Question:
What causes the sulfuric acid concentration to increase above the recommended limits in an acid copper plating bath? P. W.
Answer:
Your e-mail did not mention if the copper concentration is decreasing or if the bath uses brighteners. Assuming that the copper concentration is decreasing and that some type of brightener is being used, the two most likely causes of this are: Polarization of the copper anodes or filming of the anodes by the brightener. You should increase the anode surface area and see if that slows down the formation of sulfuric acid in your bath. If this solves the problem, which I think it will, great. If not you must investigate the brightener used in your bath. Your vendor should be able to help you with this.
