An OEE rating of 100 means the equipment is running at its maximum speed, maximum available shifts, maximum throughout, maximum product quality, minimum planned shutdowns, no unplanned shutdowns, minimum maintenance and minimum waste or scrap. Most U.S. plants operate at about 65 percent.
A number of automation vendors now offer OEE software to help operation managers determine their current OEE and measure the difference as improvements to the system are made. The OEE metrics help identify opportunities for improvements, and they also offer tangible measurements that can be converted into dollars. An improvement of 5 percent using the same equipment can be converted into dollars saved.
Rockwell Automation defines OEE as:
(Planned Availability – Planned Downtime – Changeover – Downtime)
Planned Availability
If the system had the following performance (on a daily basis):
Planned Availability (PA) = 1440 minutes
Planned Downtime (PDT) = 120 minutes
Changeover (CO) = 100 minutes
Downtime (DT) = 300 minutes
OEE = (PA – PDT – CO – DT)/PA (1440 – 120 – 100 – 300)/1440 = 64 percent
See the story that goes with this sidebar: OEE Metrics Reveal Return on Investment
