Earned value is a metric which indicates the actual time production value of a machine or cell. If a machine runs for eight continuous hours at a 100% feed rate, the earned value will be eight hours. If that machine had run at a 50% feed rate, the earned value would only be four hours.
When the lost efficency value is added to the earned value, one gets the total run time of the machine or cell in the report. Idealy, this value should be zero or close to it. If there is significant lost value, one should look to the operator(s) to see if the speed needs to be dialed up or if the NC program needs to be adjusted.
This metric allows one to look at efficiency of production by itself, without any outside influences. Simply put, In-cycle efficiency shows the feed rate average for only the time when the machine or cell is actually in-cycle. This data is calculated by dividing the earned value by total run time.