激光不同的波形对金属直接成形精度的影响

Influence of Laser Different Waveform on Accuracy of Metal Direct Forming

针对激光金属直接成形工艺中的小特征尺寸制造问题,采用数值模拟和工艺实验相结合的方法,研究了激光波形对激光金属直接成形精度的影响。研究结果表明,与连续波相比,方波和正弦波加载时具有较快的加热和冷却速度,尤其是方波,能使熔池中心具有很大的温度梯度,在平均输出功率相同的条件下,方波和正弦波能够使熔池中心达到更高的温度。同样的激光熔覆,利用方波只需要较小的平均输出功率,不但减小了热量输入,同时也减小了激光加工过程中的热影响区域。薄壁零件成形优化过程中,利用方波加载能获得最小特征尺寸的薄壁,达到提高零件成形精度的目的。

For the problem fabricating a part with small feature size in the LDMF process,the influence of laser waveform features on the accuracy of direct metal forming was studied through numerical simulation and experiments.Research shows：compared with the continuous wave,square wave and sine wave have higher rates of heating and cooling,and the square wave has the greatest temperature gradient.Under the conditions of the same average output power,square wave and sine wave make the molten pool reach a higher temperature.As to the same process,direct metal forming with square wave only requires smaller average output power,which reduces the heat input and improves the accuracy of the direct metal forming by reducing the heat-effected zone.The part with smallest feature size can be got by square wave in the process of thin-walled part forming,which improves the accuracy of LDMF.