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Electropolishing for Deburring Critical Metal Parts

Stamping and machining processes can leave metal parts with burrs that can affect the fit, function and durability of metal parts.

When these parts are destined for food or pharmaceutical production equipment or fuel lines and gear assemblies used in aerospace manufacturing, burrs are more than just a surface imperfection – they’re a potentially catastrophic defect that can prevent the proper sealing or connection between two parts, become dislodged near moving parts, or cause seizing of screws and other fasteners.

To prevent such risks, manufacturers in many industries often specify electropolishing as the final step in finishing their critical metal parts.

How Does Electropolishing Work?

Electropolishing is a highly effective finishing process for removing metal surface defects like microburrs caused by processes like broaching, fine blanking, grinding, lapping or milling.

Using a combination of a chemical bath and a rectified electrical current, electropolishing removes a precise and uniform layer of surface material, leaving behind a shiny, smooth, passive and defect-free surface.

Among other advantages, electropolishing can remove a microscopically precise amount of surface material with surface roughness improvement of up to 50%, eliminating surface defects for high-quality results within very tight tolerances.

By eliminating microcracks and other defects that can harbor bacteria or become initiation sites for corrosion, electropolishing also leaves metal parts with significantly improved resistance to corrosion and pathogen growth. The ultrasmooth surface finish that electropolishing leaves behind has been shown to inhibit the formation of bacterial biofilms that can be resistant to ordinary cleaning methods. The finish also leaves behind a surface that is easier to clean, without cracks or defects where pathogens can hide – a critical advantage for medical, pharmaceutical and food and beverage production.

Why Use Electropolishing for Deburring?

Fragile or intricate metal parts, like those used for medical devices and implants, are not well suited for finishing processes like mechanical or vibratory polishing, which can damage fragile parts or create inconsistent results for parts with complex shapes.

Successful deburring for critical metal parts is contingent upon the ability to remove a precise layer of surface material. No other process can match electropolishing for its ability to control the material removal to +/- .0002”.

By deburring the threads on metal fasteners, for example, electropolishing can reduce the risk of adhesion between two mating surfaces, also known as “galling,” which can cause material between the surfaces to deteriorate and seize up when parts are pressed together.

Burrs can also shorten the lifespan of a part, by breaking off or becoming an initiation site for corrosion.

Larger burrs that occur as the result of rough milling or displaced metal from drilling operations, however, may need pre-treatment using other methods. Likewise, heavy die break burrs caused by improper tooling maintenance will generally require additional treatment.

Much in the way that lightning is drawn to the highest points, electropolishing delivers higher current density on the high points or edges which makes it ideal for micro-deburring The customized nature of the electropolishing process, from racking to chemical formulation to timing, would be of little value if it could not be reproduced consistently. But unlike other finishing processes, electropolishing is prized for its consistent results.

Electropolishing also offers a key advantage for parts with critical microfinishes or made from the lighter, more fragile materials increasingly used in the manufacturing of medical devices, electrical components and semiconductors, among other industries. These parts are not suitable for mass finishing techniques that can create distortion, nicks and scratches. Electropolished parts are individually racked to prevent contact and ensure the even application of the process for even the most fragile parts.

Advantages of Electropolishing for Deburring

The electropolishing process can be customized by alloy, by application and by the desired results. Beyond its ability to remove a uniform layer of surface material to eliminate surface defects like microburrs, microcracks, scale and staining, electropolishing offers many collateral benefits for the manufacturers of critical metal parts.

Microscopically precise removal of surface material with control to +/-.0002”

Customized racking to accommodate fragile and complex parts small and large

Leaves parts with enhanced durability and cycle life

Creation of a pathogen-resistant surface

Superior cleanability

Ultraclean finish

Decorative finish

One stop process for cleaning and removing surface defects

30X more corrosion resistance than passivation alone

Parts are also left passivated in the process

Improves conductivity of copper and aluminum alloys

What Alloys Can Be Electropolished?

A long list of alloys can be effectively deburred using electropolishing. The process is also equally effective on parts that are fully annealed or hardened. That is one reason that electropolishing is frequently specified for the final deburring and finishing of parts after all fabrication and heat treating processes have been completed.

Electropolishing is effective for a wide variety of alloys including:

Stainless Steel 200-300 Series

Stainless Steel 400 Series

Stainless Steel: Precipitating Hardening Grades

Nitinol

Titanium

Aluminum

Carbon Steels

Copper

Brass

Nickel Alloys

Specialty Alloys

And more

Electropolishing for Critical Metal Parts

As the world’s largest electropolishing specialist with seven decades of electropolishing expertise and innovation, Able Electropolishing provides consultation and collaboration from the earliest stages of prototyping through production to create highly customized electropolishing processes for a wide variety of metal parts.