How does Minimum Production Speed impact OEE calculations?

Minimum Production Speed can impact the Availability component of OEE.

  • When the machine speed is equal to or above the Minimum Production Speed, and making production material, the machine is determined to be running and the time is considered Machine Operating Time.
  • When the machine speed is below the Minimum Production Speed, then the machine is determined to be down. By default, this time is treated as Unplanned Downtime even if it is producing material.
Note: because the material produced during this period of downtime is still included in the OEE calculations, it is feasible in a rare case of extreme conditions, that the Average Speed could exceed the maximum. This condition can only occur when the Minimum Production Speed is set to a number greater than 1.

 

  • What is the impact of setting Minimum Production Speed = 1

When the Minimum Production Speed is set to 1, then any material (whatsoever) produced per unit of time, will cause the machine to be considered running during that time.  This is the most common condition for typical machines, and it is consistent with the most common interpretation of Machine Operating Time, in which the machine is considered to be running if it is making any production quality material.

 

 

  • What is the impact of setting Minimum Production Speed > 1

In most cases, the Minimum Production Speed should be set to 1 unit rate of production.  In special cases where there are more frequent micro-stops or a machine has very slow start-up speeds, it could be set greater than 1 such that, during those periods, the machines are not considered to be both running and making production material.  However, if this parameter is set too high, then what may be considered a normal amount of micro-stops within a single unit of monitoring time can theoretically result in the machine being considered down for that entire period of time. It is better to set this parameter to a low enough value so that only an excessive amount of Micro-Stops that occur during typical machine use will be treated as downtime.

Note: The optimum value for this setting depends largely upon the machine’s unique characteristics and usage.

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