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There are many different types of surface finishing that are available. Below is a list of the most commonly used surface finishes.
Abrasive Blasting
Sandblasting
Burnishing
Chemical-mechanical planarization (CMP)
Electropolishing
Grinding
Industrial etching
Linishing
Tumbling
Vibratory finishing
Polishing
Buffing
Shot peening
Magnetic field-assisted finishing
External surface finishes are applied to components if the parts require a decorative finish or corrosion resistance.
To simplify this and help us select the best tooling and process design, surfaces of die castings are classified as one of five grades:
Class, As-Cast Finish, Final Finish or End Use
Class
As-Cast Finish
Final Finish or End Use
Utility Grade
No cosmetic requirements. Some surface imperfections are acceptable.
Used as-cast or with protective coatings: Anodize (non-decorative) Chromate (yellow—clear)
Functional Grade
Surface imperfections that can be removed by spot polishing or can be covered by heavy paint are acceptable.
Decorative Coatings: Lacquers Enamels Plating (Al) Chemical Finish Polished Finish
Commercial Grade
Slight surface imperfections that can be removed by agreed-upon means are acceptable.
Structural Parts (high-stress areas):Plating (Zn) Electrostatic Painting Transparent Paints
Consumer Grade
No objectionable surface imperfections.
Special Decorative Parts
Superior Grade
Surface finish applicable to limited areas of the casting and dependent on alloy selected; required to have maximum value in micro inches as specified on print.
O-Ring Seats or Gasket Areas.
