Metal finishing Q&As since 1989

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Finishing an aluminum die casting

How can I get a smooth finishing from a die cast aluminum part that has to be sanded after die casting? I've tried ball burnishing but it only seems to "show off" the sanding imperfections.

Thanks

Phillip Haga
Die Casting - Abingdon, VA, U.S.A.
2004

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Surface finishing is a negative process of material removal. If you don't improve the surface before polishing or sealing, it will only give you an existing surface profile of the material you are working; therefore, to improve the surface and/or blend in the rough profile, you need to remove the irregularities (peaks and valleys). This is done via a number of methods. In your case, you need a coarse and maybe finer forms of an abrasive preform ceramic media. For non-ferrous you should consider plastic media shapes. There are no short cuts. You need at least a 2 step process, maybe 3.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2004