What is the OEE?
The OEE (Overall Equipment Effectiveness) or Global Equipment Efficiency, is an indicator that allows to measure the efficiency with which an equipment or process works.
The OEE can also be understood as the relationship that exists between the time that it should have theoretically cost to manufacture the units obtained (without stops, at maximum speed and without defective units) and the time it really took.
I want to improve my processes…
Efficiency VS Efficacy
Efficiency: We can define efficiency as the relationship between the resources used in a project and the achievements made with it. It is understood that efficiency occurs when fewer resources are used to achieve the same objective. Or on the contrary, when more objectives are achieved with the same or fewer resources.
Effectiveness: Regarding effectiveness, we can define it as the level of achievement of goals and objectives. Efficacy refers to our ability to achieve what we set out to do.
Differences between Effectiveness and Efficiency
- Efficacy differs from efficiency in the sense that efficiency refers to the best use of resources, while effectiveness refers to the ability to achieve a goal even though the process has not made the best use of resources. That is, it does not matter if we were efficient in the process carried out to achieve the objective and be effective. Thus, it is perfectly possible to be efficient without being effective and we can be effective without being efficient. The ideal would be to be effective and at the same time be efficient.
Step 1.- We must know what we want to improve
Do we know the efficiency of our processes?
The efficiency of a process (or of a machine) is the relationship that exists between the actual production obtained and the maximum theoretical production.
For example:
Suppose a machine can theoretically produce 1,000 units / hour. For 8 hours, it should have produced 8,000 units. However, at the end of the day, we check its actual production and it has been 4,800 units. The efficiency of the machine has been 4,800 / 8,000 = 60%
An efficiency of 60% tells us that we are taking advantage of our machine in that percentage.
Let's remember…
Everything that can be measured… CAN BE IMPROVED
The company will be all the more competitive the higher the efficiency of its processes. Going back to the previous example…
Suppose a machine can theoretically produce 1,000 units / hour. For 8 hours, it should have produced 8,000 units. However, at the end of the day, we check its actual production and it has been 4,800 units. The efficiency of the machine has been 4,800 / 8,000 = 60%
An efficiency of 60% tells us that we are taking advantage of our machine in that percentage.
And the remaining 40%?
It has become what are called "losses."
Process losses are everything that prevents efficiency from being 100% and are classified into 3 large groups:
U = Utilization: Operating time
It is the time that we have used the equipment, due to breakdowns, material shortages, changes of reference or tools, breaks, etc. we have not been able to be producing during the whole shift.
We define the utilization as the percentage of time that the equipment has been working with respect to the load time.
We have a data capture system that tells us that there have been stops in the different concepts, of 30 minutes.
R = Yield: Net time or theoretical time
It is the time that we should have used the equipment to manufacture the number of parts that we have manufactured (both good and bad parts). It does not correspond to the operating time because it does not include the micro stops not detected or not reflected in the data capture system or the possible reduced speed of the equipment (slowdown of the operator or the machine due to not working in optimal conditions) or possible errors and rounding in data entry…
To calculate this time we carry out a theoretical calculation, so we need to have a production standard that defines the time per piece.
Example of "yield" calculation
300 pieces have been produced of a reference that has a production defined as standard of 45 pieces / hour.
Q - Quality: Useful time
Finally, we calculate the quality ratio Q, which is the percentage of good parts that we have manufactured and which in terms of time is defined as the Useful time, which is the time that we should have used the equipment to manufacture the number of good parts that we have manufactured..
These factors can encompass different concepts or / and receive other names in each company. An easy way to understand this concept is to represent it as the flow of water that circulates through an aqueduct. Each of the factors is like a crack in an arc that lets some of the circulating water lose. Thus, each arch works with the amount of water that has not been lost in the previous arch. Productivity is represented by the final amount of water that we can use at the end of the journey.
But now…
How good are the results obtained?
OEE value classification
| OEE | Qualifying | Consequences |
| <65% | Unacceptable | Important economic losses. Low competitiveness |
| ≥65% <75% | Regular | Economic losses. Acceptable only if it is being improved |
| ≥75% <85% | Acceptable | Slight economic losses. Slightly low competitiveness |
| ≥85% <95% | Good | Good competitiveness. We already enter values considered 'World Class' |
| ≥95% | Excellent | Excellent competitiveness |
