There are only three manufacturing bottlenecks that matter: demand in, flow-through and people around. They all connect to each other and any other apparent bottleneck can be grouped under one of these primary bottlenecks.
A bottleneck is a step or point in a process where free flow is restricted, and the term is used because it’s a great visual and a common experience. The difference is that the neck on an actual bottle improves the experience, but bottlenecks in your operation hurt the experience. When you open that ice cold Coke on a hot summer day, the bottle’s neck manages the flow so the Coke ends up in your mouth and not all over your shirt. When your customer expects something to ship in three days and it actually ships in eight, the bottleneck dumped a mess on your shirt.
The counterpoint to this is the luxury goods industry, where bottlenecks are created intentionally at certain points to sustain prestige and pricing. Even in that case, the difference between intentional and unintentional bottlenecks will present problems.
Visualize these parts of the system, and potential bottlenecks, together to understand how they relate. The flow of activity can be visualized as a line – something comes in one end (a sale), it goes through several steps, and it does out the other end (a shipment). A different visual is to look at the activity flow as a cycle or loop, where the starting activity and finishing activity relate to each other as well as all of the steps in between. In a world where marketing is everywhere and customer feedback is visible and constant, this seems to be a more accurate model.
So if we think of this activity flow as a cycle, imagine it acts like an inner tube and bottlenecks are felt at different points when a person squeezes the tube. Those bottlenecks can be at either side of the relationship between activities, and they often flip. One month the bottleneck is on demand (not enough demand in, extra flow-through capacity), and the next month the bottleneck has flipped (too much demand in, not enough flow through).
Flow then acts as air pressure in the system. More flow, more air pressure, lets the system both resist and respond faster to fix bottlenecks that start to appear.
For a system that is broken, doesn’t have enough flow, or has damaging bottlenecks, intensive action needs to happen to fix the problem so the system can start to work properly.
How can we make our system robust enough that the squeeze to create the bottleneck has little effect, but at the same time the flow can go-faster through the tube when demand increases?
In the next blog in this series, we’ll look at specific connections between the main bottlenecks, specific bottlenecks that appear under each one, and ways to resolve them.
Read the rest of the articles in this series: