C7

Learning Objectives

  • Explain the role and importance of inventory in business operations.
  • Discuss major inventory types and how they influence decisions.
  • Compare alternative approaches to managing inventory.
  • Describe the economic benefits and roles of warehousing.
  • Identify warehouse types and outline efficient operations.

Inventory: Core Concepts

  • Inventory = all items, goods, merchandise, materials held for sale to earn profit.
  • In Supply Chain Management (SCM): total goods & materials on hand.
  • Asset distinction example:
    • Newspaper vendor: newspapers = inventory; delivery vehicle = fixed asset.

Industry Perspectives

  • Manufacturing:
    • Inventory spans raw materials, WIP, finished goods.
    • Cookie example: packed cookies (FG), cooling cookies (WIP), QC cookies, sugar/milk/flour (RM).
  • Service:
    • Inventory is largely intangible (information, capacity, customer experience).
    • Examples: research firm’s collected data; hotel’s vacant room & customer feedback.

Inventory Management

  • Tracks flow from manufacturers ➜ warehouses ➜ point of sale.
  • Modern systems automate ordering, storing, forecasting, accounting.
  • Objective: “Right product, right place, right time.”
  • Key requirements: visibility & availability (know when/where/quantity to order & store).
  • Operational definition: arranging stocked goods & non-capital assets by shape & placement.

Benefits of Effective Management

  • Prevent dead stock & spoilage.
  • Optimize storage costs by avoiding excess.
  • Ensure continuous production through sufficient stock.
  • Enhance cash flow by balancing liquidity vs. inventory value.
  • Reduce purchase costs via bulk discounts.

Inventory Types by Production Stage

  • Raw Materials (RM)
    • Purchased inputs processed into finished goods.
    • May be externally sourced or internally generated by-products.
    • Sugarcane → juice & bagasse (all treated as RM in sugar plant).
  • Work-in-Process (WIP)
    • Semi-finished goods still undergoing transformation.
    • Represents total cost of unfinished items on factory floor.
    • Typically unsellable yet unavoidable.
  • Finished Goods (FG)
    • Ready-for-sale products.
    • Two manufacturing logics:
    • Make-to-stock: produce first, then sell; FG inventory inevitable.
    • Make-to-order: receive order, then produce; FG inventory can be minimal.

Additional Inventory Classifications

Cycle Stock (Working Inventory)

  • Qty needed to satisfy normal demand during ordering/production cycle.
  • Forecast-based; pivotal for daily operations.
  • Benefits: fewer lost sales, reduced carrying costs, protected safety stock, fewer rush “fire-drills.”

Safety / Buffer Stock

  • Surplus kept as contingency against demand spikes, delays, or failures.
  • Smoothes operations & maintains customer satisfaction.
  • Trade-off: higher carrying cost vs. service reliability.
  • Example: remote veterinarian stores extra disinfectant before flood season.

In-Transit Inventory

  • Goods already shipped but not yet received.
  • Longer transit = higher days of inventory outstanding ➜ ties capital.
  • Example: Saudi crude oil en route to Europe.

Speculative Stock

  • Purchased in anticipation of price hikes or future demand.
  • Relies on cost‐risk analysis.
  • Example: buying discounted noodles before flood-season price jumps.

Seasonal Stock

  • Demand fluctuates by weather, events, holidays.
  • Peaks & troughs: e.g., knitwear during winter/Christmas.

Dead Stock

  • Unsellable items (over-ordered, damaged, expired, obsolete).
  • Drains space, capital, and opportunity for faster movers.

Inventory Carrying Cost (ICC)

  • Total expense of holding unsold goods.
  • Components:
    • Capital Cost: interest or opportunity cost on tied-up funds.
    • Storage Space Cost: rent, utilities, maintenance, material handling labor.
    • Inventory Service Cost: taxes, insurance, IT/hardware.
    • Inventory Risk Cost: shrinkage, damage, obsolescence, pilferage.
  • Illustrative metric:
    ICC %=Total Carrying CostAverage Inventory Value×100%ICC\,\% = \frac{\text{Total Carrying Cost}}{\text{Average Inventory Value}} \times 100\%

Warehouse / Storage Management

  • Activity of storing goods systematically & making them available as needed.
  • Creates time & place utility between origin and consumption points.
  • Supplies management with item status, condition, disposition data.

Functions & Service-Enhancement Rationale

  • Customer satisfaction via availability ➜ supports revenue growth.
  • Spot-stocking, full-line stocking, and value-added services increase sales despite added cost.
Spot Stocking
  • Seasonal/temporary placement of inventory in small regional warehouses.
  • Improves responsiveness during demand peaks (e.g., fertilizer near farms pre-planting).
Full-Line Stocking / Assortment
  • Few strategic warehouses hold broad product assortments from multiple suppliers.
  • Enables one-stop shopping & larger economical shipments.
Value-Added Services (VAS)
  • Repacking, kitting, postponement, material screening, rework, customization.
  • Transforms product presentation, boosting customer value.

Warehouse Ownership Models

Private Warehouse

  • Owned/operated by the firm using it.
  • Advantages: total control, flexibility, cost control, brand reputation.
  • Disadvantages: high capital investment, fixed costs, limited scalability, full responsibility.

Public Warehouse

  • Operated by 3PL or government; space rented to multiple clients.
  • Types: general merchandise, refrigerated, bonded (tax/duty deferred).
  • Advantages: cost-effective, scalable, expertise, convenient location.
  • Disadvantages: space availability constraints, standardized systems, limited specialized services.

Contract Warehouse

  • Hybrid: dedicated space within a 3PL under multi-year contract.
  • Combines private control with public economies of scale.
  • Advantages: lower capital, VAS access, reliability, centralization.
  • Disadvantages: pricing variability, reduced process control, effort to find right partner.

Specialized Warehouse Categories in SCM

  • Distribution Centre: customer-centric, high velocity, cross-docking & value additions.
  • Smart Warehouse: employs interconnected automation (robots, drones) for receiving ➜ shipping.
  • Bonded Warehouse: government-licensed; defers duty payment up to 5 years.
  • Refrigerated / Cold Storage: controlled low-temperature for perishables, pharmaceuticals, etc.
  • Pick-Pack-Ship Warehouse: focuses on order fulfillment sequence immediately after order receipt.

Warehousing Operations & Product Handling

  • Objectives: receive, store, move, assemble orders, ship—while minimizing cost & errors.
  • Key principle: movement continuity—fewer, longer moves preferable to many short moves.

Five Fundamental Handling Activities

  1. Receiving
    • Unload large shipments via lift-trucks, conveyors; create unit loads by SKU when floor-stacked.
    • Fast unloading frees transport equipment.
  2. Put-Away
    • Move goods to active or secondary locations (floor stack, racks, flow racks).
    • Efficiency via forklifts & system-directed locations.
  3. In-Storage (Replenishment)
    • Internal moves to refill active bins from reserve stock.
    • Balance bin sizing: too large ➜ excess travel; too small ➜ frequent replenishment & stock-outs.
  4. Order-Picking
    • Assemble SKUs per customer order in dedicated areas.
    • May involve single-SKU pallets or mixed loads; employ routing, equipment, workflow optimization.
  5. Shipping
    • Verify order accuracy & condition ➜ load outbound vehicles.
    • Mix of low-volume, varied products reduces scale economies vs. receiving.

Storage Modes

  • Active Storage
    • Short-term, high accessibility for immediate replenishment.
    • Layout emphasizes quick movement & flexibility; dense storage less critical.
  • Extended Storage
    • Holds inventory beyond normal replenishment (seasonal, speculative, conditioning).
    • Focus on space utilization; slower access acceptable (e.g., banana ripening rooms).

Ethical, Financial & Practical Considerations

  • Overstocking ties capital, increases ICC, risk of obsolescence → ethical duty to shareholders.
  • Under-stocking risks lost sales, customer dissatisfaction.
  • Warehousing decisions affect environmental footprint (energy use, refrigeration, transportation).
  • Labor & automation choices influence workforce safety and community employment levels.