Warehouse Operations

Warehouse OperationsWarehouse Operations

What is Warehouse ?What is Warehouse ?

อ้�างอ้�งจาก อ้�างอ้�งจาก http://www.wisegeek.comhttp://www.wisegeek.com

• A A warehousewarehouse is a large building where is a large building where goods are stored, and where they may be goods are stored, and where they may be catalogued, shipped, or received, catalogued, shipped, or received, depending upon the typedepending upon the type . . Though in the Though in the past, many warehouses, often located in past, many warehouses, often located in industrial areas sometimes next to major industrial areas sometimes next to major shipping ports, were teeming with workers, shipping ports, were teeming with workers, the modern the modern warehousewarehouse may be either may be either completely or totally automated depending completely or totally automated depending upon how advanced the company is.upon how advanced the company is.


• Warehouses have existed for several Warehouses have existed for several centuries, and the word itself is not centuries, and the word itself is not hard to understandhard to understand . . “Wares” were “Wares” were the things possessed by a seller and the things possessed by a seller and to house these in a central location to house these in a central location meant your were storing your meant your were storing your wareswares..getting in new products, and getting in new products, and shipping out products already storedshipping out products already stored . .


• Another important part of Another important part of maintaining a good maintaining a good warehousewarehouse is is keeping keeping inventory of what products of what products

are presently in the are presently in the warehousewarehouse, what , what has been shipped and what has been has been shipped and what has been receivedreceived . .

http://www.wisegeek.com/what-is-inventory.htm

Warehouse FunctionsWarehouse Functions

• Provide temporary storageProvide temporary storage

• Put together an orderPut together an order

• Serve as a customer service facilityServe as a customer service facility

• Protect goodsProtect goods

• Perform value added servicesPerform value added services

• InventoryInventory

The Value ChainThe Value Chain

Inbound Inbound

LogisticsLogisticsOperatioOperatio

nsnsOutbounOutboun

d d

LogisticsLogistics

MarketinMarketing g

and Salesand Sales

Services Services

ProcurementProcurement

Technology DevelopmentTechnology Development

Human Resource DevelopmentHuman Resource Development

Firm StructureFirm Structure

Supporting Activities

Warehouse FunctionsWarehouse Functions

- Warehouse organizes and repackages - Warehouse organizes and repackages productproduct

- Product arrives packaged on a large - Product arrives packaged on a large scale and leaves packages on a scale and leaves packages on a smaller scalesmaller scale

““The smaller the handling unit, the The smaller the handling unit, the greater the handling cost”greater the handling cost”

Processes of reorganization of productProcesses of reorganization of product

• Inbound ProcessesInbound Processes– ReceivingReceiving– Put away/StoragePut away/Storage

• Outbound ProcessesOutbound Processes– Processing customer ordersProcessing customer orders– Order-pickingOrder-picking– CheckingChecking– PackingPacking– ShippingShipping

ReceivingReceiving

• Unloading and staging for put awayUnloading and staging for put away• InspectionInspection ( (Sampling and/or 100%Sampling and/or 100%))• Scanned for registering toScanned for registering to

– Confirm its availabilityConfirm its availability– Confirm ownershipConfirm ownership

• Normally, receiving is accounted for Normally, receiving is accounted for about about 10%10% of W/H operations cost. of W/H operations cost.

Put-awayPut-away

““Before product can be put away, an Before product can be put away, an appropriate appropriate storage locationstorage location must must be determined”be determined”

““Where the product is stored is directly Where the product is stored is directly related to how quick and what cost related to how quick and what cost to retrieve it later”to retrieve it later”

Put-awayPut-away

• W/H manager must know at all time that:W/H manager must know at all time that:– Which storage locations are availableWhich storage locations are available– How large they areHow large they are– How much weight they can takeHow much weight they can take

After product is put away, its location must be After product is put away, its location must be recordedrecorded

Cost of put away is about 15% of W/H operating Cost of put away is about 15% of W/H operating expensesexpenses

Process of customer ordersProcess of customer orders

• On receipt of customer orders the On receipt of customer orders the warehouse must perform checks such as warehouse must perform checks such as to verify that inventory is available to shipto verify that inventory is available to ship

• The warehouse must produce a “pick list” The warehouse must produce a “pick list” to guide the order pickingto guide the order picking

• The order picking include assigning The order picking include assigning operatorsoperators and and sequence sequence of order picking of order picking and shippingand shipping

Order PickingOrder Picking

• Order picking account for 55% of Order picking account for 55% of warehouse operations cost, it can be warehouse operations cost, it can be broken down to:broken down to:– Traveling Traveling 55%55%– SearchingSearching 15%15%– ExtractingExtracting 10%10%– Paper work and otherPaper work and other 20%20%*% of total order picking cost*% of total order picking cost


• Depend on type of storage and retrieval Depend on type of storage and retrieval systemsystem– Person-to-itemPerson-to-item– Item-to-personItem-to-person– Manual or ASRSManual or ASRS

• Terminology used in order picking operationsTerminology used in order picking operations– Pick-sheet or pick linePick-sheet or pick line– Pick/visitPick/visit– Pick facePick face– Pick density (# of picks per foot of travel)Pick density (# of picks per foot of travel)


• Flow time is a main indicator for Flow time is a main indicator for picking performancepicking performance

• Short flow time can lead to better Short flow time can lead to better service and responsivenessservice and responsiveness

• Flow time depend on Flow time depend on – how large the unit load, serial or parallel how large the unit load, serial or parallel

pickerspickers– Number of pickersNumber of pickers


• If the total work to pick and load a If the total work to pick and load a truck is small, one picker may be truck is small, one picker may be assign to each orderassign to each order

• If the orders to pick and load are If the orders to pick and load are large or span distant region, several large or span distant region, several pickers are needed to shorten the pickers are needed to shorten the flow timeflow time


• For a warehouse that move a lot of For a warehouse that move a lot of small products for each of many small products for each of many customers, such as shipping to retail customers, such as shipping to retail stores, order picking may be stores, order picking may be organized as an assembly lineorganized as an assembly line

• The assembly line needs to be The assembly line needs to be balance using some balance using some line balancing line balancing techniquestechniques

Checking and PackingChecking and Packing

• Packing can be very labor intensivePacking can be very labor intensive• Every item needs to be handled but Every item needs to be handled but

with minimal walkingwith minimal walking• Then, checking can be performed Then, checking can be performed

simultaneously to make sure simultaneously to make sure completeness of ordercompleteness of order

• Incomplete order leads to return Incomplete order leads to return which is expensivewhich is expensive

Checking and PackingChecking and Packing

• Packing must aim at minimizing Packing must aim at minimizing broken space when shippingbroken space when shipping

• Also, customers want orders in as Also, customers want orders in as few containers as possible to avoid few containers as possible to avoid excessive handling costexcessive handling cost

ShippingShipping

• Shipping generally handles larger Shipping generally handles larger units than pickingunits than picking

• Less labor intensiveLess labor intensive

• Goal is to Goal is to – minimize transportation costminimize transportation cost– Protect goodsProtect goods– Ease load and unloadingEase load and unloading

10-10-2121

Warehouse Warehouse Management SystemsManagement Systems

-Highly automated system that runs day-to--Highly automated system that runs day-to-day operations of a DCday operations of a DC

-Controls item putaway, picking, packing, and -Controls item putaway, picking, packing, and shippingshipping

-Features-Featurestransportation managementtransportation managementorder managementorder managementyard managementyard managementlabor managementlabor managementwarehouse optimizationwarehouse optimization

10-10-2222

A WMS

10-10-2323

Vendor-Managed InventoryVendor-Managed Inventory

Manufacturers generate orders, not distributors Manufacturers generate orders, not distributors or retailersor retailers

Stocking information is accessed using EDIStocking information is accessed using EDIA first step towards supply chain collaborationA first step towards supply chain collaborationIncreased speed, reduced errors, and improved Increased speed, reduced errors, and improved

serviceservice

Warehouse Management Warehouse Management System (WMS)System (WMS)

• The main function of WMS are to The main function of WMS are to track all product arriving and track all product arriving and shipping outshipping out

• It most fundamental capability is to It most fundamental capability is to record receipt of inventory into the record receipt of inventory into the warehouse and register its shipment warehouse and register its shipment outout (including financial transaction)(including financial transaction)

Warehouse Management Warehouse Management System (WMS)System (WMS)

• Another important function are:Another important function are:– Ability to do storage allocationAbility to do storage allocation– Routing of material handling equipmentRouting of material handling equipment– Track every place that product can be Track every place that product can be

storedstored– Known as stock locator systemKnown as stock locator system

Manu Features of WMSManu Features of WMS

• Basic featuresBasic features– Appointment schedulingAppointment scheduling– ReceivingReceiving– Quality assuranceQuality assurance– Put awayPut away– Location trackingLocation tracking– Work-order managementWork-order management– PickingPicking– Packing and consolidatingPacking and consolidating– ShippingShipping


• High-end featuresHigh-end features– Cycle countingCycle counting– ReplenishmentReplenishment– Yard managementYard management– Labor managementLabor management– Value-added serviceValue-added service– Etc.Etc.


• WMS’s are extending their functionality to WMS’s are extending their functionality to support activities in supply chain both support activities in supply chain both upstream and downstream like:upstream and downstream like:

– EXE technologiesEXE technologies– Manhattan AssociatesManhattan Associates– MARC Global SystemMARC Global System– Swisslog SoftwareSwisslog Software– etc etc

Materials HandlingMaterials Handling

Materials HandlingMaterials Handling

• Material handling is an activity that Material handling is an activity that uses the right method to provide the uses the right method to provide the right amount of the right material at right amount of the right material at the right place, at the right time, in the right place, at the right time, in the right sequence, in the right the right sequence, in the right position and at the right costposition and at the right cost

Materials Handling (Cont)Materials Handling (Cont)

• Systems perspectiveSystems perspective

• 20-70% of product cost attributed to 20-70% of product cost attributed to material handlingmaterial handling

Unit LoadUnit Load

• Unit load - number of items or bulk Unit load - number of items or bulk material arranged so they can be material arranged so they can be picked up and delivered as one loadpicked up and delivered as one load

• Large or small?Large or small?

• If large, cost/unit handled decreasesIf large, cost/unit handled decreases

• But, depending uponBut, depending upon– cost of unitizing, de-unitizingcost of unitizing, de-unitizing

Unit Load (Cont)Unit Load (Cont)

– space required for material handlingspace required for material handling– material handling carrier payloadmaterial handling carrier payload– work-in-process inventory costswork-in-process inventory costs– storage and return of empty pallets or storage and return of empty pallets or

containers used to hold the unit loadcontainers used to hold the unit load

• smaller unit load may be desiredsmaller unit load may be desired


• Seven steps to design a unit loadSeven steps to design a unit load– Unit load concept applicable?Unit load concept applicable?– Select the unit load typeSelect the unit load type– Identify most remote source of loadIdentify most remote source of load– Determine farthest practicable Determine farthest practicable

destination for loaddestination for load


– Establish unit load sizeEstablish unit load size– Determine unit load configurationDetermine unit load configuration– Determine how to build unit loadDetermine how to build unit load

Material Handling Device Material Handling Device TypesTypes

• ConveyorsConveyors

• PalletizersPalletizers

• Pallet Lifting DevicesPallet Lifting Devices

• TrucksTrucks

• RobotsRobots

Material Handling Device Material Handling Device Types (Cont)Types (Cont)

• AGVsAGVs

• Jibs, Cranes and HoistsJibs, Cranes and Hoists

• Warehouse MHSsWarehouse MHSs

ConveyorsConveyors

• AccumulationAccumulation

• BeltBelt

• BucketBucket

• CanCan

• ChainChain

Conveyors (Cont)Conveyors (Cont)

• ChuteChute

• GravityGravity

• Pneumatic or vacuumPneumatic or vacuum

• Power and freePower and free

• RollerRoller

Conveyors (Cont)Conveyors (Cont)

• ScrewScrew

• SkidSkid

• SlatSlat

• Tow lineTow line

• TrolleyTrolley

• WheelWheel

TrucksTrucks

• Hand truckHand truck

• Fork-lift truckFork-lift truck

• Pallet truckPallet truck

• Platform truckPlatform truck

• Counterbalanced truckCounterbalanced truck

• Tractor-trailer truckTractor-trailer truck

• AGVAGV

RobotsRobots

• Point-to-pointPoint-to-point

• Contouring or continuous pathContouring or continuous path

• Walkthrough or teachWalkthrough or teach

• Lead through or teach pendantLead through or teach pendant

• HydraulicHydraulic

• Servo-controlledServo-controlled

MHSs in ActionMHSs in Action

• Europe Combined Terminals (ECT)Europe Combined Terminals (ECT)

• ECT - one of largest in world and ECT - one of largest in world and largst in Europelargst in Europe

• Goods shipped from and to EuropeGoods shipped from and to Europe

• Built on reclaimed land in the North Built on reclaimed land in the North SeaSea

• Large and Small containersLarge and Small containers

MHSs in Action (Cont)MHSs in Action (Cont)

• Trucks wait to be off-loaded by Trucks wait to be off-loaded by straddle carrierstraddle carrier

• Carrier takes container to holding Carrier takes container to holding areaarea

• Shipped in approximately 2 daysShipped in approximately 2 days

• Mobile gantry cranes on tracks Mobile gantry cranes on tracks deposit containers in forward areadeposit containers in forward area

MHSs in Action (Cont)MHSs in Action (Cont)

• Mobile gantry cranes hold containers in Mobile gantry cranes hold containers in top four corners and deposit on waiting top four corners and deposit on waiting AGVsAGVs

• Fleet of AGVs in forward area take Fleet of AGVs in forward area take containers to tower cranescontainers to tower cranes

• Tower cranes deposit load on ship bedTower cranes deposit load on ship bed

• Procedure reversed for off-loading shipProcedure reversed for off-loading ship

AGVsAGVs

• Classification of MHSClassification of MHS– Synchronous systemsSynchronous systems– Asynchronous systemsAsynchronous systems

• Synchronous systems, e.g. Synchronous systems, e.g. conveyors, used in continuous conveyors, used in continuous processes or heavy traffic, discrete processes or heavy traffic, discrete parts environmentsparts environments

AGVs (Cont)AGVs (Cont)

• Asynchronous systems, e.g., AGV, Asynchronous systems, e.g., AGV, AS/RS, fork-lift trucks, monorails, AS/RS, fork-lift trucks, monorails, cranes and hoists used in light traffic, cranes and hoists used in light traffic, discrete parts environments when discrete parts environments when material handling flexibility desiredmaterial handling flexibility desired

Design and Control Design and Control Problems in AGVSsProblems in AGVSs

• Material flow networkMaterial flow network

• Location of pick-up/drop-off (P/D) Location of pick-up/drop-off (P/D) pointspoints

• Number and type of AGVsNumber and type of AGVs

• AGV Assignments to material AGV Assignments to material transfer requeststransfer requests

• AGV routing and dispatchingAGV routing and dispatching

Design and Control Design and Control Problems in AGVSs (Cont)Problems in AGVSs (Cont)• Strategies for resolving route conflicts, Strategies for resolving route conflicts,

so AGV throughput rate is maximized, an so AGV throughput rate is maximized, an other costs (purchase, maintenance and other costs (purchase, maintenance and operating costs of AGVs, computer operating costs of AGVs, computer control devices, and the material flow control devices, and the material flow network, as well as inventory costs and network, as well as inventory costs and production equipment idle costs incurred production equipment idle costs incurred due to excessive material transfer and due to excessive material transfer and wait times), are minimizedwait times), are minimized

Warehouse Operations

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