"As cast" - parts removed directly from the mould have a surface finish equal to or better than 0.8 micrometres (32 micro inches); this finish may show variable colour.
Chip rumbling - removes any sharp edges left after linishing, leaving a surface suitable for most subsequent "finishing" processes.
Automatic grit blasting - gives a uniform matt finish, suitable for most subsequent finishing operations.
Bead blasting - using stainless steel shot, is generally suitable for brass components and gives a slightly polished surface.
Glass bead blasting - produces a more highly polished surface finish and is most suitable for aluminium parts.
Special surface effects - such as textures and knurling can be incorporated in the MM casting process. Surfaces which need to be blemish free should be highlighted on a drawing.
(left) An example of highlighting a drawing to show important cosmetic surfaces.
