Aluminum is used more and more today due to the reasonable cost, ease of machining and light weight. The only negative issue that arises with aluminum is the limited metal finishing options. Unlike stainless steels, you cannot passivate aluminum in order to remove the contaminants on the surface. In addition, there are few options for improving microfinish after machining. Electropolishing is an effective means for providing a part that has an enhanced surface finish and clean surface. Many companies use the electropolishing for parts that are assembled in a clean room, such as laser components.
Aluminum is generally separated two main categories: casting and wrought alloys. Casting alloys are comprised of high amounts of silicon. This lends the casting alloys their low melting points and decent fluidity. But at the same time, lessens their desirable smooth finish.
Wrought alloys have significantly different compositions and microstructures from casting alloys. A wrought aluminum part that has been electropolished will exhibit an improved surface and will be contaminant-free. The surface will also display a shiny finish.
Common aluminum alloys and the results that can be achieved through electropolishing:
| ALUMINUM | COMMENT |
|---|---|
| 1008 | Good Bright Finish After Electropolishing |
| 1100 | Excellent Mirror Type Finish After Electropolishing |
| 2014 | Satin-Pitted Finish – Not Suited for Electropolishing |
| 2024 | Bright Finish After Electropolislhing (Slight Pitting) |
| 3003 | Good Reflective Finish After Electropolishing |
| 4032 | Gray Finish – May Come Out Better With More S/R |
| 5052 | Good Reflective Finish After Electropolishing |
| 5086 | Good Bright Finish After Electropolishing |
| 5350 (Cast) | Bright Finish After Electropolishing (Pitted) |
| 5657 | Good Bright Finish After Electropolishing |
| 6061 | Good Bright Finish After Electropolishing |
| 6082 | Good Bright Finish After Electropolishing |
| 6105-T5 | Excellent Finish After Electropolishing |
| 6463 | Bright Finish After Electropolishing (Some Pitting) |
| 7050 | Good Bright Finish After Electropolishing |
| 7073 | Good Bright Finish After Electropolishing |
| 7075 | Good Bright Finish After Electropolishing |
| Al Cu 31 | Bright Finish After Electropolishing (Pitted & Rough) |
| Al EA70-2 | Very Bright Finish After Electropolishing |
| ALUZINC | Good Finish After Electropolishing (Some Pitting) |
| 2011 | (Bright Finish After Electropolishing (Slight Pitting) |
Why electropolish aluminum? Corrosion always begins on or near the metal’s surface. Unfortunately, all handling and fabricating procedures will eventually degrade the surface integrity and properties. Surface contaminants, including metallic particles, iron, dirt, and grease are a fundamental part of welding, machining, and other fabrication procedures. Mechanical polishing, cutting, handling, and polishing tend to result in extraneous iron and other abrasive particles that are embedded within the surface of the material. These surface contaminants break down the aluminums’ naturally occurring corrosion resistant oxide layer and are often the site where corrosion begins. The electropolishing process dissolves a minute layer of surface material and contaminants, thus freeing embedded particles and increasing the part’s lifespan.
Ultimately, electropolished aluminum will increase the part’s resistance to pitting, localized galvanic corrosion, surface corrosion, crevice corrosion, cracking, stress corrosion, and microbiological corrosion.
At Able Electropolishing, we perform our signature electropolishing treatment on a variety of metal alloys, including aluminum. Following our treatment, parts have an enhanced corrosion resistance, improved microfinish, and are clean and free of harmful contaminants. Along with the commonly used 6061 aluminum, our process is suitable with other alloys such as 1100, 3003, 5002 and 7075.
Contact us to see how we can utilize our metal finishing capabilities for your aluminum parts.
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From implantable devices to surgical instruments, electropolishing is a single-process treatment that results in biocompatible, safe and ultra clean parts.
We offer aerospace vendors and original equipment manufacturers our signature metal finishing services to increase fatigue-resistance for their metal parts, rendering them capable of withstanding the stress and corrosion that comes with long-term use.
Our strict adherence to industry standards ensures that pharmaceutical components are electropolished in accordance with ASTM B912 and ASME BPE specifications. These products are clean and smooth, corrosion resistant and contaminant free.
Corrosion resistance and microfinish improvement are essential for critical automotive parts, making electropolishing an increasingly beneficial option for automakers.
Our metal finishing services help increase corrosion resistance for these parts, and by removing the outermost layer of metal withelectropolishing the durability and longevity of these appliance components is increased.
Electropolishing materials for this industry eliminates the buildup of bacterial biofilms, as well as keeping the equipment free of contaminants like Salmonella. Electropolishing delivers the level of sanitation required by a number of regulatory agencies.
From robotics to mobile equipment, the uses of electropolishing in the hydraulics and pneumatics industry are many. By helping prevent premature part failure, electropolishing reduces downtime and increases the life cycle of these components.
Improving conductivity and performance is just one benefit electropolishing offers for electronics parts. The surface finish is improved by as much as 50%, removing imperfections from the material without material removal.
The process of finishing critical metal parts for our clients in industries that include aerospace, medical device design, semiconductor manufacturing, pharmaceutical production – and many others – is incredibly precise. Success can be measured in ten-thousandths of an inch.
Passivation is a widely used chemical finishing process to remove contaminants and improve the corrosion resistance of metal parts, including stainless steel and alloys like Nitinol and titanium. While passivation can be effective for many parts, for certain parts and…
If you’re manufacturing parts with 440C stainless steel and relying on passivation to get the finish you need, you may be overlooking an opportunity to dramatically improve the corrosion resistance of your parts.
While electropolishing is best known for the results it achieves as the last step in the process for finishing critical metal parts, it can also be an interim step for improving the results of parts that will undergo plating.
