ECCC-47运用集约化规划在板坯厂优化物流及大型仓库之管理

Optimized Material Flow in Plate Plants by Integration of Scheduling and Warehouse ManagementAuthor(s) Name(s) and Affiliations(s)Ralf LoeperPSI Metals GmbHDircksenstraße 42-4410178 BerlinGermanyPhone – +49 (30) 2801-1833Fax –+49 (30) 2801-1020E-mail: rloeper@psi.deJörg HackmannPSI Metals GmbHHeinrichstrasse 83-8540239 DüsseldorfGermanyPhone – +49 (211) 60219-204Fax –+49 (211) 60219-240E-mail: jhackmann@psi.deIgor KuninPSI Metals GmbHDircksenstraße 42-4410178 BerlinGermanyPhone – +49 (30) 2801-1862Fax –+49 (30) 2801-1020E-mail: ikunin@psi.deMichael DiestelPSI Metals GmbHDircksenstraße 42-4410178 BerlinGermanyPhone – +49 (30) 2801-1806Fax –+49 (30) 2801-1020E-mail: mdiestel@psi.deContact dataRalf LoeperPSI Metals GmbHDircksenstraße 42-4410178 BerlinGermanyPhone – +49 (30) 2801-1833Fax –+49 (30) 2801-1020E-mail: rloeper@psi.deAbstractApplying a cross-functional integration of planning and scheduling with warehouse management in plate plants is crucial to win a competitive edge in today’s customer-driven market. Within a virtual factory model, scheduling details are translated into stacking instructions and transport orders. An integrated sys-tem of radar and laser technology implements the automatic tracking of the transport order execution. Ultimately, the resulting knowledge of the exact plate positions in the piles returns to scheduling in a closed loop for a further optimization. Leading European steel producers applying this approach achieve opti-mal capacity utilization, reduced costs and increased production throughput.In order to optimize the material flow between stor-age locations, staging locations and production units, several fundamental requirements are posed to a modern slab inventory management system. Firstly, the precise location of each piece of material must be known and tracked at all times. Secondly, the system must recognize and react to the stacking require-ments, not just with respect to physical limitations and safety-oriented rules, but also in consideration of any future material movements. The implementation of an integrated methodology of production manage-ment, utilizing the capability of the PSImetals Logis-tics solution in conjunction with the PSImetals Plan-ning solutions, has provided steel producers with a number of significant benefits:•increased utilization of the production units •shorter production times•less thickness jumps in the scheduling of furnace sequences•increased throughput in shipping •significantly decreased instances of “lost” material •reduced inventory with increased throughput •increased transparency of the inventory for opera-tor and end client•decreased demurrage charges Specific bench-marks include•20% increase in slab throughput that can be reached without any equipment or productionchanges, solely through implementation of thestorage and transport optimization strategies. •30% increase in throughput with new equipment, while reducing the slab yard capacity by 20% Keywords•Transport Optimization•Material Flow Optimization•Inventory Management•Warehouse Management•Capacity utilization•Troughput OptimizationIntroductionThe challenges facing heavy plate producers in to-day’s marketplace require rapid turnaround of orders and efficient handling of the material in order to meet the customer’s demands for delivery time and quality while maintaining a cost advantage in production. A major aspect of an overall efficient production proc-ess is the efficient handling of the material as it is moved between storage locations, staging locations and production units.The movement of slabs and plates must be tracked as they are transported by cranes, lifts, or other mechanisms, so that each piece’s position is known at any given time. Cranes and lifts will be equipped to identify their precise position. Other vehicles may or may not have such equipment, and will rely on the in-formation provided through the material identification, often confirmed by the operator. Material stacked in a vehicle by a crane, and then moved by that vehicle, is accurately tracked through its stack location.The stacking of plates provides more complexity than slabs. Plates have numerous different sizes, and are stacked in far larger numbers than slabs. The posi-tioning of plates on a stack is of-ten less precise, with plates of different sizes that can overlap or be dou-bled up side-by-side. Furthermore, plates are often transported offset with respect to the crane’s center position, depending on the activated magnets. The system must recognize these conditions, and also al-low adjustments by the crane operator, in order to maintain an exact record of the plate locations.Figure 1: Rules for plate stackingIn contrast to most coil yards, where fixed positions identify the only coil storage locations, plates and slabs can relatively easily be deposited in locations outside of the normal, marked storage positions. When production events require such a temporary ad hoc storage location, the system must create the lo-cation dynamically, record its exact position, and also remove it again once the stack has been emptied. Material Positioning and TrackingBased on these requirements, the PSImetals Logis-tics solution is built around a structure of halls or yards which are subdivided into logical areas based on functionality. For example, areas can be desig-nated for long-term storage, production line staging, rework, loading, shipping, transport to annealing or painting, etc. Each of these areas (fields in Logistics) are then optionally divided into rows and spaces. Each space has a specific location, dimension and orientation. This structure provides the basis for the processes of destination finding and route finding, which lie at the core of warehouse and transportation management.The detailed subdivision of the storage yard into many fields allows for a rule-based optimization of storage destination for materials, which can respect and balance the various specifications of a material in order to find an optimal location. This provides a good pre-sorting of materials, so that it can be re-trieved easier. If in addition the planned sequence of utilization of the material is avail-able, such as from the PSImetals scheduling module, the material can be stored in a pre-sorted order in preparation for processing. This allows quick access to the material when the production commences, without excessive restacking operations.PSImetals maintains all data objects necessary for production and inventory management in a central database called the Factory Model. The communica-tion of information between inventory management, transportation systems, and scheduling applications is implemented by providing this single data reposi-tory for all relevant information, including material data, production data, yard layout, scheduling data, and transport orders.The fundamental basis of the material location track-ing is the crane positioning system. Standard locator systems utilizing distance measurements with lasers are increasingly being replaced by systems using a new implementation of radar technology. The position of the crane is determined via appropriate transpond-ers and antennas, providing a contact-free and robust solution. Simple attachment of the few required pieces of equipment, low maintenance, and high pre-cision are hallmarks of the LPR (local positioning ra-dar) solution developed by Symeo. Even in dirty envi-ronments or under poor visibility the LPR technology provides a reliable solution. With precise information of the crane’s position, and appropriate information of the relative position of the crane’s load, the position of the carried material is identified. Additional infor-mation, such as which magnets are active, or per-haps a crane operator’s correction, serve to further pinpoint the exact material location.Figure 2: Local positioning radar technology by SymeoCranes position can be followed by PSImetals very easily along the entirety of their tracks using the LPR technology, whether they are in a covered or open hall, since the area can be optimally illuminated bythe radar transponders. In the case of other vehicles,for examples Kress carriers, the tracking is more complicated. On the one hand they move in areas where the radar transponders provide a well-defined coverage. On the other hand, they often leave these areas in order to transport the slabs or plates to more distant locations. As they move, they are automati-cally passed from one LPR area to another, and if coverage should not be given in an area, then their position is determined via GPS. PSImetals receives the position data from the LPR system irrespective of the technological source. Symeo ensures a seamless transition between LPR and GPS positioning. In the case where neither technology is available, PSImet-als can provide operators with the capability to an-nounce the arrival and departure of transport vehicles at specific locations. Thus, PSImetals knows at all times where each means of transport is located, and can allocate loading and unloading instructions ac-cording to the transport orders for the material. Material Transport OrdersTransport orders specify which material is to be transported, its source and destination. Transport or-ders are generated either automatically, or, if neces-sary, may be manually entered. Automatically gener-ated transport orders can be triggered by the comple-tion of production processes (supply and relief of production lines), by messages from attached trans-port systems (transport means has arrived at a cer-tain position, plate has reached a certain pickup point, etc), or by execution of a schedule released from the PSImetals sequencing module. Material pieces may be transported individually, or they may be combined into combined transports. Materials are selected for combined transports so that the number of transport movements by the transport means (usually crane) is minimized.The destination of transport orders is determined by the integrated destination finding algorithm. This al-gorithm is based on a set of rules which can easily be configured by the user. In the case of material being put away, the specification of any number of different restrictions and selection criteria identifies for each piece of material an optimal storage location. The consideration of future use of the material, in particu-lar scheduled production, can provide one of the most important selection criteria. Another considera-tion is that material is not placed on top of stacks where another item is already planned to be moved. Once a destination has been identified, the route find-ing algorithm takes over, and determines the best path to reach it. Multiple legs of the journey may be required, utilizing several different means of transport, in order to reach the final destination. If multiple paths are possible, the best path is determined. Some paths may also become temporarily blocked, perhaps due to an equipment breakdown, so that PSImetals has to adapt and find another route. For a crane transport, where multiple cranes on the same track may be available, the system may identify to which crane to allocate the transport, or it may be left to the operators to confirm.Figure 3: Multiple routes and multiple legs for trans-portsIn case of semi-automatic or manual operation, the operators of the means of transport, be they cranesor other vehicles, generally have a touch screen ter-minal in their cabin which shows the transport orders currently available to them. The proper sequence is given by priorities assigned due to configurable rules or based on production priorities, as well as physical considerations, such as stacking. The crane operator activates the selected transport order and is guidedto the source of the material. A graphical display of the material stack, the source and destination, and the crane location aids the operator in positioning, which is particularly helpful in the case of stack at ad hoc locations. Automatic load detection serves to check that the correct material has been picked up. The operator then moves to the destination location and drops off the piece. PSImetals automatically reg-isters the position and the transport completion. Graphical information identifies the stack contents at the location, as well as the contents of the crane load, with ergonomic touch screen controls for the operator to confirm transport orders, loading, and unloading.Of course, PSImetals can also incorporate fully automatic cranes, providing crane instruction and completing transport orders as the crane executes them.Integrated SchedulingWhen PSImetals plans a schedule, the material in-ventory is analyzed based on different criteria in or-der to arrive at an optimal distribution and sequence. One such consideration can be the location of the material as managed in PSImetals Logistics. If the staging yard for the production to be planned was al-ready organized in an optimal manner by PSImetals Logistics, for instance by grouping of material specifi-cations, then the sequencing algorithms building the schedule can utilize this as basis. The sequence is then built and optimized so as to minimize restacking operations, and provide the material to the production line in the correct sequence.Conversely, based on the information provided by Scheduling, predictive and preparatory transport de-cisions can be made by the system. Utilizing an opti-mization model created in conjunction with the Tech-nical University of Berlin, which provides solutions analogous to the decision process of a chess com-puter, the system will generate combinations of transport orders that are far more efficient than the decisions based on gut feeling and experience com-mon on the shop floor.Figure 4: Process flow to optimize transports based on the integration of planning and logisticsAnother possibility is the creation of a pre-sorting set of transport orders, which is executed at some point before the production sequence commences, at a time when there is a low transport volume. The pro-duction sequence can then be executed without transport delays. An example of this is the pre-sorting and staging possible for the loading of trucks or rail-cars, minimizing the wait time for these vehicles, and avoiding demurrage charges.A further opportunity can be found in the inclusion of transportation requirements in planning as a produc-tion process, for instance to move material between two halls in order to reach the next appropriate pro-duction facility. The execution of the transports is re-ported back to planning, and can be used to tune the production schedule during operations as necessary. ConclusionThe implementation of an integrated methodology of production management, utilizing the capability of the PSImetals Logistics warehouse and transport man-agement solution in conjunction with the PSImetals planning and scheduling solutions, has provided heavy plate manufacturers with a number of signifi-cant benefits:•increased utilization of the production units •shorter production times •less thickness jumps in the scheduling of furnace sequences•increased throughput in shipping •significantly decreased instances of “lost” mate-rial•reduced inventory with increased throughput •increased transparency of the inventory for op-erator and end client•decreased demurrage chargesSpecific benchmarks include:20% increase in plate throughput that can be reached without any equipment or production changes, solely through implementation of the storage and transport optimization strategies.30% increase in throughput with new equipment, while reducing the slab yard capacity by 20% AbbreviationsAbbrevation ExplanationLPR local positioning radarGPS Global Positioning System References[1] Henning, H.; Hackmann, J.; Diestel, M.; Kunin, I.: Optimized Material Flow in Plate Plants by Integration of Scheduling and Warehouse Management; AISTech 2010, Iron & Steel Technology Conference and Exposition, Pittsburgh, PA。