Everything automatic - at -24 °

His innovative spirit led the traditional baking trade into the modern age: Fritz Lieken succeeded in making bread doughs last longer through pasteurization. He introduced the mesh belt ovens in Germany, which made it possible to bake large quantities of bread in homogeneous quality. Today, Lieken AG is one of the leading manufacturers of bread and bakery products in Germany. Nevertheless: "Changing market conditions and new baked goods concepts in retail always require adjustments to production and logistics," explains Hartwig Meyer-Ruhstrat, Director of Engineering at Lieken AG.

Against this backdrop, the Group launched an extensive restructuring program in 2014. In addition to the relocation of the administrative headquarters from Düsseldorf to Dortmund and the construction of one of the Group's new production facilities in Lutherstadt Wittenberg, the focus was on an investment package for the production sites in Brehna, Lünen and Lüdersdorf. In Lüdersdorf, the production lines were expanded and the necessary expansion of storage capacity was implemented with the installation of a new deep-freeze high-bay warehouse.

Production-side storage pre-zone with stretching system, labeling and contour control. Photo: Aberle

Aberle GmbH, Leingarten, a company of the Körber Logistics Systems Business Area of the international technology group Körber AG, was awarded the contract as system integrator for racking and conveyor technology including control from palletizing onwards in the logistics project. The order includes the sister company Langhammer GmbH, Eisenberg, also from the Körber Logistics Systems Business Area, as a supplier of pallet conveyor technology and palletizing.

The system integrator Aberle implemented a fully automated solution with a deep-freeze high-bay warehouse, new pre-zones for incoming goods and dispatch, a direct conveyor system connection to production and the existing warehouse as well as the IT interfaces for system control via the warehouse management system (WMS) installed by the customer and the material flow computer. All components are designed for an ambient temperature of well below minus 24 degrees Celsius. A system visualization with the Aberle PMS-V process management system also ensures consistent transparency of system utilization and processes.

The installed technology

The new logistics facility in Lüdersdorf has been fully operational since mid-2016. Aberle built the high-bay warehouse (HRL) in silo construction within just a few months. The supports of the racking system are also the load-bearing elements for the hall roof and the attachment of the side walls. The result is a compact, three-aisle high-bay warehouse with 6,000 pallet spaces for single and double-deep storage. "In deep-freeze warehouses, every cubic meter of enclosed space requires high maintenance costs," explains Aberle project manager Stephan Kölmel. "That's why the entire system is designed for optimum space utilization, fast processes and minimal temperature losses."

Körber Logistics Systems

The Business Area Logistics Systems, which is part of the international technology group Körber and based in Bad Nauheim, Hesse, is a leading provider of fully integrated applications for optimizing complex internal and external logistics processes. Under the umbrella brand Körber Logistics, the Business Area provides digitalized solutions for the smart factory (production logistics), the warehouse, e-commerce and the management of the entire supply chain. The umbrella brand unites the companies Aberle GmbH and Consoveyo S.A. (system integration), Langhammer GmbH and Riantics A/S (product solutions) and Inconso AG and Aberle Software GmbH (software) in three Business Areas. These offer a comprehensive range of products and services from system integration to storage, palletizing, depalletizing and conveyor technology through to software.

Narrow, space-saving storage and retrieval machines (SRMs) with energy-saving energy recovery systems enable narrow aisle guidance and support energy efficiency in the warehouse. The three stacker cranes installed by Aberle have double-deep telescopic forks with two drives as load handling attachments (LAM). With its drive and lift motors, each stacker crane achieves 31 double cycles, 80 storage and 100 retrieval operations per hour/stacker crane, 4,296 pallet movements per day in the HRL's minus 24 degree Celsius ambient temperature. "That still offers us some potential for further increases in throughput," explains Meyer-Ruhstrat.

Efficient material flow solution

330 tons of bread and baked goods are produced daily at the Lieken site in Lüdersdorf. With the new high-bay warehouse, the processes between production and dispatch are fully automated. The conveyor technology installed by Langhammer GmbH forms an important basis for this. Aberle's sister company is one of the market's leading suppliers of transport and palletizing systems as well as customized solutions. With the installed roller and chain conveyors as well as the turntables and lifting tables, Aberle designed an efficient material flow solution for Lieken that links the new HBW with production and the inventory warehouse.

The HBW has two incoming goods lines for storage - a transfer point from the old warehouse and a manual feed point at the cooling lock. For the fully automated handling of pallets from the existing warehouse, the pallets are guided to a pallet check on the new conveyor system. All storable pallets are scanned for the production label and received by the MFR, which then assigns the storage location and the corresponding transport order. "It directly addresses the PLC controls of the conveyor technology and ensures fast transportation to the high-bay warehouse," explains Aberle project manager Kölmel.

The processes in the HRL are monitored via webcam. Photo: Aberle

The pallets pass through a conveyor loop upstream of the HBW. It ensures redundant distribution and controls congestion-free infeed to the three storage slots of the high-bay warehouse. The retrievals from the high-bay warehouse are routed in parallel via the same loop. "The control system also automatically generates onward transports via the loop, for example," explains Kölmel. "In this way, priorities such as fast and direct retrievals can be realized."

For goods issue, the MFR calculates the transport times on the conveyor system. The SRMs retrieve the source pallets and transfer them to the conveyor loop in front of the high-bay warehouse. From there, the MFR controls the sequenced retrieval of the frozen pallets onto two buffer lanes. There, retrievals for goods issue are pre-buffered so that the picking stations for truck loading can be supplied continuously. "This ensures fast retrieval and loading processes and supports compliance with the cold chain," emphasizes Lieken Director Meyer-Ruhstrat.

"An efficient solution with an intelligent material flow concept and efficient storage and conveyor technology," summarizes Meyer-Ruhstrat. "The new deep-freeze HBW is an integral part of our intralogistics in Lüdersdorf. The holistic networking of the processes through the IT interfaces to the conveyor technology control system, the consistently automated flow of goods and the sequenced provision of outgoing goods through loops and pallet buffers have significantly increased efficiency and throughput at the site. We are highly satisfied with the results."

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