Investigation of influence of printing parameters on the quality of 3D printed composite structures

Abstract

Composites reinforced with short or continuous carbon fibres are used for very wide applications. Additive manufacturing technologies allow to print very complex shapes of product reducing costs and production time. It is very well known that composite structures used for aerospace applications should have a minimum void volume and high fibre content; however, additive manufacturing of polymer – fibre composites with known mechanical properties and other parameters such as fibre content and void volume is extremely challenging. Understanding how the printing parameters influence the mentioned properties is a key in order to minimize void volume and improve mechanical characteristics. In this study, tensile properties of unidirectional 0° 3D printed composites were investigated. Two main printing parameters: layer height and line width were changed. Voids volume in the printed samples were studied by using computed tomography (CT) and matrix dissolution methods. Voids volume average in the samples fluctuates from 18.5% to 27.5% according CT results and have significant dependency on printing parameters: layer height and line width. After matrix dissolution, carbon fibre content was determined. Results showed that weight percentage of carbon fibre content fluctuates from 13.4% to 19.1% and depends on printing parameters. It has been determined that tensile properties are most influenced by layer height of the samples. Moreover, research results highlight that composites properties can be optimized by changing 3D printing process parameters.