Excerpt from the Connected Flow Chapter

Why Flow?
Most often the failure of implementation stems from a misguided belief that success is rooted in the application of lean tools (such as setting up the cell). We often tour clients through lean plants, in some cases Toyota plants. It is interesting to hear what they get out of the tour. They have overall impressions of cleanliness, orderliness, precision, and people engaged in their work. But their eyes really light up when they see something they can directly apply in their plants. We recall one case when a person noted how a lean plant kept small cabinets of expendable materials by each work cell and the cell leader signed out materials as needed. A kanban system was used to replenish things like plastic gloves. The “industrial tourist” was excited about going back and setting up a similar system for expendable materials in his plant. Unfortunately all he was seeing was one specific tool. He was failing to see the interconnectedness and interdependence of all the various elements. Successful creation of Lean Processes is derived from a deep understanding of how the tool is utilized to accomplish an end objective. A trained mechanic does not bring a wrench to the car, and then find a nut to loosen. He first determines the nature of the problem, what will need to be done to correct it, then selects the appropriate tools to complete the job.

In many cases we see organizations that place the tool before the understanding. This is evident in comments such as “We are going to implement visual control,” as if it were an individual piece of a jigsaw puzzle to be added. A key to long-term success is a combined effort that includes a deep understanding of the primary philosophy or concept, an effective strategy which necessitates the concept (it must become mandatory), a methodology for applying the concept, lean tools that support the method, and an effective way to measure the overall result.

We find it helpful to think about the relationship between one-piece flow and waste reduction in the context of a broader model as shown in Figure 5.1 below. Rather than leap into implementing tools for flow and pull we recommend stepping back and understanding the purpose. This model emphasizes the relationship between the primary principle of Lean - the identification and elimination of waste - and the method for achieving that objective - creating flow. The creation of continuous flow is often thought to be a primary objective when creating a lean process. In reality, the creation of continuous flow is designed to drive waste from any operation--waste elimination is the primary objective.

When material and information are flowing continuously, there will be less waste in the operation. This is true by definition. If there were a lot of waste, material and information would not be flowing. However, there is something much more profound happening here. Maintaining continuous flow between processes will create a linkage, making each process dependent on the other. This interdependency and the relatively small amount of buffering make any condition that interrupts the flow more critical. These issues cannot be ignored because they now affect a greater number of people and processes (see Genchi Genbutsu case: Connecting operations to surface waste in engineering).

Anyone who has attempted to implement single piece flow (a difficult task indeed!) understands that heightening the level of problems can be of great benefit…or of great harm. If effective systems are not in place to support the operation, the severity of problems will surely spell doom. This is the time when lean tools must be applied to provide the necessary structure to ensure success rather than failure. The lean tools can help by providing both support systems and control methods to react appropriately to the problems that surface.