Focused improvement for OEE

Posted on 15 Dec 2014 by Jonny Williamson

Overall Equipment Effectiveness tells you the size of the opportunity. But only management can deliver on that promise, finds IT Contributing Editor Malcolm Wheatley.

Go back a few years, and a concept known as Overall Equipment Effectiveness (OEE) was all the rage as a factory-floor improvement tool.

Simply put, it involved working out the theoretical maximum output from a piece of equipment or production line, and then expressing the actual output produced from it as a percentage of that theoretically achievable output.

In many cases, the result was sobering. For OEE made it abundantly clear how small losses of efficiency—temporary stoppages of just a minute, a short period of slow running or a minor breakdown—could quickly add up to a large number.

Today, the paper-based approaches to OEE systems that characterised many mid-1990s OEE implementations have largely gone. OEE calculations are now built into SCADA systems, for example, and most manufacturing execution systems (MES) will deliver OEE as a standard report. For those who want OEE—and just OEE — then specialist dedicated factory-floor terminals offer an entry-level capability.

Opportunity missed

But getting an OEE number is only the half the battle, however it is delivered. For to obtain the prospective improvement in efficiency — and output — that OEE delivers, manufacturers have to translate OEE’s implicit promise into actions and improvement initiatives. And here, even purveyors of MES systems concede that manufacturers’ approaches to this leave something to be desired.

“The buying process involved with a manufacturing execution system is typically oriented around capital expenditure, cost, and IT integration,” says Tim Barber, European business director at manufacturing execution system vendor, Lighthouse Systems. “All too often, there isn’t a matching internal dialogue about how the data is going to be used, how improvements are going to be resourced, and how the improvement impetus is going to be sustained.”

In short, sum up insiders, a manufacturing execution system project is often couched in terms of installing the system—and not in terms of actually using it to deliver improvements.

Strategic targeting

So what advice do they offer? Ask the question, and some recurring themes quickly emerge.

Short interval control, for instance—in other words, very frequent and regular reviews of OEE data, while the circumstances are still fresh in people’s minds.

“Even doing reviewing OEE data the following morning is doing it in a rear-view mirror,” says James Wood, a solutions consultant at Aptean. “Do it in real-time, with the shift that’s currently working, while people can still remember what has caused the problems.”

Sensible prioritisation is another recurring theme: aim for the most significant improvements, not just the low-hanging fruit.

“The right focus is everything,” warns Fraser Thomson, a consultant with Yorkshire-based manufacturing execution system provider Cimlogic. “What you often find is people focusing on problems that they think that they can fix, rather than on getting the biggest bang for their buck.”

Finally, says Simon Allsop, northern European director at DELMIA, a subsidiary of specialist French manufacturing software company Dassault Systèmes, don’t underestimate the improvements available through training, and having consistent skills levels.

“Look for those instances where some shifts, teams, or operatives consistently achieve a higher OEE on the same piece of equipment than other shifts, teams, or operatives,” he recommends. “That tells you it’s a skill issue—which can often be cheaper and easier to fix.”