The term ball mill brings together a large group of devices of different designs and operating principles, where grinding and mixing processes are performed using balls of different size and density, with the material varying from high-strength alloys and dense ceramics to plastics.

The most widely used in industry is a drum-ball mill, which is a cylindrical container (drum) with a horizontal axis of rotation. Milling (grinding) charges and the mill feed material (pulp) are placed in the steel drum. The grinding charges are usually round in shape (balls), but may include other forms such as cylinders and prisms. The ratio of the grinding charges to the volume of the drum determines the filling factor of a ball mill. Thus, various drum rotation speeds determine various modes of grinding. At low speeds, grinding is due to the rubbing of the mill feed material by the grinding charges as they slide and roll over on the drum surface. At medium speeds, the grinding charges go up to some height and fall down, thus, adding some striking impact. At high speeds, grinding is performed due to centrifugal force. The productivity of the mill depends on the filling factor and the rotation speed, and when they reach a certain level, productivity is at its maximum. There are dry and wet types of milling distinguished. In case of a wet milling, some liquid is added to the drum, it is used to prevent agglomeration of the particles, reduce the defects, as well as to mill and grind explosive and dusty substances.

Ball mills are widely used in industry, for example, for grinding of coal at thermal power plants and in laboratories. In labs, especially when they are used in producing nanomaterials, various types of high-energy ball mills are used. Bead and planetary mills can produce powders and suspensions with particles smaller than 100 nm. The size distribution of the particles then is quite wide, and to isolate finer grain sizes various separation techniques are applied. In addition to ball mills with rotating drums, there are also high-performance vibration mills, where a closed container with balls and the mill feed substance are exposed to vibration. In this case, the material is cut both as the balls collide with the drum and with each other, and the efficiency of mechanical activation can be greater than or equal to the performance efficiency of widely used planetary ball mills if the motion path of a container is well-calculated. There are also examples of vibration ball mill application for biological cell membrane destruction.