In my last post I began digging into the details of calculating OEE (Overall Equipment Effectiveness). The formula for calculating OEE is straightforward:
OEE = Availability * Performance * Quality
But each of these key components relies on some standard operating definitions. In the last post we looked behind the scenes at Availability. This post dives into the definition of Performance.
As with Availability, Performance is a ratio, expressed as a percentage.
Here are the components of Performance:
Performance = (Total Pieces * Ideal Cycle Time) / Available Time
Ideal Cycle Time is the optimal or expected time to produce one part that you can expect to achieve with your process. Some people call this the Theoretical Cycle Time.
Since the Ideal Cycle Time is a theoretical value, Performance is always capped at 100%. That way if you overestimate the Ideal Cycle Time, it will have a limited impact on OEE.
In the example in the last post we calculated Available Time as 343 minutes. This was based on the following data:
|Total time in shift||480 minutes (8 hours)|
|Lunch break||30 minutes|
|Machine setup||95 minutes|
|Other Down Time||17 minutes|
Scheduled Time = 480 minutes in shift – 30 minutes planned for lunch break = 450 minutes
Down Time = 95 minutes of machine setup + 17 minutes of other unscheduled down time = 112 minutes
Available Time = 450 minutes Scheduled Time – 112 minutes Down Time = 338 minutes
With just two more pieces of information, we can calculate Performance:
|Ideal Cycle Time||0.25 minutes (15 seconds) per piece|
|Total Pieces Produced||1187 pieces|
Because we are expressing all other Time measurements in minutes, we need to express the Ideal Cycle Time in minutes as well.
Performance = (1187 Total Pieces * 0.25 minutes/piece Ideal Cycle Time) / 338 minutes Available Time = 0.878 or 87.8%
How do you calculate Performance at your facility?