Dynamics Analysis And Excitation Parameters Optimization Of Single-side Exciting Vibration Mill

Vibration mill,as a kind of superfine grinding equipment for crushing high quality material,has been widely used in mining,metallurgy,medicine and chemical industries.As the requirement for the quality of powder is higher and higher,the further development of vibration mill encounters bottlenecks,such as that its product size is very difficult to break through the limit of the sub-micron size.To solve the key technical problem that the particle cannot reach the ultra-fine powder,the traditional structure of vibration mill is changed.In this paper,a new single-side exciting vibration mill is introduced.The dynamic characteristics of the new vibration mill are analyzed based on simulation model of the whole mill system.Besides,the coupling relationship between the body and the discrete material is established based on Distinct Element Method(DEM).In addition,the excitation parameters are optimized on the basis of simulation experiments.The new control method is also proposed in order to achieve the micrometer particle.At first,on the basis of the analysis of the working principle of the new type of the mill,the dynamic model is analyzed.The dynamic model of the vibration mill is established based on the Lagrange equation.Then the law of motion of the mill is discussed based on the simulation model and the validity of model is verified by the laser displacement test.The features of the time and frequency domain are compared by the test.In addition,the differences between upper body and lower body are analyzed.On the basis of the dynamic model,the influence of the amplitude and frequency on the vibration intensity is also researched.These researches provide theoretical support to optimize the exciting parameters of the single-side exciting vibration mill.Secondly,on the basis of the DEM,the motion states of the grinding medium are analyzed and the grinding effect is researched.The model of the grinding medium is established with the support of PFC3D software.The quantitative relationship between the grinding media number and fill rate is estimated and the validity of estimation formula is verified.Then the influence of grinding media on grinding effect is analyzed and the optimum ratio of the high density media is also researched.On the basis of the research of the grinding medium,the motion state of the media and low-energy region under different vibration conditions are also studied.The translational kinetic energy and the rotational kinetic energy of the media are also further researched in order to provide instructions for promoting the grinding effect.Thirdly,the reason of the phenomenon of the particle agglomeration is analyzed and the mathematical relationship between the strength of the particle agglomeration and the particle size is obtained.According to the evaluation indexes,the double factors simulation test is introduced.The optimum exciting parameters are obtained under the high vibration intensity.This can help break the agglomerations and obtain micro particles.Finally,according to the analysis of the particle agglomeration and the results of simulations,the new exciting method is proposed.The nonlinear behavior of the new mill under changing motor speed is analyzed.The different combination schemes are also compared in order to determine the optimum scheme.Diamond particles are chosen as the test material and the sizes of the product before and after optimization are also compared.Results show that the single-side exciting vibration mill can achieve smaller particles than the traditional mill and the sizes after optimization are sub-micron scale.This study has laid a good foundation for successive engineering application.