In an ideal environment, all equipment would operate all the time at full capacity producing good quality product. In real life, however, this situation is almost non-existent due to hidden losses and wastes.
OEE is a simple yet powerful roadmap that helps production floor people and management to visualize and eliminate equipment losses and wastes.
Basically OEE is about effectiveness; it is the rate between what a machine/Process theoretically could produce and what it actually did.
The three main categories of OEE are:
1- Availability:
the proportion of planned running time that is available for production.
The losses in this category include equipment breakdowns, unplanned maintenance, lack of operators or materials, being starved by upstream equipment, or being blocked by downstream equipment, etc.
2-Performance:
compares the actual running speed of machine/Process against its specified operating speed.
3-Quality:
Simply it’s the proportion of actual production throughput which meets the customer specification exactly and is right the first time.
How to Calculate OEE?
OEE= Availability *Performance* Quality
Example:
The table below contains hypothetical shift data which will be used to complete the OEE calculation.
Calculations:
Available time=Open hours- Break time= 8*60-30= 450 min.
Actual working time=Available time-Down time= 450-(20+25) =405 min.
Availability= Actual working time/Available time=405/450=0.9
Actual Speed=Total output/actual working time= 8000/405=19.75 unit/min.
Performance=Actual speed/Standard speed= 19.75/30= 0.66
Quality=quality pass output/total output= (8000-1000)/8000 =0.875
OEE=Availability*Performance*Quality = 0.9 *0.66 *0.875
OEE=52%