In an earlier article entitled Zero Defects – Realistic Goal or Dream? I stated that achieving zero defects is not a dream at all but rather a realistic goal to be pursued. In our Black Belt course, our students are challenged to complete an improvement project where they create an improved process that is as close to perfect as possible. The vision of what we consider to be a perfect process was defined by James Womack, founder of the Lean Enterprise Institute.
A process in this context is a sequence of steps that must be performed correctly, in the proper sequence, in order to create value for a customer. According to Womack, a perfect process is one in which every step is valuable, capable, available and adequate. The steps are linked and coordinated by flow, pull and leveling.
To determine if a step is valuable, ask “If we could provide the value emerging from this process without this step, would the customer miss it?” If the answer is no, then we need to work to eliminate the step. In most cases, these types of steps are unavoidable with the current configuration of the process.
A step is capable if it can be performed the same way with the same result, every time, with results that are satisfactory to the customer. Eliminating defects, where a defect is a result that is not satisfactory to the customer, is a major focus of Six Sigma and results in a more capable process. A step is available if it can be performed whenever it is needed to be performed, and within the standard cycle time for the step. This is the starting point for Total Productive Maintenance.
A step is adequate if there is enough capacity to perform the step when it is needed, without waiting. At the same time, we do not want to have excess capacity. The capacity of the process must match the demand that is being placed on the process. Creating this match is a form of variation reduction, another key part of Six Sigma. A step is flexible if it can be changed from one product or service to the next in little or no time with no impact on quality.
Perfect flow results in the steps in the process occurring in a tight sequence with little or no waiting. Perfect pull occurs when each step occurs only based on a signal from the next downstream step. Not too early, not too late, but just in time to satisfy the customer. Pull is coordinated using simple signals in real time. Demand is leveled when noise and unnecessary variation are removed from the flow of information in the process.
The Toyota approach has been expressed as follows: “We get brilliant results from average people managing brilliant processes. We observe that our competitors often get average (or worse) results from brilliant people managing broken processes.” When we take the time to compare the current process to the vision of the perfect process, we identify areas where improvement is both needed and is possible.
Your comments or questions about this article are welcome, as are suggestions for future articles. Feel free to contact me by email at firstname.lastname@example.org.
About the author: Mr. Roger C. Ellis is an industrial engineer by training and profession. He is a Six Sigma Master Black Belt with over 48 years of business experience in a wide range of fields. Mr. Ellis develops and instructs Six Sigma professional certification courses for Key Performance LLC. For a more detailed biography, please refer to www.keyperformance.com.