Milling is one of the most widely used methods for preparing different powders in different dimensions. Furthermore, this technique can be used for mechanical alloying. Ball mills are common tools which are usually utilized in milling. These mills in terms of capacity, efficiency and additional equipment for heating and cooling are different with each other. Among the ball mills, planetary ball mills are very suitable for laboratory and production of nanoparticles. In planetary ball mills, based on a mechanism, the sun wheel and grinding jars are rotating in an opposite direction. Such movements prevent the adhesion of balls to the inner wall of the grinding jars. The rotation of the grinding jars and sun wheel around a single axis creates a centrifugal force that its magnitude can reach 20 times of earth gravity. In planetary ball mills, the grinding balls and powders are alternately rolled and abraded against the inner wall of the grinding jar, in which they separated from the wall and collide to the opposite wall. Due to the high impact energy, created under these conditions, the powders are continuously welded and broken and as a result size reduction takes place. In this mill because of the high impact frequency of the grinding balls, the time of mechanical alloying can be decreased. Moreover, the impact energy of the grinding balls varies by changing the rotation speed of the sun wheel. Using larger or denser grinding balls makes it possible to increase the impact energy without increasing the rotation speed. Base on the type of powders, the grinding jars are made of various materials such as stainless steel, hardened steel, agate, tungsten carbide, zirconia, alumina and Teflon.

Application

The main applications of the planetary ball mills are as follows:

• Synthesis of ceramic and metallic nanoparticles
• Synthesis of nanocomposites
• Possibility of mechano-chemical reactions during milling

specification

Details of technical specifications are presented in the following Table.
 


Advantager of using nanotechnology

The planetary ball mill is one of the most common equipment for nanoparticles production. Based on the types of movements, i.e. rotation and transition, and impact frequency of milling balls, the planetary ball mills are able to reduce the size of particles to the range of nanometer. 

Manual and maintenance
 

• A single phase power outlet is required to set up the device.
• Device should be placed in a flat position and away from vapor and humidity; the electronic control system must be protected from direct sunshine or excessive heat.
• Fix the device on the ground using the adjusting screws on the device feet; otherwise, the device will move on its wheels during operation. 
• Grinding jars and milling balls should be clean and free from any macroscopic and microscopic contaminations. 
• To inject gas or create a vacuum inside the grinding jars, use the jars with inlet valve.
• Both Grinding jars should be fed equally; otherwise, there is no balance and the device will shake during operation, which in the long run impairs the sun wheel and main axis.
• For more details on how to use the device, refer to the device catalog and user guide.

Safety and package
 

• The laboratory environment should be well ventilated, because small parts of the chemical vapors from mechano-chemical reaction may release into the laboratory environment. 
• Be sure to close the device door.
• Check all the fittings of the sun wheel and grinding jars to be tight; otherwise, during operation at a high speed, a piece of device may be separated which may impair the device or cause personal injury.
• Turn off the main switch when the operation finished, then remove the grinding jars by opening the clamps. If grinding jars are vacuumed or filled with gas, open the inlet valve by considering the safety points a then open the lid.