激光送粉增材制造光粉交互作用机制分析

Mechanism analysis of interaction between laser and particles in laser additive manufacturing

激光同轴送粉增材制造过程中,粉末粒子和激光束发生能量交互作用的剧烈程度决定了粉末粒子进入熔池前存在的状态.借助背影增效瞬态影像捕捉方法及图像信息处理技术,从宏观和微观角度研究了激光辐照下粉末束流及粒子的变化特征.提取高亮状态粒子数量、亮区总面积和单个粒子亮区面积均值作为特征参量,综合表征工艺参数对该过程的影响规律.结果表明,通过主要工艺参数的合理匹配可以很好的实现对光粉相互作用过程的调控.激光能量密度越高,光粉作用时间越长,粉末粒子接受激光辐照的程度就越激烈,以熔融态进入熔池的可能性就越大.

The degree of interaction between laser beam and powder particles decided the statue of the particles before entered the molten pool. In this paper, both the transient state image captured by shadowgraphy enhancement and image information processing were used to analysis the change characteristics of the whole powder stream and single particles after irradiated by laser from macro and micro perspectives.Characteristic parameters, including amount of high light particles, total area of high brightness area, the intensity of a single particles irradiated by laser were extracted to analysis the influence of the different parameters on the interaction between laser and powder particles. The results show that better regulation of the interaction between laser and particles can be achieved based on the reasonable match of main parameters. By increasing the laser energy density and the interaction time of laser and powder particles, the intensity of particles irradiated by laser is increased and the particles are more likely to enter the molten pool in liquid state.