Design and Experiment of a Drum-Type Automatic Ball Adding Machine

To address the issues of low efficiency, poor safety, and difficulty in precisely controlling the grinding media fill level associated with manual ball charging in ball mills, this paper presents the design of a drum-type automatic ball feeding device. The device primarily consists of a ball storage bin, a ball-grasping drum, a baffle plate, and a transmission system. A granular model of steel balls was established using the discrete element method (DEM) via EDEM 2024 software. Taking the bin inclination angle, baffle opening height, and the shape and number of ball-retrieving brackets as experimental factors, and employing the coefficient of variation (CV) of ball accumulation at the drum and the throughput rate as evaluation indicators, orthogonal simulation experiments and parameter optimization were conducted. The simulation results indicate that the baffle opening height exerts the most significant effect on the flow stability of the steel balls. The optimal structural combination was determined to be an inclination angle of 5°, an opening height of 298 mm, and the configuration of three L-shaped retrieving brackets. Based on these optimized parameters, a prototype was developed and subjected to validation tests, using the deviation rate of ball addition quantity and the continuity of ball feeding as macro-level evaluation metrics. The experimental results exhibited good consistency with the simulation predictions, thereby confirming the effectiveness of the optimized design. This study demonstrates that the proposed device can achieve stable and reliable automatic ball feeding, effectively maintaining the fill level of the ball mill within an appropriate range, and thus providing a feasible technical equipment solution for the automation and intelligent upgrading of grinding operations.