Moonchem Case

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GPA784 – Systèmes flexibles de production (Groupe 01 – Amin Chaabane) Travail pratique #8 Cours 9-10: Gestion de l’inventaire Solution pour l’étude de cas “MoonChem” 1. What is the annual cost of MoonChem’s strategy of sending full truckloads to each customer in the Peoria region to replenish consignment inventory? MoonChem’s customer profile appears in Table 10-4 and is reproduced below: Customer Type Number of Consumption Customers (Pounds per Month) Small Medium Large 12 6 2 1,000 5,000 12,000

Each truck has a fixed capacity of 40,000 pounds and costs MoonChem $400 per delivery. The Small customers use only 12,000 pounds per year, so a 40,000 truckload represents better than a three year supply! Total policy cost is obtained using a Q=40,000, an S=$400, and an hC = (25%)($1).

SD hCQ + Q 2 $400(12, 000) (25%)($1)40, 000 TCSmall = + = $5,120 40, 000 2 $400(60, 000) (25%)($1)40, 000 TCMedium = + = $5, 600 40, 000 2 $400(144, 000) (25%)($1)40, 000 TCLarge = + = $6, 440 40, 000 2 TC = Factoring in the number of each class of customers: $5,120 ×12 + $5, 600 × 6 + $6, 440 × 2 = $107,920 2. Consider different delivery options and evaluate the cost of each. What delivery option do you recommend for MoonChem? MoonChem has the option of scheduling multiple deliveries on a single truck with a base charge of $350 for the truck and $50 for each delivery the truck makes; truck capacity remains at 40,000 pounds. Three alternatives that students might consider include creating a “supergroup”

of all customer deliveries on a single truck, creating three groups consisting of customers within each class, and creating two groups consisting of one large, three medium, and six small customers each. Costs for each of these alternatives is examined in turn. Alternative 1: The Supergroup The supergroup approach has a total annual demand of 792,000 pounds of the base chemical and would incur a shipping cost of $350+20($50)=$1350. The optimal order frequency is: k

n =
*

i =1

Di hCi

2S *

=

144, 000($1)(25%) + 360, 000($1)(25%) + (288, 000)($1)(25%) 2($1350)

= 8.56
This number of shipments per year requires a truck capable of holding far more than 40,000 pounds; dividing 792,000 pounds by the 40,000 pound truck capacity sets the number of orders per year at 19.8. Each truck will hold 144,000/19.8=7,273 pounds for the small customers; 360,000/19.8=18,182 pounds for the medium customers, and 288,000/19.8=14,545 pounds for the large customers to be divided equally among the number of customers in each size range. Cycle inventory across all customers in each class is half of the order quantity and results in annual holding costs of $909, $2273, and $1818 for small, medium, and large respectively ($5,000 total). The annual ordering cost of this policy is (19.8 orders)($1350/order) = $26,730. Total plan cost is $5,000+$26,730=$31,730. Alternative 2: Separate groups for the Small, Medium, and Large customers k

nSmall =
*

i =1

Di hCi

2S *

=

144, 000($1)(25%) 2($950)

= 4.35

k

nMedium =
*

i =1

Di hCi

2S *

=

360, 000($1)(25%) 2($650)
k

= 8.32 nLarge =
* i =1

Di hCi

2S *

=

288, 000($1)(25%) 2($450)

= 8.94 The optimal number of shipments for the Medium customers requires a capacity greater than 40,000 per truck, so dividing 360,000 pounds by 40,000 pounds/truck indicates that 9 orders per year is practical. The actual order sizes for each class and the resultant holding and ordering costs are shown in the table: Class Order Size Holding Cost Ordering Cost Small 33,082 $4,135 $4,135 Medium 40,000 $5,000 $5,850 Large 32,199 $4,025 $4,025 The total plan cost is $27,170 Alternative 3: Two groups with 6 Small, 3 Medium, and 1 Large customer each Each group has an annual demand of 396,000 and an ordering cost S=$850. k

n =
*

i =1

Di hCi

2S *

=

72, 000($1)(25%) + 180, 000($1)(25%) + (144, 000)($1)(25%) 2($850)

= 7.63 This ordering frequency exceeds...
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