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HxGN SFx | Asset Management

Using OEE

In the simplest terms, OEE can be understood as follows:

  • How much time did the equipment spend working? This is its Availability.

    • While working, how many jobs did it complete? This is its Performance.

      • Of the jobs completed, how many of them were good? This is its Quality.

Each of these component metrics is explained further below. Also explained below is how to set up OEE correctly to be sure you’re using SFx Asset Management, and your equipment, to its maximum effect.

Availability is the portion of Scheduled Time that the equipment is operating productively. This time is synonymous with “uptime.” Availability is defined as follows:

Availability = Operating time / Scheduled Time

Scheduled Time is the time that the machine is scheduled for use in a shift. This excludes planned holidays and scheduled plant shutdown time. See Using Availability below for more about Scheduled Time.

Operating Time is the time during Scheduled Time that the equipment spends executing measurements. This includes manual program execution time, such as one-off measurements or the creation of “manual alignments,” as well as automated program execution time.

Because Availability is a measure of productive operation time during scheduled hours, the calculation of Operating Time does not include operation time outside of Scheduled Time, even if this is productive operation time.

Using Availability

To use Availability correctly, each asset should be assigned a schedule defining its scheduled hours. See Managing Production Schedules to set up schedules. If you do not assign a schedule to your asset, its Availability will be calculated based on a 24/7 schedule.

Note

Availability is supported by the following metrology software versions:

  • PC-DMIS 2012 and higher

Performance is a measure of the capacity, or speed, at which the equipment is operating. This value is captured by comparing the actual output of a system to a theoretical “ideal” output. Performance is defined as follows:

Performance = (Programs Executed X Ideal Execution Time) / Operating Time

In this expression, the denominator (Operating Time) is the actual time spent in operation, and the numerator is how much time should have been spent in operation for the programs executed according to the theoretical ideal. So, for example, if the actual time spent in operation is 2 times the amount of time that should have been spent according to the ideal, then the Performance is 50%.

Programs Executed is determined by the number of “program completed” or “program ended” events.

Note

When using PC-DMIS versions between 2014.1 and 2019 R1, a program that is canceled before it is complete is considered a “program executed” for purposes of calculating Performance.

Ideal Execution Time is the shortest time required to complete a measurement program under ideal circumstances. For each program, this is a fixed value that should be set by the asset programmer. See Using Performance below for more about Ideal Execution Time.

Because it is only during scheduled hours that the Performance metric concerns itself with the operating capacity of the equipment, Performance is calculated only for measurement programs executed during Scheduled Time.

Using Performance

To use Performance correctly each program should be assigned an Ideal Execution Time. For a given program, Ideal Execution Time may vary from machine to machine based on each machine’s performance characteristics. Therefore, it is recommended to create separate program documents for assets with different performance characteristics.

See Setting Up Performance below for instructions on setting up Ideal Execution Time.

Note

Performance is supported by the following metrology software versions:

  • PC-DMIS 2014.1 and higher

Quality is a measure of the success with which the equipment completes its jobs. Because the job of a measurement system is to measure parts, for measurement systems, Quality is a measure of successfully completed measurement processes. Quality is defined as follows:

Quality = Programs Successfully Executed / Total Programs Executed

Programs Successfully Executed is the number of program executions that completed all the intended measurements of the features belonging to the program.

Total Programs Executed includes both programs successfully executed and canceled programs.

Because it is only during scheduled hours that the Quality metric concerns itself with the success of the measurement process, Quality is calculated only for measurement programs executed during Scheduled Time.

Using Quality

No set-up is required to use Quality. If you are using a metrology software version that supports Quality, SFx Asset Management will automatically keep track of both Programs Successfully Executed and Total Programs Executed.

Note

Quality is supported by the following metrology software versions:

  • PC-DMIS 2019 R2 and higher