Electropolishing Service

Q: Is electropolishing suitable for all metals?

Electropolishing works best on conductive, corrosion-resistant metals like stainless steel (especially 300 and 400 series), titanium, aluminum, nickel alloys, and copper. However, it is not suitable for magnetic carbon steels or metals that lack sufficient conductivity or passivity . The metal’s composition and structure must be compatible with the electrolyte solution and current used in the process to ensure safe, effective results.

Q: How much material is removed during electropolishing?

Electropolishing typically removes between 0.0001 to 0.002 inches (2.5 to 50 microns) of material from the surface. The exact amount depends on factors like the metal type, part geometry, surface condition, and processing time. The process is precise and controlled, making it ideal for parts requiring tight dimensional tolerances and smooth finishes.

Electropolishing is a precision process that smooths and brightens metal surfaces by selectively removing microscopic high points. It’s ideal for improving corrosion resistance, surface cleanliness, and overall appearance of stainless steel components.

Mirror-like metal finish
Enhanced corrosion resistance
Ultra-clean surface treatment

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What Is Electropolishing?

Electropolishing, also known as electrochemical polishing or electric polishing, is a precision surface finishing process that uses controlled anodic dissolution to remove microscopic layers of metal. It eliminates imperfections such as burrs, microcracks, heat tint, stains, and oxide scale, leaving metal components—like stainless steel, aluminum, and copper—ultra-smooth, bright, and highly resistant to corrosion.

This process is especially ideal for parts with complex geometries, tight tolerances, or internal features where mechanical finishing can’t reach. Often used as the final step after machining or welding, electropolishing ensures consistent, high-quality results that improve both performance and longevity of critical components.

How Electropolishing Works

Electropolishing, also known as electrochemical polishing, is a precision finishing process that improves metal surfaces by removing a thin, controlled layer of material. Here’s how it works:

1

Part Preparation

Metal components—such as those made from stainless steel, titanium, or nickel alloys—are thoroughly cleaned and mounted onto a specialized rack to ensure electrical contact and uniform exposure.

2

Chemical Bath Submersion

The racked parts are submerged in a carefully formulated electrolyte solution, typically containing a mix of acids suited for the specific metal type.

3

Electric Current Application

A direct current (DC) is applied, making the part the anode in the electrochemical cell. The electrical charge causes high points and surface irregularities—such as burrs, microcracks, and oxide scale—to dissolve at a faster rate than low points.

4

Surface Refinement

This selective removal process smooths the surface microscopically, resulting in a bright, clean finish. Unlike mechanical polishing, electropolishing removes material evenly, even in complex geometries or hard-to-reach areas.

5

Precision Finish

The process can be precisely controlled to meet strict specifications for smoothness, cleanliness, and corrosion resistance, making it ideal for critical applications in industries like medical, aerospace, nuclear, and food processing.

Microscopic flaws in sensitive components—such as surgical tools, aerospace fittings, or reactor tubing—can lead to failure or contamination. Electropolishing eliminates these imperfections, enhancing function, durability, and appearance across a wide range of metals including 300- and 400-series stainless steels, aluminum, nickel, and titanium. Get a quote for our electropolishing service for metal parts — your trusted custom parts on-demand manufacturing company.

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Why Electropolish Your Product?

Streamline Manufacturing and Reduce Costs

Electropolishing helps optimize part design early in development, improving manufacturability before regulatory approvals like FDA certification. By combining multiple finishing steps into one, it eliminates the need for additional polishing, passivation, or chemical cleaning—saving both time and cost throughout the part’s lifecycle.

Enhance Surface Preparation for Further Processing

Electropolished parts offer superior surface conditions for downstream processes. It improves weldability, ensures better adhesion for plating or over-molding, and prevents sticking in mold cavities. It’s also ideal for preparing parts for dye penetrant inspection and reduces the risk of hydrogen embrittlement.

Remove Machining and Heat Treatment Defects

The process removes surface contaminants like free iron, grinding residue, light rust, and embedded particles. It also eliminates defects such as microburrs, heat tint, oxide scale, EDM recast layers, and rough edges. For titanium parts, electropolishing can effectively remove alpha case, while also helping prevent galling in threaded parts.

Maximize Durability and Performance

Electropolishing significantly increases part longevity by improving fatigue strength, especially in components that bend or flex. It enhances corrosion resistance—up to 30 times better than passivation—and improves surface cleanliness to reduce contamination risks. For conductive parts like copper, it also enhances conductivity and reduces the risk of electrical arcing.

Electropolishing cannot remove deep or highly visible processing marks.

It is a fine finishing process designed to smooth and refine surfaces at the microscopic level, but it won’t eliminate heavy scratches, deep tool marks, or severe machining defects.

Electropolishing is not suitable for magnetic materials.

Ferro-magnetic metals like carbon steel do not respond well to the electropolishing process and may not achieve the desired finish or corrosion resistance.

Other Surface Treatment

Material Options for Electropolishing

Brass

Aluminum

Tool Steel

Copper

Stainless Steel

Titanium

Nitinol

Nickel

Carbon Steel

Other Metals

Electropolishing Parameters and Effect

Parameter	Description	Optimal Range	Effect on Surface Quality
Voltage	Applied voltage during the electropolishing process.	15–20 V	Higher voltage improves surface smoothness but may cause pitting if too high.
Current	Current density during the electropolishing process.	3–4 A	Higher current increases the rate of surface removal and improves roughness reduction.
Time	Duration of the electropolishing process.	4–90 seconds	Longer time generally reduces surface roughness but may lead to over-removal of material.
Temperature	Temperature of the electrolyte bath.	60–70°C	Optimal temperature balances current density and surface quality; lower temperatures reduce current density and increase roughness .
Electrolyte Concentration	Concentration of the electrolyte solution.	Varies by material (e.g., 6M HNO₃ for U-10Mo)	Higher concentration can broaden the voltage range and enhance current plateau, optimizing the process.
Inter-Electrode Gap	Distance between the anode and cathode.	Varies by setup	Affects the uniformity of current distribution and surface finish.
Agitation Frequency	Frequency of the electrolyte agitation during the process.	Varies by setup	Higher agitation improves mass transfer and surface uniformity.

(Click to enlarge)

Note: The optimal parameters depend on the material, geometry, and desired surface finish. Experiments and process optimization are essential to determine the best settings for each application.

(Click to enlarge)

Current Density (A/dm²)	Electropolishing Time (min)	Surface Roughness Change (ΔRa)	Electropolishing Efficiency
2.0	30	50%	Moderate
4.0	20	60%	High
6.0	15	70%	High
8.0	10	80%	Very High

Explanation:

Current Density directly affects the rate of material removal and surface smoothing. Higher current density leads to faster removal of surface irregularities, resulting in a smoother surface.
Electropolishing Time influences the extent of surface refinement. While increasing time generally improves surface quality, excessive time can lead to over-removal and surface degradation.
Surface Roughness Change (ΔRa) reflects the improvement in surface quality. A higher ΔRa reduction indicates a more effective electropolishing process.
Electropolishing Efficiency is determined by the combination of current density and time. Higher efficiency is achieved with higher current and shorter time, but must be balanced to avoid over-removal.

Frequently Asked Questions

Is electropolishing suitable for all metals?webadmin2025-06-16T05:31:31+00:00

Is electropolishing suitable for all metals?

Electropolishing works best on conductive, corrosion-resistant metals like stainless steel (especially 300 and 400 series), titanium, aluminum, nickel alloys, and copper. However, it is not suitable for magnetic carbon steels or metals that lack sufficient conductivity or passivity. The metal’s composition and structure must be compatible with the electrolyte solution and current used in the process to ensure safe, effective results.

How much material is removed during electropolishing?webadmin2025-06-16T05:30:01+00:00

How much material is removed during electropolishing?

Electropolishing typically removes between 0.0001 to 0.002 inches (2.5 to 50 microns) of material from the surface. The exact amount depends on factors like the metal type, part geometry, surface condition, and processing time. The process is precise and controlled, making it ideal for parts requiring tight dimensional tolerances and smooth finishes.

What’s the difference between electroplating and electropolishing?webadmin2025-06-16T05:41:35+00:00

What’s the difference between electroplating and electropolishing?

Although both are electrochemical processes, electroplating and electropolishing serve entirely opposite purposes.

Electroplating is a surface enhancement process where a thin layer of metal—such as nickel, chrome, gold, or zinc—is deposited onto the surface of a conductive part. The goal is usually to improve aesthetic appearance, increase corrosion resistance, enhance wear resistance, or improve electrical conductivity. The process involves immersing the part in a metal salt solution and applying a current that causes the metal ions to plate the part’s surface.
Electropolishing, by contrast, is a surface refinement or finishing process that removes a controlled, microscopic layer of metal from the part’s surface. Instead of adding material, it uses anodic dissolution to eliminate burrs, roughness, heat tint, oxide scale, and embedded contaminants. The result is a smoother, brighter, and cleaner surface with improved corrosion resistance and reduced product contamination risk.

Electropolishing is especially suitable for stainless steel and other corrosion-resistant alloys used in medical, food processing, aerospace, and semiconductor industries. It’s particularly beneficial for parts with complex geometries, internal passages, or surfaces that require ultra-smooth finishes and high purity.

In summary:

Electroplating = adding metal to enhance or protect the surface
Electropolishing = removing metal to clean, smooth, and perfect the surface

Each process has distinct advantages and is selected based on the specific performance or functional goals for the finished part.

What types of parts benefit most from electropolishing?webadmin2025-06-16T05:27:40+00:00

What types of parts benefit most from electropolishing?

Electropolishing is particularly effective for parts with challenging geometries that are difficult to finish by mechanical means. These include:

Deep internal bores and narrow-diameter tubes where brushes or abrasives can’t reach
Tight radii, fine threads, and sharp corners that require uniform edge rounding without deformation
Micro-holes and small ports in precision assemblies where burrs or debris would compromise function
Intricate lattice structures, screened surfaces, or wire forms that need a smooth, consistent finish without damage
High-aspect-ratio features found in machined or 3D-printed components that must be cleaned and deburred internally

Such geometries are common in medical devices, aerospace fittings, semiconductor parts, and pharmaceutical equipment, where internal cleanliness, corrosion resistance, and dimensional integrity are critical. Electropolishing delivers a consistent, high-purity surface finish even in the most inaccessible areas.

Can electropolishing remove scratches or machining marks?webadmin2025-06-16T05:25:39+00:00

Can electropolishing remove scratches or machining marks?

Electropolishing is designed to smooth surfaces at a microscopic level, so it can remove light surface imperfections and burrs. However, it will not eliminate deep scratches, heavy tool marks, or major surface defects. For parts with those features, pre-polishing or surface preparation may be needed.

What’s the difference between electropolishing and mechanical polishing?webadmin2025-06-16T05:24:03+00:00

What’s the difference between electropolishing and mechanical polishing?

While mechanical polishing uses abrasives to physically grind the surface, electropolishing removes metal through an electrochemical reaction, producing a smoother, cleaner, and more uniform finish—especially in hard-to-reach or intricate areas where mechanical tools can’t access.

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