Theory of Constraints Handbook - James Cox Iii [690]
1. The methodologies were viewed as “tools in a toolbox,” where each tool was perceived as best for particular uses.
2. Expertise in all methodologies was not available, making true integration impossible.
3. An effective integration process for the three methodologies was not developed.
Our purpose is to show how to effectively integrate these methodologies, but let’s first provide a short overview of each of them.
Copyright © 2010 by Avraham Y. Goldratt Institute, a Limited Partnership.
Lean
The origin of lean manufacturing in the United States can be linked to Henry Ford (the assembly line), Fredrick Taylor (industrial engineering), and Dr. Deming (father of quality management). In Japan, these concepts were refined and honed by Taiichi Ohno, Eliji Toyoda, and Shingeo Shingo to create what is now known as the Toyota Production System (TPS). As shown in Fig. 36-1, Taiichi Ohno once described the goal of TPS simply as to shrink the time-line from order to cash by removing non-value added waste, muda (Ohno 1988, 9).
Ohno identified seven types of waste. There are several ways to describe these “7 deadly types of waste” that occur in a system. The most common are:
1. Overproduction—producing more than the customer has ordered. Many times producing to forecast or batching to save setups can lead to over-producing.
2. Waiting—time when no value is being added to the product or service. High levels of inventory, people, parts, or information can lead to long non-value added waiting.
3. Transportation—the unnecessary movement of parts, moving multiple times, movement that does not add value. High levels of inventory, the layout of the system, and priority shifting are just a few things that can also lead to non-value added transportation.
4. Inventory—unnecessary raw material, work-in-process (WIP) or finished goods. “Stuff” we have made an investment in that the customer doesn’t currently need. Long cycle times, “just in case” thinking, and flow issues can also add to inventory issues.
5. Motion—unnecessary movement of people that does not add value. Poor workplace organization and workplace design can lead to waste in motion. These motions at times can lead to serious health and safety issues.
6. Overprocessing—adding steps or processes that don’t add value to the customer, thinking that continuing to work on something makes it a higher quality part or service. This is considered waste when the customer doesn’t require that “extra” touch.
7. Defects—work that requires rework or, even worse, work effort that needs to be scrapped. Bad processes, equipment issues, and lack of in-process control can add to the defect problem. Obviously, the more “stuff” in the system, the higher the percentage of defects.
Recently, an eighth waste has become very common and that is the waste of not tapping into human creativity.
Logically you can see how over-producing can lead to contributing to all the other waste. All wastes can be associated with any environment, not just production. Understanding and identifying waste in the system can help target improvement efforts.
The titles, “Lean Manufacturing” and later “Lean Thinking” were coined in the United States by James Womack and Daniel Jones in the 1990s to describe the Toyota Production System (TPS) (Womack and Jones, 1996). Womack and Jones introduced us to the five principles of Lean:
FIGURE 36-1 Goal of TPS.
1. Specify value.
As stated by Womack and Jones, “The critical starting point for lean thinking is value. Value can only be defined by the ultimate customer and it’s only meaningful when expressed in terms of a specific product (a good or a service, and often both at once), which meets the customer’s needs at a specific price at a specific