5 years ago

f+h Intralogistics 5/2014

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f+h Intralogistics 5/2014

Cranes and hoists Demag

Cranes and hoists Demag process crane increases efficiency of plasma cutting system The installation of a fully automated plate metal processing facility has enabled a Chinese manufacturer of mining equipment to increase productivity in production and to achieve a significant improvement in quality. The central part of the installation is a Demag process crane system, which provides for the precise storage and retrieval of plate metal as required in 24/7 operation. Thanks to the automated logistics, a reliable flow of material and the continuous utilisation of six flame cutting tables are ensured within the installation. The Chinese mining industry is booming and there are capable plant engineering companies that cover the entire range of mining equipment. One of them is the Zhengzhou Coal Mining Machinery Group, which was established in 1958. It is one of the market leaders both for stationary equipment for roof and long-wall support as well as for mobile machinery that operates in mines. The company traditionally utilises a high level of vertical integration and processes large quantities of steel in high quality grades. At the plant in Zhengzhou, the capital of Henan province, a production line with plasma cutting machines has entered service. The cutting system for this pilot installation stems from the MicroStep Group, which supplied a fully automated processing system in co-operation with Terex Material Handling. The centerpiece of the installation is provided by the logistics function, which features a Demag process crane system. This is used to supply and remove the metal plates and to serve the flame cutting tables in 24/7 operation (Image 01). The Demag warehouse management system has configurable strategies that are used to link the installation with the upstream and downstream steps in production, to control the entire batch process and, therefore, to ensure that the machinery is utilised continuously. Fully automated plasma cutting of metal plates An enclosed area measuring 120 × 18 m has been created in the spacious production facility for the storage and processing of metal plates which measure up to 12,600 mm long and 40 mm thick. The material is initially fed into this zone via a rail-mounted transverse transporter. The process crane, which is equipped with a magnet spreader (Image 02), picks up the metal plates at a defined transfer point and transports them to one of two buffer zones, which are assigned to each of the six flame cutting tables. From here, they are fed – also by crane – to the high-performance plasma cutters for processing. To optimise its travel motions, the automatic crane also deposits the metal plate to be processed direct at a free position of a flame cutting machine. The process crane, which has a span of 16.5 m, travels at a height of 12.6 m along a crane runway that measures 120 m in length. Fitted with two multi-purpose winch units, it has a load capacity of nine tons. High operating speeds ensure that the material is supplied to the individual flame cutting tables as required. Thanks to the additionally integrated load sway damping system and as the spreader is moved to the highest lifting position, fast travel speeds can be achieved. The crane travels at speeds of up to 120 m/min and the crab at up to 70 m/min. Precise crane positioning Maximum precision is required for reliable handling of the metal plates. The automatic crane is equipped with a barcode positionmonitoring system in the long-travel direction and a laser measuring system in the cross-travel direction. The demanding requirements in terms of positioning accuracy are additionally satisfied by measurement of the height co-ordinates by 36 f+h Intralogistics 5/2014

Cranes and hoists 01 The logistics function provided by the process crane ensures that the six flamecutting machines operate 24/7 02 The Demag process crane is equipped with a magnet spreader to transport the metal plates and to pick up the flame-cut material means of a rotary encoder installed on the hoist gearbox. The crane receives travel commands from the Demag warehouse management system, which is integrated into the higher-level control system. From this system, the warehouse management system first receives information scanned via barcode on the metal plates to be fed into the automatic system. The target co-ordinates are then determined, and afterwards optimised travel About Terex Material Handling paths are specified for control of the process crane. When the cutting operation has been completed, the crane automatically positions above the table, picks up the entire cut material and then transports it to a conveyor belt. The metal plates are then conveyed out of the automatic zone and transported to the next step in the process. The good and the waste parts are separated by hand. The workers are assisted at this stage by handling equipment with magnets, which can be easily positioned via a crane installation from the Demag KBK modular light crane system. Complex system solution Terex Material Handling and MicroStep, as the manufacturer of the plasma cutting equipment, entered new territory when the installation was being planned. The challenges included synchronisation of the operating processes between the cutting systems and the process crane. For this purpose, the Demag warehouse management system and the crane control system were integrated into the customer’s overall system and connected to his host computer, which enabled a complete IT solution to be created for storage, conveying, handling and processing of the metal plates. Whereas the individual orders including the calculated processing times are managed by the customer’s host computer, the warehouse management system is responsible for controlling the entire logistics including assignment of the machinery. In this role, the Warehouse Management System co-ordinate Terex MHPS is one of the world’s leading suppliers of crane technology with Demag industrial cranes and crane components. The core competence of the Terex Material Handling business group lies in the development, design and production of technically sophisticated cranes, hoists and components and the provision of services for these products. The business group manufactures in 19 countries on five continents and is present in more than 60 countries, reaching customers in more than 100 countries. the storage of the raw material, deliveries to the machinery and further the transport of the processed material with the aim of ensuring uniform utilisation of the individual cutting tables and minimising any downtimes. In this way, the crane control system plays a key role in the production process. Processing capacity increased by 40 % The gains in productivity and quality were major factors that influenced the decision to invest in a fully automated processing line. Every day, up to 155 metal plates can be processed in three-shift operation. Every cutting operation now only takes one to two hours, compared with the four to eight hours previously. The installation of this system has helped to achieve a production output of up to 12,000 tons – and the plant has been able to boost its processing capacity for metal plates by 40 percent to 28,000 tons per month. In addition, the optimised software makes it possible to utilise the existing material even better, so that less material needs to be melted down. The company not only benefits from a better organised flow of material, but also from improved safety at the workplace: a dedicated access concept prevents any personnel from entering the individual processing areas when they are automatically approached by the crane. When routine maintenance work is performed on one of the flame cutting systems, the automatic crane by-passes the danger zone in order to protect the personnel. Lutz Dowy, Vice President Global Product Management & Process Cranes at Terex Material Handling, explains: “Based on our experience with fully automated stores, also for the steel industry, we have now taken the next step towards production. The automated solution implemented in cooperation with MicroStep certainly paves the way for other manufacturing sectors.” Photos: Terex Material Handling f+h Intralogistics 5/2014 37