Just-in-Time (JIT) manufacturing aims to produce only what is needed, when it is needed, and in the quantity needed. Originating from the Toyota Production System, JIT treats inventory as waste — capital tied up in materials sitting on shelves adds cost without adding value. The goal is to flow materials through production with minimal buffers.
JIT requires tight coordination with suppliers, reliable production processes, and robust quality systems. When a machine breaks down or a supplier delivers late in a JIT environment, there is no safety stock to absorb the disruption — production stops. This makes JIT a forcing function for solving underlying problems: unreliable machines, inconsistent quality, and unpredictable suppliers all become urgent issues.
The COVID-19 pandemic and subsequent supply chain disruptions challenged pure JIT strategies. Many manufacturers now practice "just-in-case" buffering for critical or long-lead materials while maintaining JIT principles for items with reliable supply. The key is data-driven decisions about where safety stock is worth the carrying cost.