Shadows after Electropolishing Stainless Steel

Q. We recently starting electropolishing stainless steel. As we get into more complex and larger parts, we get results that look like shadows on them. Do you have any suggestions on how to prevent this problem? –M.T.

A. You have a problem with current distribution. There a few things you can try to solve this problem. The cathodes can be rearranged to give you better coverage of the part. You can use conforming cathodes to do the same thing. Shields made of plastic can be placed around the high-current-density areas of the parts being electropolished. Ideally, you want the parts to have a “clear view” of the cathodes, meaning that you need a current density that does not vary greatly on different areas of your parts. This is where conforming cathodes and shields play an important role.

Which of these methods will work best for you? You will have to do some experimentation to determine this. You can get a better understanding of the process by going to pfonline.com and searching with the keywords “conforming anode”* and “shields.”

*Note: In the case of electropolishing you are using conforming cathodes, but the basic principles are the same for conforming anodes and cathodes.