Just in Time System

Just In Time system (JIT) was developed at the Toyota Motor company in Japan in the mid- 1970s by Taiichi Ohno and several of his associates. The roots of JIT system can be traced to the Japanese environment wherein lack of space and lack of natural resources necessitated efficiencies in processes and the use of limited natural resources. Thus the Japanese have developed an aversion to waste of any type, whatever it may be. Scrap and rework were also considered waste and thus they strive for perfect quality. From their point of view, anything, which does not contribute value to the product, is viewed as waste. Therefore, as a result of aversion to waste, it was natural for the JIT philosophy to develop and nurture in Japan. Another major tenet in this philosophy is utilizing the full capability of the workforce, i.e., the workforce is made responsible for producing quality products/parts just-in-time to support the next production process. If they fail to meet their responsibility, they are required to stop the production process (JIDOKA) and call for help. Additional responsibility is also given for improving the production process through participating in quality circles for process of production improvements.

The objective of JIT system is to encourage the workforce to participate in programs for work improvement, leading to increased profits through operating cost reduction, inventory reduction and product quality improvements. Thus, the effort is always towards eliminating waste.

Interestingly, this philosophy is based upon two criteria:

• JIT refers to the production and supply of required number of parts when needed. Hence the term “just in time” production system. If work-in-process inventories including parts and products are expected to decrease (even to zero), this system is called stockless (zero-inventory) production system.

• Another criteria is Jidoka (self-actuation). When an unusual event happens in a production line, the