ERNE AG Holzbau has made a name for itself since 1965 by constructing innovative buildings from prefabricated elements and is part of the ERNE Group, which celebrated its 111 year anniversary this year. With 300 employees, the family-run business serves private customers and communities and acts as a general contractor and general planner for larger projects.
One of the company’s main goals is to advance the use of “room modules” in timber construction. These modular elements can be combined to form larger buildings when necessary. For example, if a school becomes too small after five years, Erne can quickly incorporate additional classrooms into the overall structure. In addition to schools, these solutions are also used to expand hospitals, office buildings or daycare centers and to provide age-appropriate housing for the elderly.
For the past several years, the wood working specialist has been using an automated system to produce floors and ceilings. They then decided to automate the production of walls as well. “When we received the inquiry from ETH Zurich to construct the curved ceiling elements from square beams, it quickly became clear that we needed a system that could produce not just walls but custom designs as well,” Thomas Wehrle explains. The curved, freeform roof also required the construction of 168 lattice girders up to 15 meters in length. The employees in charge of the project contacted various machine manufacturers. But the costs estimates they received made their heads spin. Because of the complicated requirements, a standard system was out of the question. They decided to contact Güdel AG based on a recommendation from faculty from the digital production department at ETH. The automation specialist, which is based in Langenthal in the Swiss canton of Bern, provides finely tuned and parameterized handling and production units that can be easily integrated into processes. The partners quickly came to an agreement: The proposed gantry system covers a large work area and meets the required degrees of freedom. Vacuum grippers from Schmalz are used for the handling tasks.
Joint Tests on Various Materials
The system was eventually ordered, and just a few months later Erne was constructing its first beams. The collaboration with Güdel and Schmalz was extremely productive. “Güdel completed the project very quickly, and the integrated vacuum grippers from Schmalz provided high process reliability,” says Wehrle. Both partners impressed with their solution-oriented approaches. Erne is also very satisfied with the service provided by the employees during the project and in the after sales phase. “We chose Güdel because of their expertise in mechanical engineering and automation,” says Wehrle. It was Güdel who brought Schmalz into the picture. But the company was no stranger to Wehrle: “I know Schmalz from the vacuum technology industry and I know their expertise. That helped build trust from the very beginning,” he says. Together, the project partners carried out on-site tests on materials such as oriented strand board (OSB), plaster fiberboard and medium-density fiberboard (MDF). During the tests, one thing became very clear: “Our MDF and plaster fiberboards are extremely porous and require a special gripper solution. That surprised me,” Wehrle explains.
A linear gantry with a length of 53 meters and a height of 12.40 meters is used to produce walls, ceilings, facades and structural components. The gantry picks up various attachments that saw, mill, drill or nail depending on the application. The robot also transports square beams to be cut at the circular saw. The system processes workpieces up to 48 meters long, 5.60 meters wide and 1.40 meters high. The large-format wooden boards are transported using a Schmalz suction spider that is attached to the gantry system. The system picks up the boards from the stack and guides them precisely to the machining station. The spiders are very flexible. Schmalz configures its solutions from more than 3,500 modules, tailoring them to the customer’s needs. Since the conditions for each workpiece were quite different, the Schmalz system consultants recommended using eight suction plates for this project. Notably, the process of destacking the various materials from the stack store using various equipment was accomplished with just a single gripper.
Erne is very satisfied with the overall performance of the gantry system: “The technology makes us more creative and flexible. This allows us to successfully implement the customer’s requests,” explains Wehrle. By automating its production, the Swiss company has significantly strengthened its position on the market and is able to meet the high quality requirements of its clients. The gantry robot makes quick and precise cuts, leaves clean edges and reliably transports wooden workpieces of various sizes. The result is a cost-effective machining process.
Erne seeks to push forward with the automation process into the future. In particular, the company sees potential for further development in the area of digitalization. Wood is an organic material and cannot always be purchased in the same quality. “When working with wood, we sometimes run into the problem that small differences in quality can lead to deviations. The robot does not yet detect this reliably,” Wehrle explains. The system still needs to learn how to register and compensate for such deviations. The company is already looking for an appropriate solution. Wehrle has no doubt where to find the assistance he needs. “Güdel and Schmalz did outstanding work. I give them my highest recommendation.