue-saturation-value (HSV) image analysis effectively estimates residual stress intensity. The study identifies holding pressure and barrel temperature as dominant factors affecting residual stress development. Furthermore, when measured at optimally defined locations, individual sensing quality indices adequately monitor residual stress variations in thin-walled injection-molded parts. This research establishes a practical methodology for real-time monitoring of residual stress intensity in thin-walled injection-molded components.