Influence of process parameters on flexural properties of composites reinforced with continuous fiber produced by material extrusion

Abstract

Additive manufacturing revolutionized the production of personalized objects from 3D models across various industries, including medical, aerospace and automotive, primarily through the widely accessible material extrusion process. Despite additive manufacturing advantages, the parts fabricated using additive manufacturing often exhibit lower elastic properties compared to conventionally injection-molded thermoplastic components. Adding fiber-reinforced polymer composites during printing has a significant influence both on tensile and flexural strength, as well as on the overall quality of resulting composite structure. Adding a low volume of reinforcement (<15%) to a sample is advantageous without increasing the stiffness of the sample significantly. This study aims at investigating the impact of low reinforcement volume and placement on the flexural properties of samples while assessing the repeatability of the printing process through 3-point bending tests. A finite element model of the test is also proposed in order to predict the flexural properties of samples. Process induced defects such as voids are modeled in the samples as the results show that the addition of fiber-reinforced polymer led to an increase in the porosity rate. The experimental results of 3-point bending test were compared with those of finite element analysis. Printing rules aimed at minimizing errors and addressing limitations inherent in the printing process are defined in the current study.