92 ◾ Lean Production Simplified, Third Edition
Basic Principles of JIT
Toyota introduced just-in-time production (JIT) in the 1950s and continues
to refine it. JIT was first introduced to North America in the 1980s along
with quality circles, statistical process control (SPC), and other Japanese
innovations. JIT enjoyed a brief bloom in North America then wilted, as the
ground proved infertile.
JIT production follows a few simple rules.
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1. Don’t produce something unless the customer has ordered it.
2. Level demand so that work may proceed smoothly throughout the
plant.
3. Link all processes to customer demand through simple visual tools
(called kanbans).
4. Maximize the flexibility of people and machinery.
Womack and Jones have also defined ...