Difference Between Push and Pull Manufacturing System:

In push system, when work is finished at a workstation, the output is pushed to the next station; or, in the case of the final operation, it is pushed on to the final inventory. In this system, work is pushed on as it is completed, with no regard for whether the next station is ready for the work or not. In this way, the WIP is unbalanced in all operations throughout the shop floor.

Table 1 : Pull and Push System 

The push system is also known as the Materials Requirements Planning (MRP) system. This system is based on the planning department setting up a long-term production schedule, which is then dissected to give a detailed schedule for making or buying parts. This detailed schedule then pushes the production people to make a part and push it forward to the next station. The major weakness of this system is that it relies on guessing the future customer demand to develop the schedule that production is based on and guessing the time it takes to produce each part. Overestimation and under- estimation may lead to excess inventory or part shortages, respectively.

Whereas in pull system; each work station pulls the output from the preceding station as it is needed. Output from the final operation is pulled by customer demand or the master schedule. Thus in pull system work is moved in response to demand from the next stage in the process. The Kanban system is used to monitor the effective pull process. Table 1 helps to differentiate Pull and Push system.