x Categories within Availability

Q: What categories (types) of time should we define within the availability of OEE?

Categorizing time

To calculate the ‘availability‘ of the equipment, time is categorized in the following types:

  1. Is the equipment running? Something is coming out?
    Production
  2. If not:
    1. Was it broken down, was there a technical failure to the equipment?
      Failure
    2. Was there an organizational reason why it did not run; it was technically ok, but had to wait anyway?
      Waiting
    3. Was there a logistical reason why it stopped?
      Line Restraint
    4. Was it taken out of service during normal shift operation?
      Unscheduled
    5. Was it not scheduled to run at all? No shift planned?
      Not Scheduled

The goal is: To categorize events according to its major-loss type.

TypeNameDefinition
PProduction time = Running timeSomething is coming out of the equipment, regardless of the amount, speed or quality.A machine, spinning at top speed, not generating output therefore is not running…Caution: Batch producing equipment (like cookers, brick-ovens) are considered to run during their batch processing time.
FFailure time = Breakdown timeThe machine is not having output due to a machine related technical problem.
WWaiting time = Idle timeThe machine is not producing output because it has to wait for something (like a setup, or raw material).Therefore, waiting for a technician during a breakdown is not Failure time, but Waiting time!
LLine restraint timeThe equipment cannot generate output because it gets no input from the line, or cannot give its output to the line.•  Applicable to equipment with a technical link to the line (pipe, conveyor).•  Applicable to equipment with a non-technical link in a line (cell, a chain of equipment).•  Applicable to equipment with logistic links anywhere (Line Restraint by supply chain).
UnscheduledThe equipment is scheduled out of the total operations time, for reasons beyond the scope of the production team.
Not ScheduledTime where there are no operations-activities going on at all.“The factory is closed, the lights are out“.
A machine is running
when there is output,
regardless of the quantity or quality

Source: www.oeeIndustryStandard.org

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