Electropolishing

Our electropolishing services are an integral component of our comprehensive turnkey manufacturing solutions, available when you engage Macfab for CNC machining. These services are not offered independently but are seamlessly integrated within our complete manufacturing process.

By adopting electropolishing processes, Macfab has further enhanced its precision machining operations. Performing this process in-house reduces issues that can arise from handling and transport, and the vertical integration allows us to deliver finished, ready-to-use parts to our customers.

While tumbling, vibration, and hand deburring are effective processes and generate marginal improvements in surface finish, electropolishing is a superior method. It ensures a precision finish at the microscopic level and burr removal for parts. Electropolishing is generally only performed at tight tolerance and precision machining facilities, such as MacFab. This process was developed in the 1950s. During the years since its development, it has also been called electrochemical polishing, anodic polishing and electrolytic polishing.

Five metal products whit holes and two two thin metal bars

The Value of Electropolishing

Excellent machining or grinding operations can still leave imperfections invisible to the human eye, such as microburrs, microcracks, heat tint, oxide scale, and heat tint. Fortunately, all these blemishes can be addressed by electropolishing. It is an electrochemical process that removes a small layer, 0.001 to 0.0025 inches, from the surface of the workpiece. Think of it as the reverse of an electroplating operation.

This process is typically performed on stainless steel (series 300 or 400) machined or welded parts that Macfab specializes in. However, aluminum and nitinol materials can also benefit from this finishing process. The parts are left bright, clean, and microscopically smooth with a Ra of 8 to 16 microinch finish achievable.

The process eliminates burrs and microcracks, leaving the parts with improved corrosion resistance, fatigue life, and pathogen resistance. Corrosion resistance is up to 20 times greater than passivation processes such as allodizing, as it only removes contaminates on the part’s surface.

Metal product before and after electropolishing

The Electropolishing Process

The electropolishing process delivers a broad enhancement to parts. The parts are first loaded onto a metallic tree or fixture for good electrical contact. The fixture is then connected to the positive side of a Direct Current (DC) circuit, making the parts the anode of the reaction. A second metallic plate is submerged in the tank and connected to the negative side of the DC circuit. The tank is filled with an electrolytic solution matched to the part’s material.

Electricity is then applied to the workpiece so the solution breaks the bonds of the stainless steel atoms. Imagine having a small lightning bolt pass through the burr or high points on the part’s surface. What is left is a metallic salt. The part is now burr-free, with an improved surface finish at the same time.

Below are a few of the industry standards covering electropolishing that Macfab uses in developing and controlling our process.

ASME BPE

Standards for Electropolishing
Bioprocessing Equipment

SEMI F19

Electropolishing Specifications for
Semiconductor Applications

ASTM B912

Passivation of Stainless Steels Using
Electropolishing

Our electropolishing services complement our full turnkey manufacturing approach, exclusively available when you leverage Macfab for CNC machining. It's important to note that these services are an inherent part of our comprehensive manufacturing solution and are not provided as standalone offerings.