光粉交互对同轴送粉增材制造能量传输的影响

Effect of the interaction between laser beam and powder particles on energy transmission in coaxial powder feeding additive manufacturing

激光同轴送粉增材制造涉及复杂的光粉交互作用,也是决定粉末物化状态和激光能量有效利用的关键.因此,借助背影增效瞬态影像捕捉技术和图像处理技术,以时间序列上粉末粒子亮区面积的实时值与平均值变化规律为依据,分析光粉交互作用过程及其对用于熔化基体剩余激光能量的影响.结果表明,送粉速率和光粉作用距离是影响有效熔化基体能量的关键因素;送粉速率不变时,载气流量增加提高了粉末颗粒的飞行速度,但是对有效熔化基体的能量影响很小;粉末粒径较小时,光粉交互作用过程越激烈,有效熔化基体的能量随之下降.总体而言,粉末颗粒飞行速度不变时,光粉作用过程中亮区面积的大小和有效熔化基体能量呈正相关.

Coaxial Laser powder feeding additive manufacturing involves complex interaction between laser beam and powder particles,which is also the key to determine the effective utilization of laser energy.Therefore,based on the real-time value and the average value of the bright area of powder particles in time series,the interaction process of light and powder and its influence on the residual laser energy for melting matrix are analyzed by using the back image enhancement transient effect capture technology and image processing technology.The results show that the powder feeding rate and the distance between the powder and the powder are the key factors affecting the effective melting matrix energy;the increase of the carrier gas flow rate increases the flying speed of the powder particles,but has little effect on the loss of laser energy after the interaction of the powder and the powder;when the particle size of the powder is small,the more intense the interaction process of the powder and the effective melting matrix energy decreases.In general,the size of the bright area is positively related to the loss of laser energy when the particle velocity is constant.