Can you improve the effectiveness of your automation with automation? DMS Powders, of Meyerton, South Africa, has shown that you can. The trick was to deploy information technology (IT) in a way that enabled management to employ a useful parameter called overall equipment effectiveness, or OEE. As the product of three percentages—availability, performance, and quality—the parameter gave DMS managers an objective index for judging the effectiveness of the company’s equipment and taking steps to improve it.

OEE helped the company to go beyond simply improving control over its processes for milling and atomizing ferrosilicon (FeSi), an important ingredient for separating minerals and scrap metals. Although improving process control is a laudable endeavor, it can consume a lot of resources for small, incremental improvements, especially if the process is already in control as currently configured. It does not evaluate the process itself.

Finding opportunities

OEE, on the other hand, provides that evaluation. Moreover, if the OEE score is below an acceptable benchmark, an analysis of its three components can direct the attention of managers toward much greater opportunities for improvement. OEE, therefore, is a tool that can help analysts to identify downtime and other indicators of poor performance, determine their causes and rectify them.

At DMS Powders, putting this tool in place was a task outsourced to ABB Asset Management Services, a unit of Zurich-based ABB that specializes in managing the maintenance and continuous improvement of other companies’ production processes. Experts from ABB sold DMS on OEE as the logical next step in the continuous improvement program. Although an extensive information network was already in place, DMS’s management and ABB’s experts still had a number of questions about the causes of downtime. They needed a way to isolate such problems.

ABB recommended a tool called DT Analyst software from Wonderware, a Lake Forest, Calif.-based unit of Invensys Systems Inc. Not only does the software calculate OEE, its components and other efficiency indicators, but it also fit easily into the other Wonderware factory management software already gathering, processing and disseminating information throughout the plant.

Since the installation of the software, real-time OEE figures have become a regular feature of morning production meetings. “The DT Analyst software is helping DMS Powders to map cause-and-effect scenarios and detect the root causes of problems at many levels,” says Piet van der Merwe, an automation specialist at ABB.

By drawing attention to the activities limiting availability and performance of the induction furnaces, for example, OEE has helped the staff at DMS Powders to reduce the eight- to 10-hour daily downtime to only five to eight hours. In the chipping plant, an OEE-based analysis of electrical current uncovered the fact that the motors actuating the activity there were idle 70 percent of the day. Now, the motors run 70 percent of the day, and production there has skyrocketed.

The evaluation of performance is not limited to downtime and productivity. “The software is also making DMS more environmentally friendly by continuously monitoring stack emissions and warning the operators when dust blown into the atmosphere reaches unacceptable levels,” explains van der Merwe.

Plant comparisons

Other large corporations extend the parameter beyond just individual machines and production lines to measure and compare the performance of their many plants. OEE ends most of the debate among managers on how to make these comparisons fairly. “This is one metric that is really facility independent,” says Jeff Nuse, Wonderware’s product manager for DT Analyst and OEE. “It bundles three important parts of plant effectiveness into one metric that can be easily used by managers at all levels.”

OEE is finding wider application on this level because the data already exist in the controllers running automatic equipment, and because calculating the parameters is relatively easy now. “Automation hardware is more enabled than ever to store historical data and make it available,” says Scott Teerlinck, director of marketing, customer support and maintenance at Milwaukee-based Rockwell Automation. Modern information technology can reach across computer networks into those controllers in real time and retrieve that data for use by software capable of computing the latest OEE values.

In fact, failing to use information technology to automate the calculation of OEE is a big mistake. “When data is entered manually, it is subject to human error, interpretation and manipulation,” explains Jim Feltman, vice president at Vorne Industries Inc., a manufacturer of real-time monitoring products based in Itasca, Ill. “Every time operators have to enter downtime data or log an event, it pulls their focus away from the process ...