What is Electropolishing?

Electropolishing, also known as electrochemical polishing or electrolytic polishing. Electropolishing is an electrochemical process that removes material from a metallic workpiece like a stainless steel steam sterilizer. All PRIMUS shelving and loading equipment is electropolished after the complete manufacturing process.

Electropolishing removes material at a controlled rate and can be controlled to . 0002” accuracy.

It is often described as the reverse of electroplating. Electroplating is basically the process of plating a metal onto the other by hydrolysis mostly to prevent corrosion of metal or for decorative purposes. The process uses an electric current to reduce dissolved metal cations to develop a lean coherent metal coating on the electrode.

Why Electropolish?

The electropolishing process restores the natural corrosion resistance of stainless steel, improve surface finish, enhance aesthetics, and make products easier to clean and sterilize.

This process of electropolishing stainless steel improves the corrosion resistance of stainless steel by enhancing the thickness and properties of the passive chromium oxide layer. Furthermore, electropolishing stainless steel is significant when the parts are used in a harsh environment, such as the interior of a steam sterilizer.

What’s more, electropolishing has many applications in the metal finishing industry because it can be applied to objects of complex shapes. The process is also familiar, relatively simple, and inexpensive.

What is the advantage of Electropolishing a sterilizer?

Electropolishing dissolves free iron, inclusions, and embedded particles from the surface of the material surface. Electropolishing improves the near surface chemistry of stainless steel. Additionally, the process removes embedded particles and inclusions, it also improves the atomic ratios of the materials alloying elements.

How does Electropolishing work?

A power source converts AC current to DC at low voltages.

A tank, typically fabricated from steel and rubber-lined, is used to hold a thick electrolyte bath (most often concentrated sulfuric acid and phosphoric acid solutions).

A series of lead, copper, or stainless steel cathode plates are lowered into the bath and installed to the negative side of the power source.

A part or group of parts is fixtured to a rack made of titanium, copper, or bronze.

The rack is dipped in a bath of electrolytes. The rack and its parts serve as the anode as it is connected to the positive terminal of the DC power supply.

A DC current passes from the anode, where metal on the surface of the part is oxidized and dissolved in the electrolyte, to the cathode.

Gassing in the form of oxygen occurs at the metal surface, furthering the cleaning process.

At the cathode, a reaction occurs, which produces hydrogen.

Then, once the processis completed, the part is run through a series of cleaning and drying steps to remove clinging electrolyte. The resultant surface is clean and bright.

Benefits of Electropolishing

While the process is best known for the bright polish left on a surface, there are
additional important benefits from electropolishing, include:

  • Deburring
  • Size control
  • Microfinish improvement

Have a question? Talk to Dave Schall, our PRIMUS sterilizer expert who is here to assist you anytime at 877.679.7800 extension 1212 or email at dschall@spire-is.com.

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