TheWarehouseDesignandControlProblem

1、The Warehouse Design and Control ProblemBased on Rouwenhorst et. al.,EJOR, Vol. 122, pgs 515-533, 2000Yoon, C. S. and Sharp, G., IIE Trans., Vol. 28, pgs 379-389, 19961Topics already coveredThe roles of the Warehouse in contemporary distribution networksBufferConsolidationValue Adding ProcessingWare

2、house classification based on Customer typesFactory WarehouseRetail Distribution WarehouseCatalog RetailerSupport to Manufacturing operations2Topics already covered (cont.) Warehouses processes and the associated material flowReceivingShippingReserve StorageandPallet PickingCasePickingBrokenCasePick

3、ingAccumulation, Sortation & PackingCross-dockingDirectputawayto reserveDirectputawayto primaryReplenishmentReplenishment3Topics already covered (cont.)Major warehouse equipment, its functionality, and justificationContainers & Unitizing EquipmentStorage and Retrieval EquipmentUnit LoadSmall LoadCon

4、veyorsWarehouse docks and dock-related equipmentAutomatic Identification and Communication Equipment4Major decisions underlying the Warehouse deployment and operationsConfiguration issuesOrganization of the material flowUnit LoadsEstablishment of a forward areaitems to be included in the forward are

5、asizing of the forward areaZoning, Time Windows and Pick WavesEquipment selection and its sizingstorage modesorder picking and material handling equipmentWarehouse management system and automatic identification and communication equipmentLayout: Allocation of Storage CapacityPersonnel skills and siz

6、ing5Major decisions underlying the Warehouse deployment and operationsPoliciesReceiving policiesAssigning trucks to docksStorage policiesAssigning received material to storage locationsReplenishment policiesOrder processing policiesorder batching policieszoning policiespicker routingSortation and co

7、nsolidation policiesShipping policies6Decision / Performance CriteriaResponsivenessQualityCostInvestment +OperationalSpace/Equipment/LaborProduct qualityOrder accuracyOrder flow timethroughputfill ratevolume flexibility/storage capacitymix flexibility= Multi-criteria Optimization Problem!7Warehouse

8、types/missions and Competitive StrategiesFactory warehouse: Interfaces production with wholesalerssmall number of large orders dailyadvance info about order composition= focus on cost and order accuracy(responsiveness depends heavily on production schedules)Retail Distribution warehouse: Serves a nu

9、mber of captive retail unitsadvance info about order compositioncarton and item picking from a forward areamore orders per shift than consolidation/shipping lanes= focus on cost, accuracy and fill rate(responsiveness depends heavily on truck routing schedules)Remark: If the retail units are not capt

10、ive, then responsiveness becomes a crucial issue!8Warehouse types/missions and Competitive StrategiesCatalog Retailer: A warehouse filling orders from catalog salesa large number of small (frequently single-line) ordersitem and, sometimes, carton pickingdaily composition of orders usually unknownonl

11、y statistical information available= focus on cost and response timeSupport of Manufacturing operations: A stock room providing raw material and/or work-in-process to manufacturing operationsmany small ordersonly statistical information available about order compositionstringent time requirements (e

12、.g., response in 30 min)= focus on response time but also accuracy and cost9Yoon & Sharps design procedureMANAGERIAL CONSIDERATIONSPRODUCT DATAORDER DATADATA ANALYSISDATA ANALYSISSPECIFICATION OF ORDERPICK SYSTEM STRUCTURESPECIFICATION OF EQUIPMENTSPECIFICATIONOP. STRATEGIESMATERIALFLOWINFORMATIONFL

13、OWSUBSYSTEMISUBSYSTEMIISUBSYSTEMNSUBSYSTEM RECONCILIATIONEVALUATION & SELECTIONOVERALL PERFORMANCE ANALYSISINPUTSTAGESELECTIONSTAGEEVALUATIONSTAGE10Defining Department and Subsystem structureDepartment ADepartment BSubsystem A1Subsystem A2Subsystem AnSubsystem B1Subsystem B2Subsystem BnTransport Equ

14、ipment 1Transport Equipment 2Transport Equipment kStorage structure (e.g., Gravity Flow Rack)TransferDeviceStorageEquipmentRetrievalEquipment(e.g., pick to light)Transfer DeviceTransportEquipment(e.g., forklift)TransportEquipment(e.g., BeltConveyor)11Determining the basic system structureProduct dat

15、a:Activity levelrequested quantitiesproduct propertiesvendor typesOrder data:number of line itemsnumber of itemscubic volumeshipping prioritiesproduct correlationManagerial requirements /company strategy Definition of major functional areas / departments Definition of departmental sub-systems Storag

16、e and material handling modes Operational policies storage policies replenishment policies order picking policies batching sorting zoning routing receiving & shipping policies12Warehouse Activity Profiling(c.f. Bartholdi & Hackman, Chpt. 10)The careful measurement and statistical analysis of the war

17、ehouse activity.The process of understanding the customer orders that drive the systemSifting through historical data for opportunities and insights that might confer advantage.WAPSKU dataOrder dataLocationdataSummary statisticsDistributions “Structural” Characterizations, e.g., prevailing patterns/

18、trends relations dominant elements13Addressing the problem complexity:Hierarchical DecompositionStrategic-level decisions: they have the longer-lasting impact on the operation of the warehouse, and involve major investmentprocess flow designequipment selectionTactical-level decisions: medium-term de

19、cisions which might still involve significant investmentsizing of the facility areas and its equipmentStorage layoutresolution of organizational issues like the storage and replenishment schemes, and batch sizingOperational-level decisions: Decisions and policies related to the real-time operation o

20、f the facilityassignment and control problems of people and equipment14Strategic-Level Concerns (Rouwenhorst et.al.)ReceivingStoringOrderpickingShippingResourcesProcessesOrganizationSeparatereserve area?Batching?Differenttypes ofstorage?Types ofstorageStorageunitTypes ofsorting eq.15ReceivingStoring

21、OrderpickingShippingResourcesProcessesOrganizationTactical-level concerns(Rouwenhorst et. al.)Forward andreserve areaStorageconceptPick zonesBatch sizeNumberof docksTech. zonesNumberof docksLayoutStoring and Picking eq. capacityPeripheral eq. and workforce capacity16Operational-level concerns(Rouwen

22、horst et. al.)ReceivingStoringOrderpickingShippingResourcesProcessesOrganizationDockAssignmentReplenish-ment PolicyStorageplanDockAssignmentBatchformationPicking taskAssignmentRoutingDwell pointChute AssignmentWorkforce Assignment17General RemarksThe decomposition is ad-hoc: no theoretical justifica

23、tionTop-down approach: Higher-level decisions constitute constraints for lower-level decision making: However, they must be revised if the lower-level problems become infeasibleMost existing quantitative analysis addresses tactical and operational issuesStrategic level issues hard to formally model and analyze due tounderlying problem complexityelusive / intangible nature of some of the c