1. Method Name

Just-in-Time (JIT)

2. Alternative Names

Right on time—the Toyota Production System (this is one of its pillars)

3. Brief Description

JIT is a manufacturing and logistics strategy aimed at producing and delivering only what is needed, when it is needed, and in only the quantity required. This minimizes or completely eliminates inventory (of raw materials, work-in-progress, and finished goods).

4. Purpose / When to Use

It is used to drastically reduce waste (Muda)—particularly waste in the form of excess inventory—and to increase flexibility and responsiveness to customer demands. It is the cornerstone of Lean management.

5. Procedure / How to Apply It

JIT is not a single tool, but a system based on several principles:
1. Pull System: Production is driven by actual demand from the next step (or from the end customer), not by a central plan. Kanban is often used as a tool.
2. Continuous Flow: Organizing production so that products move through the process smoothly, without waiting or accumulating inventory between operations. The ideal is “One-Piece Flow” (one-piece flow).
3. Short Takt Time: Synchronizing production speed with customer demand.
4. Quick Changeovers (SMED): The ability to quickly and efficiently change over a production line enables production in small batches.
5. High Quality at the Source (Jidoka): A zero-inventory system cannot afford to produce defects. Quality must be ensured at every step.
6. Reliable Suppliers: This requires close collaboration with suppliers who are capable of delivering small batches of material frequently and exactly on time.

6. A Real-World Example

Toyota is a classic example. The seat supplier has a factory right next to Toyota’s assembly line. When a car of a specific color and trim level arrives for seat installation, the system sends a signal to the supplier, who delivers exactly the right seat directly to the line within a few minutes. As a result, Toyota does not keep any inventory of seats.

7. Benefits

- Dramatic reduction in costs tied up in inventory
.- Improved cash flow
.- Improved quality: Problems are detected immediately because they are not hidden in inventory
.- Increases flexibility and shortens lead times.
- Saves space in the factory.

8. Risks / Limits

- High vulnerability to disruptions: The system is highly sensitive to any disruptions (machine breakdown, supplier delays, quality issues). It has no “buffers” in the form of inventory
.- It requires extremely stable and reliable processes
.- Heavy reliance on suppliers
.- Implementation is complex and time-consuming.

9. Practical Tips

- JIT isn't just about inventory: It's a comprehensive philosophy. Focusing solely on reducing inventory without implementing other elements (quality, SMED, stability) leads to disaster.
- Start with internal JIT: First, implement JIT among your own departments, and only then expand it to external suppliers.
- JIT vs. JIC (Just-in-Case): JIT is the opposite of the traditional “Just-in-Case” approach, where companies hedge against uncertainty by holding large inventories.