What is Electropolishing?

What is electropolishing and how it works

Electropolishing will smooth and streamline the microscopic surface of most metal objects, improve surface finish, improve corrosion resistance and achieve passivation—typically stainless steel or similar alloys. Electropolishing typically takes off between 0.0002 and 0.0003 of an inch from the surface of an object. Learn more about how much material electropolishing removes.

The electropolishing process may improve the surface finish of your metal part by 10%-40% (depending on part tolerances and surface finish) or more—rendering the surface of the metal microscopically featureless and void of any tiny imperfections. Often, during a standard run, total material removal is limited between 0.0002” to 0.0003” per surface—but the removal rate can be adjusted depending on a part’s tolerances.

It’s important to note that electropolishing only improves the surface of a metal part on a microscopic level. Any macroscopic textures or surface scratches will only result in a smoother texture or smoothed scratch if taken through the electropolishing process. For macroscopic surface imperfections, mass finishing is the more appropriate process for the job.

The Electropolishing Process

How do we do it? We first load the parts onto racks, which we dip into a tank filled with a phosphoric and sulfuric acid solution. The tank is lined with metal plates that function as cathodes so we can run a positive electric current through the bath.

We can adjust the removal rate to a specified tolerance, and we check throughout our process to ensure we are meeting the targets we set. This is especially important during electropolishing of large batches of parts, so we ensure that our quality is consistent from the first part to the last. Learn more about the electropolishing process. 

Can Electropolishing Achieve Passivation? Yes.

The Passivation of stainless steel is the removal of free iron from the surface of a part. Electropolishing will remove free iron, as well as de-burr and deeply clean the surface. This can be especially important when you have small parts with trace amounts of free iron and micro-burrs.

The passivation of stainless steel at NEE can be performed to industry standards such as ASTM A967 and ASTM B912.

To learn more about Electropolising, please watch the video on this page or visit our electropolishing resources page for more information.

Understanding Electrochemical Polishing

Electrochemical polishing serves as an umbrella term encompassing various specialized processes aimed at refining metal surfaces through controlled chemical reactions. These processes include electropolishing, citric acid passivation, electrolytic polishing, and more. Each method offers unique advantages and applications, but they all share the common goal of achieving superior surface quality and finish. Whether it’s enhancing corrosion resistance, improving aesthetic appeal, or optimizing functionality, electrochemical polishing techniques provide versatile solutions for a wide range of industries, from aerospace and automotive to medical devices and beyond. Contact us today to discuss what would be the ideal treatment for your needs.

Electrolytic Polishing

In the world of metal finishing, the terms “electropolishing” and “electrolytic polishing” often coexist, but they aren’t interchangeable. Electrolytic Polishing sometimes referred to as Electrolytic CMP or E-CMP is a metal finishing process that combines elements of CMP (chemical mechanical polishing) with that of electro-dissolution. While both processes involve the use of electric current to polish metal surfaces, the gold standard for stainless steel passivation remains Electropolishing. This specialized technique offers a level of precision and quality that surpasses traditional methods, ensuring metal components achieve a flawlessly smooth, corrosion-resistant finish.

At New England Electropolishing, we stand by the importance of accurate terminology and feel it’s important for our customers to understand the difference between electrolytic polishing and electropolishing. Electropolishing is not just a process; it’s a refined science, meticulously designed to enhance the surface of metal alloys to perfection. Our expert team of electropolishers understands the nuances of this technique, ensuring your components are treated with the utmost care, resulting in an unparalleled level of quality and durability.