The cost-efficiency of a high-performance AS/RS crane is not only demonstrated by its speed, payload or low power consumption. The additional benefit for the user lies in the intelligent networking of all control, mechanical, and functional features, which are clearly determined in practical use and are ultimately decisive for availability and life span. The entire design, implementation, service and system operator know-how of the general contractor WITRON has been incorporated into the development of mechanical and control technology for the latest stacker crane generation. The standardized vehicle convinces logistics experts worldwide in highly dynamic distribution centers for groceries, E-Commerce and other distribution channels, and is suitable for both normal ambient temperatures as well as in fresh and frozen food areas - designed for continuous operation 365 days a year, 7 days a week, 24 hours a day.
“We always have a holistic mindset concerning our technical developments”, says Martin Stich, Technical CEO at WITRON. "In terms of our conveyor element, this means that all features and components are seen as one single unit. The goal is to integrate this unit into the logistics ecosystem of a forward-looking supply chain with maximum efficiency”.
High dynamics - High flexibility
With a conveying speed of over 6 m/s, an acceleration of more than 4 m/s2 and a lifting speed of 3 m/s, the WITRON cranes can transport totes and trays as well as corrugated boxes with a payload of 200 kilograms per cycle. Since there are two highly dynamic and innovative loading device units per vehicle it is possible to move up to eight transport units at the same time during storage and retrieval processes that happen parallel. The result: maximized storage and retrieval performance. Within WITRON's already realized high-performance systems, each device moves up to 600 transport units per hour. In practice, however, this performance density can only be achieved because an intelligent and sophisticated software optimizes the driving cycles accordingly and the availability of involved devices is correspondingly high.
When implementing complete systems, WITRON always puts the customers, who always expect a reliable and highly available system, first. That is why WITRON always takes care to keep the optimized balance between new and proven technology and still incorporates new ideas and concepts both in new developments and in evolutionary stages. One example is the aluminum mast, which provides optimum driving and vibration behavior in all temperature ranges as a lightweight mast made of one piece with maximum stability and corresponding "flexibility". The working knowledge used for the aluminum mast lies in the static structure of the mast itself in order to achieve the best possible vibration characteristics with the lowest possible weight. Other concepts such as lattice masts or GRP materials involve risks as they can be too stiff or too elastic, do not have the same properties in different temperature zones or, for example, are only held together by screw and clamp connections in the case of lattice masts. The proven one-piece aluminum mast still offers the optimum static characteristics in terms of life span, reliability and driving behavior. "When new concepts and materials offer only distinct advantages, but are not yet convincing across the board, it makes no sense for us to implement them”, explains Martin Stich.
For WITRON, the crane is primarily only one highly dynamic element in an overall logistics solution. The decisive factor for the concept, however, is to combine the elements in a reasonable way. "For our solutions, for example, it is much more economical in terms of performance and storage capacity to place two cranes with ten meters on top of each other instead of building devices that are over 20 m high”, according to Martin Stich.
New innovative computer and control technologies in accordance with the standard Smart Logistics 4.0, combined with a future-oriented and web-based operator and visualization concept ensure high efficiency in system operation, high availability and fast, transparent service in daily operation. "In this area, we can again take advantage of our 46 years of experience in the realization of crane concepts”, adds Martin Stich.
Low energy consumption - Feedback into the power supply network
The WITRON devices are also innovative in terms of energy management. A minimum power consumption could be achieved by means of constant development of proven concepts with regenerative modules, which have successfully worked for many years without wear. The WITRON control logic, developed over several years, links all drives so that the respective units can operate energy-optimized in direct relation to the other units without affecting the throughput performance. Even the latest positioning control systems available on the market cannot meet this requirement, since all relevant information is available exclusively in the PLC.
"Real measured values prove, for example, that the average consumption of a tote crane at full load reaches minimum energy values”, according to Martin Stich. The surplus braking energy, which cannot be used directly on the crane, is returned directly to the grid via the regenerative modules and immediately reused by other elements within the logistics system. As a result, no energy is wasted unnecessarily or additional effort must be taken for temporary storage. In terms of power consumption and energy efficiency, WITRON considers energy recovery, which has been in successful use for many years and is constantly being further developed, as a clear advantage. Other systems, e.g. concepts of decentralized energy storage with PowerCaps, which are currently being discussed on the market, must first prove themselves in terms of technology, life span, availability, operating costs, weight, temperature independence, etc. in continuous operation compared to the wear-free regenerative module.
Outstanding production quality - Perfectly timed maintenance cycles
The holistic development approach of WITRON is not a coincidence. "Since WITRON designs, manufactures and implements the automated systems of its customers itself, and since its own OnSite service team guarantees permanently high system availability directly on site, these returns are reflected in the product quality of the conveyor system components. By doing so, we benefit from an invaluable increase in experience with each individual project", Martin Stich is certain. Proactive maintenance processes, based on production data acquisition and in connection with WITOOL, a self-developed web-based service management tool, would stand for a long life span, flexibility and cost-efficiency of the WITRON systems. "This ensures the success of our customers and makes WITRON a reliable partner". Especially this customer focus and the permanent "close ear to the market" ensure a continuous improvement process, which ultimately results in developments that meet the highest demands.