Overall equipment effectiveness (OEE) is an important measure of manufacturing operating performance. The measure can be calculated for workstations, equipment, process lines, departments, or overall plants and provides managers with excellent insight into the measured entity's performance. Companies across all industries are using this measure to develop performance improvements based on its results.
How to Calculate OEE
The OEE metric consists of three components, each measuring a different operating characteristic. The three components of OEE are availability, performance, and quality. Values for each of these components are gathered from the process line and consolidated to calculate OEE.
Availability is the ratio of an equipment's actual run time compared to that equipment's planned run time. The formula for availability is run time / planned production time. Thus, any downtime the equipment experiences will reduce the availability percentage and, ultimately, the OEE value.
Performance is a value based on the speed of the equipment. This value accounts for both actual operating speeds, including slow or interrupted cycles, as well as micro stops due to any cause. Performance is calculated using production counts as the basis for developing a value for operating speed.
The formula for calculating performance is (ideal cycle time x total count) / run time. The resulting value compares the fastest time in which production could be completed with the actual time the production required.
Quality is the OEE component value that compares the number of good parts produced with the number of total parts produced. Good parts are those parts that pass through the manufacturing process and inspection the first time, with no need for rework. Total parts produced are all parts that pass through the process, including those needing rework and those that are rejected. The formula for calculating quality is (good parts count / total parts count).
Finally, to calculate OEE, the three values (performance, availability, and quality) are multiplied together to arrive at a final value. The resulting number can then be compared to previous values for the equipment or values for similar equipment operating under similar conditions elsewhere in the plant. Based on these numbers, improvements can be made in downtime, waste, line speeds, and communications.
The OEE calculation can be expressed as follows:
- OEE = (availability) x (performance) x (quality)
The variables in the above calculation can be found as follows:
- Availability = actual operating time / planned production time
- Performance = ideal cycle time / (operating time / total number good pieces)
- Quality = good pieces / total theoretical pieces
Each of the three values above is expressed as a percentage. OEE is the product of these three values and is also expressed as a percentage. Analysis of both the individual components of OEE and the overall OEE calculation can highlight areas ripe for improvement.
OEE Can Be Used to Measure Line or Plant Effectiveness
Plant-wide OEE values can gauge how a particular plant is operating compared with other similar plants in the same industry. Some broad, cross-industry standards have been recognized and used as guidelines for monitoring a plant's performance. These guidelines are very general, however, and are as follows:
- An OEE value of 100 percent is considered perfect production.
- A value of 85 percent reflects equipment operating at a world-class level, although this varies by operation type.
- Levels of OEE at 60 percent are considered to be typical.
- An OEE value of 40 percent is considered low but is not uncommon.
Because these values are only general guidelines, OEE for any given equipment, process line, or plant may vary significantly from these rules of thumb. OEE values vary because operating situations vary, so it can be challenging to draw comparisons between different situations. However, comparing the OEE value from period to period for the same operation is an excellent way to monitor both ongoing performance and performance improvements.
Conduct an OEE Assessment to Understand Improvement Possibilities
To demonstrate both the value of OEE as a productivity metric and the effectiveness of our Smart Factory real-time data capture and analysis methodology, Worximity Technologies is offering a complete seven-day OEE assessment of a single piece of process line equipment. This assessment can provide important information about a company's operation or process and uncover possible areas for improvement. This demonstration includes:
- One TileConnect Smart Sensor data collection device attached to one piece of equipment
- Remote setup assistance
- Access to TileBoard, Worximity’s real-time Smart Factory analytics software
- Seven days of actual production data collection
- OEE calculations, assessment, and recommendations to improve production performance
- Industry benchmarking
Companies interested in improving operations by using the power of OEE based on Worximity’s advanced digital manufacturing solution should check with us today. If your company qualifies for a free seven-day OEE assessment, we will work with you to install our equipment, calculate OEE, and analyze your operation.
OEE is one of the most valuable measurement tools in a production manager’s tool kit. With it, supervisors can both assess the level of current production and identify areas for improving operations. Utilizing the power of real-time data and applying Worximity’s Smart Factory analytics gives companies the edge needed in today’s highly competitive marketplace.