占空比变化对环形激光光内送粉熔池温度场影响研究

Study on The Molten Pool Temperature Filed in Variable Duty Cycle Ring Laser Inside-Beam Powder Feeding

基于光内同轴送粉激光快速成形工艺,建立了熔池温度场瞬态有限元模型,对占空比K(环形光内外径之比)可变的环形激光光内送粉的熔池温度场的数值模拟表明:占空比的变化对环形激光光内送粉熔池的形状、大小和能量密度分布有很大影响。在相同工艺参数条件下,取K为0、0.35、0.6分别进行单层熔覆实验,对比CCD熔池图像与对应温度场云图,结果显示:各熔池形貌与对应的数值模拟温度场云图比较一致,从而印证了数值模拟的正确性。实验表明:K为0.35的环形光所得的熔覆层微观组织较佳,熔覆层与基体的冶金结合效果较好。

Aimed at the process of laser rapid prototyping ＇with inner coaxial powder feeding, the finite element model on the transient temperature field of the molten pool is built and the transient temperature field of the molten pool under the laser with variable duty cycle is simulated numerically. The results show that the duty cycle of the laser affects the shape, dimension and power distribution of the molten pool. In the same process parameter conditions, take K is 0, 0.35 and 0.6 separately single-layer cladding experiment, contrast CCD image of molten pool in the corresponding temperature field image, the results showed that： the images are close to the numerical simulation nephograms and then demonstrate that the numerical simulations are right. Experiments show that when K is 0.35, the cladding layers microstructure is better, the cladding laver and the base of metallurgical combination effect is good.