There are lots of reasons that favour smoothing workpiece surfaces, such as aesthetics, lower friction or air resistance, lower wear, quieter running, and many more. These apply whether your surfaces are made from metal, ceramics, plastic, wood or other materials.
Aluminium is one of the most commonly machined materials, as most forms of the material feature excellent machinability, and is thus a commonly used material in manufacturing. Because of this, the competition for aluminium machining can be intense. Machinists have turned to mass finishing to separate themselves from the competition. Not only will mass finishing improve the cosmetic look but it also removes machine lines and sharp edges. This will eliminate the need for hand finishing which in turn will end up saving machinists a lot of time and money.