Just-In-Time (JIT) Production Systems
Just-in-time or JIT production systems were urbanized in Japan to minimize inventories, especially WIP. In a Just-in-time production system, merely the essential products, at the necessary time, in the essential quantity are manufactured and stock upon hand is held to a minimum.
In other words we can say, an ideal JIT production system produces and delivers exactly the required number of each component to the downstream operation in the manufacturing sequence just at the time when that component is needed, to ensure that all components is delivered "just in time". This delivery discipline minimizes WIP and manufacturing lead time and the space also and money invested in WIP. Just in time is based upon a pull system of production control, whether the order to make and deliver parts at every workstation in the production sequence arises from the downstream station that employs those parts. While the supply of parts at a specified workstation is about to be exhausted, such station orders the upstream station to replenish the offer and only after that the upstream station is authorized to generates the needed parts. Via comparison, in a push system of production control, parts at every workstation are generated irrespective of the immediate require at its respective downstream station. The risk in this category of system is get more works scheduled in the factory than it can handle, resulting in huge queues of machines of parts in front.
To implement a pull system to production control, there are various ways. The Kanban system, improved and made famous by Toyota, the Japanese automobile company such is just individual of them. This uses cards set that travel in between subsequent and preceding processing point, communicating what parts are required at the subsequent process, and hence controlling work-in-process, inventory flow, and production.