Planetary ball mill: What exactly does planetary mean?

I believe that many readers, like me, have no idea what the term "planetary ball mill" means when they first heard it. Ball mills are more vivid and understandable, but the planets in planetary mills are a bit confusing.

To understand the origin of the name of planet in planetary ball mills, we must start with its appearance and working principle. When the ball mill first appeared, it was a small horizontal ball mill, similar to the current drum ball mill, but it was relatively simple and could only process some materials with low requirements. After continuous improvements, the efficiency has been improved, but it still cannot meet the increasing particle size requirements of various materials. For some materials, the drum ball mill is already "out of ideas" even today.

The advent of the planetary ball mill is precisely to solve this problem. Its appearance has also led to the rise of technologies such as mechanical crushing and mechanical alloying. The grinding jar of the planetary ball mill not only rotates at high speed, but also revolves around the center, like the movement of a celestial planet. This is why the planetary ball mill is named after a planet.

The complex movement of the grinding jar brings extremely high energy to the grinding balls and materials in it. They collide, grind, and squeeze each other in the grinding jar, grinding the materials to nanometer-level particles more quickly. The complex movement trajectory makes the collision and squeezing between the materials, grinding balls, and the walls of the grinding jar faster and more unpredictable, making the materials more thoroughly broken, with no dead angles at all. The development of omnidirectional planetary ball mills and double planetary ball mills is to provide more complex and unpredictable movement trajectories for the grinding balls and materials.