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INVENTORY MANAGEMENT. Inventory. Raw material In-Process Finished Goods Components & spare Parts Inventory Costs Purchase Cost Ordering Costs Carrying / Holding Costs Shortage Costs. Types of Inventory. Seasonal Inventory Arise out of seasonality Decoupling Inventory
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INVENTORY MANAGEMENT WWW.PPTMART.COM
Inventory • Raw material • In-Process • Finished Goods • Components & spare Parts Inventory Costs • Purchase Cost • Ordering Costs • Carrying / Holding Costs • Shortage Costs WWW.PPTMART.COM
Types of Inventory • Seasonal Inventory • Arise out of seasonality • Decoupling Inventory • Work-in progress- output of preceding stage becomes input for succeeding stage • Inventory decisions require analysis of workstation capacities, resource availability & bottlenecks • Cyclic Inventory • Inventory in repeated cycles and consumed overtime • Average cyclic inventory = Q/2 • Pipeline Inventory • It is carried according to the lead time • Done to avoid shortage due to delays in delivery • It is the additional inventory to buffer against uncertainties in demand & supply of raw materials & components WWW.PPTMART.COM
Economic Order Quantity (EOQ) It is an idealized inventory system to calculate the fixed order quantity that minimizes total costs. This optimal order size is called EOQ. Reorder Level Reorder level = lead time × demand per unit time ROL = LT × D WWW.PPTMART.COM
Fixed Order Quantity System or ‘Q’ System EOQ Reorder Level Minimum Level Safety Stock T1 T2 T3 Time WWW.PPTMART.COM
Fixed Order Period System or ‘P’ System Q2 Q3 Q1 M L Safety Stock T T T TIME WWW.PPTMART.COM
EOQ Model Total Cost Curve Holding Cost Min Tc Annual Cost Ordering Cost Order Quantity EOQ WWW.PPTMART.COM
EOQ = Optimum Quantity = Least Total Cost Total cost = Tc = D*Cp + D*Co + Q*Ch Q 2 Where, Tc = Total Cost D = Annual demand (units) Cp = Purchase cost / unit Q = Order quantity (EOQ) Co = Cost of Placing an order Ch = Holding cost WWW.PPTMART.COM
Total Cost (Min.) = Ordering Cost = Carrying Cost D * Co = Q * Ch Q 2 Where, D/Q = No. of orders, Q/2 = Average Inventory Thus, Q² = 2 D Co Ch Or Q =√2 D Co = EOQ Ch WWW.PPTMART.COM
Q1. Telco Ltd. Uses 2,400 of particular type of component per year. ‘X’ enterprise supplies this at a price of Rs. 10 each. Ordering cost is Rs. 100 per order & carrying cost is 10% at Telco. ‘X’ enterprise wants to give 10% discount if order quantity is 1000. Is it advisable to accept the discount offer? WWW.PPTMART.COM
Sol.1 EOQ =√2 D Co = √2*2400* 100 = 690 units Ch 1 Where, Ch= 10% x 10 Now, Total Cost for EOQ: Tc1 = D. Cp + D . Co + Q . Ch Q 2 = 2400 x 10 + 2400 x 100+690 x 10 x 10=24,693 690 2 100 Total cost for Discount offer i.e. for order of 1000 units Tc2= 22,340 Hence, it is better to take discount offer as Tc2 < Tc1 WWW.PPTMART.COM
Q2. Company ‘XYZ’ buys 2000 pencils/year at Rs 1/- each. The ordering cost is Rs 10/- per order. Inventory carrying cost is 16% per annum. Find: (1) EOQ (2) No. of orders & (3) Total inventory cost/year WWW.PPTMART.COM
Sol 2. (1) Given: D = 2000 units, Co = 10, Ch = 16 % of Cp = 16 % x 1 = .16 EOQ =√2x2000x10 = 500 units 0.16 (2) No. of orders = D = 2000 = 4 orders Q 500 (3) Tc = D . Co + Q . Ch =4 x 10+250 x 0.16 = 80 Q 2 WWW.PPTMART.COM
ABC Analysis • Also called “Always better Control” • It takes into account both value & volume of consumption of items WWW.PPTMART.COM
A items represent 10% of the total inventory items, but70–80% of the total cost. • Plywood • B items are of mediumvalue that represent 20% of the items and 15–25% of the total cost. • Electrical wiring • Upholstery for seats • The low price items are class C items, representing 70% of the items and 5–10% of the total cost. • Nuts WWW.PPTMART.COM
100 90 Annual Consumption value of Total 70 C A B 30 100 10 0,0 Quantity WWW.PPTMART.COM
VED ANALYSIS • Also called Vital (v), Essential (E) & Desirable (D) analysis • Concerned with functional importance of items regardless of their volume &value • ‘V’ items have large inventory • ‘D’ items have minimum stock JIT METHOD Also referred as • ZIPS (Zero Inventory Production System) • MAN (Materials as Needed) • NOT (Nick of Time) • ZIN (Zero Inventories) WWW.PPTMART.COM