So when you have multiple production lines how do you calculate your oee?

Here’s a great question that was asked to the experts at www.themanufacturer.com:

“How can I calculate the OEE for the whole factory, taking in consideration that the production line consists of many separate stations feeding each other, some of them are M/Cs and others are manual assembly lines? So should we calc OEE for all stations separately and put factor for each station or only calc OEE for M/Cs and for assembly line calc efficiency?”

This article does a great job of examining how OEE can be applied as a benchmarking tool or as a diagnostic tool and in essence recommends that it’s not a good measure for benchmarking your facility. Whilst i personally agree with the sentiment to an extent of this i would like to add an additional thought:

• When we carry out factory benchmarking, which we do at least three times a month, we still find it useful to look at the OEE of the multiple lines on the site to identify relative priority. Do you work on line 1 or line 3 in your site? Or when you have multiple sites with multiple lines again where do you focus?
• When we do this we take each line as an individual entity and then identify the % contribution to the profitablity of the site. This gives us a weighted contribution of that line to the business.
• We then take the OEE for each line and ask – if we improve OEE by 5% what is the profit contribution to that line?

This instantly gives us a relatively real way of linking OEE improvement across sites and networks in a meaningful way. Typically this also challenges some interesting assumptions about how people are currently spending their time. Of course it doesn’t take into account business criticality….but that’s an email for another day!