Mass finishing is the general description of the contact of abrasive media around a number of non fixtured parts, moving randomly within the mass of media. Various types of equipment generate energy, which is transferred through the media to the part being processed. The transfer of energy to the randomly moving parts automates the finishing process.

Vibratory finishing media transmits the energy from the machine to the work piece. It carries the compound for cleaning or brightening and protects the parts.

The weight and size of the media has a lot to do with the amount of work it is capable of doing. Heavier and larger media cut faster and do more work because of the higher surface area and mass. A smaller media will create a tighter mass capable of holding more fluid, and with less voids within the mass it will work to protect the part.

The shape of the media allows it to get into an area to get something done or stay out of an area so it will not lodge. A round or cylindrical shape will finish better because of single point contact with the part, like a ball pean hammer effect. A flat shape, such as a triangle, has a wide surface to rub over an edge allowing quicker deburring.