In this case the bottleneck is the machine (or operation) number 6. The bottleneck can stop or stifle the work on all other machines or operations in a cell. When we work with two shifts per day, which is 900 minutes, then daily capacity of this whole layout is 900 ÷ 3.5 = 257.14 pcs. But, is this capacity a fixed number? When a team leader assigns a slow operator to the bottleneck, this slow operator can slow down everybody’s work in the cell even more. When a team leader assigns a quick operator, the material flow can increase and another machine or operation (in the Table 2 it is machine number 4) can become a new bottleneck.
Table 2: Set of machines with a changed bottleneck process
Machine 1 2 3 4 5 6 7 8 9 10 Process
time/pcs 1.4 1.8 2.3 3.2 1.5 3.0 2.8 2.2 1.5 2.5
The calculations above are quite simple. This is because we need to be aware that we cannot approach the ordinary operators with complex calculations that would they hardly understand. When we want to persuade the operators about our ideas or we need to explain them the productivity issue, we need to approach the operators with simple, but persuasive calculations and information. The calculations above are important for finding out what is our productivity, our performance, what we have to do when things does not go as desired, and to know the conditions for 100% productivity. Based on the calculations we can decide what and when to change something in these conditions.