物流学英文版版教学课件第8章

1、Contemporary LogisticsTwelfth EditionChapter 8Inventory ManagementContemporary LogisticsTwelfth Learning Objectives (1 of 2)8.1 To learn about the ways that inventory can be classified8.2 To discuss inventory costs and the trade-offs that exist among them8.3 To identify when to order and how much to

2、 order, with a particular emphasis on the economic order quantity8.4 To differentiate the various inventory flow patternsLearning Objectives (1 of 2)8.Learning Objectives (2 of 2)8.5 To discuss special concerns with inventory management8.6 To identify several contemporary approaches to managing inve

3、ntory Learning Objectives (2 of 2)8.Inventory Management (1 of 3)Inventory Refers to stocks of goods and materials that are maintained for many purposes, the most common being to satisfy normal demand patternsInventory Management (1 of 3)IInventory Management (2 of 3)Inventory decisions drive other

4、business activities like:WarehousingTransportationMaterials handlingObjectives can differ for different functional areas of an organizationInventory Management (2 of 3)IInventory Management (3 of 3)Must consider inventory costsCarrying costsOrdering costsStockout costsInventory Management (3 of 3)MI

5、nventory Classifications (1 of 2)Cycle, or base, stockRefers to inventory that is needed to satisfy normal demand during the course of an order cycleSafety, or buffer, stockRefers to inventory that is held in addition to cycle stock to guard against uncertainty in demand or lead timeInventory Classi

6、fications (1 oInventory Classifications (2 of 2)Pipeline, or in-transit, stock Inventory that is en route between various fixed facilities in a logistics system such as a plant, warehouse, or storeSpeculative stockRefers to inventory that is held for several reasons, including seasonal demand, proje

7、cted price increases, and potential shortages of a productPsychic stock Inventory carried to stimulate demand (retail)Inventory Classifications (2 oInventory Costs (1 of 10)Assets cost money, which means that inventory costs moneyInventory costs between 2010 and 2014 represent approximately one-thir

8、d of total logistics costsInventory cost should factor into an organizations inventory management policyLogistics manager must understand nature of each cost as well as trade-offsInventory Costs (1 of 10)AssetInventory Costs (2 of 10)Inventory costs include:Carrying costOrdering costStockout costInv

9、entory Costs (2 of 10)InvenInventory Costs (3 of 10)Inventory carrying costsCosts associated with holding inventoryIn general, expressed in percentage terms and this percentage is multiplied by the inventorys valueResulting number represents dollar value associated with holding the particular invent

10、oryInventory Costs (3 of 10)InvenTable 8.1: Magnitude of Inventory CostsYearValue ofbusinessinventory($ billion)Inventorycarryingcost (%)Inventorycarryingcost($ billion)Totallogisticscost($ billion)Inventory as apercentage oftotal logisticscost2010206419.2396121132.72011218419.1418128232.62012226920

11、.1457135433.82013245919.1469141033.32014249519.1476145032.8Sources: Annual State of Logistics Report, various years, prepared by Rosalyn Wilson for the Council of Supply Chain Management Professionals ()Table 8.1: Magnitude of InventTable 8.2: Components of Inventory Carrying CostObsolescence costsI

12、nventory shrinkageStorage costsHandling costsInsurance costsTaxesInterest costsTable 8.2: Components of InvenInventory Costs (4 of 10)Ordering costsRefer to those costs associated with ordering inventory, such as order costs and setup costsInventory Costs (4 of 10)OrderInventory Costs (5 of 10)Order

13、ing costsExamples include:Costs of receiving an order (wages)Conducting a credit checkVerifying inventory availabilityEntering orders into the systemPreparing invoicesReceiving paymentInventory Costs (5 of 10)OrderInventory Costs (6 of 10)Trade-off between carrying and ordering costsCosts respond in

14、 opposite ways to the number of orders or size of ordersAn increase in the number of orders leads to higher order costs and lower carrying costsInventory Costs (6 of 10)TradeInventory Costs (7 of 10)Calculations Ordering Cost = # of orders per year x ordering cost per order Carrying Cost = average i

15、nventory x carrying cost per unitInventory Costs (7 of 10)CalcuInventory Costs (8 of 10)Stockout costsAn estimated cost or penalty for a stockoutInvolve an understanding of a customers reaction to a company being out of stock when a customer wants to buy an itemInventory Costs (8 of 10)StockTable 8.

16、3: Determination of the Average Cost of a StockoutAlternativeLossProbabilityAverage Cost1. Brand-loyal customer$ 00.00.10$ 00.002. Switches and comes back37.00.259.253. Lost customer1,200.00.65780.00Average cost of a stockoutblank1.00$789.25These are hypothetical figures for illustration.Table 8.3:

17、Determination of thInventory Costs (9 of 10)Stockout costsThe higher the average cost of a stockout, the better it is for the company to hold some amount of inventory (safety stock) to protect against stockoutsThe higher the probability of a delayed sale, the lower the average stockout costs and the

18、 lower the inventory that needs to be held by a companyInventory Costs (9 of 10)StockInventory Costs (10 of 10)Trade-off between carrying and stockout costsCosts move in opposite directionsHigher inventory levels (higher carrying costs) result in lower chances of a stockout (lower stockout costs)Inv

19、entory Costs (10 of 10)TradTable 8.4: Determination of Safety Stock LevelNumberof Units ofSafety StockAdditionalSafety Stock($480 per Unit)25% AnnualCarryingCostTotal Value ofIncrementalSafety StockAdditionalOrdersFilledStockoutCostsAvoided10$ 4,800$1,200$1,20020$8,000.00209,6002,4001,200166,400.003

20、014,4003,6001,200124,800.004019,2004,8001,20083,200.005024,0006,0001,20062,400.006028,8007,2001,20041,600.007033,6008,4001,20031,200.00Table 8.4: Determination of SaWhen to Order and How Much to Order (1 of 6)Key issue involves when product should be orderedCan order a fixed amount of inventory (fix

21、ed order quantity system)Or, orders can be placed at fixed time intervals (fixed order interval system)When to Order and How Much to When to Order and How Much to Order (2 of 6)Reorder (trigger) point (ROP) Level of inventory at which a replenishment order is placedNecessary for efficient fixed orde

22、r quantity system When to Order and How Much to When to Order and How Much to Order (3 of 6)Reorder point (ROP) calculations:ROP = DD x RC under certaintyROP = (DD x RC) + SS under uncertaintyWhere DD = daily demand RC = length of replenishment cycle SS = safety stockWhen to Order and How Much to Wh

23、en to Order and How Much to Order (4 of 6)Economic order quantity (EOQ)Deals with calculating the proper order size with respect to two costs:Costs of carrying the inventoryCosts of ordering the inventoryDetermines the point at which the sum of carrying costs and ordering costs is minimized, or the

24、point at which carrying costs equal ordering costsWhen to Order and How Much to When to Order and How Much to Order (5 of 6)Economic order quantity (EOQ) in dollarsWhere:EOQ = the most economic order size, in dollars A = annual usage, in dollars B = administrative costs per order of placing the orde

25、r C = carrying costs of the inventory (%)When to Order and How Much to When to Order and How Much to Order (6 of 6)Economic order quantity (EOQ) in unitsWhere:EOQ = the most economic order size, in units A = annual demand, in units B = administrative costs per order of placing the order C = carrying

26、 costs of the inventory (%) I = dollar value of the inventory, per unitWhen to Order and How Much to Figure 8.1: Determining EOQ Using a GraphFigure 8.1: Determining EOQ UsTable 8.5: EOQ Cost CalculationsNumber ofOrders per YearOrderSize ($)OrderingCost ($)CarryingCost ($)Total Cost (sum of Ordering

27、 and Carrying Cost ($)11,000251001252500505010033337533108425010025125520012520145Table 8.5: EOQ Cost CalculatioFigure 8.2: Flow DiagramFigure 8.2: Flow DiagramInventory Flows Safety stock can prevent against two problem areasIncreased rate of demandLonger-than-normal replenishmentWhen fixed order q

28、uantity system like EOQ is used, time between orders may varyWhen reorder point is reached, fixed order quantity is orderedInventory Flows Safety stock cInventory Management: Special Concerns (1 of 3)ABC analysis of inventory Recognizes that inventories are not of equal value to a firmAs such, all i

29、nventory should not be managed in the same wayDead inventory (dead stock)Is a fourth category, D, to ABC analysis where D stands for either “dogs” or dead inventory (dead stock)Refers to product for which there are no sales during a 12-month periodInventory Management: Special Inventory Management:

30、Special Concerns (2 of 3)Inventory turnover Number of times that inventory is sold in a one-year period (compare with competitors or benchmarked companies)Inventory turnover = cost of goods sold average inventory Inventory Management: Special Inventory Management: Special Concerns (3 of 3)Complement

31、ary productsInventories that can be used or distributed together (e.g., razor blades and razors)Substitute productsProducts that can fill the same need or want as another productInventory Management: Special Contemporary Issues with Managing Inventory (1 of 4)Lean manufacturingFocuses on the elimina

32、tion of waste and the increase of speed and flowIdentifies seven major sources of waste including inventoryJust-in-time (JIT) is one of the best-known lean inventory practicesContemporary Issues with ManagContemporary Issues with Managing Inventory (2 of 4)Lean manufacturingJust-in-time (JIT)Seeks t

33、o minimize inventory by reducing (or eliminating) safety stock while having the required amount of materials arrive at the production location at the exact time they are neededContemporary Issues with ManagFigure 8.3: Trailer That Opens on the Side and Is Used for Rapid Discharge of PartsSource: Pho

34、to courtesy of Max Blain/Fotolia.Figure 8.3: Trailer That OpensContemporary Issues with Managing Inventory (3 of 4)Service parts logisticsInvolves designing a network of facilities to stock service partsDeciding upon inventory ordering policiesStocking the required partsTransporting parts from stocking facilities to customers11Mehmet Ferhat Candas and Erhat Kutanoglu