Manufacturing is a complex operation. There’s more involved than just
bringing raw materials in the front door, performing some work and
shipping finished product out the back door. The complex organization of people, machinery and equipment required for production needs visionary and skilled leaders. Theorists have developed methods for improving operations, and suppliers have rushed to provide tools to help leaders implement them. Some of the tools even help leaders sustain their advantages after the initial rush of implementing change.

The goal of manufacturing is to produce finished goods for sale by the company in an efficient, cost-effective and timely manner within the quality parameters set by customers and the regulatory decrees set by governments. The complexity of manufacturing demands study and reflection to keep production lines moving. One of the biggest challenges is finding where the problems are that cause reduced output of finished goods. Hence, a fable:

A plant manager of a manufacturing enterprise promised to take his son’s Boy Scout troop on a hike in the woods and hills. Once they had parked

at the beginning of the trail and prepared for the trip, the boys self-organized a line for the hike. The fastest boys went first, then the slower ones. Finally, at the end of the line was a chubby, out-of-shape kid. During the morning, the troop establish a pattern. The fast kids take off at a rapid rate and soon the boys are spread over a long area of the trail. Then the first ones must stop and wait for the rest to catch up. With every stoppage, their

frustration grows. This leads to grumbling and complaints to the slow ones to “speed up.”

As the plant manager contemplates the process that evening, it occurs to him that this is similar to his plant. Some machines speed along and produce great amounts of parts, but the number of finished products doesn’t increase. That number is constrained by the slowest machine. Only by putting all attention on the slowest process can the amount of finished product be increased.

The next morning, the troop leader reorganized the troops. He put the chubby kid at the head of the line. The troop was not going to go further than he could go anyway, so this way, they could maintain a steady pace. And by giving this boy special attention, he was encouraged to pick up the pace. Previously, he was so discouraged that he actually got slower. In this manner, the troop reached its destination more quickly than it would have, and with much better spirits.

This fable is paraphrased and condensed from a novel by Eliyahu Goldratt and Jeff Cox, “The Goal: Excellence in Manufacturing.” This 1984 book describing the workings of the Theory of Constraints has become a classic, and has been updated and reprinted many times. Some consultants continue to argue the superiority of Lean Thinking, overall equipment effectiveness (OEE) or Six Sigma over the Theory of Constraints. Practitioners have discovered that using all of these manufacturing strategies can lead to operational excellence in manufacturing. These strategies apply equally well in just about every type of manufacturing.

Finding constraints

The trick in using the Theory of Constraints is, of course, in finding the real constraint. Dennis Cocco, chief technology officer of Activplant, a London, Ontario, Canada-based factory software supplier, says, “If the downtime of a machine does not affect the number of products produced at the end of the line, then it should not be the focus of the study.” He advises finding the places in the production line where a stoppage—even if only for 20 seconds at a time—does affect final production tallies. Activplant, like many other automation suppliers, has developed tools to assist manufacturing leaders to find and correct production problems.

Maryanne Steidinger, Chicago-based discrete industry marketing manager of Simatic IT for automation vendor Siemens AG says, “ ‘The Goal’ was MES.” Steidinger is a proponent of OEE as an analysis tool supplemented with a manufacturing execution system (MES) application as an automated data collection and presentation tool. “OEE is a way to manage individual assets,” continues Steidinger. “You can compare different machines or lines and look at efficiency and identify bottlenecks. It’s the proactiveness that OEE provides that is so valuable. Coupling OEE with report tools merging data from other sources allows you to be in control.”

Another MES supplier sees similar customer uses for its tools. Claus Abildgren, production management marketing manager at Wonderware, in Lake Forest, Calif., says, “Customers are focused on ...