Vibration And Optimization Research Of Ring Die Pellet Mill

Ring die pellet mill is the main equipment for processing feed pellets and biomass solid pellets.It has the characteristics of good forming effect,fast pelletizing speed and low energy consumption.For the ring die pellet mill vibration,higher energy consumption and parts life and other problems.In this paper,the analysis and experimental study of the driving system of the ring die pellet mill were carried out,which provided a reference for improving the life of the key parts of the ring die pellet mill.Specific research contents are as follows:(1)In this paper,the granulation process of ring die pellet mill is introduced,and the analysis methods of random vibration are enumerated.According to the related theory of fatigue life of random vibration,the Gaussian distribution and Miner’s linear cumulative damage law are determined as the calculation methods of fatigue life of ring die.(2)The structure and characteristics of drive system of SZLH420 ring die pellet mill was studied.The torque and acceleration of drive shaft were measured by practical production experiment.The time domain curve obtained from the test was converted into frequency domain curve by fast Fourier transform.The correctness of the modal analysis was verified by comparing the results of finite element modal analysis with the torque frequency domain curve.(3)The vibration of the driving system of the ring mold pellet mill was analyzed,and the natural frequency of the system direction was obtained.The harmonic response and random vibration of the driving system were analyzed by using the principle of modal superposition and the test data,and the vibration amplitude and stress of the driving system were obtained.The fatigue damage and fatigue life of annular die were calculated based on Gaussian distribution,Miner’s linear damage accumulation rule and material property data manual.(4)According to the particle swarm optimization algorithm(PSO),taking the angular acceleration of the drive shaft as the minimum objective function,taking the parameters of the mechanical transmission system as the optimization variables,and taking the value range of kinetic energy equation and design variables as the constraint conditions,the parameters of the transmission system of the ring mold pellet mill was optimized.According to the parameters before and after optimization and the torque obtained from the test,the angular accelerations of the main motor,pinion,big gear and ring die after optimization are obtained.The results show that the amplitude of angular acceleration decreases obviously after optimization,indicating that the vibration displacement of the transmission system decreases,which proves that the method improves the stability of the transmission system of the ring mold pellet mill.