Overall Equipment Effectiveness (OEE)
The Overall Equipment Effectiveness is a method of analysis of the production process productivity following the LEAN concept. The method is aimed at controlling and improving production efficiency and is based on the measurement and processing of specific production indicators. This term is most often used in the “OEE” format.
Components of OEE
Overall Equipment Effectiveness starts from the total operating time of the enterprise and analyzes the time of planned stops and other losses (stop losses, speed losses, quality losses) to reduce and eliminate them.
OEE is based on three criteria:
- Availability (A) is the time during which the equipment created or could create products, i.e. was in working order. The indicator analyzes losses on stops, including unscheduled stops.
- Performance (P) is a theoretical period – part of the actual time spent during which the actual volume of production could be produced at the highest speed for a particular device (mostly passport). It takes into account the loss of speed compared to the maximum possible.
- Quality (Q) is the share of quality products in the total production of the line. It takes into account the loss of quality, including the production of non-compliant products.
Quality enterprise asset management is impossible without equipment condition monitoring and OEE measuring.
How Is OEE Measured?
The indicator of the general efficiency of the equipment is presented in two formats:
- In figures – measured causes of losses, grouped by certain, depending on the type of equipment, categories.
- In percent – the calculated indicator, the relative value for a certain time.
If the enterprise has the OEE indicator:
- less than 65% – it is necessary to understand that the company urgently needs help;
- from 65% to 75% – a satisfactory level of efficiency, but there is a significant reserve that is not used;
- more than 75% – a good result, but even in this case, there is room for improvement.
What Causes a Decrease in OEE?
Among the reasons that may adversely affect the level of overall efficiency are the following:
- Loading time (scheduled time): time of preparation for the start of the production process, including reconfiguration of equipment, information download period, unscheduled stops to check equipment, personnel, and quality.
- The time during which production is not scheduled. Includes scheduled equipment maintenance stops, meetings, time to issue test batches (if this product is not going to be sold), planned preventive maintenance, staff training (if no product is being produced), and non-working hours – holidays and weekends.
- The amount of substandard product.
- Stop time – scheduled and unscheduled.
- Operation of equipment at a lower speed than expected for the production of this volume and format. This is the time lost, which is the difference between the time required and the time spent on the production of the product.