The OEE index is your process validation expressed as percentage. This percentage provides you an impression of the efficiency of the process. e.g. An O.E.E. of 73% indicates your process matches the World Class Manufactoring standard.
The OEE is the result of three factors, each a percentage themself.
OEE = availability(%) x performance(%) x quality(%)
In case every factor scores 90%, the OEE result is:
OEE = 90%3 ==> OEE = 73%
These are the fundamentals of the Overall Efficiency Equipment.
Depending on the type of process the number of factors can variate to increase insight about the performance of your process.
Displayed below is an example of a PASABAN sheeter OEE for the paper- and (solid)board industry.
Sheeter OEE = Planning(%) x Availability(%) x Machine speed(%) x Quality(%) x Surface utilization(%)
For a five factor OEE, the WCM norm of 73% is very difficult to obtain. A correct World Class Manufacturing norm should include the number of factors as well.
WCM = OEE = the number of factors x 90(%)
In the graph below you see the progress of the O.E.E. and the subfactors of a solidboard sheeter over a period of 16 months.
According a project proposal, with a budget of a € 150.000,--, a 15% speed increase should be gained on a large range of products. On this condition a green light was given for modification.
Four months after the modification the OEE graph printed above was generated
According to the original project proposal, shortly after the turn of the year, the machine speed index should rise significantly.
As anyone can see in the graph, there is no significant speed incease gained. With the help of furher OEE software, build by S&S System, we could quickly determine what went wrong and take corrective actions.
In reality with this machine, the operators complained, that the machine could not deliver the set quality level, as neither a good surface utilisation.
In response to these claims, a lot of time and money was spend to improve these assets.
However, if one studies the OEE quality index, over the complete period, the index stays well above the World Class Manufacturing norm of 90%.
The same applies to the OEE surface utilisation index. It stays well above the WCM norm.
The OEE availabilty index stays almost all the time below the 90% WCM norm. Hence the moderate final overall OEE index is not due to bad quality or bad surface utilisation but due to a lack of raw material. So the big gain for this factory is to fine tune interal logistics.
With these real life cases we hope to enhance your understanding of the overall equipment efficiency (OEE) index and show the value of a on demand OEE reporting system for fact-based management.
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