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2 Definition of Time

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

  • Is the equipment running? Something is coming out?
    Production

If not:

  • Was it broken down, was there a technical failure to the equipment?
    Failure
  • Was there an organizational reason why it did not run; it was technically ok, but had to wait anyway?
    Waiting
  • Was there a logistical reason why it stopped?
    Line Restraint
  • Was it taken out of service during normal shift operation?
    Unscheduled
  • Was it not scheduled to run at all? No shift planned?
    Not Scheduled

Goal: To categorize events according to its major-loss type.

Time Types
Type Name Definition
P Production time = Running time Something 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.

F Failure time = Breakdown time The machine is not having output due to a machine related technical problem.
W Waiting time =       Idle time The 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!

L Line restraint time The 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).
- Unscheduled The equipment is scheduled out of the total operations time, for reasons beyond the scope of the production team.
Not Scheduled Time 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
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