Modelling and path planning for additive manufacturing of continuous fiber composites

Official URL: http://risc01.sabanciuniv.edu/record=b1817062 (Table of Contents)

Material-extrusion based Additive Manufacturing (AM) is one of the leading (AM) technologies, which produces three-dimensional (3D) parts by extrusion of molten thermoplastic polymers layer by layer. However, its applications are limited due to the low strength and stiffness of the parts produced by this technology. One of the ways to improve the mechanical properties of the parts is to use a reinforced thermoplastic polymer with a filler such as chopped or continuous fibers. The resulting additively manufactured continuous fiber reinforced thermoplastic (CFRTP) composites could have superior mechanical properties and hence can be used in high-performance applications such as for aerospace and automotive industries. This thesis is divided into two sections. The first section is related to the modeling of additively manufactured continuous fiber composites for evaluation of the mechanical properties. The current studies for evaluating the mechanical properties of additively manufactured CFRTP composites are based on experimental results. Therefore, there is very limited study available to determine and optimize the process parameters. In this section, a finite element based study is presented to determine the effect of process parameters such as nozzle diameter, layer thickness, volume fraction and infill percentage on elastic properties of additively manufactured CFRTP composite structures. The second section presents the development of a continuous path planning algorithm for additive manufacturing of continuous fiber composites. The existing path planning algorithms used in material extrusion-based processes cause discontinuities in the material deposition if complex shapes are manufactured. Moreover, they cannot be used for continuous fiber composite printing, since the use of continuous fiber as a reinforcement requires continuous deposition of material throughout the printing process. In this thesis, a novel path planning algorithm has been developed to generate continuous deposition path for 3D printing of continuous fiber composites. The algorithm has been implemented for various complex geometries to generate continues deposition paths for the designed complex parts. The research conducted in this thesis can expand to the additive manufacturing of CFRTP composites with various reinforcing materials. The developed continuous path planning algorithm can be coupled with the optimized process parameters obtained from modeling results to produce v highly complex shape functional composite parts that could replace the conventional metal parts and processes by providing light-weight solutions for various industrial applications.