Molecular Dynamics Simulation for Grinding Interface Under Minimum Quantity Lubrication

To research the cooling and lubricating effects on the grinding interface under minimum quantity lubrication, a molecular dynamics simulation of grinding interface under minimum quantity lubrication with ionic liquid is performed. The heat partition relationship on the grinding interface is analyzed, and the generation and transfer mechanisms of grinding heat on the grinding interface are revealed. The variations of grinding force, grinding force ratio, and the liquid film between abrasive grain and workpiece are investigated. The results show that the cooling effect of the ionic liquid droplet is outstanding. The heat partition ratio of the workpiece reaches 74.1% in dry grinding, and under minimum quantity lubrication, the heat partition ratio of the workpiece is reduced to 68% - 69%. Grinding heat is mainly generated from the lattice deformation of the workpiece material in the shear zone, and the secondary heat source is friction between the abrasive grain and the workpiece. The generated heat is firstly transferred into the workpiece substrate, the abrasive grain, and the grinding chip directly, afterwards, a portion of heat in the grinding chip is transferred into the ionic liquid droplet, then a portion of the heat in the ionic liquid droplet is transferred into the abrasive grain. The grinding force linearly increases with the increasing undeformed chip thickness. As the abrasive grain cutting into the workpiece, highly compressive stress appears on the grain-workpiece and grain-chip interfaces, which leads to difficulty in forming a boundary lubricating film. © 2020, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.