Successful conversion of the long goods warehouse at Günther+Schramm, a systems service provider for steel and aluminium with its main warehouse in Königsbronn, eastern Württemberg: Including the modernization of the high-bay warehouse by Kasto, it took just four weeks. Now everything is running like clockwork again.
The company's approximately 180 employees supply all of southern Germany and neighboring countries with around 60,000 tons of metals and plastics annually. Besides product quality, on-time delivery is particularly important. A prerequisite for this is a smoothly functioning warehouse.
“And that’s precisely where we increasingly reached our limits”recalls Michael Sticke. He is the deputy operations manager at Günther+Schramm (G+S) in Königsbronn and thus also responsible for the high-bay warehouse. After around 30 years of operation, the mechanics regularly caused problems, and downtime became more frequent. “That was a prime example of the bathtub curve”says Sticke. Such a diagram vividly illustrates the typical lifespan of equipment: In the first phase, the failure rate steadily decreases, followed by a long period without incident. Finally, aging and wear cause increasingly frequent failures, and the curve rises sharply. “Procuring spare parts after such a long period of operation was very difficult. There was always the risk that we would have to wait one or two weeks for a new component and would be unable to serve our customers during that time.”
The decision was therefore made: The existing SNLS 5000/7100 S long goods storage system, the predecessor of the Unitop, had to be modernized. This high-bay warehouse has a payload capacity of 5000 kg per cassette and a storage length of 7100 mm. "We are very satisfied with the technology and, in addition to the warehouse, also use various sawing solutions such as the variospeed C 15 with the KASTOsort robotic handling system. It was therefore clear to us that we would tackle the extended retrofit together with Kasto"emphasizes Sticke. And one more thing was essential: It had to be done quickly, because without a functioning long goods storage system, G+S cannot deliver.
During the modernization, G+S and Kasto pulled out all the stops – only the steel structure and cassettes remained; everything else had to go. "We replaced the storage and retrieval machine, the undercarriage, and two four-station carousel stations"explains Alfred Schwörer, Sales and Retrofit Project Manager at Kasto. "Of course, we also brought the safety and control technology up to the latest standards – that was absolutely essential."
Everything else had to go
The challenge: The complete modernization had to be finished in four weeks. "That was really ambitious"confirms Schwörer, "but we managed it." With a detailed schedule, they got to work and received strong support from the G+S employees. It started with opening the roof of the high-bay warehouse to lift the old storage and retrieval machine out of the building with a crane. Carpenters had already installed a platform directly under the warehouse roof beforehand to ensure the safety of the employees working at such heights. With up to seven of their own employees, the systems and the control and safety technology were then modernized.
The centerpiece of the retrofit is the new overhead crane-style storage and retrieval machine with chassis, hoist, and load beam. The rolling bearings are permanently lubricated. Thanks to the frequency-controlled three-phase drive, the machine can be positioned precisely via power transmission using pre-stretched and individually selected precision roller chains. An energy chain provides reliable and wear-free power. The system allows for quick access to the cassettes. "The design is geared towards process reliability – exactly what we need to ensure we can deliver at any time"explains Sticke.
The coupling of the intermediate drive circuit of all motion axes, including the hoist drive, enables energy exchange within the system. Excess current, generated, for example, during braking, can be used to operate other axes. The entire drive system, including the hoist, feeds excess energy back into the customer's grid. "This creates an efficient and sustainable solution that conserves resources"says Schwörer.
The new undercarriage has two positions on roller platforms. The moving cassette principle optimizes the number of travel movements, as storage and retrieval operations occur simultaneously. The rolling bearings are lubricated for life, just like those of the stacker crane. A servo inverter continuously controls the drives, and an electronic synchronization function minimizes positional deviations between the two drives.
The modernized warehouse also includes two custom-designed carousel stations with undercarriage trolleys for storing and retrieving cassettes. The stations consist of a 2 x 9 m long roller frame located outside the racking system.
