Kanban System: A visual signaling method (often using cards or electronic signals) that authorizes the movement or production of items only when a downstream process signals a need.
Single-Minute Exchange of Die (SMED): A methodology for drastically reducing the time it takes to change over a machine from one product to another, which is essential for making small lot sizes economical.
Supplier Partnerships: JIT relies on a small number of highly reliable, often local, suppliers who can deliver high-quality components frequently and in small quantities.
Cellular Manufacturing: Arranging equipment and workstations in a sequence that supports a smooth flow of materials, minimizing transport and handling time.
| Feature | Just-in-Time (JIT) | Just-in-Case (JIC) |
|---|---|---|
| Logic | Pull (Demand-driven) | Push (Forecast-driven) |
| Inventory | Minimal/Zero buffer | High buffer (Safety stock) |
| Suppliers | Few, long-term partners | Many, competitive bidding |
| Batch Size | Small, frequent lots | Large, infrequent lots |
| Risk | Supply chain disruption | Obsolescence and high costs |
Link Benefits to Risks: When discussing JIT, always pair a benefit (e.g., lower storage costs) with its corresponding risk (e.g., vulnerability to delivery delays). This demonstrates a balanced understanding of lean systems.
Focus on Cash Flow: Remember that JIT is as much a financial strategy as a production one; reducing inventory releases working capital that can be reinvested elsewhere in the business.
Identify Prerequisites: If a question asks if a firm should adopt JIT, check for 'enablers' like stable demand, reliable suppliers, and a flexible workforce. Without these, JIT is likely to fail.
The 'Symptom' Concept: View inventory not just as a cost, but as a 'blanket' that hides underlying problems like machine breakdowns or poor quality. Removing the inventory forces the firm to fix the root causes.
JIT is not just 'Low Inventory': Simply cutting stock levels without improving process reliability or supplier relationships will lead to frequent stockouts and production halts.
Universal Applicability: JIT is not suitable for every industry. It struggles in environments with highly volatile demand, long lead times from global suppliers, or where bulk-buying discounts significantly outweigh storage costs.
Supplier Pressure: A common mistake is assuming JIT only benefits the manufacturer. If a manufacturer forces JIT on a supplier without coordination, the supplier may simply hold the inventory themselves, increasing total supply chain costs.
