Dynamics Analysis And Application Research Of Mechanical Alloying Vibration Mill

Mechanical alloying is a new method of preparing alloy materials.The working principle of this new method is that phase transition occurs in two or more metal powders under the effect of high energy collision and impact motion of the grinding cylinder and grinding ball.Planetary ball mill,stirring ball mill and vibrating ball mill(vibrating mill)are often used as mechanical alloying equipments commonly.Especially,the grinding efficiency of vibrating mill is the highest.The key to study the working mechanism of vibrating mill is that analysing the dynamics of rigid body and granular body of vibrating mill.The study also provides reference value for selecting proper mechanical alloying parameters.In this paper,QM-3A high-speed vibration ball mill will be used as the research object.The dynamic simulation analysis,based on two aspects of rigid body and bulk mainly,was carried out and a series of preliminary experimental studies were conducted.Firstly,the kinematics and dynamics models of the grinding cylinder were established.The six-degree-of-freedom kinetic equation was deduced by homogeneous coordinate transformation and Lagrange method respectively.The vibration shape and vibration trajectory of the grinding cylinder were simulated and analyzed.It was found that the trajectory of the grinding cylinder is elliptical swing and the vibration trajectories of the radial points,located in the section of the cylinder,vary greatly.Secondly,the rigid body-bulk coupling model of grinding cylinder and grinding ball were established from the perspective of bulk.The average force of grinding ball,the force of grinding cylinder and the kinetic energy of grinding ball were calculated according to the different ratio of combination that eccentric shaft speed,eccentricity,the size and quantity of grinding ball.It was found that it's conducive to the occurrence of mechanical alloying when the grinding cylinder under the conditions that low speed,high amplitude and the combination of different size.Finally,the microcosmic process of ball collision is studied by high speed camera method.The instantaneous velocity and displacement of the single ball were extracted when contacting with the desktop and bouncing off during the process of free fall.According to this,the normal contact stiffness of the grinding ball was calculated.By contrast with the value of theoretical calculation,it was found that the magnitude of stiffness data is identical,but there is a numerical error.The feasibility of the experimental method was discussed preliminarily.In this paper,the dynamic simulation and analysis of vibration mill was carried out from two aspects of rigid body and loose body.The analysis provides theoretical basis for setting up mechanical parameters of mechanical alloying.Particularly,a preliminary experimental study was carried out by use of high-speed camera and the normal contact stiffness of the single ball was calculated.Other mechanical parameters,such as ball loading and ball to material ratio,can be further simulated and analyzed in the following research.In the experimental part,the experimental error can be reduced by increasing the experimental data and installing the force sensor.Moreover,high-speed camera can be used continuously to study the micro parameters.