Lean manufacturing is a disciplined process considered the brainchild of Henry Ford, who used it to mass-produce automobiles. By applying lean manufacturing tools, production is systematized by the application of strategies, also known as lean tools. The best lean manufacturing tools typically are organized into a list referred to as the five S’s. The Japanese automobile industry adopted Ford’s ideas and further refined his process by using a just-in-time approach to manufacturing, so the five S’s are often listed using both Japanese and English terms.
Seiri, or sorting, is the first step in lean manufacturing, but it is not just the simple act of sorting. Instead, it refers to a sweeping reorganization of the workplace, with a critical eye toward the way that people and materials operate and move throughout the manufacturing process. Seiton, the next step, is also referred to as setting things in order. This means positioning tools, personnel, equipment and materials in the optimally efficient arrangement.
Those who are familiar with lean manufacturing strategies understand the critical importance of creating a process flow diagram. The first two steps in implementing a lean manufacturing strategy create this diagram. It charts the movements of both people and materials throughout the manufacturing process.
The third step is seiso, which is also called shining. This refers to systematically cleaning items and putting these items in their proper storage place at the conclusion of the workday. Seiketsu, or standardizing, is the fourth step, and it harks back to Ford’s assembly line, only with a new twist. Instead of having a worker stationed in one place throughout his or her shift, any worker assigned to a particular part of the manufacturing task should be able to move to another identical workstation and have the same tools at hand for the manufacturing task without encountering bureaucratic obstacles or territory issues with other workers. This allows for optimal use of personnel.
The first four S’s would appear to complete the transformation to lean manufacturing, except for one major annoyance in an otherwise perfectly executed plan: the human tendency to drift back into previous patterns of behavior. This is why the last step in instituting a leaner operation is shitsuke, or sustaining. Sustaining this new manufacturing paradigm is the most critical of the five lean manufacturing tools.
The goal of lean manufacturing is to eliminate waste in both time and materials. When a worker spends 10 minutes searching for a tool that has not been put back in its place, time is wasted. Without the continued discipline instilled by these lean manufacturing tools, however, workers will allow such inefficiencies to creep back into the manufacturing operation.