What is Overall Equipment Effectiveness (OEE)?
Overall Equipment Effectiveness (OEE) is defined as a metric, expressed in percentage, used in lean manufacturing to measure the utilization rate of machinery and equipment. It is used during continuous improvement, to identify which areas need attention.
Despite seeming complex, the OEE indicator is easy to calculate when you count with detailed data information from the machinery. Manufacturing monitoring systems like Blackbird solutions will provide that information in real- time for operators and managers.
In the picture below you can see how the information is displayed, in real-time, on the Blackbird software.
Components of the OEE calculation
The OEE manufacturing formula is quite simple to express:
Availability focuses on major unplanned stops. This is when production stops for a significant amount of time, for instance during changeover and equipment failure. Changeovers can be complicated and vary depending on how many products run on a line, meaning they can’t be eliminated but only reduced.
Performance consists of lowered cycle time and micro-downtime. The lowered cycle time refers to the speed of production going slower than the maximum potential, and micro-downtime are stops that occur for a short amount of time, yet frequently. This can occur for several reasons, such as constant machine malfunctions or operator inefficiency.
Quality encompasses waste as being all the products, which did not meet the quality standard. These products are removed at different stages of production and have a more negative effect toward the later stages in manufacturing.
How to get the most out of your data
Blackbirds uses the categories below to calculate the OEE counting different loss types in a waterfall approach to make it easy to spot bottlenecks and the stops that have the greatest impact on efficiency.
TCU gives an overview of planned downtime, such as vacations, meetings, breaks, or simply no-production planned
OEE 3 accounts for all planned maintenance work to be done, which are also planned stops in nature. This time is often placed during the weekends since the lines only run for a third of the time, according to the schedule.
At this stage, potential stop causes can be:
- Planned maintenance
- Validation
- Personnel activities (i.e. meetings, training)
OEE 2 is associated with the time that the production line is not running due to batch changeovers. These stops are planned in nature, meaning that it is anticipated that the line will regularly stop for changeover activities between batches. For example, in the beverage manufacturing industry, several products are produced on the same lines, meaning cleaning and overall hygiene is a top priority.
At this stage, potential stop causes can be:
- Batch Changeover (i.e. preparation, re-tooling)
- Resupply (i.e. material, package, label)
- Cleaning (i.e. end shift cleaning) at
OEE 1 measure is associated with the time that the production line is scheduled to be running. Several circumstances can cause the line to stop or run slower than expected. These stops are unplanned and redundant in nature. OEE1 covers the downtime, cycle time and scrap of production.
Downtime = time where products aren’t being made and is considered as wasted time.
Cycle time = the speed production is moving.
Production scrap = all the products that were rejected during production and didn’t make it to the customer.
At this stage, potential stop causes can be:
- Machine Defects
- Process Defects
- Waiting time (i.e. material, operator)
- IT (i.e. network issues)
- Cleaning
Closing thoughts
Ensuring that we get a thorough understanding of OEE is the first step toward improving production performance and developing tailored strategies to meet OEE goals.