4.1. Formulas¶
4.1.1. Durations¶
4.1.1.1. Workplace-Related Durations¶
4.1.1.1.1. Setup Time¶
The setup time of a workplace is the sum of the durations of all operating states which belong to the time base SETUP. The summation is done for a considered time period on a workplace:
4.1.1.1.2. Production Time¶
The production time of a workplace is the sum of the durations of all operating states which belong to the time base PRODUCTION. The summation is done for a considered time period on a workplace:
4.1.1.1.3. Scheduled Operating Time¶
The scheduled operating time is the sum of the durations of all operating states which belong to the time base SCHEDULED_OPERATING_TIME. The summation is done for a considered time period on a workplace:
4.1.1.1.4. Occupancy Time¶
The occupancy time of a workplace is the total duration that the workplace is occupied by at least one operation during its scheduled operating time for a considered time period. An operation occupies a workplace during its setup phase and during its processing phase. Time periods outside the scheduled operating time (e.g. shift breaks or nonworking shifts) do not increase the occupancy time of the workplace, even if an operation is logged on to the workplace during these periods. The occupancy time of a workplace is the sum of the execution times of all operations while they were logged on to the considered workplace during the period under consideration. The occupancy time of a workplace is the total duration that the workplace is occupied by at least one operation during its scheduled operating time for a considered time period. An operation occupies a workplace during its setup phase and during its processing phase. Time periods outside the scheduled operating time (e.g. shift breaks or nonworking shifts) do not increase the occupancy time of the workplace, even if an operation is logged on to the workplace during these periods. The occupancy time of a workplace is the sum of the execution times of all operations while they were logged on to the considered workplace during the period under consideration.
Note
In joint production, only the execution times of the leading operations are considered.
4.1.1.2. Operation-Related Durations¶
Important
The durations must be determined in the following order
4.1.1.2.1. Setup Time¶
The setup time of an operation is the setup time of the workplace (as defined above) while the operation was executed at the workplace. An operation is executed during its setup phases and its processing phases. If an operation has been executed at more than one workplace, the setup time of the operation is the sum of setup times of all these workplace during the execution of the operation at each workplace.
Note
Even during the processing phase of an operation, the respective workplace can nevertheless be in an operating state that is assigned to the SETUP time base, for example, intermediate setup during the processing phase.
4.1.1.2.2. Setup Phase Duration¶
The duration of a single setup phase period of an operation is the duration of all scheduled operating times of the workplace at which the operation was registered from the start date of the setup phase until the end date of the setup phase. Time periods outside the scheduled operating time (e.g. shift breaks) do not increase the duration of the setup phase of the operation. If an operation has been in the setup phase several times (and this may be at several workplaces), the duration of the individual setup phases is cumulated in order to calculate the entire duration of a the setup phase.
Note
Since setup times can also occur during the processing phase, it is possible that the entire duration of the setup phase is less than the setup time of an operation.
4.1.1.2.3. Processing Phase Duration¶
The duration of a single processing phase period of an operation is the duration of all scheduled operating times of the workplace at which the operation was registered from the start date of the processing phase until the end date of the processing phase. Time periods outside the scheduled operating time do not increase the duration of the processing phase of the operation. If an operation has been in the processing phase several times (and this may be at several workplaces), the duration of the individual processing phases is cumulated.
4.1.1.2.4. Execution Time¶
The execution time of an operation is the total time an operation was executed at any workplace. Since an operation is executed during its setup phases and its processing phases, the execution time of an operation is the sum of the duration of its setup phase and the duration of its processing phase according to the definition above, i.e.
4.1.1.2.5. Processing Time¶
The processing time of an operation is its execution time minus the setup time.
Note
Since setup times can also occur during the processing phase, it is possible that the processing time of an operation is less than the duration of the processing phase.
4.1.2. Key Performance Indicators¶
4.1.2.1. Workplace-Related Key Performance Indicators¶
The availability of a workplace is the production time divided by the scheduled operating time of the workplace during the considered period. The availability of an operation is the production time divided by the scheduled operating time of the workplaces where the operation has been executed during the execution time on these workplaces:
The availability is also the product of the following three key performance indicators.
The occupancy rate of a workplace is the occupancy time divided by the scheduled operating time of the workplace during the considered period. In addition, the occupancy time is the sum of the execution times of all operations at the respective workplace.
Note
This can differ from the sum of the total execution times of these operations if individual operations were executed partly at the relevant workplace and partly at another workplace.
The setup reduction of a workplace is the sum of the processing times of all operations at the respective workplace divided by the occupancy time of the workplace during the considered period.
Note
The processing times at the respective workplace can differ from the total processing times of these operations if individual operations were processed partly at the relevant workplace and partly at another workplace.
The process availability of a workplace is the production time divided by the sum of the processing times of all operations at the respective workplace during the considered period.
Note
The processing times at the respective workplace can differ from the total processing times of these operations if individual operations were processed partly at the relevant workplace and partly at another workplace.
The performance of a workplace is the following quotient during the execution time of the operations which have been performed on this workplace during the considered time period:
The performance of a single operation is:
The time-based quality rate of a workplace is the following quotient during the execution time of the operations which have been performed on this workplace during the considered time period:
The quantity-based quality rate of a workplace is the following quotient:
This is also the quality rate of a single operation. For a single operation there is no difference between the time based and the quantity based calculation.
The following two key performance indicators can be applied to recorded data from the past as well as to planning scenarios for the future:
The occupancy rate of a set of workplaces during a considered time period:
The setup reduction of a set of workplaces during a considered time period:
4.1.2.2. Order-Related Key Performance Indicators¶
The Scheduling Efficiency of a single production order:
where the \(\sum_{Operations}(Execution Time)\)
is the execution time of the production order itself.
The Scheduling Efficiency of a set of production orders, which have been completed or are planned to be completed during a considered time period:
The adherence to delivery dates of a set of production orders, which have been completed or are planned to be completed during a considered time period: