The coal cutter pick is the core part for the shearer drum to cut the coal seam, and the cutting pick is prone to failure during the coal-cutting process of the shearer. Due to the complex and harsh operating environment of the underground coal mining face, the cutting pick needs to bear the compressive stress, wear, impact force, and shear stress of the coal block during the cutting process, which leads to the failure of the cutting pick. To effectively address these issues, we can do so by understanding the indicators that influence its destructive failure.

The failure of coal cutter picks mainly depends on the strength of coal and rock, coal rock contact strength, the elastoplasticity and brittleness of coal and rock mass, the friction of coal and rock mass, and the cutting force of the roller and the cutting pick.

Coal rock strength

The strength of coal rock refers to the critical value of external force when coal rock resists damage under certain conditions. The strength of coal rock depends on the internal friction and cohesion between coal rock particles. Coal rock strength is the main index for studying the damage of mining coal seam and coal cutter pick. Using the change law of shearer strength in the coal seam working face can reduce the specific energy consumption of the shearer and effectively prolong the service life of the coal cutter pick.

Coal rock contact strength

Coal rock contact strength refers to the ultimate stress value of coal and rock mass when it is starting to be destroyed by external force under certain conditions, which indicates the pressure of coal per unit area on rock mass, and also indicates the ability of coal and rock mass to resist external forces as a whole. When the coal mining machine cuts the coal seam, it should try to utilize the tensile or shear destruction to reduce the stress or energy consumption of the cutting pick.

Elasticity, plasticity and brittleness of coal and rock mass

The elasticity, plasticity, and brittleness of coal and rock mass reflect the relationship between external force on the coal and rock mass and its deformation.

Elasticity is the property of the coal and rock mass to recover its original shape after the withdrawal of external force. The higher the elasticity of the coal and rock mass, the higher the energy required for cutting and the more difficult it is to break.

Plasticity is the property that the coal and rock mass can not recover its original shape after the external force on the coal and rock mass disappears. The higher the plasticity, the more energy is required when cutting.

Brittleness is the performance of a coal and rock mass without residual deformation when breakage occurs. Coal and rock mass with high brittleness is easy to break and consumes less energy when cutting.

Abrasiveness of coal and rock mass

The degree to which coal and rock wear steel and cemented carbide are called abrasiveness. During the cutting process of coal and rock mass, the cutting pick will inevitably collide and rub against the coal and rock mass, which not only aggravates the wear of the cutting pick, increases cutting resistance and production costs, but also reduces the working performance and start-up rate of mining machinery.