Let’s start at the beginning – with All Time. This is also called 24/7 time (it includes every minute of every day).
From All Time, you subtract Schedule Loss, which includes all time that should be excluded from OEE analysis because there is no intention of running production during this time (e.g., plant shutdowns, breaks/lunches, or periods where there are no orders). Schedule Loss is part of TEEP (Total Effective Equipment Performance). It is not part of OEE.
The remaining time is your Planned Production Time. OEE begins with Planned Production Time and scrutinizes all efficiency and productivity losses that occur within that time, with the goal of reducing or eliminating these losses.
Availability takes into account Availability Loss, which includes any events that stop planned production for an appreciable length of time (usually several minutes; long enough for an operator to log a reason).
Examples of things that create Availability Loss include Unplanned Stops (such as equipment failures and material shortages), and Planned Stops (such as changeover time). Changeover time is included in OEE analysis, since it is time that could otherwise be used for manufacturing. While it may not be possible to eliminate changeover time, in most cases it can be significantly reduced. Reducing changeover time is the goal of SMED (Single-Minute Exchange of Dies).
The remaining time after Availability Loss is subtracted is called Run Time.
Performance takes into account Performance Loss, which accounts for anything that causes the manufacturing process to run at less than the maximum possible speed when it is running (including both Slow Cycles and Small Stops).
Examples of things that create Performance Loss include machine wear, substandard materials, misfeeds, and jams.
The remaining time after Performance Loss is subtracted is called Net Run Time.
Examples of things that create Quality Loss include scrap and parts that need rework. OEE Quality is similar to First Pass Yield, in that it defines Good Parts as parts that successfully pass through the manufacturing process the first time without needing any rework.
The remaining time after Quality Loss is subtracted is called Fully Productive Time.
Now that you have taken a look at how the three OEE Factors are defined we can quickly review each type of loss and its relationship to the OEE factors.
We can delve even deeper into productivity losses by understanding the Six Big Losses.