Demag pilot project for efficient sheet metal working
The installation of a fully automated plate metal processing facility has enabled a Chinese manufacturer of mining equipment to increase productivity in its production facility by 40%. Demag process crane engineering in the pilot installation provides for the precise storage and retrieval of plate metal and serves the cutters as required in 24/7 operation.
The Chinese mining industry is booming and, therefore, so is the mining equipment sector. The Zhengzhou Coal Mining Machinery Group 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. At its plant in Zhengzhou, the capital of Henan province, the company has commissioned a production line with plasma cutting machines including a material flow system. The cutting system stems from the MicroStep Group, which supplied a fully automated sheet and plate processing system in co-operation with Terex Material Handling. The heart of the installation is provided by the logistics system, which features a Demag process crane and a Demag warehouse management system (WMS). They are used to supply and remove the metal plates and to serve the flame cutting tables around the clock.
Every day, the new installation can process up to 155 metal plates in three-shift operation, since the cutting operation for each machine now only takes one to two hours, compared with the four to eight hours previously. The intralogistics system implemented for this solution also ensures that the machinery is utilised to a consistently high level. The impressive result of this pilot installation: production in the entire plant has been increased by 40% for a monthly machine output of 12,000 t.
WMS performs key function
Terex Material Handling and MicroStep entered new territory when the installation was being planned, as the plasma cutting equipment and process crane had to be synchronised with each other. For this purpose, the Demag WMS together with the crane control system was integrated into the customer’s IT system and linked to his host computer. Whereas the individual orders including the calculated processing times are managed by the host computer, the WMS is responsible for controlling the entire logistics including assignment of the machinery. In this role, the WMS co-ordinates storage of the raw material, deliveries to the machinery and further transport of the processed material with the aim of achieving uniform utilisation of the individual cutting tables and minimising any downtimes.
High performance and precision
An area measuring 120 x 18 m was fenced off within the production facility for the storage and processing of metal plates, which measure up to 12.6 m long and 40 mm thick. The material is fed into this zone via a rail-mounted transverse transporter. The process crane, which is equipped with a magnet spreader, picks up the metal plates at the transfer point and transports them either direct to a vacant machine position or to one of two buffer zones, which are assigned to each of the eight flame cutting tables.
The process crane travels at a height of 12.6 m along a crane runway that measures 120 m in length. Fitted with two Demag multi-purpose winch units, it has a load capacity of more than 9 t. Thanks to the additionally integrated load sway damping system and since the spreader can be moved to the highest lifting position, the crane can reach long-travel speeds of up to 120 m/min, the crab can achieve cross-travel speeds of up to 70 m/min. In addition to a barcode position-monitoring system in the long-travel direction and a laser measuring system in the cross-travel direction, the height co-ordinates are also detected at the hoist gearbox for maximum precision.
When the cutting operation has been completed, the crane picks up the entire cut material and 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, where they are sorted 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.
The customer that invested in this pilot installation 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.
Paving the way also for other industries
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 co-operation with MicroStep is a milestone and certainly paves the way for other manufacturing sectors.”