Application of PFC3D to simulate a planetary ball mill

Abstract

Planetary ball mill is a versatile machine which has been used for grinding different types of materials for size reduction and lately for hemp decortication. PFC3D, software employing the discrete element method (DEM), was used to simulate the power and energy requirement of grinding hemp for fibre using a planetary ball mill. The simulation was facilitated through a series of hemp grinding tests using the planetary ball mill to examine the power draw of the mill. The test results identified that grinding speed had a significant effect on the power draw of the mill. The power draw data were used to calibrate the discrete element parameters for different grinding speeds. Using the calibrated parameters, one was able to predict the kinetic energy and friction power loss of the ball mill. The average value of kinetic energy predicted, for grinding speeds of 200 – 500 r/min, ranged between 0.01 and 0.07 J per grinding ball. The prediction showed that frictional power losses dispersed approximately 10% of the total power requirement of the ball mill. Overall, the simulation using PFC3Dimproved understanding about the dynamics of the grinding balls within a planetary ball mill as well as the energy available for transfer in collisions between the grinding balls and hemp material.