Functionally Graded Rapid Prototyping

Functionally Graded Rapid Prototyping (FGRP) is a novel design approach and technological framework enabling the controlled spatial variation of material properties through continuous gradients in functional components. Such variations are traditionally achieved as discrete delineations in physical behavior by fabricating multiple parts comprised of different materials, and assembling them only after the fabrication process has been completed. Recent advances in Computational Topology Design (CTD) and Solid Free-Form Fabrication (SFF) are promoting the creation of building components with controlled micro-, and macro-architectural features. The FGRP approach combines a novel software environment with a mechanical output tool designed as a 3-D printer to allow computer control of material distribution within a monolithic structure. Inspired by the integration of material, structure and form found in natural systems, this biologically inspired design approach allows for physical prototyping of graduated properties in product and architectural design scales. FGRP introduces the potential to dynamically mix, grade and vary the ratios of different materials, resulting in continuous gradients, and structurally optimized designs with efficient use of materials, reductions in waste and production of highly customizable features. The paper presents the FGRP technology as part of an overall integrated design approach to functionally gradient design fabrication. Two work-in-progress explorations of FGRP implementation are presented: a robotic arm able to 3-D print concrete with controllable density and a 3-D printer for UV-curable polymers exploring variable elasticity. Research methods and processes devised for its development are presented and design applications demonstrated. Current technological limitations and future directions are discussed and their implications reviewed.