【原】What is OEE

原文作者： Sagar Wankhade

What is Overall Equipment Effectiveness?

OEE (Overall Equipment Effectiveness) is the gold standard for measuring manufacturing productivity. Simply put – it identifies the percentage of manufacturing time that is truly productive. An OEE score of 100% means you are manufacturing only Good Parts, as fast as possible, with no Stop Time. In the language of OEE that means 100% Quality (only Good Parts), 100% Performance (as fast as possible), and 100% Availability (no Stop Time).

Measuring OEE is a manufacturing best practice. By measuring OEE and the Underlying Losses you will gain important insights on how to systematically Improve your manufacturing process. OEE is the single best metric for identifying losses, bench marking progress, and improving the productivity of manufacturing equipment (i.e., eliminating waste).

WHERE DO WE START?

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.

Now we will look at the three OEE factors, each of which takes into account a different type of loss. They are Availability, Performance and Quality.

AVAILABILITY

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

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.

QUALITY

Quality takes into account Quality Loss, which accounts for manufactured parts that do not meet quality standards.

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.

Our goal is not simply to measure OEE – it is to maximize Fully Productive Time.