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OEE
OEE (Overall Equipment Effectiveness) is a metric that describe the effectiveness of a system, in many cases a machine, within a specified period.
It is a single metric that describe combination of 3 independent metrics, that is, Availability, Performance, and Quality.
It is usually use to track and compare effectiveness between systems.
OEE Calculation
To calculate OEE, it is required to determine the following terms:
Actual Run Time. Refers to how the machine was running.
Expected Run Time. Refers to the duration the machine was expected to run. This usually refers to the shift hours.
Best Job Time. Refers to the fastest time a specific job can be done by the machine.
Actual Job Time. Refers to the actual duration of specific job done by the machine.
FPY (First Past Yield). Refers to the ratio of number of good units (not including reworks) vs total units produce by machine.
In this case:
Availability = Utilization = Actual Run Time / Expected Run Time
Performance = Best Job Time / Actual Job Time
Quality = FPY = Good Units / Total Units
OEE = Availability * Performance * Quality
OEE Real Time
By using a Programmable Edge Device, we can setup multiple timers. One timer to monitor shift timing and another timer to monitor Machine Run Time. At the beginning of shift we start shift timer and counts up in seconds. Machine timer only counts up when machine runs and pause when machine is stopped.
Real Time Utilization = Machine Run Time / Shift Time
Best Job Time can be recorded base from Manufacturing Engineer Input.
Actual Job Time is monitored by machine. At every end of job, Edge Device will record machine performance by Best Job Time divided by Actual Job Time.
Real Time Ave Performance = (Previous Ave + Real Time Performance)/2
Usually quality check are done at a later time, so is not included on Real Time calculation of OEE.
Therefore:
Real Time OEE = Real Time Utilization * Real Time Ave Performance
OEE or Overall Equipment Effectiveness is a machine monitoring metric made famous by car manufacturers. OEE is over-rated, it is the last thing that you need to monitor but everyone talks about it. Looking at OEE of a machine will not give you something to Act On.
This what makes our system more attractive, because we use programmable hardware and software. This way we can modify the logic, the formula behind, the visuals, notifications and so on. We can modify things very quickly and the use cases are limitless