选区激光熔化水平悬垂面成形质量影响因素分析

Analysis of Affecting Factors of Horizontal Overhanging Surface Forming Quality by Selective Laser Melting

水平悬垂面是一种特殊的悬垂结构,也是选区激光熔化(SLM)成形技术存在的难题。结合图像处理的方法,研究了不同激光功率下其首层表面轮廓特征的成形特点和成形质量的关系。结果表明:使用"线"形扫描策略,首层表面存在与扫描方向呈一定倾斜角度且不同大小的亮斑和孔隙,并随激光能量的输入而变化;减小激光功率,首层表面孔隙变大,熔道间的结合强度变低;通过"旋转式"重熔的扫描策略可以提高首层表面抵抗外力变形的能力,并有效地避免成形面翘曲变形、塌陷现象发生。

The horizontal overhang is a special overhang structure, and it is also a problem with selective laser melting(SLM) molding technology. This paper studies the relationship between the forming characteristics of the first-layer surface profile features and the forming quality at different laser powers by image processing. The results show that there are bright spots and pores of different sizes on the surface of the first layer by using the "Meander" scanning strategy, which have an angle with the scanning direction and change with the input of laser energy;when the laser power is decrease, the pores on the surface of the layer are enlarged, and the bonding strength between melt tracks becomes lower. The scanning strategy of "rotary" remelting can improve the ability of the first layer to resist external force deformation, and effectively avoid the warping deformation and collapse of the forming surface.