According to an analysis by Statista, Germany-wide sales in the refrigerator segment will increase to almost EUR 1,625 million by 2023. However, the production of refrigerator housing parts is extremely complex, as the materials used must be perfectly flat for the subsequent processing steps despite their high residual stress - a time-consuming process. In order to meet the increased demand, BSH Hausgeräte GmbH has replaced an outdated system at its plant in Giengen with a modern multi-blanking system from the b+s group. It straightens and cuts in a single pass so that even changing cut sizes can be produced quickly, efficiently and to the highest quality in-house without any additional logistics effort. The new system enables a speed of up to 30 m/min with insertion limits of over 300 N/mm2 and material strengths of over 500 N/mm2.
As the housings of refrigerators are visible parts, perfect processing of the sheet metal used is essential and the blanks must not be scratched during production. This is only possible if the components are absolutely flat, but they tend to ripple due to the high residual stress and must therefore first be straightened before cutting. "Due to the sharp increase in demand, our previous system reached its limits and led to a capacity bottleneck," reports Dominik Schiffner, Project Manager within Production Planning Prefabrication at BSH Hausgeräte GmbH in Giengen. "We therefore decided to replace it with a modern multi-blanking system from the b+s group. It allows several precise and individual sheet metal blanks to be produced in a single pass." Thanks to this system, BSH now has a greater vertical range of manufacture and can therefore react more flexibly to changing market requirements.
Efficient multi-blanking line with a SCHNUTZ straightening machine
In order to meet the increased demand for household appliances while maintaining the highest quality standards, BSH has opted for a new multi-blanking line from the b+s group. (Source: b+s group)The new system has been running smoothly at the BSH plant in Giengen since June 2019. It combines a cut-to-length line with a slitting line and is designed for sheets with a material width of up to 1,650 mm and a material thickness of 0.35 to 0.6 mm. Thanks to the straightening expertise of SCHNUTZ, the world's first straightening machine manufacturer, it is particularly suitable for strengths of over 500 N/mm2 and yield strengths of over 300 N/mm2. "Before the first cut, the coil is first straightened and only then divided into longitudinal strips," explains Baral. "These strips are then cut crosswise, resulting in up to two sheet metal blanks of the desired length per segment." The stacking and packaging area plays an important role due to the high quantity of sheet metal blanks with small dimensions. For this reason, the b+s group paid attention to different stacking technologies such as a blown air stacker.
Compared to the old system, the new multi-blanking system is around 70 percent more efficient, which has increased the daily throughput. The straightening result also corresponds exactly to BSH's desired specifications - for example, the result is extremely low in burrs. "Our employees appreciate the ergonomic benefits of the new system," says Schiffner. "It also operates at less than 75 dBa, which has significantly reduced noise emissions. This naturally contributes to a much more pleasant working environment." Based on this positive feedback and the comprehensive support provided throughout the project, further lines from the b+s group are already planned in other BSH plants.
Intensive on-site consultation and individual custom-made products
Initial planning for the project began in 2016. b+s group's team first visited the BSH plant in Giengen to ensure that the new system was optimally adapted to the requirements. "Every machine park poses different challenges when designing a new system," explains Thomas Baral, Managing Director of Burghardt + Schmidt GmbH. "That's why on-site appointments are essential for our service - this is the only way a new system can be optimally integrated into the existing production processes. In addition, individual requirements can be discussed much better in a personal meeting and we can provide support with our many years of expertise." The control and drive technology, the straightening technology and the production speed of the system played a decisive role in the conceptual design.
Other requirements could be taken into account directly in the design thanks to the efficient preliminary planning. "For safety reasons, for example, it was important for us that the new system enables automatic strapping with edge protection," reports Schiffner. "The new system also had to manage without a pit, but have a sample drawer so that the quality of the blanks could be checked. In addition, the lowest possible noise level was desirable in order to minimize the exposure of our employees to unnecessary noise emissions." Once all the requirements had been recorded, the construction of the individualized multi-blanking system could begin. Thanks to the synergy effects of the individual companies in the b+s group, all special requests could be implemented promptly so that the turnkey system could be delivered in March 2019.
