According to the analyses on the forming principle of the pellet mill and the relative motion state between the roller and the die during the extrusion process, the mathematical models of the extruding height of material and the extruding velocity of the material were developed. Based on the models, the influences of the radius ratio λ of the roller and the die and the maximum seizing angle θ on the maximum extruding height of material hmax and the pellet quality were analyzed and calculated. The calculation results show that the increases of θ and λ in a certain range are beneficial to the production yield, increasing the effective work area, and improving the pellet quality. The results provide a theoretical basis for optimizing structural design of the pellet mill.
