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-----Finishing Standards for Pharmaceutical Vessels
Quickstart:
Electropolishing is a process resembling electroplating in reverse. The components are immersed in an acidic solution, made the anode, and (hopefully) their small burrs and asperities dissolve into the acid, smoothing the finish. Many different metals can be electropolished, with stainless steel being the most common.
Electropolishing may sometimes be more economical than mechanical polishing, but the compelling feature is the nature of the finish. Mechanical polishing always creates a finish resembling (under magnification) a farmer's plowed field; the scale of the furrows and clods can be reduced but always remains. Electropolished surfaces resemble (under magnification) gentle ocean swells with minimal tooth, no clods to dislodge, and no hiding places.
Q. Looking for standards regarding finishing of pharmaceutical grade tanks. Is there anything out there that states tanks must or should be electropolished versus mechanically polished for tanks that are used in the manufacture of drug products?
John Tienpharmaceutical company - Berkeley, California
2005
A. Such tanks should probably be electropolished whether the specs require it or not, John. Just as a fractal image looks the same regardless of magnification, any mechanically polished surface resembles a plowed field, with metal folded over and contaminants furrowed under, and loose clods. Increase the magnification and they will be there no matter how fine the polishing. Those tiny metal shards ought to be dissolved away, not just smushed around at a smaller scale. The
Electroplating Engineering Handbook ⇨
explains and illustrates it well. Good luck with it.
Ted Mooney, P.E.
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Q. I am in charge of process equipment in the vaccine production.
We usually specified for our process tanks / pipe a surface roughness of Ra <0.6 µm electropolished.
There is an internal discussion to challenge the efficacy of electropolishing. Is there any studies that shows the efficacy of electropolishing regarding bacterial growth, cleanability? ⇦ Answer?
- LYONS, Rhône, FRANCE
2005
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