In Germany, the modernization of existing precast plants has become extremely common because many producers are currently using aged equipment whilst the construction industry is booming. However, installing a new production line in an existing factory building is rather an exception to this rule. BWN Betonfertigteilwerk GmbH & Co. KG based in Neuwied, Germany, has embarked upon this route and joined forces with Progress Group to install a combined carrousel system for the manufacture of four different products. The new precast plant was commissioned in October last year.
It is no small feat to integrate a complete carrousel system into an existing building and to design its layout in such a way that it optimally utilizes available space whilst ensuring a perfect production sequence. For this purpose, it was necessary to adjust the design to the existing shop floor environment as far as reasonably possible. In close collaboration with Ebawe Anlagentechnik and Progress Maschinen & Automation – two members of the Progress Group –, BWN Betonfertigteilwerk GmbH & Co. KG located in the German State of Rhineland-Palatinate succeeded in installing a new precast production line fully geared towards the “Industry 4.0” concept within an existing factory building.
Flexible product range
The production line is suitable for the manufacture of precast floor slabs, solid and double walls with and without integrated insulation; it was installed and tested in 2015. At the beginning of this year, the commissioning process was finalized and the line put into service at a capacity of three pallets per hour.
“The fact that four different products can be manufactured on a single carrousel system is quite remarkable in and of itself,” says Axel Schwarz, managing director of the business. This diversification has been a means to an end, as it were, because a single production line serves to produce all the elements that BWN requires for its customers in residential as well as industrial construction.
Fully automated shuttering process
Yet the production line also excels with some sophisticated solutions from an engineering point of view. For instance, the shuttering storage and the associated storage robot were positioned on an intermediate level above the shuttering robot. From there, the storage robot transports required shutters to the shuttering robot so that they can be placed on the shuttering surface with pinpoint precision.
After the end of the production process, the same system scans the pallet, unlocks the shutters and feeds them back to the cleaning system and to the storage area. Schwarz is pleased about the result: “All these work steps are handled by ultra-precise, fully automated systems that support a seamless production process.”
Second level used for prefabrication of reinforcement
Due to the limited space available in the existing building, machines had to be arranged so as to minimize their footprint. This is why the entire reinforcement prefabrication unit was installed on a second level. This fully automated system is called “Wire Center”; it straightens, cuts and installs both reinforcing steel from the coil and lattice girders. An integrated MSR straightening and cutting machine produces longitudinal and transverse rebar just-in-time and feeds it into the production line via a cascaded output system that connects to the first level.
At this point, a robot grabs the reinforcing bars and moves them to the pallet to install them in a fully automated process. Lattice girders are conveyed to a GTA cut-to-length machine where they are cut to size whilst residual pieces are joined by welding, which reduces offcuts to a minimum. In the next step, a dedicated transport system also moves the lattice girders down one level, where they are automatically placed on the pallet.
Perfect pallet quality ensured by custom grinding process
According to Axel Schwarz, it was the right decision to install the production line on several levels. “As a result, we are able to utilize the large ground-floor area exclusively for pallet circulation.” The 50 pallets circulating on the line were manufactured at Ebawe Anlagentechnik in Eilenburg. “During the supplier selection process, we have put great emphasis on equipment quality.” According to him, the quality of the pallet surface is the key to ensuring outstanding results in terms of precast element surfaces. “This is where Ebawe scored the highest,” Schwarz adds.
At Ebawe, pallets are manufactured from a single form plate. A custom grinding process that pallet surfaces are subjected to during the production sequence additionally ensures premium quality. The company designed the fully automated machine used for this work step specifically for this purpose. After grinding, each pallet is measured using a laser system, which guarantees a consistently high quality standard of shutter surfaces.
Fully automated concrete spreader reduces production costs
The use of a fully automated concrete spreader significantly reduces production costs. This spreader ensures uniform, accurate concrete distribution across the pallet. Perfect spreading prevents raw material wastage and reduces manufacturing costs compared to manual concrete placement.
Complete package includes software suite in line with “Industry 4.0” approach
The entire carrousel system is controlled via Ebos, a software suite developed by Progress Group. This complete solution goes beyond the concept of a simple master control computer and consistently supports all aspects of the production sequence, including process planning, the manufacturing process itself, and follow-up process analysis. Ebos is thus an important component of the BWN production line.
The custom analytical features integrated in Ebos make a major contribution to improving planning capability and transparency of production. For instance, the PTS test (“Production Test Service”) enables verification of CAD data feasibility before production even starts. This tool also makes it possible to optimize the production process. Another feature called GPA (“Graphical Performance Analyzer”) provides the option of playing back and evaluating the detailed process sequence post-completion. Any bottlenecks as well as room for improvement can thus be identified very quickly.
According to managing director Axel Schwarz, this complete package was the key argument in favor of collaborating with Progress Group. “We got everything from a single source – a well-engineered, sound solution.”