(1) The brittleness, the brittleness of material has great influence on the function of sand making machine. The material before and after sand making machine does not change or change little is called brittle material. The material is called plastic material when the sander first deforms and then breaks. Brittleness is proportional to the difficulty of sand - making machine.

(2) Friability - fragility refers to the specific power consumption of a material from a certain granularity machine to another specific dimension under certain conditions. Because the process of sand making machine is affected by many factors, it is impossible to use strength, brittleness and hardness to comprehensively represent the difficulty of the material making machine, so there are many ways to express the material vulnerability. Currently, the bond performance index is widely recognized.

It should be pointed out that the physical properties of materials are not uniform. The binding force between different materials is less than that of the same material. The binding force of the same material surface is smaller than that of the material interior. Generally speaking, the smaller the material particle size is, the less effective the material strength is. As the strength of materials increases, sand making machines are difficult to make materials.