Principle (Diminishing Return to Buffering): The decrease in line WIP level from adding a unit of buffer space at a station in an open line decreases as the size of the buffer increases.
As we have seen in the buffering principle, adding buffer space decreases the line WIP level (or at least does not increase it). However, this decrease in WIP does not continue indefinitely as we add more and more buffer space. The diminishing returns to buffering principle states that the benefits of additional buffer spaces will decrease as the size of the buffers grow. This is an example of the general principle of diminishing returns. The reason it occurs here is that the decrease in line WIP level from adding buffer occurs because it decreases the likelihood that machines will become blocked. However, as buffer sizes increase, the likelihood of filling them and experiencing blocking decreases. Hence, the impact of additional buffers also decreases.
At some point, for sufficiently large buffer sizes, the likelihood of blocking/starving becomes negligible. As this occurs, the performance reaches the level of open lines with infinite buffers. Thus, for a given finite buffer line, the the infinite buffer open line case provides an upper on performance.
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