The issue in OEE is that sometimes the quality feedback is not immediate. In FMCG businesses, a customer complaint can be received three months or more after production. In these cases it is best not to include quality in the OEE Custom fabrication services calculation and use a more customer focused measure for quality number of complaints etc. If there is no way we can use the Quality component of OEE in a real time improvement cycle, then it is pointless to measure it.Loss AnalysisThe next level of analysis is the seven (or six or eight or sixteen) losses. Within OEE we usually talk about seven losses, although TPM loss structures have been known to define 23 losses in all.Availability losses are primarily Breakdowns and Changeovers. Changeovers can be separated into Tool changes, Material changes and Reduced Yield at start up, but fundamentally these are the same issue. Further analysis reveals breakdowns to have two fundamental types, those due to deterioration because of inadequate maintenance and those due to inherent machine characteristics.
This gives us three basic responses to availability issues improve changeovers through SMED, improve basic maintenance and improve machine characteristics. Depending on the Pareto analysis of losses we may need to act on one, two or all three of these.Performance losses are usually separated into speed loss and minor stops is the machine running slow, or is it stop-starting? The definition of minor stop is also open to debate originally it was less than ten minutes, then five minutes, then three minutes. The pragmatic approach is to say that if you can measure the amount of time lost for a stop it is a breakdown, not a minor stop. If you can only record the quantity of stops, then they are minor stops.There is some practical use for the speed/minor stop distinction if a machine is running slow we can always speed it up, whereas if it is jamming we need to look at the physical mechanism and try to remove the cause of the jams (my favourite example is where we found the root cause was when metal washers were being loaded into a hopper with a metal shovel, which damaged some, which then jammed the feed the solution was a plastic shovel!).
We can however also make a useful distinction between performance losses due to deterioration or contamination and those caused by inherent machine characteristics. As with breakdowns this gives us two improvement approaches better maintenance or equipment re-design.ImprovementThe only reason to measure and analyse anything is to improve it. If we are not going to use the whole improvement cycle there is no point in measuring OEE. It tells us nothing we do not already know. At a gross level all OEE tells you is how much you made compared to what you wanted to make, and any schedule adherence measure would tell you that already. Averaging OEE's over whole plants or time periods just hides issues OEE is a specific measure for use in specific improvement projects.The biggest misuse of OEE is to use it to compare different processes, plants or machines. OEE is not a useful executive KPI. It is not even a very useful operational measure. It is an improvement measure, for people who want to improve their equipment performance.
How to massage your OEE1) When the machine breaks down, log it to planned maintenance2) Do changeovers during planned maintenance or at weekends if not 24/73) Use an easy performance standard4) Measure the best machine and quote that figure5) Set arbitrary targets and achieve them through the aboveUsing the above strategy you should be able to report decent OEE's and even make some money if pay is OEE performance related. What this will not do however is improve your ability to meet customer demand.How to improve performance1) Measure against customer demand (OTIF or similar)2) Measure OEE on constraints or problem equipment3) Set realistic performance standards4) Analyse losses to identify issues for improvement5) Use the whole improvement cycle.