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为分析脉冲个数对烧蚀凹腔形貌的影响,利用纳秒脉冲激光在灰铸铁表面加工微凹腔造型,分析了凹腔相貌与脉冲个数的关系。在低于10个脉冲的作用下,凹腔深度随脉冲数的增加近似呈线性增长,之后,凹腔深度随脉冲数增加的增长趋势逐渐变缓,凹腔直径随着脉冲个数的增加会有所增大,但增大幅度很小。当脉冲个数大于15以后,由于凹腔较深,熔融的金属难以喷溅出凹腔,导致加工质量较差。凹腔直径随着脉冲个数的增加会有所增大,但增大幅度很小。对加工过程的温度场进行数值模拟,得到了烧蚀过程中温度的变化曲线和凹腔相貌的变化规律。将模拟得到的凹腔深度与实验结果相比较,两者基本吻合,验证了模型的合理性。
In order to analyze the influence of the pulse number on the appearance of the ablated cavity, the shape of the concave cavity was machined on the surface of the gray cast iron by nanosecond pulse laser. The relationship between the appearance of the cavity and the number of pulses was analyzed. Under the condition of less than 10 pulses, the cavity depth increases linearly with the increase of the number of pulses. After that, the growth of the cavity depth with the increase of the number of pulses gradually becomes slower. The diameter of the cavity increases with the number of pulses Has increased, but the increase is small. When the number of pulses is more than 15, due to the deep cavity, the molten metal is difficult to splash out of the cavity, resulting in poor processing quality. The diameter of the cavity will increase with the increase of the number of pulses, but the increase is small. The temperature field of the process is numerically simulated, and the change curve of the temperature and the change of the cavity appearance during the ablation process are obtained. The simulated cavity depth and experimental results are compared, the two basically agree, verify the rationality of the model.