Increase OEE and save costs: Where it works and when it pays off
By susanne.gutermuth@cosmino.de InThe overall equipment effectiveness OEE evaluates the productivity of machines and systems
However, the focus should not be on the key figure itself, but on the recorded losses, i.e. the times that have led to an OEE of less than 100% being achieved.
To make this possible, the entire running time of a machine must be recorded, as incomplete data does not reflect reality. The recording should also take place in the production cycle if possible, i.e. if a problem occurs, it must be recorded immediately (start, end, reason). Otherwise, particularly short but regular disruptions will remain under the radar and end up giving a false picture of production.
The cause of each downtime is just as important to record as the duration. The optimization potential is derived from this, so the loss designation should be clear. A machine symptom from the PLC is not meaningful enough unless it can be clearly assigned to a reason for the downtime. It has proven to be a good idea for an employee to select the reason for loss on the basis of a prepared selection in an entry dialog.
Only if it is possible to break down all OEE losses on the machine into a manageable number of clearly defined loss types will automatic analyses provide the desired information.
How many cost savings or profit increases can be achieved by recording OEE?
In our experience, an OEE increase in the double-digit percentage range is quite realistic if all machine times are recorded, analyzed and optimized. With the same machine running time and personnel deployment, more can then be produced in percentage terms. A higher output in the same period of time means:
- I can produce more products and more cheaply - this increases turnover and, above all, profit.
- Or I save costs because I can achieve the required quantity in less time and with fewer operating resources and personnel requirements.
- The increase in OEE may mean that previous overtime and extra shifts are no longer necessary, which creates further savings potential.
- If I reduce quality losses, I save in the same way as above, but also material and rework costs.
- Savings are also made if the increase in productivity on existing machines makes the purchase of additional machines or tools unnecessary.
Optimizations on bottleneck machines are worthwhile. Even a small improvement can be enough to resolve the bottleneck, with added value for the entire process. In other words, key figures such as cycle time and delivery reliability can be improved and production becomes more flexible.
It is interesting to note that many effective improvements are possible without significant additional investment, as organizational issues account for a large proportion of disruptions - but we are not aware of exactly which ones and to what extent without recording them. A transparent reporting system that aggregates the downtime of each type of loss and, at best, even expresses it in euros, turns a “something should be done” into a clear improvement order with significant added value for the production result.
Transparency creates facts and increases the ability to react.
Finding out immediately that a machine is currently experiencing certain problems ensures that everyone involved reacts promptly and correctly. This inherently prevents long downtimes and thus increases efficiency - without any significant downtime.
And the workers?
They are not monitored at all by the recording. The OEE is purely a machine performance indicator. However, your employees have the opportunity to contribute to the improvement process with their knowledge and ideas. It makes perfect sense to involve the personnel at the plants from the outset, to include them in the definition of the causes of losses and to let them participate in the reporting and improvement process.
The human factor is still an important component in many manufacturing processes. Use this advantage if it exists in the process.
We will be happy to answer any further questions you may have.