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Uneven finish when beadblasting aluminum  

June 30, 2009

I did a bead blasting on an aluminum part. But somehow I cannot achieve an even surface finish. The parts spec calls out for RzD = 21+/-5um. I used a size 16 grit. Will I be able to achieve that surface finish of RzD = 21+/-5um using the size 16 grit? Also, what are the possible cause of uneven finish?

Jess Balagot
Employee - Manila, Philippines

Not exactly sure of the D in RzD; however, if you are looking for a smooth finish using a blasting system, about the best you can do with a 120 or finer grit is about what you are now getting. It's the nature of the process. Meaning it is an impact technology and you will get dimples from the media being used. A smoother surface finish can be gotten using mass finishing. A typical finish of 16-18 is common and as smooth as 4-8 Rz is possible.

AF Kenton Nova Finishing Systems Inc. Huntingdon Valley, PA