Polishing is a machining process for various materials. The polishing grain contained in the polishing paste mechanically penetrates the surface. Uneven areas, furrows and grooves are levelled out. When polishing clear automotive lacquer, the surface should be as smooth as possible. This means that incident light is reflected evenly and strongly, which the eye perceives as high gloss. In the industrial polishing of brass, for example, polishing serves to produce surfaces that are as uniform as possible so that the workpiece is optimally prepared for downstream processes such as electroplating.
Grinding is a cutting manufacturing process known since antiquity for fine and finish machining of workpieces. It can be used manually or on grinding machines. As with all machining processes, excess material is separated in the form of chips. The edges of the microscopically small, hard, mineral crystals in the grinding tool act as cutting edges.
The term sandblasting (also abrasive blasting) refers to the surface treatment of a material or workpiece (blasting material) by the action of abrasives, e.g. sand as an abrasive against rust, dirt, paint, scale and other impurities or for surface design by matting.