OEE-Overall Equipment Effectiveness

Overall Equipment Effectiveness (OEE) is a metric that identifies the percentage of planned production time that is truly productive. It was developed to support TPM initiatives by accurately tracking progress towards achieving “perfect production”.

• An OEE score of 100% is perfect production.
• An OEE score of 85% is world class for discrete manufacturers.
• An OEE score of 60% is fairly typical for discrete manufacturers.
• An OEE score of 40% is not uncommon for manufacturers without TPM and/or lean programs.

OEE consists of three underlying components, each of which maps to one of the TPM goals set out at the beginning of this topic, and each of which takes into account a different type of productivity loss.

Component	TPM Goal	Type of Productivity Loss
Availability	No Breakdowns	Availability takes into account Down Time Loss, which includes all events that stop planned production for an appreciable length of time (typically several minutes or longer).
Performance	No Small Stops or Slow Running	Performance takes into account Speed Loss, which includes all factors that cause production to operate at less than the maximum possible speed when running.
Quality	No Defects	Quality takes into account Quality Loss, which factors out manufactured pieces that do not meet quality standards, including pieces that require rework.
OEE	Perfect Production	OEE takes into account all losses (Down Time Loss, Speed Loss, and Quality Loss), resulting in a measure of truly productive manufacturing time.

It is extremely important to measure OEE in order to expose and quantify productivity losses, and in order to measure and track improvements resulting from TPM initiatives.

Benefits of Automated OEE Tracking

Manually calculating OEE is a great way to start. It can be done with pencil and paper or with a simple spreadsheet, and only 5 pieces of data are needed (Planned Production Time, Down Time, Ideal Cycle Time, Total Pieces, and Good Pieces). Performing manual OEE calculations helps reinforce the underlying concepts and provides a deeper understanding of OEE. However, there are also very strong benefits to quickly moving to automated OEE data collection:

Item	Benefit
Down Time	The accuracy of manual down time tracking is typically in the range of 60 to 80% (based on real-world experience across many companies). With automatic Run/Down detection, this accuracy can approach 100%.
Small Stops and Slow Cycles	For most equipment it is impossible to manually track small stops and slow cycles. This means that a great deal of potentially useful information, such as time-based and event-based loss patterns, is not available.
Operator Focus	With automated data collection the operator spends more time focused directly on the equipment (versus spending time on paperwork).
Real-Time Results	Automated data collection provides results in real-time, enabling improvement techniques such as SIC (Short Interval Control).