In today’s competitive world, shorter product lifecycles, rapid customer demands, and the rapidly changing business environment are putting a lot of pressure on manufacturers for faster response and shorter cycle times. Now manufacturers are putting pressure on their suppliers. One way to ensure a quick response is to maintain inventory, but inventory costs can easily become prohibitive. A smarter approach is to make your production agile, able to adapt to changing customer demands. This can only be done with the JUST IN TIME (JIT) philosophy.

Taiichi Ohno, a former shop manager and eventually vice president of Toyota Motor Company, is the person most credited with developing just-in-time. It is a term used to describe Toyota’s production system, and it is widely recognized today as one of the most efficient manufacturing systems in the world. In simple words, we can explain JIT that only requires the necessary units to be provided in the necessary quantities at the necessary times. Producing an extra unit is just as bad as keeping one less unit. Completing one day early is just as bad as finishing one day late. Items are delivered “just in time”. Ohno describes the development of JIT as

* Really trying, several problems are known. As many problems gradually cleared up, they taught me the direction of the next step. I think we can only understand how all these pieces fit together in hindsight.

The concept is very simple, if you produce only what you need when you need it, then there is no room for error. JIT has truly changed the face of manufacturing and transformed the global economy. JIT is both a philosophy and a collection of management methods and techniques used to eliminate waste (in particular, inventory). At JIT, workers are cross-functional and must perform different tasks. The machines are also multi-functional and arranged in small U-shaped work cells that allow parts to be processed in a continuous flow through the cell. Workers produce pairs one at a time within cells and transport those parts between cells in small batches. The environment is kept clean and free of debris so that any unusual occurrences are visible. The schedules are prepared only for the final assembly line, in which several different models are assembled on the same line. The requirements for the components and sub-assemblies are then drawn through the system. The “PULL” element of JIT will not work unless production is consistent and batch sizes are low. The extraction system is also used to order material from suppliers (usually fewer in number). They are required to make multiple deliveries of the same item on the same day, so the manufacturing system must be flexible.

Just-in-time inventory is considered a waste of resources and is seen as a roadblock to improvement. As there is little buffer inventory between workstations, quality must be high and efforts must be made to avoid machine breakdowns. When all of these things are taken into account, system produces high-quality products, quickly and at low cost. This system is also being able to respond to changes in customer demands. These JIT elements can also be applied to almost any operation, including service operations. * K. Suzuki, The Manufacturing Challenge (New York: Free Press, 1985), p250