Five categories of Activity: [P],[W],[L],[F] & [U]
To simplify subsequent analyses, the OEE Coach distinguishes five categories of activities; OEE Coach uses 5 colors to identify them:
- P: Production (green)
- W: Waiting (Orange)
- L: Line restraint (Blue)
- F: Failure (Red)
- U: Unscheduled (Yellow)
Each defined activity needs to be assigned to one of the categories. In this paragraph the five categories are explained.
When the machine is operating and produces products (irrespective of the quality and the speed), the activity defined for that period of time will be of category [P]roduction.
A machine that ‘runs’ while nothing is being produced, has stopped according to the definition of the OEE-measurement!Note: Later on you will read that a machine can produce products that are labeled scrap or rework.
If [W]aiting is recorded for the Activity of the machine, the machine is not producing. This means: ‘nothing is coming out of the machine’, because the machine is waiting for something, such as changeovers, searching for materials, operators, etc. It may be that the machine is running ‘full steam’ in a technical sense; when nothing comes out, it waits! It is an organizational reason that that prevents the machine from running and that is being registered.
L: Line restraint
A special category of waiting occurs when the supply of raw materials to- or the transport of products from the machine is not taking place. The OEE Industry Standard has a special category for this: [L]ine restraint. This category is applicable to equipment with a technical link to a line, but can also be used to visualize line restraints in chains of equipment that have no physical connection, or even supply chains. The machine itself would be fully capable of producing.
[F]ailure is recorded as the Activity of the machine, when the machine is not manufacturing products due to a machine related technical problem.
Note: in this situation you record the phenomenon, not the cause e.g. ‘breakdown palletizer’ and ‘breakdown press’.
If [U]nscheduled is recorded, the machine is not producing because no production was planned for reasons beyond the influence of the production team (e.g. there are no orders, it is a holiday, or the machine is not needed).
Unscheduled should be read as: “Normally the machine would be scheduled, but operations management decided to un-schedule it”
Note: The Activities in the category [U]nscheduled have no influence on the OEE. The total of these types of Activities is deducted from the Total Operations time, resulting in the Loading time, which is the basis for the OEE calculation.
However, this category is included when calculating the OOE.
Because this loss of time is not part of the availability rate and therefore not part of the OEE, it often does not receive the attention it deserves. Therefore, place as few as possible Activities in this category. Remember that the objective of measuring the OEE is not to make it as high as possible, but to gain insight in the losses. Make sure this time is always registered, even when no crew is present. It can be visualized as a loss in the Overall Operations effectiveness (OOE) and Total Equipment Effectiveness (some call this TEEP)
EXAMPLE: If a machine is not running for 200 minutes during a shift of 480 minutes because personnel has not been scheduled to work deliberately (for instance, during Christmas Eve), the OEE is calculated based on a Loading time of 280 (= 480 – 200) minutes.