OEE stands for Overall Equipment Effectiveness. It is a metrics which is used to understand how effective a manufacturing process is utilized.
OEE is determined by three factors
- Availability
- Performance
- Quality
Mathematically OEE = Availability X Performance X Quality.
Availability: Availability is calculated as the ratio of Operating Time to Planned Production Time. Availability takes into account Down Time Loss, and is calculated as:
Availability = Operating Time / Planned Production Time
Operating time is the planned production time less downtime loss.
Operating Time= Planned Production Time – Down Time
Planned Production time is the total shift time the equipment available for production less Planned stoppage time.
Planned Production Time= Shift Length – Planned stoppage time
Performance: Performance takes into account Speed Loss, and is calculated as:
Performance = (Total Pieces / Operating Time) / Ideal Run Rate
Ideal run rate is the maximum expected production quantity as per the cycle time.
Quality: Quality takes into account Quality Loss, and is calculated as:
Quality = Good Pieces / Total Pieces
Example for calculating OEE
| Description | Data |
| Shift Length | 8 hours = 480 min. |
| Planned maintenance for 5S and TPM | 30 minutes |
| Down Time | 47 minutes |
| Ideal Run Rate | 60 pieces per minute |
| Total Pieces | 19,271 pieces |
| Reject Pieces | 423 pieces |
Calculating Availability
Availability= Operating Time / Planned Production Time
Planned Production Time= Shift Length – Planned stoppage time.
= 480 – 30 = 450 minutes
Operating Time= Planned Production Time – Down Time
= 450 – 47
= 403 minutes
Availability= Operating Time / Planned Production Time
= 403 / 450
= 0.8955 or 89.55%
Availability = 89.55%
Calculating Performance
Performance = (Total Pieces / Operating Time) / Ideal Run Rate
= (19,271 pieces / 403 minutes) / 60 pieces per minute
= 47.81 / 60
= 0.7969 or 79.69%
Performance = 79.69%
Quality = Good Pieces / Total Pieces
= 18,848 / 19,271 pieces
= 0.9780 or 97.80%
Quality = 97.80%
OEE = Availability x Performance x Quality
= 0.8955 x 0.7969 x 0.9780
= 0.6979 or 69.79%
OEE = 69.79%
Overall Equipment Effectiveness of the above indicated process from which the data is used for calculation is 69.79%.
From the above data the area needed for focus to improve the OEE is performance since it is having the lowest value compared to availability and quality.To improve the performance the speed loss has to be reduced. By doing it the OEE of this process can be improved.
You can calculate the Overall Equipment Effectiveness for your requirements below
Recommended Books to Read:
- AN INDUSTRY FRAMEWORK FOR BUILDING A SMART FACTORY: Implementing modern changes to transform the factory status quo into a Smart Factory
- The OEE Primer: Understanding Overall Equipment Effectiveness, Reliability, and Maintainability
Content is worth to know about OEE in simple way.