Nestled in the foothills of the Swiss alps, sits one of the most advanced prefab construction factories in Europe. Renggli, a 100 year old firm, builds high-performance, energy-efficient, modular structures. They use a variety of machines to automate construction like CNCs, suction cup lifts, robotic saws, tilting tables, gantry cranes and more.
Materials Management
Drawing inspiration from the automotive industry, Renggli adopts a platform system for materials management. This system efficiently stores and retrieves drywall, timber, sheathing, and other materials, ensuring an organized and streamlined production process. BIM models play a key role in tracking and managing every component with unique barcodes, allowing for optimized material usage and reduced waste.
CNC Machines
The factory’s CNC machines are at the heart of precision cutting. Guided by data from BIM models, gypsum boards and wood panels are accurately shaped and sized. This process generates minimal waste, thanks to optimization and effective dust suction systems, contributing to a clean and eco-friendly production environment.
Hundegger Saw
For large wood pieces, Renggli employs the advanced Hundegger saw. This fully automated machine executes precise cuts, drills, and punctures as dictated by BIM models. The exclusive use of engineered wood like glulam beams ensures unparalleled precision and quality in off-site construction.
Butterfly Table
Building wall, ceiling, and floor panels becomes seamless on butterfly tables. The smart design enables safe and efficient flipping of panels, reducing the risk of injuries and enhancing assembly ease. Metal pins act as guides for wood studs, further streamlining the process.
Gantry Crane System
While much of Renggli’s factory is automated, the final assembly section relies on skilled labor. The gantry crane system facilitates the addition of insulation, drywall, and wiring, maintaining organization and cleanliness to ensure efficiency. While most of the other areas were fully automated, this final assembly section was still reliant on manual labor. However, unlike typical job sites, it was organized and clean. Every station had a supply cart that was fully stocked. They had dedicated people making sure no one ran out of supplies.
Once the panels were complete, they were lifted by cranes and flipped in the vertical position. Panels are stacked on transport platforms and draped with plastic. They are heat sealed to protect them from moisture. Outside the factory, they had rows of protected panels waiting to be transported to job sites. Unfortunately, the plastic cannot be reused in the factory again but they send it to a recycling plant.
Sustainable Materials
Renggli’s commitment to sustainability is evident in their choice of materials. Sustainably harvested wood, rapid-growth softwood, and triple-glazed windows contribute to a lower carbon footprint compared to traditional construction methods. Solar panels power their factory and office, promoting renewable energy usage.
Disadvantages
Despite its advantages, modular construction has its challenges. Stone wool, used for insulation, poses a higher initial carbon footprint. The high-quality materials used in Renggli’s process make it a relatively more expensive option compared to conventional stick building. Additionally, the uniqueness of each project makes full automation a difficult endeavor in the construction industry.
Conclusion
I hope our industry embraces modular, off-site construction more and starts thinking of buildings and an assembly of products. It’s going to take a while and it’s going to be messy, but with companies like Renggli proving that it can be done, there’s hope. Be sure to check out my entire conversation with Daivd Renggli on my podcast channel.
