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  for Metal Finishing since 1989
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How to get 35 microinch finish on anodized aluminum

 1999

Looking for machining and polishing methods to achieve less than a 35 microinch roughness on 2 mil thich hard coat on 6061-T6. Expect to pre-anodize polish the metal surface to a < 15 microinch.Looking to have a discussion on polishing methods. Thanks, Gary

Gary Escher

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Any machining/polishing method which results in a surface finish of <15 should result in <35 after hardcoat on wrought alloys such as 6061-T6. The exception is methods such as burnishing which achieves the surface finish by moving rather than removing metal. The hardcoating process flakes off this displaced metal exposing the rougher base metal. After hardcoat, polishing, grinding, and/or honing can further improve the surface finish. It is possible to achieve finishes as low as 5rms. Due to natural porosity, good surface finishes on castings are much more difficult. Resin systems are needed to fill the voids where hardcoat can not fully form.

Chris Jurey, Past-President IHAA
Luke Engineering & Mfg. Co. Inc.

Wadsworth, Ohio

1999

Consider cryogenically treating the metal before polishing. The process results in evening out the hardness spread in metals and makes it easier to get a better finish.

F. J. Diekman
- Streamwood, Illinois, USA
1999