Adaptive Detailing: Design and Fabrication Methods for In Place Wire and Arc Additive Manufacturing Connection Details

Abstract

This thesis presents an additive joining technique and an adaptive detailing pipeline for robotic assembly of spatial structures. The thesis starts by identifying how designing for and building with robots brings new challenges for the designer who –now in explicit control of both design and production– needs to be knowledgeable in the possibilities of robotic joining tools and processes. The context of inquiry is a case study of spatial structures in steel with non-planar interfaces between elements. The three-dimensional nature of the interfaces presents an unprecedented building challenge in robotic fabrication, requiring an investigation of appropriate materials, processes, and fitting techniques to fix the parts in space. These challenges, dependent on diverse expertise and knowledge, funnel back to the current lack of consolidated detailing concepts and methods for robotic fabrication. The investigation is, therefore, twofold: First, an additive joining technique to join metal parts is developed. The technique applies the known Wire and Arc Additive Manufacturing (WAAM) process in place directly on the parts to be joined during assembly, in contrast with typical approaches where connections are prefabricated in an exclusive 3D printing environment. The resulting in place WAAM (IPWAAM) technique is developed alongside tolerance handling procedures to measure and adapt to the actual location of parts, as well as collision control methods to move safely between obstacles during the 3D printing process. Second, a computational detailing pipeline is developed to coordinate the different challenges of designing and building IPWAAM connection details. The pipeline integrates robotic, material, and functional requirements and, by linking the digital and physical models of the IPWAAM connections, it allows the design to adapt as needed based on the building data gathered during production, resulting in a novel adaptive detailing approach. The thesis develops through physical experiments to test the joining and detailing approaches and virtual experiments to anticipate the challenges of their application in the context of spatial structures. As a result, the physical outcomes demonstrate an unprecedented method for joining non-planar metal parts. Finally, the adaptive detailing approach provides a basis for detailing computationally in the context of robotic fabrication, aiming to support the current efforts of building a rich and transparent digital building culture.