Diagnosis of multi-stage injection molding process by ultrasonic technology at a T-shape extension nozzle

Abstract

Abstract In this study, a modified T-shape extension nozzle (TsEN) with a high temperature (HT) ultrasonic transducer (UT) rod connected to its barrel and mold to carry out the injection molding (IM) process diagnosis is used. Two integrated HTUTs were fabricated on both sides of a rod for monitoring IM process at elevated temperatures real-time, non-intrusively as well as non-destructively. Two plastics, polypropylene (PP) and acrylonitrile–butadiene–styrene (ABS), were employed to demonstrate the effects of various operation settings and materials on the molded sample quality. Based on the provided information, an innovative way of controlling the supply to structure process in regards to the plastic from the barrel into the nozzle, mold and the final product during the IM process is presented. Each phase of the process, including closing mold, injecting material, packing, and feeding material can be analyzed by an ultrasonic waveform during the various settings of the IM process of PP and ABS plastics. The various injection speeds of the PP and ABS plastics cause different deflection performance of the molded samples. This phenomenon can be observed by measuring the ultrasonic velocity at the beginning stage of molding. Therefore, a modified TsEN with an HTUT rod could provide a rigid structure and an innovative solution for how to run continual diagnosis during the IM process to verify the dynamics of process and analyze the flow rate and the state of the molten plastic to ensure better product quality.