Traditional manufacturing operations are push-type systems. They are based on the assumption that it is better to anticipate future production requirements and plan for them. Traditional systems produce goods in advance in order to have products in place when demand occurs. Products are pushed through the system and are stored in anticipation of demand, which often results in overproduction because anticipated demand may not materialize. Also, there are costs associated with having inventories of products sitting in storage and waiting for consumption.
As noted earlier, JIT uses a pull system rather than a push system to move products through the facility. Communication in JIT starts either with the last workstation in the production line or with the customer and works backward through the system. Each station requests the precise amount of products that is needed from the previous workstation. If products are not requested, they are not produced. In this manner, no excess inventory is generated.
JIT is based on a “pull” system rather than a “push” system.
To see the difference between a push and a pull system, suppose that you have decided to have a backyard cookout for your friends. You have invited 20 people and are anticipating that each one will eat at least one hamburger and one hot dog. When your friends arrive, you decide ...