全球运营管理课件new gom8-inventory management.ppt

GOM8Inventory ManagementGOM8存货管理General ConceptslFunctions of Inventories (5)¡Transit inventories: exist because materials must be moved from one location to another (also pipeline inventories)¡Buffer inventories: to protect against the uncertainties of supply and demand (also safety stocks) as against stockout¡Anticipation inventories: such as a price increase, strike, seasonal change….一般概念l存货功能(5)¡运输存货：是由于原料必须从一个地方运输到另外一个地 方（包括管道库存）¡缓冲存货：防止出现不确定的供给和需求造成的脱销（安 全库存）¡预期存货：例如价格上涨，罢工，周期性的变化……General Concepts¡Decoupling inventories: between machines acting as shock absorbers¡Cycle inventories: lot size inventorieslForms of Inventories¡Raw materials¡Maintenance, repair, and operating supplies¡Work-in-progress (WIP)¡Finished goods一般概念¡退耦存货：在机器间做减震器¡循环存货：大量的存货l存货的形式：¡原材料¡维护和运转供应品¡在进行中产品¡产成品General ConceptslInventory-related Costs¡Ordering or Set up costs¡Inventory Carrying or Holding CostslCapital costslStorage costslRisk costs¡Stockout Costs¡Opportunity Costs: the overtime required to increase capacity….the cost of idle time….一般概念l存货相关的成本¡订货成本¡存货成本l资金成本l存储成本l风险成本¡缺货损失¡机会成本：超时满负荷…停机成本 ……General ConceptslTypes of Inventory Management SystemslReorder point systemslPeriodic review systemslMRP systems¡Reorder point systemslAn inventory level is specified at which a replenishment order for a fixed quantity of the inventory item is to be placed.lThe quantity of inventory to be ordered is often based on the economic order quantitylTwo bins system一般概念l存货管理系统的类型l再订货点系统l周期性检查系统lMRP（物资需求计划）系统¡再订货点系统l库存达到一个预先设置的固定点时需要重新补充库存 。

l库存订货数量依据经济订购量l双箱系统The ABC Concept¡Periodic Review SystemslThe inventory level is reviewed at equal time intervalslReorder quantity= maximum level – on-hand inventory – on-order quantity + demand over lead time.lPriorities for Inventory Management: The ABC concept¡Based on the annual dollar purchases of an inventoried item.基本概念¡周期性检查系统l每间隔一段时间检查库存水平l再订货数量＝最大存货数量－当前库存－ 已定购但尚未交货的数量＋订货至交货这 段时间的需求数量l存货管理的优先权：基本概念¡依据存货盘点清单的年货币购买The ABC ConceptAnnual Quantity UsedPercentage of Total ItemsAnnual Dollar PurchasesPercentage of Total Purchases 5214.8$15,400,00050.75745.36,200,00020.410239.43,600,00011.8114510.52,300,0007.6375434.01,800,0005.9390636.01,100,0003.6Total 10,923100.0$30,400,000100.0基本概念年使用数量占总数量的比例年货币购买占总购买的比例5214.8$15,400,00050.75745.36,200,00020.410239.43,600,00011.8114510.52,300,0007.6375434.01,800,0005.9390636.01,100,0003.6总计 10,923100.0$30,400,000100.0The ABC ConceptlA: High-value items. The 15-20 percent or so of the items that account for 75 to 80 percent of the total annual inventory valuelB. Medium-value items. The 30 to 40 percent of the items that account for approximately 15 percent of the total annual inventory valuelC. Low-value items. The 40 to 50 percent of the items that account for 10 to 15 percent of the annual inventory value.基本概念lA：数值大的项。

大约15到20％能够解释 75％到80％的总年度库存值lB：数值中的项30％到40％可以解释大约 15％的总年度库存值lC：数值小的项40％到50％可以解释10 ％到15%的总年度库存值The ABC ConceptlThe Analysis of the ABC Concept¡The A items should be subject to the tightest control, with detailed inventory records and accurate, updated values of order quantities and reorder points¡B items are subject to normal control, with order quantities set by EOQ, but with less frequent updating of records and review of order quantities and reorder points.¡C items are subject to little control; orders are placed for a 6-month to 1-year supply so that relatively little control must be exercised and inventory records can be kept simple.基本概念l基本概念分析¡A将会通过详细的库存记录，精确的最新订货数 量和再订货点的数值得到最严格的控制¡B通过经济定购量来确定订购数量，从而达到一 般性的控制，但是很少更新库存记录检查订货数 量和再订货点。

¡C很少控制；订单是6个月或者1年的供给，所以 很少运用相关的控制，库存记录可以简单的保存 The ABC Concept20 50 100Percentage of Total Items1009075Percentage of Total Dollar UsageABC基本概念20 50 100各个项目的占比1009075总资金的使用比例ABCThe Economic Order Quantity (EOQ)lEOQ¡Applies to inventory items that are replenished in batches or orders and are not produced and delivered continuously. Only carrying costs and opportunity costs are considered.¡The basic EOQ modellRage of demand is constant (e.g. 50 per day)lShortages are not allowed经济定购量lEOQ¡应用于存货的分批或者订购，不是连续的产出和 交货。

只考虑运输费用和机会成本¡基本的经济订货量模型l需求量的变化是固定的（例如每天50）l不允许缺货The Economic Order Quantity (EOQ)lLead times are known with certainty, so stock replenishment can be scheduled to arrive exactly when the inventory drops to zero.lPurchase price, ordering cost, and per-unit holding cost are independent of quantity ordered.lItems are ordered independently of each other.¡VariableslQ = order quantitylU = annual usagelCO =cost to place one orderlCH=annual holding cost per unit经济订购量l订货到交货的时间是确定已知的，可以安排为刚好到 存货减少到0的时候交货l采购费用，订货成本，单位保管费用与订货数量无关l各项之间无关¡变量lQ = 订购数量lU = 年度使用lCO =一次订货成本lCH=每年单位存储成本The Economic Order Quantity (EOQ)lExample:¡A water distributor sells 1000 5-gallon bottles per month (30 days) and purchase in quantities of 2000 per order. Lead time for the receipt of an order is 6 days. The cost accounting department has analyzed inventory costs and has determined that the cost of placing an order is $60 and t。