Just-In-Time Philosophy:

Just-in-time system was developed initially by Japanese companies like Toyota. Later on it was adopted by other manufacturing companies of USA and Europe. Now it has become one of the most advocated and popular manufacturing philosophy, especially for large volume repetitive manufacturing operations like in automobile industry. Since, JIT is a common approach; mostly the basic principles could also be implemented on other type of operating systems.

JIT has been described as involving 'the production of the essential items in the required quantities at the desired time'. In other term, with this approach, the materials and items required by the process are made available as and while they are required, and not before. This seemingly simple idea in fact contrasts markedly with practice in many operating systems those based upon substantial inventories. With the JIT approach queues waiting processing at an operation are minimal. Work-in-process inventory therefore is minimum. Throughput times are dropped off, space requirements are less, and the flow through the system is continuous. Considerable managerial effort is needed to bring about and sustain such a situation. Given the uncertainty which exists in most operating situations, for example uncertainties of demand, the processing time of particular operations, scrap and losses etc., it has been quite common to construct inventories into the system to provide some degree of safety and to 'decouple' processes. If an inventory exists among two processes then the failure of one does not immediately impact on the activities of the other. An inventory may also exist so that increases in demand may be met without the immediate need to change the rate at which the operating system works. Thus, inventories of output items, work in process and raw materials are maintained in every industry. The JIT approach, however, completely reverses this principle. In JIT, inventories are kept minimum and work is not done until required. Items are not processed until required at the next process, and processes are independent.

Therefore, the principle feature of the JIT approach concerns the management of inventories. JIT aims to make a zero or low inventory operating system. Reduction in inventory helps space requirements, reduce the amount of tied up capital, reduce the risk of loss and damage, and decrease handling requirements. Additionally the minimisation of inventories is considered to have considerable managerial benefits. If, as is often the case, the inventories have grown up in order to protect an operating systems again uncertainties, then it may be argued that such inventories serve to conceal the real problems JIT aims to reveal them in order that they may be tackled at source. Hence, with low inventory production system, the problems may be identified and solved. If input stocks of the material have been held in order to protect an organisation from disruptions in supply, then utilizes of JIT requires that those problems be overcome through. For instance, use of different vendors, and/or the establishment of different arrangement with suppliers may help in smoothening the supply. If work in process stocks has been held to protect against the breakdown of the equipment, the introduction of JIT requires that the causes of breakdown be identified and eliminated. Therefore JIT has both system and managerial advantages.