What is OEE
OEE is an abbreviation for "Overall Equipment Efficiency", and it's a way of measuring productionefficiency. Below is a short introduction to how OEE is calculated. OEE consists of three parts, A = Availability, E = Equipment efficiency and Q = Quality.
These three parameters all affect the final OEE number in their own way, as shown below.
Availability is measured as the part of the planned productiontime the machine actually was running. The remaining time is various types of stops, scheduled or off-the-cuff ones. The number is presented as percentage.
Equipment efficiency is measured as speedlosses compared to the parts optimal cycletime. This number may contain shorter "microstops"
The quality yielded over time is measured as the percentage good quantity in relation to the number of produced quantity.
Calculation of the parts contained in the OEE
number
Availaility =
(scheduled time - stoptime) / scheduled
time
Availability is a number
which describes how much of the maximum possible productiontime the machine
actually produced. At a facility where there are two shifts a day, each
consisting of 8 hours, 16 hours would be the maximum theoretical number of
productionhours.
Equipment efficiency = measured production / ((scheduled
time - stoptime) * optimal production)
This number tells us how fast compared to the theretical
maximum we're producing when the machine is running.
Quality = (produced quantity - scrap) / produced quantity
Quality is ismply put the percentage units which are produced that meets the standards of the parts qualityrequirements.
When all of the above numbers are calculated,
they are multiplied with one another, which results in the OEE
number.
When studying the above numbers, one can conclude that all factors
must be high in order to yield a good OEE number.
What actually IS a
good number is very much depending on what type of products are produced, so
usually it's used in studying trends over time, and aiming to get better over
time.