Effects of process conditions on tensile strength and crystallinity of polymeric parts fabricated using ultrasonic vibration‐assisted injection molding

Abstract

AbstractPolymeric parts have been widely used for various applications and injection molding is one of the most commonly used approaches to fabricate polymeric parts. Both the mechanical properties and microstructures of fabricated parts are severely affected by the process conditions. In this article, polyamide (PA66) was selected as the exemplary polymer to make dogbone‐shaped polymeric specimens. First, the effects of key process parameters including melt temperature, mold temperature, injection pressure, and injection speed on the tensile strength and crystallinity of the specimens were systematically investigated. Then, the effects of external ultrasonic vibration field on the mechanical properties and microstructures were studied using tensile tests, X‐ray diffraction, and polarizing light microscope imaging. After that, the orthogonal experiments were designed to analyze the affecting extent of each process parameter and achieve the optimal combination of the process parameters. Finally, using the optimal process conditions, the polymeric part with the best tensile strength and crystallinity was successfully fabricated. The knowledge from this article can be expanded to the injection molding of polymeric parts from other polymers, unveiling the mechanisms during fabrication and providing guidelines for the selection of optimal process conditions in the future.