Building Facade Prototyping by Fused Granular Fabrication (FGF)-Introduction and Analysis of Experiments in Design-Build Praxis-

As complex forms of building facades and 3D printing technology in architecture prevails, many efforts have been made to demonstrate implementation of 3D printing for different types of architectural works such as buildings, pavilions, facades, interior partitions, prototypes and products. Ninety examples were collected and analyzed from online sources that indicated PLA was used for the experimental stage of fabrication studies in spite of its weakness against code compliance mainly due to its relatively easier application for large-scale robotic fabrication. Five precedents exemplifying plastic additive manufacturing were selected and reviewed to discuss the plastic feedstock types and equipment for large-scale production. For 3D printing fabrication of building facades, Fused Granular Fabrication (FGF) utilizing extruders with pellet-type plastic gained prominence. From this background, a design-build graduate seminar course aimed to integrate digital design and FGF fabrication of building facade elements as shading devices took place over a 14-week semester. From this course, two prototyping projects were developed and fabricated with the FGF method by two groups of students involving after series of 3D printing tutorials, case-studies, application to exercises, and individual proposals by FDM. This study illustrated the sequential processes of design-build experiments and evaluated final prototypes with the proposed criteria in four categories of design, process, fabrication and level, which were introduced after analyzing selected praxis-based literature. From the prototype evaluation, the following criteria were noted for improvement: fabrication-informed design, construction process, material-informed process, assembly, connection, detail, and machine control. The evaluation-based discussion presented the direction for the continuing further research regarding how to approach and improve design and fabrication methods in building facade prototyping implementation by FGF.