Problem 12.2, HR7E ABC Analysis R. Saltzman

Transcription

1 Problem 12.2, HR7E ABC Analysis R. Saltzman Item Annual Demand Cost/Unit Annual $ Cost A B C D E F G H I J Total Sorted Data: Item Annual Demand Cost/Unit Annual $ Cost % Total Cum. % Class G % 41.4% A F % 64.4% A A % 78.2% A C % 84.4% B D % 89.9% B B % 94.3% B E % 96.1% C I % 97.7% C J % 98.9% C H % 100.0% C Total 100.0% Note: There is no absolutely correct way to draw the lines between the classes.

2 Problem 12.3 HR7E ABC Analysis R. Saltzman Item $ Usage Sorted: Item $ Usage % Total Cum. % Class % 24.5% A % 44.6% A % 59.8% A % 71.4% A % 78.0% B % 83.4% B % 87.0% B % 90.2% B % 93.0% B % 95.3% B % 97.0% B % 98.3% B % 98.7% C % 99.0% C % 99.3% C % 99.5% C % 99.7% C % 99.9% C % 100.0% C % 100.0% C Total

3 Problem 12.8, HR7E Water Beds R. Saltzman Annual Demand D = 400 units/year Ordering Cost S = 40 $ Holding Cost H= 5 $/unit/year a) To minimize total costs, order Q* = 80.0 units each time b) What happens if H = 6 $/unit/year? Q* = 73.0 units each time

4 Problem 12.10, HR7E Fast Moving Product R. Saltzman Daily Demand d = 100 units/day Lead Time L = 21 days Appropriate Reorder Point ROP* = 2100 units Problem 12.11, HR7E Notebook Binders Annual Demand D = units/year Lead Time L = 5 days Working Days per Year = 300 days Reorder Point ROP* = 167 units

5 Problem 12.12, HR7E Industrial Valves R. Saltzman Annual Demand D = 4000 units/year Ordering Cost S = 25 $ Holding Cost H = 9 $/unit/year Cost per Valve P = 90 $/unit Lead Time L = 5 days Number of Days per Year = 250 working days/year a) Economic Order Quantity Q* = units each time rounded Q* = 149 b) Average Inventory Q*/2 = 74.5 units c) Optimal # Orders/yr D/Q* = 27 orders/year d) # of days b/w orders Q*/d = 9.3 days between orders e) Total annual inventory cost = $/year f) Reorder Point ROP* = dl = 80 units Problem 12.13, HR7E Brackets Annual Demand D = 2500 units/year Ordering Cost S = $ Holding Cost H = 1.50 $/unit/year Lead Time L = 2 days Number of Days per Year = 250 working days/year a) Economic Order Quantity Q* = 250 units each time b) Average Inventory Q*/2 = units Ave. Inv. Holding Cost HQ*/2 = $/year c) Optimal # Orders/yr D/Q* = 10 orders/year Annual order cost DS/Q* = $/year d) Total annual inventory cost = $/year e) Time between orders Q*/d = 25.0 days between orders f) Reorder Point ROP* = dl = 20 units

6 Problem 12.16, HR7E POQ Model R. Saltzman Annual Demand D = units/year Setup Cost S = 200 $ Holding Cost H = 1.00 $/unit/year Daily Demand d = 50 units/day Daily Production Rate p = 200 units/day Number of Days per Year = 200 working days/year Production Order Quantity Q* = 2309 units each time Problem 12.17, HR7E Flashlights Annual Demand D = units/year Setup Cost S = 50 $ Holding Cost H = 0.10 $/unit/year Daily Demand d = 40 units/day Daily Production Rate p = 100 units/day Number of Days per Year = 300 working days/year Cost per light = 1.00 $/unit a) Production Order Quantity Q* = units each time rounded Q* = 4472 b) Ave. Holding Cost (HQ*/2)((p-d)/p) = $/year c) Ave. set cost DS/Q* = $/year d) Total annual inventory cost = $/year (including cost of the lights)

7 Problem 12.18, HR7E POQ Model R. Saltzman Annual Demand D = units/year Setup Cost S = 40 $ Holding Cost H = 0.60 $/unit/year Daily Demand d = 50 units/day Daily Production Rate p = 500 units/day a) Production Order Quantity Q* = units each time rounded Q* = 1217 b) Max. Inventory Held Q*((p-d)/p) = 1095 units c) # of Production Runs/year D/Q* = 8.22 d) Total annual inventory cost = $/year

8 Problem 12.20, HR7E EOQ with Quantity Discounts R. Saltzman Without Discount With 3% Discount Annual Demand D = 1000 units/year Annual Demand D = 1000 Ordering Cost S = 40 $ Ordering Cost S = 40 Unit Cost P = 50 $/unit Unit Cost P = Holding Cost H = $/unit/year Holding Cost H = Economic Order Quantity = 80 Quantity Discount Amount 200 Annual Ordering Costs DS/Q = Annual Ordering Costs DS/Q = Annual Holding Costs HQ/2 = Annual Holding Costs HQ/2 = Annual Purchase Costs PD = Annual Purchase Costs PD = Total Annual Costs $/year Total Annual Costs So, take the discount: Order 200 at a time. Problem 12.21, HR7E EOQ with Quantity Discounts R. Saltzman Without Discount With 5% Discount Annual Demand D = 1400 units/year Annual Demand D = 1400 Ordering Cost S = 25 $ Ordering Cost S = 25 Unit Cost P = 400 $/unit Unit Cost P = 380 Holding Cost H = 80 $/unit/year Holding Cost H = 76 Economic Order Quantity = Quantity Discount Amount 300 rounded Q* = 30 Annual Ordering Costs DS/Q = Annual Ordering Costs DS/Q = Annual Holding Costs HQ/2 = Annual Holding Costs HQ/2 = Annual Purchase Costs PD = Annual Purchase Costs PD = Total Annual Costs $/year Total Annual Costs So, take the discount: Order 300 at a time.

9 Problem 12.22, HR7E EOQ with Quantity Discounts R. Saltzman Without Discount Discount when Q = 75 or more units: Annual Demand D = 45 units/year Annual Demand D = 45 Ordering Cost S = 10 $ Ordering Cost S = 10 Unit Cost P = 20 $/unit Unit Cost P = Holding Cost H = 1.00 $/unit/year Holding Cost H = 0.93 Economic Order Quantity = 30 Quantity Discount Amount 75 Annual Ordering Costs DS/Q = Annual Ordering Costs DS/Q = 6.00 Annual Holding Costs HQ/2 = Annual Holding Costs HQ/2 = Annual Purchase Costs PD = Annual Purchase Costs PD = Total Annual Costs $/year Total Annual Costs Discount when Q = 100 or more units: Annual Demand D = 45 Ordering Cost S = 10 Unit Cost P = Holding Cost H = 0.79 So, take the steepest discount: Order 100 at a time. Quantity Discount Amount 100 Annual Ordering Costs DS/Q = 4.50 Annual Holding Costs HQ/2 = Annual Purchase Costs PD = Total Annual Costs

10 Problem 12.27, HR7E Variable Demand R. Saltzman Mean LT Demand (µ) 60 Normally Distributed Std Dev. LT Demand (σ) 7 Desired Service Level (SL) 90% => z = 1.28 (see Appendix I) a) Safety Stock SS = zσ = 8.96 or, 9 (Round up to ensure desired SL) b) ROP = µ + zσ = or, 69 units Problem 12.28, HR7E Variable Demand Mean LT Demand (µ) 50 Normally Distributed Std Dev. LT Demand (σ) 5 Desired Service Level (SL) 97% a) Required z = 1.88 (see Appendix I) b) Safety Stock SS = zσ = 9.40 or, 10 (Round up to ensure desired SL) c) ROP = µ + zσ = or, 60 units