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de Man realizes two automatic buffer stores for Hettich: Two automatic small parts warehouses from de Man ensure that the Hettich company in Spenge has smooth warehouse processes. Initially, a buffer store for damping systems was built here, which was expanded to double its length after some time due to the increased production volume. This warehouse is stocked by a robot from the manufacturer Comau. As the next project, de Man realized a buffer warehouse for the assembly of running parts for Hettich, a newly created production area. The expansion with a robot and additional storage and retrieval processes are already under discussion here.
The Hettich company was founded in 1888 and is now one of the global furniture fitting manufacturers. More than 6,700 employees in almost 80 countries develop and produce intelligent technology for furniture. At the location in Spenge (North Rhine-Westphalia), damping systems and running parts for cabinet systems are stored in automatic storage systems by the automation specialist de Man Automation + Service from Borgholzhausen. The goals in the implementation of the automatic buffer store were to guarantee production security through inventory reserves, short replenishment times and unmanned KLT handling. Both storage systems are certainly not only used for the controlled storage and smooth production processes, but also for a uniform separation between the production and packaging area in the production hall.
Storage system 1: buffer storage for damping systems
This warehouse was realized as the first project and subsequently expanded with both a robot assembly and an extension to increase the storage area. It is used to compensate fluctuations between the production on the assembly lines and the needs in the customer-specific packaging. This includes both the setup processes when changing products, as well as the difference between production-optimized lot sizes and customer requirements. The warehouse takes over the provision of empty KLTs at the assembly systems, the palletizing / depalletizing system and a manual storage and retrieval location, as well as the storage of full KLTs from all the locations mentioned. The range of services also includes the provision of full KLTs at the packaging stations and the re-storage of these containers.
Since the expansion, the warehouse has been 40 meters long, 6.30 meters wide and 5 meters high. The damping systems are stored in two different types of small load carriers (KLTs), which differ in height and weight. Since the KLTs are also traded at the packing stations by employees, the maximum permissible weight when filled is 15 kilograms. For storage, the handling robot (Smart NJ40-2.5 from the manufacturer Comau) depallets KLT delivered on Euro pallets and places them on a storage roller conveyor. The gripper consists of four pneumatically swiveling gripper arms for safe handling of the containers. The position of the KLT is recognized by laser scanners. For safety reasons, the robot is inside a protective fence with a protective door. The driven single-storey roller conveyors convey the KLT to the storage and retrieval machine (RBG), which it stores in the assigned storage locations. The RBG travels along a rack within a closed protective housing. The upper part is guided by rollers on the guide rail. The pull-in and push-out device pulls the KLT from the roller conveyor via flat belts, pneumatic cylinders align it. The RBG now stores the KLT in a parking space assigned by the warehouse management computer.
Upon request for the removal of a KLT, the pull-in and push-out device pulls in the corresponding container from the parking space and transfers it to the roller conveyor to be removed. An employee removes the KLT, places it on one of the work tables and removes the required number of parts. After processing, the operator places the empty or partially filled container back on the roller conveyor and confirms the storage. Completely empty KLTs are conveyed out of the storage system and stacked on empty pallets by the robot for transport. The system includes 15 different motor-driven roller conveyors: six for discharging full KLTs, three for feeding full KLTs, two for feeding empty KLTs, two for returning full KLTs and one for returning empty KLTs. Containers that have been identified as "not in order" are removed from the system.
Storage system 2: buffer storage for running part assembly
The buffer store for the assembly of running parts extends over a length of approx. 22.1 meters, a width of approx. 4.44 meters and a height of approx. 5 meters. The warehouse includes 17 motorized roller conveyors. Two different sized Eurotec containers are stored here, which differ in height, volume and weight. These small load carriers (KLT) are fed to the storage and retrieval machine via the roller conveyors. This can transport two KLTs at the same time and, depending on requirements, store them in the storage spaces on the shelves or push them onto the roller conveyors for retrieval for delivery to the assembly systems. The RBG moves along a rack. At the top, it is guided by rollers on the guide rail. The retraction and extension device conveys the KLT from the roller conveyor or onto the roller conveyor via a toothed belt. The KLT is aligned by pneumatic cylinders and stored in a parking space assigned by the warehouse management computer. The RBG station is raised or lowered using lifting chains. The stroke position is monitored and corrected using a rope length sensor.
de Man MasterMind controls all processes
For both warehouses, the shelves and the driving areas of the RBGs are surrounded by a protective housing for safety and dust protection reasons, the area around the robot is secured by a protective fence. The system areas are accessed via a protective door. Before opening the protective door, the protective door register button on the control element must been pressed so that the system can run to the end of the cycle. The safety interlock with guard locking prevents the door from opening until the danger has passed. An emergency release allows trapped people to leave the cell.
The functions of the system controls are displayed on a touch panel and selected by the operator. The main view offers quick, simple and intuitive access to all functions via a schematic representation of the system. The core of the material flow system is the warehouse management computer (LVR). The server software of the de Man software product MasterMind runs on the LVR. The LVR is connected to the Hettich company network and maintains a connection to a database in which all relevant system data is stored. He is also a connection partner to SAP, from which transfer orders are transferred and to which confirmations are submitted. The LVR uses the data to generate transports for the RBG and conveyor technology. All KLTs are marked with a barcode on both long sides. Stationary scanners on the conveyor technology can clearly identify each container. The robot cell has its own operating PC, the surface of which also comes from the de Man MasterMind system family and blends in with the user-friendly look and feel of the warehouse management computer.