Optimal Placement of Elliptic Voids in 3D Printing Products

Deok-Soo KIM
Hanyang University, N/A, Korea

Keywords: 3D printing, support-free hollowing; ellipse packing, Voronoi diagram

Hollowing 3D shape is critical to 3D printing for reducing weight, material use, manufacturing time, cost, etc. This research presents a novel method for generating support-free elliptic hollowing for 3D shapes which can avoid supporting structure. The proposed method facilitates designing the interior material layout of 3D model so that a fabricated replica satisfies application-specific demands on its physical properties such as resistance to external loads. It turns out that the product designed and 3D-printed using the proposed method can significantly reduce material without stress concentration. The key idea of the proposed algorithm is to pack the 2D ellipses (with support-free constraint) within a polygon which is in a cross-section of a 3D model. The ellipse packing within a polygon is efficiently and correctly solved via the Voronoi diagram of a polygon and ellipses within the polygon. We repeat this ellipse packing for the polygons within each cross-section. Then the packed ellipses from the polygons are extruded into 3D volume.