The bucket wheel of the excavator must be cut, loaded and unloaded in the course of one turn.When cutting, the bucket teeth are required to cut into the material quickly.Therefore, the bucket must have sufficient strength and stiffness to withstand the reaction force of the material.In the process of loading, the material should be smoothly into the barrel inside (which would reduce the cutting resistance), at the same time, when the materials in the barrel filling, should fill the bucket space, should not have too big squeeze pressure, otherwise, due to the increase of the extrusion pressure, bucket wall and material can increase the adsorption capacity of (under certain adsorption coefficient, adsorption capacity is proportional to the positive pressure between the two objects), lead to clean emissions or scattered material at the time of discharge.