Development and validation of a multi-material extrusion additive manufacturing method

Abstract

The adoption of Additive Manufacturing (AM) for low production run parts has created the need for more versatile AM materials to aid engineers, students, enthusiasts, and the maker community. Current low cost AM processes (e.g.: material extrusion and vat photopolymerization) have limited materials that are questionably suitable for load bearing components. A composite approach to AM can improve mechanical properties of components by integrating multiple developed materials, thus gathering the beneficial material properties of each separate material in an AM-produced composite. In this thesis, I present the development and validation of two composite AM processes through multiple material testing case studies. Throughout the validation procedure, I explore variations in matrix material, infill density, infill type, and fiber reinforcement. 2D localized strain analysis is presented via digital image correlation to analyze coupon failures, multi-material interactions, and infill and fiber-reinforcement effectiveness. Material testing shows distinct differences in samples produced from the same two or three materials and demonstrates how mechanical property improvement can be achieved through design for tunable materials given a geometric constraint. Implementation of this process is a step towards achieving tunable material properties for low cost AM technologies.