Essay about Operation Management

1554 Words Jun 17th, 2016 7 Pages
| Cleaning Time | Waxing time | C1 | 9 | 6 | C2 | 6 | 2 | C3 | 5 | 7 | C4 | 3 | 5 | C5 | 8 | 4 |
41. (7 points) An automobile detailing shop has the following jobs waiting to be processed. All jobs (cars requiring detailing) must first be cleaned, then waxed.

a. What processing sequence will minimize the makespan for these jobs?

Job | Cleaning Time time | Cleaning Time end time | Waxing time time | Waxing time end time | Waxing time idle time | C4 | 3 | 3 | 5 | 8 | 3 | C3 | 5 | 8 | 7 | 15 | 0 | C1 | 9 | 17 | 6 | 23 | 2 | C5 | 8 | 25 | 4 | 29 | 2 | C2 | 6 | 31 | 2 | 33 | 2 |

b. What is the minimum makespan for this set of five jobs?

Makespan is 33

(POM SW output is attaced in excel)

42. (10 points)
…show more content…
Annual usage of this item is expected to be 3120 units. The firm is open for business 52 weeks per year, so weekly demand is 60 units per week, with a standard deviation of 30 units. The firm’s cost accountants have estimated that it costs $60 every time an order is placed for more components, and that carrying the item in inventory costs about $10 per unit per year. Past experience with their supplier indicates that the time from ordering more items to receipt of the shipment of those items is 21 days (assume they are open 7 days per week).

a. What quantity should be ordered each time? (Assume that the EOQ assumptions apply.)
Annual Demand D = 3120
Ordering cost C0 = $60
Unit Price P = $20
Holding rate H = 50%

(Holding rate = Holding cost / Unit cost = $10/$20 = 50%)
EOQ = Sqrt[(2 x annual usage x cost per order)/(unit price x holding rate)]
Ie EOQ =SQRT((2*D*C0) / (P*H)) = SQRT((2*3120*60) / (20*50%)) = 193.49

EOQ as calculated below is 194 units approx.. So each order should be for 194 units.

Demand rate, D | 3120 | Ordering/Setup cost, S | 60 | Holding cost, H | 10 | Unit Price, P | 20 | Daily demand rate, d | 8.57 | Lead time in days, L | 21 |

Optimal Order Quantity, Q* | 193.49 | Maximum Inventory | 193.49 | Average Inventory | 96.75 | Number of Orders | 16.12 | Holding

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