Overall Equipment Effectiveness is arguably the #1 key performance indicator on manufacturing floors. It is used to measure how well manufacturing equipment is utilized compared to its full potential, during periods when it is scheduled to run. As a result, it provides unique insight into the productivity and effectiveness of a manufacturing operation.
Overall Equipment Effectiveness (OEE) is typically calculated with the formula:
OEE = Availability X Performance X Quality.
Therefore, an OEE of 100% would be a theoretical reference point for a machine that is running without interruption, operating at its maximal speed and producing only quality products.
Availability refers to uptime. It defines the percentage of scheduled time that the equipment is available to operate. Specifically, if the machine is expected to be running for 7 hours, 100% availability refers to the machine running for those 7 hours – and does not penalize the machine for planned downtime. One of the key differences between specific OEE software like Scytec DataXchange and machine-based software is that OEE software can account for downtime in-cycle. In other words, if the shift is 7 hours, but tools need to be changed once a shift, only Scytec DataXchange will capture that as planned downtime, versus software that tracks uptime through voltage, which will assume that the machine is down and unfairly lower your OEE score.
Performance refers to the speed of the machine as a percentage of its maximal speed. In theory, if the machine is running slower than it should be, output is reduced and there are “performance losses” to what should have been produced. One of the key differences between OEE-specific software and simple monitoring is that OEE software will account for deliberately reducing speed, whereas simple monitoring won’t account for that in your OEE score.
Quality refers to the number of “good” units produced as a percentage of the total units produced. Quality is often called First Pass Yield, First Time Right or Throughput Yield. Logically, any product that does not meet quality standards is deemed waste and is called a quality loss.
Fundamentally, measuring an accurate OEE is critical to setting a baseline and creating opportunities for improvement. Only Minitab can offer Scytec DataXchange, to properly monitor OEE, without any misleading information about availability or performance. The machine output should be properly measured with Minitab’s Prolink or Real-Time SPC software to ensure the accuracy of the quality contribution to OEE. Once the true baseline is set, use the Minitab Solution Center’s lean tools like Minitab Brainstorm and analytical tools like predictive analytics to help you identify root causes.