What Is Lean?
Written by Dave Turbide
If you ask 20 people to define Lean manufacturing, you'll probably get 25 different answers. A kind of consensus definition simply states that Lean is the elimination of waste. Waste can be defined as non value-adding activities or any aspect of the process that adds cost, handling, lead-time, delays, etc. but does not add value for the customer. The obvious high potential waste generators are inventory, scrap and rework, handling and movement, and any unnecessary activities that inhibit the timely completion of the process.
Interestingly, this definition closely matches the definition of Just-In-Time and a whole series of other improvement efforts that have followed JIT through the intervening years. That's not to say that Lean is the same old stuff or is dated and irrelevant; it just means that we are still focused on the things that are most important to the improvement of manufacturing processes and competitiveness. Like JIT, Lean is much more an attitude and an approach than it is a particular technique or process.
Most of the early Lean success stories came from the automotive industry, and that's understandable since Lean originated as the Western adaptation of the Toyota Production System. Thus, many people associate Lean with production lines and work cells, kanbans, and "flow" manufacturing in high volume, repetitive plants.
That's certainly a valid observation, since Lean is more widely used in these environments and the majority of references, tools, and studies have been developed and applied there. As the Lean support industry has matured, however, and as interest in Lean has become more widespread, there is a growing recognition that Lean initiatives need not be limited to flow manufacturing and repetitive production. This is fortunate, because many companies would like to become more Lean but may be discouraged by the cost and disruption of a conversion to flow manufacturing. And in some cases, where the company makes a small number of complex products a year and no two are alike, flow manufacturing is simply not appropriate.
Essentially, anything that reduces inventory, shortens lead-time, and helps a company be more responsive to customer requests can be considered part of a Lean initiative. One of the techniques gaining more recognition as a Lean tool is the Theory of Constraints / Drum-Buffer-Rope (DBR) popularized by Dr. Eli Goldratt in his classic business novel The Goal. DBR is a production management technique that focuses on the management of constraint or bottleneck resources to optimize the flow of work through the plant. Production at non-constraints is coordinated to the overall flow of work, which, in turn, is slaved to the constraint; so excess inventory and overproduction are reduced. DBR delivers shortened lead-times, reduced inventory, increased throughput and improved customer service.
If the manufacturing plant is operating below capacity and therefore has no internal constraint, a new technique called Simplified Market Pull (SMP) combines the benefits of DBR-like throughput improvements and reduced inventory and lead-time with a quick and simple implementation process.
The message here is that Lean is not limited to big companies in high-volume businesses. Lean ideals can be applied in a company and there are a variety of tools available to bring Lean benefits to the plant floor regardless of the specifics of the production environment or condition.
For more information on Lean Manufacturing In A Make-To-Order Environment, click here.
Click here for more information on Simplified Market Pull.
For more than twenty-five years, Dave Turbide has been a consultant specializing in manufacturing technologies, consulting, and education. He has extensive first-hand knowledge of manufacturing functions and management practices, automated information systems, and vendor manufacturing software offerings. He also has experience in industry analysis, writing, engineering, project management, technical analysis, and management. He has exceptional analytical and communication skills as demonstrated by his published books, articles, papers, and speeches.