Understand quality

The quality efficiency component of OEE measures a system's output quality while producing units during a given interval.

Quality = Good Output / Total Output

Entity Quality

In MES, entity quality is:

Quality = Good Production / (Good Production + Rejected Production)

where only production at the entity is considered.

Line Quality

In MES, line quality is:

Quality = Good Production / (Good Production + Rejected Production)

Good production counts for a line are captured at the line's production entity (or entities, if there is more than one entity at that line position). If an entity at a line position is not designated to capture good production counts, then the last entity in the line (based on the child order of the line) is used to collect good production counts. Rejected counts are captured at the production entity and any upstream entities during the given time period.

The production counts are normalized to the line’s unit of measurement (UOM) before calculating the quality metrics. Therefore, if the UOM of the production item is different than the UOM of the line’s item, a conversion factor from the production item to the line’s item must be defined in the system. An error is returned if no conversion factor exists to convert the production counts to the line’s UOM.