财务管理与财务分析运营管理课件.ppt
财务管理与财务分析运营管理课件2IInventory Systems for Independent DemanduBasic fixed order quantity systemConstant DemandUncertain demanduBasic fixed time period systemuNewsvendor modeluSupply chain contract3I4Purposes of Inventory1. To maintain independence of operations2. To meet variation in product demand3. To allow flexibility in production scheduling4. To provide a safeguard for variation in raw material delivery time5. To take advantage of economic purchase-order size4I5I6IInventory CostsuHolding (or carrying) costsuSetup (or production change) costsuOrdering costsuShortage costs .7IClassifying Independent Demand SystemsuFixed-Order Quantity The reorder point uFixed-Time Period uHybrid Systems - Both Together - Order Periodically unless we reach the reorder point.8IInventory Systems for Independent DemanduBasic fixed order quantity systemConstant DemandUncertain demanduBasic fixed time period systemuNewsvendor modeluSupply chain contractOPERATIONS MANAGEMENT CLASS9IFixed-Order Quantity ModelsEconomic Order Quantity (EOQ): AssumptionsuDemand for the product is constant and uniform throughout the perioduLead time (delivery time of the order) is constantuPrice per unit of product is constant .10IFixed-Order Quantity Models Economic Order Quantity: Assumptions (contd)uInventory holding cost is based on average inventory.uOrdering or setup costs are constant.uAll demands for the product will be satisfied (No lost sales are allowed) .11IuBook Store Mug Sales Demand is constant, at 20 units a week Fixed order cost of $12, no lead time Holding cost of 25% of inventory value annually Mugs cost $1.00, sell for $5.00uQuestion How many, when to order12IEOQ Model-Basic Fixed-Order Quantity ModelR = Reorder point = L*d Q = Economic order quantityL = Lead timed = Demand per Unit of TimeLLQQQRTimeNumberof unitson hand.13ICost Minimization GoalAnnual Ordering CostsHoldingCostsQOPTOrder Quantity (Q)COSTAnnual Cost ofItems (DC)Total Cost.TAHC = H*(Q/2)TAOC = S*D/QTAC = TAHC + TAOCS: cost of placing an order or setup cost14IBasic Fixed-Order Quantity ModelTC = DC + DQ S + Q2 HTotal Annual Cost =AnnualPurchaseCostTotal AnnualOrderingCostTotal AnnualHoldingCost+TC Total annual costD DemandCCost per unitQ Order quantitySCost of placing an order or setup costRReorder pointLLead timeHAnnual holding and storage cost per unit of inventory.15IDeriving the EOQ - Calculus MethoduUsing calculus, we take the derivative of the total cost function and set the derivative (slope) equal to zero .Q = 2DSH = 2(Annual Demand)(Order or Setup Cost)Annual Holding CostOPT Reorder point, R = d L_d = average daily demand (constant) L = Lead time (constant)_16IuRecognizing TAHC = TAOC at OptimaluTAHC = H*Q/2TAOC = S*D/QuH*Q/2 = S*D/Q, Solving for Q Yields:Q = 2DSH = 2(Annual Demand)(Order or Setup Cost)Annual Holding CostOPT Reorder point, R = d L_d = average daily demand (constant) L = Lead time (constant)_Deriving the EOQ - Graphical Method17IuOptimal Quantity = uSo for our problem, the optimal quantity is 316 (2 * Demand * Setup Cost)/holding cost18IEOQ ExampleAnnual Demand = 1,000 unitsDays per year considered in average daily demand = 365Cost to place an order = $10Holding cost per unit per year = $2.50Lead time = 7 daysCost per unit = $15Determine the economic order quantity and the reorder point.19ISolutiond = 1,000 units / year365 days / year = 2.74 units / dayQ = 2DSH = 2(1,000 )(10)2.50 = 89.443 units or OPT90 units Reorder point, R = d L = 2.74units / day (7days) = 19.18 or _20 unitsWhy do we round up?.20IIn-Class ExerciseAnnual Demand = 10,000 unitsDays per year considered in average daily demand = 365Cost to place an order = $10Holding cost per unit per year = 10% of cost per unitLead time = 10 daysCost per unit = $15Determine the economic order quantity and the reorder point.Note: (Tag hidden-slide icon to project solution) .21ISolutiond = 10,000 units / year365 days / year = 27.397 units / dayQ = 2DSH = 2(10,000 )(10)1.50 = 365.148 units or OPT366 units Reorder point, R = d L = 27.397 units / day (10days) = 273.97 or _274 units.22IInventory Systems for Independent DemanduThe definition and purpose of inventoryuInventory costsuBasic fixed order quantity systemConstant DemandUncertain demandCustomer Service - Achieving Percent Fill RatesuBasic fixed time period systemuNewsvendor modelOPERATIONS MANAGEMENT CLASS23IAchieving High Customer ServiceuAdd buffer stockuOrder earlier uAchieve desired customer service uPercent fill rate = .99 = 9,900/10,000 are supplied directly from stockFixed Order Quantity System Under Uncertainty24IAdding Safety Stock to Order EarlieruFixed Order Quantity System Under UncertaintyR = Reorder pointQ = Economic order quantityL = Lead timeL = Standard Error of Estimate During LeadtimeB = Buffer stock set to achieve PLLQQQR = dL + B = dL + Z L TimeB = Add buffer stock in case demand during leadtime expected d*L25ISTRATEGIC IMPORTANCE OF %FILL (P)u P is set by top managementu P is strategic performance measure uP=99.8 is becom
