Evaluation of Alternative Material Composites for Additive Manufacturing
From mere prototyping solutions to the full-fledged additive manufacturing systems, the technology platform, commonly known as 3D printing has grown in leaps and bounds. Despite the astounding features, the enormous growth, and the wider application potentials, the additive manufacturing methods suffer from certain shortcomings. The point-by-point or line-by-line material consolidation mechanics is complex and often lead to dynamic thermal fields, uncontrolled meso- and micro-structures, and unwanted residual stresses and strains. Flat-layer slicing often leads to stair-step effects and fibre-discontinuity issues in specific cases. Complications also arise from the need to use support structures, depending on the part geometry and build orientation options. While most of these problems have been investigated and amicable solutions developed to varying degrees of success, a major drawback still remains at large: Limited material options available for processing.
A significant amount of research effort was placed evaluating alternative materials for different additive manufacturing technologies. Different polymer, ceramic, and metallic material systems have come into commercial use through the efforts in the past decade. Considering the point-by-point material processing approach, composite materials in particular attain more attention with the additive technologies as the possibility to control the dispersion of the filler materials is an inherent characteristic. Based on the literature review and the collaborations with the materials research groups, Crown Research Institutions, and industry partners in New Zealand, four different composite material systems were identified for evaluation with four specific additive manufacturing processes in this research: 1) PLA-elastomer-nano-cellulose fibre polymer composite for extrusion 3D printing in the pellet form, 2) Seashell powder-plaster ceramic composite for binder-jet 3D printing, 3) Polymer-keratin composites for selective laser sintering, and 4) stainless steel 316L and nano silicon nitride metal matrix composites for selective laser melting. Empirical experimental research methods have been used to evaluate the materials for the respective processing methods, exploring the material, process, structure, and property relationships. The meso- and micro-structural relationships, physical, and mechanical property responses indicate all the four material and process combinations to be successful. While these are preliminary impressions from the initial experimental investigations, these material alternatives for additive manufacturing offer great application potentials if further scientific investigations targeting material and process optimisation are undertaken.