Automated digital fabrication concept for composite facades

摘要

The buildings we inhabit consume a considerable amount of the energy each year however therenis currently a global movement towards minimising the impact human society has on thenenvironment. This is driving the demand for more complex, and even intelligent facade systemsnto reduce the requirements of air conditioning and lighting while maintaining comfort. Throughnthe development of 3D modelling and analysis software, architects and engineers have thenability to digitally produce innovative solutions. However, when complex, double curvedngeometries are proposed, the costs and difficulty associated with conventional fabricationntechniques often make the transition to reality impractical.nDetailed within this paper, is the investigation and development of an alternative fabricationnconcept the utilises an inexpensive, reusable lpin boardr mould that is autonomously set tonvarious CAD derived surface geometries by a 6-axis robotic arm manipulator. A digitalnalgorithm models a double curved test facade, subdivides it into manageable panels based onnthe dimensional parameters of the mould, creates a robotic toolpath simulation to map thensurface geometry and generates the required machine-driving code.nActive trails successfully set the pins of the mould to within 0.6mm of the analytically predictedncoordinate. At fully operational speeds, this process is estimated to take less than 2 minutes. Tonestablish a proof of concept, automated setting of the mould was conducted for twonneighbouring panels of the facade with unique but respective geometries. Under its design intentnconditions, the set mould was used to fabricate samples of the digitally designed panels out ofncomposite materials to assess the concepts strengths and weaknesses.This resulted in geometries that adequately resembled the curvature of the CAD model,nhowever preliminary samples exhibited considerable surface and structural defects. Alterationnof composite material selection and minor mould modifications refined subsequent panelsnsufficiently to allow for their assembly. While imperfections still exist, the continuation ofncurvature from one panel to its neighbour exhibits good correlation and the assembled facadensection can easily be identified from the digital surface.nAt all stages of experimentally testing the concept, limitations were identified and addressed asnfar as practically possible. For those remaining, solutions are detailed such as designnmodifications and algorithm improvements, that if implemented in future works will aid thendevelopment of the automated fabrication concept, potentially towards a full-scale compositenfacade fabrication method that permits complex geometries while remaining cost effective.n