Just in Time

Key concepts associated with this principle include:

• KANBAN

• SUPERMARKET

• MILK-RUN

• SMED (Single-Minute Exchange of Die)

• HEIJUNKA (Production Leveling)

• ONE-PIECE FLOW / FLOW PRODUCTION 

The McDonald's Example: Push vs. Pull System

Imagine a McDonald's restaurant. If it operated under a traditional management style (PUSH), it would just keep grilling burgers non-stop, regardless of whether every single one actually found a customer. This method of manufacturing immediately creates several types of waste: unnecessary labor, the need for storage space, and unsold burgers ending up in the trash.

The exact same scenario plays out in many companies today when they produce goods for which they have no market demand. In today's business environment, CASH is absolutely critical. If a company generates scrap or ties up capital in warehouse inventory, its ability to maintain a healthy financial reserve is severely crippled.

Companies that embrace Lean thinking manage their production using the PULL system. This means that the signal to start production—whether it's for a hamburger or a car gearbox—is always triggered by the customer.

Just In Time is one of the foundational and most important principles of Lean manufacturing. Its core rule is simple: "Produce only what the customer requires." (Taiichi Ohno). It is a fundamental shift in the manufacturing paradigm from a "PUSH" system to a "PULL" system.