Final treatments applied post-manufacturing to engineer a part’s exterior layer.
Performance:
Block corrosion/wear (plating/anodizing)
Tune friction (polish/texture)
Boost/block conductivity (gold plate/anodize)
Aesthetics:
Texture control: Grit blast → matte, Polish → gloss
Color application: Wet paint/powder coat
Finish type: Brushed satin, Etched patterns
Preparation:
Deburr: Vibratory tumbling
Strip scale: Acid pickling
Remove oils: Alkaline soak
Methods:
Subtractive: Grinding, blasting, polishing (material removal).
Additive: Plating, painting, PVD/CVD (layer deposition).
Transformative: Heat treating, passivation (surface alteration).
Critical Constraints:
Material limits: e.g., Anodizing suits aluminum; not steel.
Geometry challenges: Blind holes? Thin features? Dictates method viability.
Cost/environment: PVD > paint; Hex-Cr waste, VOC emissions, sludge disposal.
Why it matters:
Surface finishing bridges function and market appeal. Neglect = premature failure or rejected parts.
Ex.: Aluminum housing: Bead blast → Chem film → Powder coat → Cure.
