Stripping of flexible circuits is intended to clear resist layer to expose the copper on the board after etching. Does operation of stripping of flexible circuits going smoothly, dependent on equipment design and preparation of the liquid two main parts.
Stripping is relative simple compare to etching of flex circuit with the complex machine. But the “film residue” filtering, and recycling waste shall be disposed properly.
The chemical liquid of stripping, generally use the traditional NaOH(based),solution concentration is about 1-3% in weight, and temperature of the solution between about 40-55 ℃. The major reasons to use the NaOH in our industry: for dry film with good solubility, low prices and easy got. However, according to the actual use of that low concentration of NaoH work not very well, so now the mostly use KoH instead of NaoH as the solution for stripping.
The chemical properties of KoH and NaoH are very similar, but because of the dissolution of K for the dry film with excellent performance, and enhance the effect of stripping. This way don’t need to change the existing production equipments and the filtering effect of the film residue are improved.
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