Key Inventory Management Models to Know for Intro to Industrial Engineering

Inventory management models are essential for optimizing stock levels and minimizing costs in industrial settings. These models, like EOQ and JIT, help balance ordering and holding costs, ensuring efficient operations and customer satisfaction in a dynamic supply chain environment.

1. Economic Order Quantity (EOQ) Model

   • Determines the optimal order quantity that minimizes total inventory costs, including ordering and holding costs.
   • Balances the trade-off between ordering frequency and inventory holding.
   • Assumes constant demand and lead time, making it ideal for stable environments.

2. Continuous Review (Q,R) Model

   • Involves monitoring inventory levels continuously and reordering when stock reaches a predetermined reorder point (R).
   • Helps maintain service levels by ensuring that stock is replenished before it runs out.
   • Suitable for high-value or critical items where stockouts can be costly.

3. Periodic Review (s,S) Model

   • Inventory is reviewed at fixed intervals, and orders are placed to raise inventory to a target level (S).
   • Allows for bulk ordering and can reduce ordering costs by consolidating orders.
   • Useful in environments with fluctuating demand and lead times.

4. ABC Inventory Classification

   • Categorizes inventory into three classes (A, B, C) based on value and turnover rate.
   • A items are high-value, low-quantity; B items are moderate; C items are low-value, high-quantity.
   • Helps prioritize management efforts and resources on the most critical items.

5. Just-In-Time (JIT) Inventory

   • Aims to reduce inventory levels by receiving goods only as they are needed in the production process.
   • Minimizes holding costs and reduces waste, promoting efficiency.
   • Requires strong supplier relationships and reliable demand forecasting.

6. Safety Stock Calculation

   • Determines the additional inventory held to mitigate the risk of stockouts due to demand variability or supply delays.
   • Calculated based on service level requirements and variability in demand and lead time.
   • Essential for maintaining customer satisfaction and operational continuity.

7. Reorder Point Determination

   • Establishes the inventory level at which a new order should be placed to avoid stockouts.
   • Takes into account lead time and average demand during that lead time.
   • Critical for effective inventory management and ensuring timely replenishment.

8. Lot-Sizing Techniques

   • Methods for determining the optimal order quantity to minimize costs while meeting demand.
   • Includes techniques like Economic Order Quantity (EOQ), Lot-for-Lot, and Silver-Meal heuristic.
   • Helps balance ordering costs with holding costs and demand variability.

9. Material Requirements Planning (MRP)

   • A system for managing manufacturing processes by calculating material requirements based on production schedules.
   • Ensures that materials are available for production while minimizing inventory levels.
   • Integrates with other systems to enhance overall supply chain efficiency.

10. Vendor Managed Inventory (VMI)

    • A collaborative approach where suppliers manage the inventory levels of their products at the customer's location.
    • Reduces stockouts and excess inventory by leveraging supplier expertise in demand forecasting.
    • Enhances supply chain efficiency and strengthens supplier-customer relationships.