One of the most important methods for processing powder materials is the milling process, which has been widely used in various industries. Furthermore, milling can also be used for processes such as mechanical alloying. This process can also change the dimensions of the particles. Thus, so far various milling machines which operate with different mechanisms have been constructed. Planetary ball mill is one of them that is highly potential in reducing particle size and mechanical alloying. In this mill, based on a mechanism the rotating plate and the chamber are rotating in an opposite direction. In planetary ball mills, milling chamber like Solar System Planets have two real-time moves, i.e. around itself and a transitional movement. This type of movement prevents the adhesion of balls to chamber wall. The rotation of the chamber and the rotating plate around a single axis creates a centrifugal force that its magnitude can reach 20 times of earth gravity. This type of movement leads to the balls and powders are alternately rolled and abraded on the chamber inner wall; In this case, under high impact energy, the powders are continuously welded and broken. In this type of mill, the mechanical alloying time decreases with respect to the high frequency of ball hitting. In this type of mill the time of mechanical alloying decreases because of the high impact frequency of balls. Moreover, the impact energy of the balls alters by changing the speed of the rotating plate. Using larger or denser balls can increase the impact energy without need to increase the rotation speed and decrease the milling time. With respect to the type of materials, the chamber is made of various materials such as stainless steel, hardened steel, agate, tungsten carbide, zirconia, alumina and Teflon. It should be noted that in mechanical alloying the chamber and balls are chosen from the same material.