This approach assumes the machine can not run while you are having your coffee or lunch. The reason to include it in the OEE is to make the production team aware of this potential loss. Is there really no way to let the machine run 15 or 30 minutes without operator interference? Would it be possible to have an other operator at the machine? Could an other operator watch your machine while you go away?

Exactly! So Maintaining a machine is not meant to reduce its effectiveness… No, we clean and maintain to RAISE its effectiveness. By taking this time out of the OEE, we will never see if the effort we spent to clean and maintain is bringing us a higher effectiveness at the bottom line!

You, the operator, are part of a production team. Together with your maintenance and engineering colleagues you are responsible for the effectiveness of the equipment. If you, the operator, can prove with facts and figures that you are suffering severe losses due to repeated breakdowns and too little (preventive) maintenance, or due to too frequent PM, it serves a mutual interest if you bring this up in your production team meeting!

Here too: If PM reduces your effectiveness: stop it, otherwise: do it!

At first glance that seams to make sense. But OEE is not a breakdown registration system, but a loss detection system.
Let me explain the consequences: Imagine after 3 months registering OEE data, it shows the main loss is in availability. So now you want to know what you need to do to get your availability up. So you take one of the seven tools and draw a pareto diagram of all your time-events. Lets assume each of the 85 breakdown items occurred at least once. What you will see is a pareto with an immense long tail, not giving a clear clue where the main losses are located.
In the other approach where you would have registered failures on, lets say, 5 process parts of the equipment (like ‘incoming conveyer, pre-heater, moulder, compressor, outgoing conveyer’) it would show what part of the equipment is restraining the process most. Then you start temporarily to focus on that part. A simple registration card (maybe even showing the 85 breakdown items) for some weeks will give detailed insight what’s going on. Sometimes it is a matter of simple maintenance, sometimes a Small Group Activity can solve the problem for once and forever. By this circle of focused improvement the equipment will become better and better. This example also shows another disadvantage of the ‘breakdown registration approach’; if you handle each breakdown in the best way, thus eliminating it forever (either by reengineering or taking it into PM), it will not reoccur, while other breakdowns may start to occur. So after a while the breakdown registration system will not reflect the reality anymore. In the other approach this is less likely to happen.

The reason why the equipment stopped running is not the cleaning but the ‘waiting for technician’ or the raw material. Always register the true reason why the machine is stopped, not how you spent that time.

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