Cohesion can be divided into two types: one is that the cohesive force acts on the inside of the crystal, between the particles of the crystal, and the other is between the crystal and the crystal. The physical properties of the two cohesive forces are the same, the difference lies in the numerical value, the former is much larger than the latter. Its crushing process is a very complex material size change process, mainly including the strength, hardness, toughness, shape, size, humidity, density and homogeneity of the material, which are related to many unestimable factors.

　　External conditions such as the interaction and distribution of material blocks at the moment of crushing are also important factors affecting the crushing process. All of these factors complicate the dimensional variation of the crushing process to the point that a rigorous and complete rationale for the process has not been developed to this day. The size of the cohesion depends on the nature and structure of the crystal itself in the material, and is also related to various defects in the crystal structure. These defects may be macroscopic and microscopic cracks. Due to the presence of cracks, the connection between the crystal groups becomes weaker.

　　According to the structure of the crystal and the nature of the force between the particles, the cohesion of the crystal can be theoretically calculated. As for the structure of the crystal, the size of the cohesion between the particles, and the influence of all factors that reduce the compatibility of the material block, it is currently impossible to calculate calculate.