Support-free frame structures

Recently, different com plex lightweight structures are designed to save printing material, while satisfying specific demands on physical and geometrical properties. However, most structures need additional interior support structures to help print, which not only damage the physical properties of the objects but also consume additional material, time, and energy. To handle the above problem, a sparsity optimization framework with support-free constraints is proposed in this work, to ensure the generated frame structures are support-free when manufactured with FDM printers. A struts elimination strategy is presented to avoid both inner and outer impending nodes. In addition, angles between adjacent inner struts and radii of struts are further optimized to reduce printing material while achieving a given structural strength. Extensive experimental results demonstrate the effectiveness and practicability of our algorithm. © 2017 Elsevier Ltd. All rights reserved.