悬垂圆孔激光选区熔化成形质量研究

Research on Forming Quality of Overhanging Round Hole by Selective Laser Melting

对圆孔试样进行分区分析,研究了激光功率、扫描线角度以及轮廓扫描次数对悬垂圆孔结构成形质量的影响。结果表明,激光功率对圆孔成形质量的影响显著,随着激光功率的增大,圆孔圆度值增大,尺寸精度降低,同时悬垂面出现细而长的熔池,部分熔池断裂球化成球状熔滴;当扫描线方向平行于悬垂面边缘线时,悬垂面质量较好,但在成形圆孔顶部近水平悬垂面处出现严重塌陷;在设置的扫描次数范围内,增加轮廓扫描次数可降低悬垂曲面表面粗糙度,优化表面质量。

By means of selective analysis for round hole specimen,the influences of laser power,scanning line angle and number of contour scans on the forming quality of overhanging round holes are investigated.The results show that,the laser power has a significant effect on the forming quality of round holes.With the increase of laser power,the roundness of round holes increases and the dimensional accuracy decreases.At the same time,there are many thin and long melt pools on the overhanging surface,and part of them are fractured into spherical droplets;the overhanging surface quality is better when the scanning line direction is parallel to the edge lines of the overhanging surface,but there occurs a serious collapse on the top of round holes and near to the horizontal overhanging surface.Within the setting number of scans,the increase of the number of contour scans can reduce the surface roughness of the overhanging surfaces and optimize the surface quality.