The logistics module, a fully automated single-aisle high-bay warehouse, acts as a production buffer between machining and hardening processes. Built from 70 tons of steel, it features two 9 m-high racks spanning 76 m and provides 2,300 storage locations. Two automated stacker cranes transport hardening racks between production, furnaces and storage. With a total conveying distance of 152 m, each crane handles loads of up to 510 kg per rack.
A clear run for mobile robots
As a specialist in automated storage systems, SIVAplan implemented the logistics module and higher-level control system as general contractor together with PROCAM Steuerungstechnik GmbH. The system coordinates machines, vehicles and warehouse processes while interfacing with the SAP ERP system, helping ensure efficient, autonomous production. A key element is Leuze sensor technology. “SIVAplan’s solutions and Leuze’s sensor expertise complement each other perfectly,” says Christian Langsdorf. The long-standing partnership is based on confidence in the reliability and quality of Leuze products, which help ensure safe and efficient rack loading and unloading.
This starts when SEW-EURODRIVE mobile robots automatically transport finished components to the high-bay warehouse. Guided by the master controller, the robots access the system through material transfer stations secured by two Leuze RSL 400 safety laser scanners. The scanners generate a vertical protective field that opens only after successful robot identification and closes again once the vehicle has passed. After picking up materials from production, the robots transport and transfer them via four storage and retrieval bays. The integrated PROFIsafe/PROFINET interface enables straightforward integration of the RSL 400 into the safety control system.
In-process contour check
After AGV transfer, racks are conveyed to a contour inspection station. Leuze HT25C diffuse sensors detect the racks and control conveyor movements. CML 720i measuring light curtains capture outer contours during passage and transmit inspection data via PROFINET. Additional Leuze sensors monitor rack presence and control the light curtains. A practical feature is the sensors’ ability to ignore high-visibility clothing, preventing false detections caused by personnel near the transfer stations. Industrial Leuze IP cameras mounted beside and above the inspection area provide additional rack images.
Safe loading and unloading
Each transfer station includes a manual workstation for rack unloading and inspection. MLC 530-SPG safety light curtains ensure safe loading and unloading while reducing space requirements through patented sensorless Smart Process Gating (SPG). The gating function is activated via a PLC signal and interruption of the protective field by transported goods, eliminating the need for additional muting sensors. The compact type 4 light curtains meet EN IEC 61496 requirements and achieve PL e and SIL 3 safety levels. Because racks are repeatedly exposed to extreme furnace temperatures, they can deform over time. For this reason, racks are automatically routed to the workstation for remeasurement after a defined number of furnace cycles.
Reliable routing via barcode
After the goods destined for the hardening shop have been measured, one of the stacker cranes picks up the rack. Here, too, precise processes are essential to ensure that the goods reach their designated storage location safely and reliably. The stacker cranes are therefore positioned using Leuze FBPS 600i safety barcode positioning systems, which ensure safeguarded velocity monitoring in conjunction with the latest generation of MOVI-C® inverters from SEW-EURODRIVE. The FBPS 600i enable safe position detection. The stacker cranes’ position and velocity are continuously monitored based on the system status. This is particularly important because the two stacker cranes operate on the same rail. Accurate position detection is also required to reliably safeguard two pedestrian walkways in the high-bay warehouse. To do this, the system switches the travel range’s safety envelopes. If people cross the aisle, the stacker cranes are “held” in defined segments and monitored to allow a safe crossing.
The 600i safety bar code positioning system only requires one sensor for safe position detection. This greatly simplifies integration and makes the system much easier to set up. Two FBPS 600i are installed on each stacker crane: One for positioning the lifting axis and the other for the travel axis. The FBPS 600i safety barcode positioning systems can be used flexibly thanks to their reading distances of 50 to 170 millimeters from the bar code tape. Multiple codes are read with each scan; these are processed redundantly internally and then again with millimeter precision in the SEW inverter’s safe connection unit via the dual SSI interface. “The scanning beam is intentionally positioned at an angle. The device’s movement along this angled path ensures each code is scanned at different points. This prevents reading errors caused by local dirt or damage,” says Oliver Gortner, Key Account Manager Intralogistics at Leuze. This solution is compact and spacesaving and allows the stacker cranes to be positioned precisely and safely in accordance with Performance Level e / SIL 3. In addition, the extremely short error response time of just 10 milliseconds allows short braking distances and, consequently, faster speeds. In this way, the FBPS 600i plays a decisive role in maximizing the high-bay warehouse’s performance – with minimal installation effort and a high level of safety.
Camera-based precision compartment placement
Leuze sensors also support the stacker cranes and storage areas. Diffuse sensors detect rack presence, while barcode positioning guides the stacker crane to the correct storage location. For precise compartment positioning, each crane is equipped with a Leuze IPS 200i camera-based sensor with integrated PROFINET interface. The compact sensor focuses on a reflector mounted on the shelf support and transmits absolute position values to the SEW controller. This enables accurate rack placement in the designated compartment while eliminating the need for multiple diffuse sensors.
Summary
With the fully automated high-bay warehouse, SIVAplan has implemented a highly advanced logistics system that integrates seamlessly into SEW-EURODRIVE’s production processes in Graben-Neudorf. Leuze sensor technology is used throughout the system to ensure safe, reliable and automated operation. It secures material transfers, detects and measures racks, and enables precise stacker crane positioning. The resulting production buffer warehouse supports flexible production, absorbs peak loads and can be expanded easily thanks to its modular design.
