Applications of advanced off-site manufacturing for steel modular buildings

Steel modular construction offers significant benefits but remains constrained by high product variety and fragmented systems. This paper presents the design and industrial deployment of an intelligent off-site manufacturing system tailored to steel modular buildings, with GS-Building and ME-House as representative product families. The system organises profile and plate preparation, sub-assembly, final welding and straightening, and inspection and logistics into a continuous, flow-oriented line supported by flexible automation, including automated cutting and marking with nesting optimisation, jig-based assembly, horizontal welding and sensor-assisted straightening of H-sections, parametric robotic welding for most non-standard members, and intelligent logistics using vision-guided handling devices, automated guided vehicles and dynamic storage. These physical processes are integrated through a cyber-physical ‘digital backbone’ comprising an optical network, manufacturing execution system and a production-line digital twin for real-time traceability. Prototype deployment and comparative analysis against conventional steel fabrication show that the system replaces error-prone manual data handovers with a continuous digital thread, enables dynamic scheduling and just-in-time logistics and turns the workshop from a black box into a transparent, data-driven environment. The results demonstrate a practical pathway for industrialising steel modular construction and a foundation for future data-driven optimisation.