Non-planar granular 3D printing

Abstract

Most approaches to 3D printing at various scales are layer based, meaning they start with a 3D CAD model that is sliced into planar print paths to be translated to machine code. However, this approach entails a number of drawbacks, such as slow printing speeds, limited build volumes, allowable geometric properties, and material diversity. To overcome these limitations, the authors have developed a novel additive manufacturing process called Non-Planar Granular Printing (NGP). Compared to its layer-based counterpart, NGP enables non-planar 3D printing by selectively binding reusable granular particles to create free-form structures. In doing so, NGP leverages traditional powder-based additive manufacturing processes. However, instead of enclosing the extruded compounds within a three-axis layer-based system, NPG combines multi-axis robotic deposition capabilities with customizable build volume parameters, which drastically improves print speed, scalability and material versatility. The result is a process whose main advantage is to enable the rapid production of support-free and complex geometric forms using a wide range of materials in granular form. This paper introduces and analyzes a series of benchmark experiments conducted to demonstrate the practical workflow, general output capabilities, and volume-material limitations of the system. The research also lays a foundation of non-planar 3D extrusion that enables material transitions for functional gradience capabilities.