CrossFill: Foam Structures with Graded Density for Continuous Material Extrusion. (September 2019)

• Record Type: Journal Article
• Authors: Kuipers, Tim; Wu, Jun; Wang, Charlie C.L.
• Is Part Of: Computer aided design. Volume 114(2019)
• Page Start: 37
• Page End: 50
• Publication Date: 2019-09
• Subjects: Space-filling surface -- Graded density -- Continuous material extrusion -- Functionally graded material -- Fused deposition modeling; Computer-aided design -- Periodicals; Engineering design -- Data processing -- Periodicals; Computer graphics -- Periodicals; Conception technique -- Informatique -- Périodiques; Infographie -- Périodiques; Computer graphics; Engineering design -- Data processing; Periodicals; Electronic journals; 620.00420285
• DOI: 10.1016/j.cad.2019.05.003
• Languages: English
• ISSNs: 0010-4485

Abstract

Abstract: The fabrication flexibility of 3D printing has sparked a lot of interest in designing structures with spatially graded material properties. In this paper, we propose a new type of density graded structure that is particularly designed for 3D printing systems based on filament extrusion. In order to ensure high-quality fabrication results, extrusion-based 3D printing requires not only that the structures are self-supporting, but also that extrusion toolpaths are continuous and free of self-overlap. The structure proposed in this paper, called CrossFill, complies with these requirements. In particular, CrossFill is a self-supporting foam structure, for which each layer is fabricated by a single, continuous and overlap-free path of material extrusion. Our method for generating CrossFill is based on a space-filling surface that employs spatially varying subdivision levels. Dithering of the subdivision levels is performed to accurately reproduce a prescribed density distribution. We demonstrate the effectiveness of CrossFill on a number of experimental tests and applications. Highlights: A novel self-supporting space-filling surface which supports spatially graded density. A scheme for refining the structure to match a prescribed density distribution. An algorithm for merging the toolpath of an infill structure with the input model's boundary so as to retain continuity.