Special Considerations

Production activities are often continuous and therefore require performance metrics to be calculated over relatively small time intervals. To support this requirement, production performance data is calculated on an hourly basis and stored as individual performance records. Each record contains a start time, an end time, and KPIs calculated for that period. In addition to the hourly records, additional records are generated when these events are detected:

• Shift changes
• Order changes

In these cases, records are generated for the exact duration between the events, and KPIs are calculated accordingly.

Since some performance records may not be exactly one hour in duration, the term ‘period’ is used to refer to the duration defined by the start and end time of each performance record.

By default, the Production Performance report excludes records where the entire period consists of excluded time. For example, if the production line is stopped for a reason whose stop type is set to ‘Excluded Time’, that period is omitted from the report.

When the application detects that a machine or line is not running, the stoppage event is mapped to a stop reason. The stop reason determines whether the stoppage is considered as excluded time.

These are the various types of manufacturing stop scenarios that are excluded time:

• Any machine stop reasons whose stop type is set to excluded time.
• Any production stop reasons whose stop type is set to excluded time.
• Any non-shift time – time periods when the shift schedule for the machine is set to non-working.

Performance records are retained in the database even when the entire duration consists of excluded time. These records can be included in the report by enabling the Show Excluded Periods check box on the More tab.

When grouping is applied to this report, the evaluation is performed at the aggregated level rather than at the individual record level. As a result, grouped data is included whenever the aggregated data contains some non-excluded time, regardless of whether the Show Excluded Periods check box is enabled.

For example, a department may consist of multiple lines, one or more of which have no working time. If grouping by department is applied and the department has > 0 working time overall, then all lines, including those with only excluded time, are included in the grouped results. This is because the department is considered to have operated during the reporting period, and therefore all associated data contributes to the performance calculations.

When Line Input and Line Output counters are used, Production loss is automatically calculated as the difference between the Line Input counter and the Line Output counter values.

Depending on the line configuration, production loss can contribute to the Quality percentage (Qu%) or the Performance percentage (PE%) component of OEE.

OEE% = PE% * Qu% * Av%

Use the Treat Production Loss as a Quality Loss for OEE check box on the line to determine how production loss affects OEE calculations:

• When checked (enabled), production loss contributes to Quality (%).
• When unchecked (disabled), production loss contributes to Performance (%).

Example: During one hour of production, no downtime occurs and production loss equals 10%.

Result: OEE = 90%

If production loss is set to impact Qu% for OEE, the loss can be qualified into accounted or unaccounted scrap.

• Accounted scrap is the quantity for which scrap has been recorded.
• Unaccounted scrap is the quantity is the remaining production loss - the scrap which has not been recorded.

For example:

• Line Input Count = 1200
• Line Output Count = 1000
• Production Loss = 200
  • Unaccounted Scrap = 200
  • Accounted Scrap = 0

If the operator records scrap to specify a quantity of 75, then:

• Accounted Scrap = 75
• Unaccounted Scrap = 125
• Production Loss = 200