In modern mass finishing, some kind of media are almost always used. Not only as an abrasive, but also to keep the workpieces apart and to prevent the parts from damaging each other. Media also adds weight to the mass so that the necessary pressure is created for the grinding and/or polishing to be carried out. There are two main types of media, ceramic bonded chips and polyester-based plastic chips.

Ceramic chips can be used for all materials and are normally more abrasive than plastic chips. Plastic chips have a lower density and are often used in pre-treatment of soft materials like aluminium and brass.

By choosing the right shape and size, you avoid the chips getting lodged in cavities on the part.

One must also take into account the separation method to be used and choose a sufficient size difference between chips and part to get good sieving. Generally speaking, cylindrical chips do not stick easily to cylindrical holes and triangular chips should be larger than the hole. Or so small that the total length of three chips is less than the diameter of the hole.