IntermediateTopic 39 of 102Manufacturing, Robotics & Systems

Inventory management

Balance holding cost against stock-outs with EOQ and just-in-time.

In depth

Inventory balances holding cost against ordering and shortage costs: EOQ=√(2DS/H), reorder point, safety stock for service level, ABC analysis, JIT, VMI. Minimising inventory frees capital but raises disruption risk. Bullwhip effect amplifies demand variation upstream.

Key points

  • Cycle stock
  • Lead time demand
  • Service level z-factor
Example

With D=10 000/yr, S=$50, H=$2, EOQ=707 units.

Why it matters

Inventory control balances the cost of holding stock against the cost of running out, so it affects both working capital and service.

Where this is used

  • Calculating the order quantity that minimises total ordering and holding cost.
  • Setting a safety stock level for a critical spare part.
  • Changing to just-in-time delivery from a nearby supplier.

Frequently asked questions

What is Inventory management?

Balance holding cost against stock-outs with EOQ and just-in-time.

Why is it important to understand inventory management?

Inventory control balances the cost of holding stock against the cost of running out, so it affects both working capital and service.

What is the economic order quantity?

The order size that minimises the sum of ordering cost and holding cost, found from the square root of two times demand times ordering cost over holding cost.

What is just-in-time?

A method that delivers parts just when they are needed, which reduces stock but requires reliable suppliers and short lead times.

How is Inventory management used in practice?

Typical applications include calculating the order quantity that minimises total ordering and holding cost, setting a safety stock level for a critical spare part and changing to just-in-time delivery from a nearby supplier.

What should I learn before Inventory management?

Study "Production planning and scheduling" first (topic 38 of 102 in Manufacturing, Robotics & Systems). It covers the groundwork this topic builds on.

What are the key points of Inventory management?

Cycle stock. Lead time demand. Service level z-factor.

Can you give an example of Inventory management?

With D=10 000/yr, S=$50, H=$2, EOQ=707 units.

What comes after Inventory management?

The next topic is "Supply chain and logistics", which builds directly on this one.

How difficult is Inventory management?

It is classed as Intermediate in Manufacturing, Robotics & Systems (topic 39 of 102). It is an intermediate topic. Work through the beginner topics in Manufacturing, Robotics & Systems first.

Learning path

Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.

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