Exposed copper area migration from EC to CD

In EC there is a field called "exposed copper area", which is probably important for determining the amount of gold needed in ENIG or other raw materials for other final finishes.

Right now it is calculated as a percentage, but the question then is: Percentage of what?

If the calculations are to be exact, plated holes and non-covered vias would also have to be  a part of the total surface area covered.

There is a field in CD called "coverage" for final finish, would it be a good idea to use this in conjunction with information on hole plating and type to determine  the total surface area and present this as an aggregate number? Could be available in the summary perhaps, but still keep the data sources as top, bottom and holes surface areas in CD.

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  • Elias Bakken  conversion from EC to Cd is an internal Elmatica issue, but having said that it is interesting  for CD forum as well how we calculate surface finish area, specially for gold and silver due to cost factor.   Today the exposed  copper area is calculated as percentage of the single PCB area. Andreas Lydersen can you confirm this? 

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  • You are right Jan, the EC to CD is Elmatica internal, but regardless of where the data is coming from, if we want to have the data stored somewhere in CD, where would be a good place to have it?

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  • Elias, I think we need this information for several reasons like surface finish with high cost materials such as gold and silver.  What we are looking for is exposed copper as a function of copper pattern and soldermask. We should then calculate the soldermask open area before we add clearance.

    Anyone in the forum have a good solution?  

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