Difference Between ED Copper and RA Copper

The base material for FPC is FCCL, which are Copper +PI or Copper + AD + PI.As below picture shown, you may clearly know the relation of these three products.

 So originally, copper is very key for the flex circuits material. Which kind of copper we could choose? The answer is ED Copper (Electrodeposited Copper Foil) and RA Cooper (Rolled Annealed Copper Foil). Then what the difference between these two? I will show it from below 4 aspects:

1. Definition & Manufacturing Method
Different copper is defined by its manufacturing method. ED Copper, which is made from CuSO4 solution, by using electrolysis method, made Cu²⁺ dip into spinning cathode rolls and stripping, then made it into ED copper. RA Copper, which is made from high purity copper(>99.98%), by using pressure process, made copper into different copper thickness.

2.Form

ED Copper (Electrodeposited Copper Foil)

RA Cooper (Rolled Annealed Copper Foil)

3. Performance
Due to different manufacturing methods and different shapes, the performance of them is not same. ED copper has better conductivity than RA copper. While as for extensibility, RA copper is much better than ED copper. Details about performance comparison can be understood via below chart : 

4. Application
Because of different performances, RA copper and ED copper are used in different products which tend to different product requests. For example, the flex board needs to be bendable a lot, so obviously, RA copper will be a good choice. Otherwise, we could use ED copper with high electrical conductivity.  

Whatever, you should select copper according to your circuits' requests (final board performance, cost, function...)