Process steps "shortened"

2024/05/03   |   Frankfurt/Oder   |   Germany

Creative handling of the raw material is an integral part of the DNA of a timber construction, which provides the industry with new building materials and systems time and again. In view of new business areas and market participants, the incentive for new developments is particularly strong at the moment. So you should be prepared for surprises. One of them will be experienced by visitors to the new production plant of B&O Bau GmbH, based in Bad Aibling, in Frankfurt (Oder). This is not only because of the equipment supplied by WEINMANN Holzbausystemtechnik, which is already worth seeing for itself with a fully automatic frame work station, four multifunction bridges, a blow-in bridge and three rows of work and turning tables. What is particularly surprising is the product that runs through the production line. The difference is already evident in the frame work station. According to B&O Bau Development Manager Michael Schäpers, this is one of several unique products developed during planning discussions with WEINMANN. Equipped with a robot, the station processes studs that are processed on a BEAMTEQ B-660 in the neighboring hall and supplied via a fully automatic storage system. What is unusual about this process is that thanks to special software, the robot not only positions timber frame constructions, but also studs on studs: after being deposited, the new stud is connected to the previous stud using two shaft nailing units. This results in a load-bearing, solid component made of a vertical solid construction timber, the top and bottom plates of which lie not above the upright wood, but rather on the sides of the component as slim CLT planks. Regularly recurring stops in the plates ensure that the component remains dimensionally accurate over the entire length. Depending on the static requirement, stronger load-bearing supports (steel, beech) can be installed between the upright timbers. Windows and doors are not cut out as with other solid construction systems, but rather are bridged by lintels in a way that saves on resources. For Michael Schäpers, "this is the only way to achieve a continuous, material-efficient production process as found in the automotive industry. I save processing time, I don't lose any time and money disposing of offcuts and don't have to pay for the material that was in the openings."

Serial timber construction for five to eight stories

Avoiding the use of horizontal timbers in the static load-bearing wall core already demonstrates that B&O Bau is reaching for the skies in terms of wall construction. In fact, the focus is primarily on multi-story construction of between five and eight stories. To be precise, high-quality and cost-effective multi-story construction in (almost) pure timber construction: on the construction site, the seam between walls and ceilings is provided with a type of ring armature made of reinforced in-situ concrete. The high quality of the wood components is achieved, among other aspects, by high mechanical precision and a double-layered wall structure: solid components and timber frame constructions produced alternately are combined with each other at the end of the first production phase, whereby the solid components act as load-bearing elements, while the timber frame constructions act as insulating elements. On the way through the production line, the components pass through further new developments, such as a WALLTEQ M-300 insuFILL with a cleaning mechanism that ensures a clean contact surface of the insulating plate after each element. Another special feature is the "backflushing mechanism" that returns most of the residual insulating material contained in the blow-in lines back into the storage container. This makes the weighing process more precise — the insulating material returned is weighed again — and the "backflushing" also simplifies changing the insulating material, as insulating material remains in only one short supply section. Depending on the customer's requirements, cellulose or mineral fiber insulating materials can be blown in in Frankfurt (Oder). The four large insulating material storage tanks, including the supply for the insulating material packages, are an in-house design by B&O Bau. At the end of element production, both elements are joined together on a turning table. Placed on top of one another, they move on a mobile work table to line three, where both layers are bolted together — the modified screw units with 200 mm long screws are another unique feature in the line. The production process is completed by the attachment of the facade sealing sheet, the mechanical placement and fixing of the slats and contra slats by two multifunction bridges and finally, the assembly of the facade.

Complete supplier across the whole of Germany

The company that developed the wall construction is just as complex as the construction itself. The family-run B&O Gruppe has been involved in renovation for 30 years and has been active in wood and wood hybrid construction for 15 years. Today, the group of companies is divided into the main divisions B&O Service and B&O Bau (which deals with construction). While B&O Service is responsible for service areas such as supporting residential complexes, including repairs and breakdown service, B&O Bau acts as the general contractor for turnkey construction projects. As such, the company realizes new buildings and extensions, builds over parking lots and carries out renovations — including, with increasing tendency, serial renovations, which are regarded as a "significant growth market." B&O Bau employs around 750 people — including 350 carpenters — at regional sites throughout Germany. These regional companies take care of customer acquisition and offer their clients from the housing industry support for the entire project via a local contact person. They offer a wide range of products at various quality levels to interested parties, including residential construction companies, project developers or investors — the portfolio includes timber parking garages made from beech, for example. The projects are planned by internal or external planners of the group, with each planner specializing in the respective construction task. On the one hand, the components for implementation come from external partner companies whose timber elements are still used in corresponding projects. On the other hand, the group is increasingly producing at its own sites, such as bath modules in Croatia and in-house production of ceilings is also planned in Bad Aibling. This is an expansion of the company's own manufacturing expertise, which is in the context of a paradigm shift toward cost-optimized system construction. Since the completion of the plant in Frankfurt (Oder), all projects at an advanced stage also go through a process in which their compatibility with the system design of the group is checked.
The new construction system enriches the group's portfolio with an extremely interesting offer. "The customer gets their building much faster and cheaper than with any other construction method," explains Michael Schäpers. "And at a very high quality."

A modular system for serial construction

To achieve this, a low-cost wall system is not enough. The paradigm shift is made possible only by combining a minimum use of resources and automated production of highly standardized components with a largely automated digital process that can be used to shorten entire process steps using a BIM model created with Revit and autoCAD. "Based on the clearly defined performance of the profiles installed in the wall, the system can tell me, for example, immediately after the design is completed, which stud in the wall is stressed 23 percent and which is stressed 89 percent," explains Michael Schäpers. Clearly speaking, a large part of the static key data is output automatically and only needs to be checked. "Thanks to our static tools, we can also proceed in an extremely material-efficient way, meaning that the walls contain exactly the right amount of wood and not one millimeter more." The prerequisite for this is a largely standardized production toolkit and a comprehensive digital library in which all components and details of the construction system are stored — the mammoth task within the project, which required a great deal of effort and knowledge. On the basis of the data generated mainly in the regional companies, the planning software can also calculate the thermal properties of the selected building shell, for example, so that the building physicist can derive an assessment from a building physics perspective directly from the planning. The end-to-end digital process also includes third-party contractors such as electrical installation: if an electrical socket is planned in the 3D model of the design, the circuit diagram is automatically updated in the background, while a bore hole for the socket and a standard gypsum fiberboard with the cable guides are created in the CAD system. The work preparation is shortened significantly by such processes; Schäpers speaks about a reduction of 95 percent from about 30 to as little as two days per building. "While a work preparation employee draws up each building from scratch for individual planning, our panelization comes largely from the finished design and the library." The savings potential over the entire project is enormous, with Michael Schäpers estimating up to 50 percent. The modular design system is open for all typings, which means that very individual solutions can be implemented. Since the load-bearing system, insulation level and facade form a multi-layer system, the load-bearing core — normally made of 12.5 cm thick studs — can be reinforced by larger cross-sections depending on the structural analysis. The customer, who sees the building in advance in the BIM model, can choose a different facade from the modular system, but also a different insulation level. This means that a whole range of wall and ceiling systems, development cores and proven details are available to the customer during the planning phase. This flexibility also has other advantages. For example, it enables CO2 to be stored permanently in the solid core of a reversible building, the facade of which can be easily renewed after the end of its life and the insulation level of which can be replaced with new materials at any time if more extensive requirements come into force. In production, the three-layer model has the main advantage that timber frame elements for low-rise buildings that are efficient for living spaces — the group also offers solutions here — run through the system without any changeovers. The same applies to timber frame elements in serial renovation, which currently accounts for the majority of orders in Frankfurt (Oder). In terms of production technology, there is no difference to the insulation level of the new buildings, even if the planning preparation of a renovation project — with an inventory scan, a 3D point cloud and a digital model of the building — is more complex. To compensate for dimensional deviations, the existing building is also packed in a 30–40 mm thick layer of insulation, which ensures a precise fit during assembly of the system shell.

Perfectly equipped for high numbers of units

In conjunction with the production line in Frankfurt (Oder), the modular system also provides the capacities required for large-scale projects. B&O Bau currently states the production capacity of its plant at 25,000 m2/a, but with one-shift operation and cycle times of 40 minutes for a two-layer element and around 20 minutes for a timber frame element, this is almost certainly not the end of the story. Michael Schäpers, who considers further cycle time optimization to be possible and a second shift to be probable in the foreseeable future, sees potential for up to 200,000 m2/a under full load in the plant. We can assume that the quantities in Frankfurt (Oder) will increase rapidly in view of the cost, time and quality advantages of the proven, more breakdown-proof system. This is also due to the fact that around 95 percent of the projects executed by B&O Bau prove to be compatible with the modular system during the compatibility test. With a grid size of 12.5 cm, this is no surprise, as such changes in dimensions are irrelevant in large-scale projects.

Good cooperation resulted in good solutions

With the Frankfurt (Oder) plant, B&O Bau has succeeded in achieving something that, in retrospect, borders on a miracle for Michael Schäpers. "In around two years, we have created a radically new construction system and the associated production plant." The idea arose at a meeting of the management in 2021, when shareholder Dr. Ernst Böhm suggested that the production process should be taken into the company's own hands in the future. "It was already clear at that time that the demand for affordable housing could only be met by a comprehensive process optimization. It was therefore clear that the development of multi-story construction would be moving toward industrialization. If we wanted to be involved, we had to take on a pioneering role and set new standards in planning and production." For Michael Schäpers, who had designed heavy equipment for several years as a wood engineer, the development of the new modular system began with a blank sheet of paper and visits to component manufacturers and machine manufacturers — initially with little success. It was only when WEINMANN offered the option of combining a frame work station with a robot that led to the idea of producing a solid wall element from studs: "The machine can do this at high speed. In this way, we achieve high material efficiency with a low-cost raw material range, extreme resilience and a flow process in which all machines are integrated via the MES production control station from granIT." WEINMANN was open to new developments, "so we went through the system item for item until the machine layout was finished." B&O Bau initially used the consulting services of SCHULER Consulting, "which was very helpful for the start, since we practically started from scratch. In view of our very specific wishes, however, we quickly got into the planning phase with the development departments and soon arrived at the current layout. A good solution was found for every task thanks to cooperation on an equal footing. Today, as a wood engineer, there is nothing that makes me nervous about the machines in our plant. WEINMANN also proved to be very well positioned for topics such as preventive maintenance and preventive unit monitoring." They took their time over implementation of the production processes in the new plant, starting in 2022 with a pilot system and a lot of manual work. This enabled the staff to be trained and introduced to the new product. Commissioning of serial production took place only at the beginning of this year. "Two and a half months after commissioning, we are achieving a solid 90 to 95 percent in all areas, and the target cycle is already considerably undercut. "This means that we can now produce a load-bearing wall — which in a conventional line would be subject to 40 minutes of trimming alone and would take around four to six hours in a woodworking shop — in just 15 minutes. Everyone involved can be proud of this."