Make Sure you Have Taken these Steps before Electropolishing
The final touches of a project are typically the most important step in the process. Electropolishing is usually the last step of manufacturing and preparing the parts properly will lead to favorable results. If the surface finish is not properly prepared, you risk not getting the final results you need. The following are the steps you need to take to ensure that you’re ready to finish with electropolishing.
Remove Scratches, Macro Burrs, Traces of Soap Lubricants, Adhesives, and Coatings
Some think that electropolishing will remove scratches on the surface of the metal. Not so. In fact, this kind of polishing will highlight imperfections. The rule of thumb is that if you can feel a scratch or defect, electropolishing won’t be able to get rid of it. Removing only thin surface layers, deeper scratches will be visible.
Finishing methods such as vibratory or barrel tumbling should be used to remove large burrs. Sometimes the width, not the height, will determine whether the burrs will be taken off by the electropolishing. Testing part samples will also help you confirm the effectiveness of a deburring process before sending in production lots.
The third thing to remove is soap, lubricant and other surface contaminants. It is important to remove all traces of the soap because they contain silicates that cling to the metal. If not removed, they can lead to resist patterns or stains.
Finally, removing both adhesives and coatings is crucial to the process of readying metal for electropolishing. Certain kinds of prefinished stainless steel have vinyl coatings with a clear adhesive. Peeling these off must be done prior to the polishing. Vapor degreasing will not remove adhesive on its own. Pre-cleaning methods are easily implemented to avoid an uneven finish that needs to be removed mechanically.
Know Microfinish Value
You should be aware the electropolishing can improve the Ra value of a part up to 50 percent. It is key to determine your desired final Ra to ensure that you properly prepare for the process of electropolishing. To lower the Ra finish, you may need to add a secondary operation such as grinding or mechanical polishing before moving on to electropolishing.
Make Sure Welds are Airtight and Clean
Even a pinhole can lead to electrolyte trapping which are difficult to remove. They can also leech out of the part when in use. It is also imperative to clean out the excessive black char and discoloration from welded areas. Oils and lubricants can burn into the part and affect both the quality and appearance of a part.
Remove Advance Scale
Advanced scale must be removed from heat-treated parts. Treating a part with heat insulates and reduces conductivity, creating resist patterns. Eliminating the scale before the electropolish will lead to uniform, vibrant products.
Make Drain Holes
If you are working with round or square parts, adding drain holds on weldments that are made with butt welded tubing will effectively remove entrapped electrolyte and other liquids. These drain holes should be designed into part drawings.
Use High-Quality Wire
Electropolishing quality wire has a smoother and brighter finish that has a chrome appearance. Using it for springs, racks, and other parts made from stainless steel wire will result in parts that have a lackluster finish.
Use 2B Finish
Specifying a 2B finish, you will receive a bright and uniform electropolish. For a mirror-like finish, use bright-annealed material.
Learn more about how to prepare for electropolishing by contacting our experts. Kramer Industries will make sure you receive a top-quality end-result.