According to the contact mode between abrasive particles and grinding tools, polishing can be divided into fixed abrasive particle polishing and free abrasive particle polishing. Free-abrasive particle polishing is the most widely used polishing method, and the study of material-removal mechanism during the polishing process is of great significance for the selection and optimization of process parameters. A coupled finite-element model was established for titanium with multiple abrasive particles and the same scratch path during nanoscale material-removal process. In the actual polishing process, the possible overlap rate of abrasive particle trajectories in the adjacent scratch paths (micro-trajectory of abrasive particles) of the workpiece material is between 0 and 100%. This special case of 100% overlap rate is selected for research, and through the study of this special case, universal rules are revealed. A comparative analysis was conducted on the effect of abrasive particle quantity on the surface material-removal behavior of workpieces under different polishing process parameters, and the depth, strain, and stress of material removal during the polishing process were compared and analyzed, in order to study the effects of process parameters and the number of abrasive particles on the physical field of the scratch contact zone. The results show that, during the abrasive material-removal process of, there are two stages: initial and stable scratching. The depth of material removal during the initial scratching stage is relatively low. As scratching progresses, the scratching heat softens the material, and the depth of material removal gradually deepens, entering the stable scratching stage. The results show that when the abrasive particles are scratched at low speeds, the material are continuously removed, while when the abrasive particles are scratched at high speeds, the material is intermittently removed. Multiple abrasive particles can improve the uniformity of material-removal depth compared to single abrasive particle. The results show that the average depth of material removal increases with the increase of scratch force, and the width of the groove increases with the increase of scratch force. Scratch speed affects the amplitude and period of the fluctuation. In the process of discontinuous material removal, as the scratch speed increases, the number of contacts between the abrasive particles and the material gradually decreases; but, the depth of single removal gradually increases. The results show that there is a positive correlation between the stress value in the scratch zone and the depth of material removal. The stress value in the scratch zone increases with the increase of scratch force, while the number of abrasive particles has no significant effect on the average stress value. The strain value in the scratch zone increases with the increase of scratch force, and the average strain value also increases with the increase of abrasive particles. The number of abrasive particles has a significant impact on the average strain value. As scratch progresses, the temperature in the scratch zone gradually decreases, and the descent speed is very fast. The highest temperature in the scratch zone increases with the increase of scratch force and scratch speed. The influence of scratch force and scratch speed on the highest temperature in the scratch zone is significant. When the abrasive particles scratch at low speed and reach the maximum material-removal depth, the normal force of the workpiece on the abrasive particles is equal to the scratch force. Therefore, it is an approximate fixed-depth, material-removal method. When the abrasive particles scratch at high speed and reach the maximum material-removal depth, the normal force of the workpiece on the abrasive particles is greater than the scratch force, and the material-removal depth gradually decreases, The normal force of the workpiece on the abrasive particles also decreases at the same time. When the normal force is less than the scratch force, the material-removal depth gradually increases and repeats, producing a wavy motion trajectory. The mechanism that the number of abrasive particles affects the material-removal behavior during the micro material removal process of polishing is revealed.
