Mechanical Surface Finishing is a broad range of industrial processes that alter the surface of a manufactured item to achieve a certain property. Finishing processes may be employed to: improve appearance, adhesion or wettability, solderability, corrosion resistance, tarnish resistance, chemical resistance, wear resistance, hardness, modify electrical conductivity, remove burrs and other surface flaws, and control the surface friction. In very limited cases some of these techniques can be used to restore original dimensions to salvage or repair an item. An unfinished surface is often called mill finish.
Surface finishing processes can be categorized by how they affect the workpiece:
Mechanical processes may also be categorized together because of similarities the final surface finish.
Mechanical finishing processes include:
Abrasive blasting, more commonly known as grit blasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants. A pressurized fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material (often called the media).
There are several variants of the process, using various media; some are highly abrasive, whereas others are milder. The most abrasive are shot blasting (with metal shot) and grit blasting with aluminum oxide. Moderately abrasive variants include glass bead blasting and media blasting with ground-up plastic stock or walnut shells and corncobs.