Q. We are vibratory finishing an aluminum part and then blasting it to achieve a uniform pre-anodized finish. Can you recommend a process that can give a visual blasted finish in our vibratory machine to eliminate the blasting process?
A. Vibratory finishing can produce a visual finish very close to the tight patterned satin reflective blasted finish. Certain vibratory medias, compounds and machines are required.
The high-energy centrifugal barrel works best, but vibratory machines also get close.
The two types of medias that work best in obtaining a blasted finish are a random shape 10- to 16-grit ceramic aluminum oxide media, or a smaller ¼ " to 3/8" polyester plastic cone or pyramid-shaped preformed media.
The random media works the best with both vibratory and centrifugal barrel machines and tends to lodge in holes. The smaller, pre-formed polyester media also works in a centrifugal barrel and vibratory processes. The vibratory compounds affect different surface brightness.
Originally published in the January 2017 issue.