ReciproFrame Timber Gridshell: From CAM Data Interface Modeling to Operating Industrial Joinery Machine for Scaling up Reusable Timber Structures

This research extends the work from our previous study on utilizing digital technologies to turn short solid timber elements into framed timber systems designed for the rapid assembly and disassembly of cost-effective, material-efficient, reusable gridshells. In a former paper, we developed an innovative reciprocally-reinforced topology of trivalent polyhedral frames, termed "ReciproFrame", enabled by the development of a CSV file to leverage the precision and speed of multi-axis robotic arms, which was then utilized in the construction of a small-scale, 7.5-meter research demonstrator. Although the multi-objective analysis confirmed the efficiency of the production method in constructing structurally-efficient catenary cross-sections without the need for any steel nodes-a feat not achievable with previous geodesic domes-we realized that the automated construction of larger structures in future timber industry would require an industrial-class production workflow featuring high-performance units equipped with powerful and efficient machining capacities for varied timber processing. As a solution, this paper presents a 24-hour industrial fabrication workflow, enabled by a self-developed data interface plugin that generates XML-based, industry-standard CAM data for the direct instruction of Hundegger K2 machines. It addresses the operational problems and technical challenges related to interoperability between the data interface programming and the operation of industrial joinery machines. Finally, the paper discusses the possible applications and limitations of the production workflow, while presenting the design-to-assembly process of a medium-scale research demonstrator with a maximum span of 15 meters, made of 768 industrially-fabricated Laminated Veneer Lumber (LVL) beams.