1、Safety StockJapan ReviewJanuary 2003Safety StockSafety stock is buffer inventory to protect against fluctuations in demand or supply during the order lead time安全庫存是用于訂單交期內(nèi)需求或供應(yīng)發(fā)生波動時的緩沖庫存;Typically safety stock is set to a “comfortable” level for all SKUs通常,安全庫存是對所有品類設(shè)計(jì)一個所謂的舒適的水平; E.g. 30 days, 60 da

2、ys 如30天,60天This often leads to excessive inventory for fast moving SKUs and, sometimes, insufficient inventory for slow moving SKUs這通常會導(dǎo)致對流動較快的品類導(dǎo)致庫存過大，而對于流動較慢的產(chǎn)品來講，導(dǎo)致庫存不足；Place order下單Place order下單Place order下單Stock out庫存虧空Periodic Review Inventory Model 階段性庫存模型階段性庫存模型LInventory on hand (in units)在

3、手庫存Safety stock安全庫存TLTLTTime周期Inventory in the Supply Chain 供應(yīng)鏈中的庫存Type類型Use目的Drivers驅(qū)動器Safety StockTo buffer against uncertainty in demand or supply Total demand Lead time Demand variation Manufacturing reliability QA Loss/DelayCycle Stock Number of SKUs & Lines Changeover time Lot sizing Delivery

4、freq.Function of lot sizing or ship quantities Anticipation Stock 預(yù)期庫存預(yù)期庫存To cover future demand. Avoid or delay Capital expenditure. Product transitions產(chǎn)品產(chǎn)品切換切換 Technology transitionsPipeline Stock Product in transit or work in process FOQ Transportation lead times QA cycle timeInventory TargetsSta

5、tistical Safety Stock Model SIPOCINPUTS-Service level-Lead time-Order frequency-Avg demand (per SKU)-Std deviation (per SKU)PROCESSStatistical Safety Stock ModelOUTPUTS-Safety stock (per SKU)-Total inventory req.SUPPLIERS-Affiliates-Customers-IMCUSTOMERS-Affiliates-Customers-Global Log. Planning-Fin

6、anceGather inputsLoad modelRun modelExport results to planning systemExecuteReplen.Process(DRP)Continuous evaluation of input parametersRecent Model Enhancements Analysis of low versus high variability SKUs Low Variability Standard deviation is less than 50% of demand Ability to specify different se

7、rvice levels Use one % for high variability items Use a different % for low variability itemsService Level Probability of No Backorders Percentage indicates the statistical chance of backorder every x replenishment occasions 99.99 = 1 every 10,000 99.9= 1 every 1,000 99.0= 1 every 100 99.9% 1 every

8、1,000 replenishment occasions 1 every 1,000 shipments from Jax/Irl 1 every 20 years (weekly shipments) 1 every 7 years (three shipments per week)JPNINPUT AREAOUTPUT AREAStatisticalCustomer Service MeasureProbability of no backordersSafetyDesired fill rate99.9900%Std Cost per lens (US $)0.3200StockPr

9、obability of no backorders (low variation)99.5000%Average total stock (days):4.6Total Cost (US$) (Decr)/Inc(4,174,045.76)ModelProbability of no backorders (high variation)99.9000%Average cycle stock (days):1.5Shipping Days Per Week6Order Interval (days)3 Average safety stock (days):3.1Lead time (day

10、s)10Recommended Daily demandModelModelManuCurrent Current ManuSS ChangesItemDescriptionAverageStd. Devn.SS (Lenses)SS (Days)SS(Days)SS(Days)SS (lenses)(Decr)/Inc73390502724 1D R85-0501094.00497.454,6204.224.916D17,047(12,427)73390502725 1D R85-0751490.33599.225,5663.74.416D22,973(17,407)73390502726

11、1D R85-1002981.671055.299,8013.33.813D41,910(32,109)73390502727 1D R85-1254105.001381.4212,8303.13.613D57,178(44,348)73390502728 1D R85-1505686.331808.8616,8003.03.413D80,184(63,384)73390502729 1D R85-1756955.672083.9219,3542.83.213D96,725(77,371)73390502730 1D R85-2008622.672686.6524,9522.93.413D12

12、0,833(95,881)73390502731 1D R85-2258995.672589.2524,0482.73.113D125,982(101,934)73390502732 1D R85-25010636.673220.9229,9142.83.38D101,768(71,854)73390502733 1D R85-27510200.003214.6829,8562.93.48D97,154(67,298)73390502734 1D R85-30011975.003715.4934,5072.93.48D115,444(80,937)73390502735 1D R85-3251

13、0414.003325.7430,8883.03.58D101,252(70,364)Using Shipping data from August 30, 2002 to December 18, 2002 ImplementedAverage Manu safety stock (days): 4.3Model EnhancementNew ParameterEVC Savings Original ModelProductNew Calculated Statistical Safety StockCurrent Manugistic SS Settings Dated W/E Jan.

14、 26, 2002Increase (Decrease)Cost (US$) Increase (Decrease)Acuvue112,566157,647(45,081)(37,417)Acuvue 2262,036366,895(104,859)(119,539)Surevue146,260188,081(41,821)(34,711)One Day Acuvue2,025,6542,909,107(883,453)(212,029)Bifocal71,9907,32064,67091,185Torics156,558245,224(88,666)(118,812)Colours63,90

15、4209,642(145,738)(151,568)TOTALS2,838,9684,083,916(1,244,948)(582,892) Original Model EVC Savings Enhanced ModelUsing 99.5% for items with low variabilityProductNew Calculated Statistical Safety StockCurrent Manugistic SS Settings Dated W/E Jan. 26, 2002Increase (Decrease)Cost (US$) Increase (Decrea

16、se)Acuvue100,818157,647(56,829)(47,168)Acuvue 2261,934366,895(104,961)(119,656)Surevue129,347188,081(58,734)(48,749)One Day Acuvue1,742,0292,909,107(1,167,078)(280,099)Bifocal71,4207,32064,10090,381Torics156,558245,224(88,666)(118,812)Colours63,904209,642(145,738)(151,568)TOTALS2,526,0104,083,916(1,

17、557,906)(675,671)Enhanced Model ( Accounting for low variability items)Incremental US$92,000 using enhanced modelManugistics & Safety Stock Forward Coverage Specified in days Calculated using latest forecast Requires accurate forecasts Automatically adjusts as forecast changes (up or down) Specific

18、number of lenses Specified in lenses Used for some specialty products Used if forecast accuracy is poor Must be updated manuallyService Level Test in EVC beginning February 2003 Use 99.5% for low variability items Monitor inventory Potential use of 99.0%Safety Stock DriversSafety Stock Drivers Deman

19、d Variability “Standard Deviation” in the Raj model The higher the deviation, the higher the safety stock Typically the biggest impact on safety stock Options Understand drivers of demand variability Change customer behaviorJapan VariabilityOne Day Acuvue 9.0-500,0001,000,0001,500,0002,000,0002,500,

20、0003,000,0008/30/20029/9/20029/19/20029/29/200210/9/200210/19/200210/29/200211/8/200211/18/200211/28/200212/8/200212/18/2002DatesQtySeries19/2/029/20/0215/15/0211/5/0211/11/0210/28/0210/21/0210/0/029/30/029/24/029/9/0211/18/0211/25/02 12/2/0212/9/0212/16/02EVC Acuvue BifocalBifocal05,00010,00015,000

21、20,00025,00030,00035,000807021E+052E+052E+053E+0550802908022E+052E+053E+0520902609021E+052E+052E+053E+05410021E+052E+052E+053E+0511102711021E+052E+053E+053E+05512021E+052E+052E+05DateQtyBifocal25-Jul-024-Sep-0219-Sep-021-Oct-0217-Oct-026-Nov-26-Nov-02Korea 1 Day AcuvueOne Day Acuvue020,00040,00060,00080,000100,000120,000140,000160,000180,000200,00002/08/2002/08/2602/08/3002/09/0502/09/1102/09/1702/09/2402/09/3002/10/0702/10/1102/10/1702/10/2302/10/2902/11/040