Zeng Junyong, Zhang Wei, Guo Ting, Lou Yan, Wang Wenqi, Zhao Zhenyu, Wang Chao
School of Sino-German Robitics, Shenzhen Institute of Information Technology, Shenzhen 518172, China.
College of Mechanical and Control Engineering, Shenzhen University, Shenzhen 518061, China.
Micromachines (Basel). 2023 Sep 13;14(9):1765. doi: 10.3390/mi14091765.
Laser polishing is an emerging efficient technique to remove surface asperity without polluting the environment. However, the insufficient understanding of the mechanism of laser polishing has limited its practical application in industry. In this study, a dual-beam laser polishing experiment was carried out to reduce the roughness of a primary Ti6Al4V sample, and the polishing mechanism was well studied using simulation analysis. The results showed that the surface roughness of the sample was efficiently reduced from an initial 10.96 μm to 1.421 μm using dual-beam laser processing. The simulation analysis regarding the evolution of material surface morphology and the flow behavior of the molten pool during laser the polishing process revealed that the capillary force attributed to surface tension was the main driving force for flattening the large curvature surface of the molten pool at the initial stage, whereas the thermocapillary force influenced from temperature gradient played the key role of eliminating the secondary roughness at the edge of the molten pool during the continuous wave laser polishing process. However, the effect of thermocapillary force can be ignored during the second processing stage in dual-beam laser polishing. The simulation result is well in agreement with the experimental result, indicating the accuracy of the mechanism for the dual-beam laser polishing process. In summary, this work reveals the effect of capillary force and thermocapillary force on molten pool flows during the dual-beam laser polishing processes. Moreover, it is also proved that the dual-beam laser polishing process can further reduce the surface roughness of a sample and obtain a smoother surface.
激光抛光是一种新兴的高效技术，可去除表面粗糙度且不污染环境。然而，对激光抛光机理的认识不足限制了其在工业中的实际应用。在本研究中，进行了双光束激光抛光实验以降低原始Ti6Al4V样品的粗糙度，并通过模拟分析对抛光机理进行了深入研究。结果表明，使用双光束激光加工可将样品的表面粗糙度从初始的10.96μm有效降低至1.421μm。关于激光抛光过程中材料表面形貌演变和熔池流动行为的模拟分析表明，表面张力引起的毛细力是初始阶段使熔池大曲率表面变平的主要驱动力，而温度梯度影响的热毛细力在连续波激光抛光过程中起到消除熔池边缘二次粗糙度的关键作用。然而，在双光束激光抛光的第二个加工阶段，热毛细力的影响可忽略不计。模拟结果与实验结果吻合良好，表明双光束激光抛光过程机理的准确性。总之，这项工作揭示了毛细力和热毛细力在双光束激光抛光过程中对熔池流动的影响。此外，还证明了双光束激光抛光过程可进一步降低样品的表面粗糙度并获得更光滑的表面。
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