Lecture 24 - Order Quantities (Continued). The contents of this chapter include all of the following: Probabilistic models and safety stock, probabilistic demand, other probabilistic models, fixed period system, EOQ consequences, period order quantity model. | Lecture 24 Order Quantities (Continued) Books Introduction to Materials Management, Sixth Edition, J. R. Tony Arnold, ., CFPIM, CIRM, Fleming College, Emeritus, Stephen N. Chapman, ., CFPIM, North Carolina State University, Lloyd M. Clive, ., CFPIM, Fleming College Operations Management for Competitive Advantage, 11th Edition, by Chase, Jacobs, and Aquilano, 2005, .: McGraw-Hill/Irwin. Operations Management, 11/E, Jay Heizer, Texas Lutheran University, Barry Render, Graduate School of Business, Rollins College, Prentice Hall Objectives Probabilistic Models and Safety Stock Probabilistic Demand Other probabilistic models Fixed period system EOQ consequences Period order quantity model Probabilistic Models and Safety Stock Used when demand is not constant or certain Use safety stock to achieve a desired service level and avoid stockouts ROP = d x L + ss Annual stockout costs = the sum of the units short x the probability x the stockout cost/unit x the number of orders per | Lecture 24 Order Quantities (Continued) Books Introduction to Materials Management, Sixth Edition, J. R. Tony Arnold, ., CFPIM, CIRM, Fleming College, Emeritus, Stephen N. Chapman, ., CFPIM, North Carolina State University, Lloyd M. Clive, ., CFPIM, Fleming College Operations Management for Competitive Advantage, 11th Edition, by Chase, Jacobs, and Aquilano, 2005, .: McGraw-Hill/Irwin. Operations Management, 11/E, Jay Heizer, Texas Lutheran University, Barry Render, Graduate School of Business, Rollins College, Prentice Hall Objectives Probabilistic Models and Safety Stock Probabilistic Demand Other probabilistic models Fixed period system EOQ consequences Period order quantity model Probabilistic Models and Safety Stock Used when demand is not constant or certain Use safety stock to achieve a desired service level and avoid stockouts ROP = d x L + ss Annual stockout costs = the sum of the units short x the probability x the stockout cost/unit x the number of orders per year Safety Stock Example Number of Units Probability 30 .2 40 .2 ROP 50 .3 60 .2 70 .1 ROP = 50 units Stockout cost = $40 per frame Orders per year = 6 Carrying cost = $5 per frame per year Safety Stock Example ROP = 50 units Stockout cost = $40 per frame Orders per year = 6 Carrying cost = $5 per frame per year Safety Stock Additional Holding Cost Stockout Cost Total Cost 20 (20)($5) = $100 $0 $100 10 (10)($5) = $ 50 (10)(.1)($40)(6) = $240 $290 0 $ 0 (10)(.2)($40)(6) + (20)(.1)($40)(6) = $960 $960 A safety stock of 20 frames gives the lowest total cost ROP = 50 + 20 = 70 frames Safety stock units ROP Place order Probabilistic Demand Inventory level Time 0 Minimum demand during lead time Maximum demand during lead time Mean demand during lead time Normal distribution probability of demand during lead time Expected demand during lead time (350 kits) ROP = 350 + safety stock of = Receive order Lead time 6 Probabilistic Demand Safety stock Probability of no .
