Through many of our articles we focus on the future of manufacturing, such as upcoming trends and keeping up with new technology, but how did we get here? It’s important to take some time to think about the history of manufacturing and those visionaries whose contributions are still appreciated and felt today — whether you know about them or not. Let’s take some time to put the spotlight on Eliyahu Goldratt and the major contributions he made to manufacturing.
Goldratt’s The Goal: More than Just a Great Story
Almost everybody in manufacturing has heard of Eliyahu Goldratt’s groundbreaking book The Goal. First published in 1984, The Goal has been translated into 32 languages and gone through multiple updates. As of this writing, it still ranks extremely high in sales, coming in at No. 1 on Amazon in the “organizational change” category.
Goldratt’s book taught generations of manufacturing professionals his Theory of Constraints (TOC) through an entertaining story that demonstrated the underlying principles and benefits of applying TOC to typical manufacturing problems.
The main character in the book is a harried plant manager, Alex Rogo. Alex is under pressure from all sides. Management is threatening to shut down his plant and his wife is threatening to leave him because he works such long hours. He bumps into an old professor who wisely uses TOC principles to guide Alex to solutions to his problems. This professor’s name is Jonah, which became the name for the highest-level TOC credential.
Applying the Theory of Constraints in the Real World
Goldratt based his theories on the assumption that businesses could be measured and managed using only three levers: business expense, throughput and inventory. Throughput is defined in this case as the rate at which an organization generates money through sales.
In the real world, there are limits on how much throughput an organization can generate because of operational constraints. TOC’s primary message is that all other resources in an organization should be subordinated to the constraint to maximize throughput. In simple terms, if a machine can produce a maximum of 10 units a day, all other aspects of the organization should be focused on ensuring that nothing gets in the way of those 10 units. Otherwise, the company’s revenue is adversely affected. The organization should also look at ways to increase output through the constraint if it hopes to increase revenue.
A Simple but Sophisticated Management Focus
Constraints in the real world now become the management focus:
- How to prevent problems that restrict flow through the constraint
- How to increase flow through the constraint
- How to ensure that only the right items flow through the constraint.
One way to ensure maximum flow through the constraint is to use buffers. People often confuse these buffers with safety stock or inventory in the queue at a work center, but neither of these concepts is completely analogous. A TOC buffer is usually measured in time, so a company might decide to have work equal to one hour or one shift, for example, in front of the bottleneck at all times as a buffer.
One of the most interesting parts of Goldratt’s TOC is drum-buffer-rope. It gets its name from an episode in The Goal in which one out-of-shape boy scout is holding back the entire troop on a hike. After carefully testing where to position the “constraint” in the line of hikers, Alex realizes that the best place to position the slow scout is at the head of the line, making all the other scout’s pace subordinate to his. This enables the entire troop to complete the hike in the shortest possible time and still stay together throughout the hike.
On the manufacturing floor, the drum is the pace that the bottleneck operates at, while the buffer is the time inventory that sits in front of the constraint to ensure it never has idle time. The rope is the dispatching method that releases work to the plant and ensures that work is completed in the right priorities.
Goldratt’s Other Contributions
In addition to publishing multiple business books, including The Race, The Haystack Syndrome, It’s Not Luck, Critical Chain, The Choice and Isn’t It Obvious, Goldratt wrote hundreds of articles and white papers promoting his theories. He also founded the Goldratt Institute in 2000 and the Viable Vision Initiative. Sadly, Goldratt died in 2011, but his contribution to manufacturing best practices and principles live on. Read other Heroes of Manufacturing articles to learn more about those who laid the foundation for the methods we operate by today.