InventoryManagement仓储管理课件

Begin End order order receipt receipt
Time
•InventoryManagement仓储管理
•12-20
•InventoryManagement仓储管理
•12-3
Inventory and Supply Chain Management
Bullwhip effect
demand information is distorted as it moves away from the end-use customer
▪ Ordering cost
▪ cost of replenishing inventory
▪ Shortage cost
▪ temporary or permanent loss of sales when demand cannot be met
•InventoryManagement仓储管理
PART VTPAOALTRUAELT
9 $30,6100
8 16,0200
2 1
154,,4030000
4 4,8400
3 3,9500
6 5
CL33A,,6067S00S00
10 7
$85211,,,ABC447089000000
%UOVNFALITTUOETCAOL ST%QOUFAANTNTOITNTAYUL A%L CUUSMAMGULEATIVE
▪ Demand is known with certainty and is constant over time
▪ No shortages are allowed ▪ Lead time for the receipt of orders is
constant ▪ Order quantity is received all at once
System
•InventoryManagement仓储管理
•12-1
What Is Inventory?
Stock of items kept to meet future demand
Purpose of inventory management
how many units to order when to order
Inventory provides independence between stages and avoids work stop-pages
•InventoryManagement仓储管理
•12-4
Two Forms of Demand
▪ Dependent
▪ Demand for items used to produce final products
35$.960
6.0
183.750
Hale Waihona Puke 5.0166..4330
4.0 9.0
5.680
6.0
4.630
10.0
ITEM43..S252100 % OVFALT11UO83E..T00AL
9, 1, 6,
485,,,2232135..80012, 007
20
71.20.0 161.75.0 12.5
90 6.0
UNIT COST
$ 60 350
30 80 30 20 10 320 510 20
ANNUAL USAGE
90 40 130 60 100 180 170 50 60 120
•InventoryManagement仓储管理
•12-10
ABC Classification: Example (cont.)
•InventoryManagement仓储管理
•12-13
Inventory Order Cycle
Order quantity, Q
Demand rate
Inventory Level
Reorder point, R
0
Lead
time
Order Order
placed receipt
•InventoryManagement仓储管理
Lecture Outline
Elements of Inventory Management Inventory Control Systems Economic Order Quantity Models Quantity Discounts Reorder Point Order Quantity for a Periodic Inventory
Inventory must be sufficient to provide high-quality customer service in TQM
•InventoryManagement仓储管理
•12-6
Inventory Costs
▪ Carrying cost
▪ cost of holding an item in inventory
EOQ
optimal order quantity that will minimize total inventory costs
Basic EOQ model Production quantity model
•InventoryManagement仓储管理
•12-12
Assumptions of Basic EOQ Model
Class B
30 % of units 15 % of value
Class C
50 – 60 % of units 5 – 10 % of value
•InventoryManagement仓储管理
•12-9
ABC Classification: Example
PART
1 2 3 4 5 6 7 8 9 10
•InventoryManagement仓储管理
•12-2
Types of Inventory
Raw materials Purchased parts and supplies Work-in-process (partially completed)
products (WIP) Items being transported Tools and equipment
Annual cost ($)
Minimum total cost
Slope = 0
Total Cost
Carrying Cost =
CcQ 2
Optimal order Qopt
•InventoryManagement仓储管理
CoD Ordering Cost = Q
Order Quantity, Q
assumption that Q is received all at once is relaxed
p - daily rate at which an order is received over time, a.k.a. production rate
d - daily rate at which inventory is demanded
TC Q
=
CoD Q2
+
Cc 2
0=
C0D Q2
+
Cc 2
Qopt =
2CoD Cc
•InventoryManagement仓储管理
Proving equality of costs at optimal point
CoD Q
=
CcQ 2
Q2
=
2CoD Cc
Qopt =
2CoD Cc
•12-16
EOQ Cost Model (cont.)
Annual ordering cost =
CoD Q
Annual carrying cost =
CcQ 2
Total cost =
CoD Q
+
CcQ 2
•InventoryManagement仓储管理
•12-15
EOQ Cost Model
Deriving Qopt
TC =
CoD Q
+
CcQ 2
•12-17
EOQ Example
Cc = $0.75 per yard Co = $150 D = 10,000 yards
Qopt = Qopt =
2CoD Cc
2(150)(10,000) (0.75)
TCmin
=
CoD Q
+
CcQ 2
(150)(10,000) (0.75)(2,000)
TCmin = 2,000 +
•12-7
Inventory Control Systems
▪ Continuous system (fixedorder-quantity)
▪ constant amount ordered when inventory declines to predetermined level
▪ Periodic system (fixed-timeperiod)
higher safety stock inventories to are stored to compensate
Seasonal or cyclical demand
Inventory provides independence from vendors
Take advantage of price discounts
2
Qopt = 2,000 yards
TCmin = $750 + $750 = $1,500
Orders per year = D/Qopt = 10,000/2,000 = 5 orders/year
•InventoryManagement仓储管理
Order cycle time = 311 days/(D/Qopt) = 311/5 = 62.2 store days
•12-18
Production Quantity Model
An inventory system in which an order is received gradually, as inventory is simultaneously being depleted
AKA non-instantaneous receipt model
•InventoryManagement仓储管理
•12-5
Inventory and Quality Management
Customers usually perceive quality service as availability of goods they want when they want them
▪ order placed for variable amount after fixed passage of time
•InventoryManagement仓储管理
•12-8
ABC Classification
Class A
5 – 15 % of units 70 – 80 % of value
▪ Tires stored at a Goodyear plant are an example of a dependent demand item
▪ Independent
▪ Demand for items used by external customers
▪ Cars, appliances, computers, and houses are examples of independent demand inventory
A40
130
11.0 15.0 24.0
B60 30.0
100 40.0
11C8756%0000QOUFA1261N505T0578...OT0813000....IT0000TAYL
120
Example 10.1
•InventoryManagement仓储管理
•12-11
Economic Order Quantity (EOQ) Models
Lead time
Order Order placed receipt
Time •12-14
EOQ Cost Model
Co - cost of placing order Cc - annual per-unit carrying cost
D - annual demand Q - order quantity
•InventoryManagement仓储管理
•12-19
Production Quantity Model (cont.)
Inventory level
Q(1-d/p) Q (1-d/p) 2
Maximum inventory level
Average inventory level
0
Order receipt period