Electropolishing for Ultra High Purity
Who Utilizes This Service?
Industries such as semiconductor, photonics, medical, automotive and pharmaceutical have special applications that require their machined or fabricated metal parts be electropolished and cleaned to very high standards. Typically, the specifications on this class of parts call for Ra values of 15 or less and have limitations on acceptable particulate after electropolishing. To insure that the cleanliness is maintained until final assembly, special packaging may include packaging in a clean bench in nitrogen purged sealed bags.
One of our customers manufactures fittings for the semiconductor industry. The various 316L stainless steel parts are mechanically polished to an Ra less than 10 prior to being sent for electropolishing. To maintain the buffed finish and remove the contaminants, the parts have to be electropolished with a controlled amount of material removal. By processing samples prior to receiving production parts, we were able to establish the proper material removal and processing parameters to meet the customer’s needs. These parameters are added to our permanent engineering record which is issued to the shop with each order. Upon completion of the electropolishing, the parts receive multiple rinses with the final rinse being deionized water. After centrifugal drying the fittings are moved to our class 100 clean bench for packaging. We then proceed to package individually in double bags that have been purged with nitrogen and sealed.
We have another customer that sends us 6061 aluminum machined components for electropolishing that are used in laser cutting equipment. Since the laser equipment is assembled in a clean room, the OEM requires that the parts be clean and have a smooth finish free of burrs, scratches and pits. The specification for electropolishing calls out .0006” to .0008” material removal (.0003” to .0004” per surface. After electropolishing and drying, the parts are wrapped in a special tissue paper and placed in a sealed plastic bag. When electropolishing aluminum, the material removal can vary from .0005” to .002” depending on the condition of the parts and what the customer is trying to achieve. The general rule is when removing .001” material removal we will improve the Ra value by as much as 50%.
Metal Alloys We Electropolish
Able Electropolishing is capable of electropolishing nearly any metal alloy. Along with the 300 series SS and aluminum mentioned above, we electropolish 400 series SS, precipitating hardness grades, copper alloys, nickel alloys, carbon steels, titanium, Nitinol and others.