在装备200 W光纤激光器的快速成型设备Dimetal-280上进行选区激光熔化(SLM)成型工艺研究。为了优化316L不锈钢粉末的成型工艺参数,设计了6因素5水平正交实验进行工艺实验,总结出6种典型表面形貌,并测量了6种典型表面形貌对应样品的相对密度与z轴方向尺寸精度。分析发现,粉末熔化完全后样品能获得较高的密度,而当粉末部分熔化或未熔时,样品密度比较低;实际加工层厚在成型过程中有逐渐增大的趋势,影响了样品最终的尺寸精度。综合考虑表面形貌、样品相对密度与尺寸精度的影响,获得优化的工艺参数,设计了包含尖角、悬空等独立几何成型性能的样品测试系统,几何样品相对密度达89%,尺寸精度96.8%,表面粗糙度Rz约25 μm,获得了良好效果。

Study on the technology of selective laser melting (SLM) is carried out on Dimetal-280 system with 200 W fiber laser. Orthogonal experiment of six factors and five levels is designed to optimize parameters for 316L stainless steel powder. Six typical surface profiles are summarized,and the relative density and dimensional accuracy along z-direction are measured correspondingly. Results show that the density of samples is high when powders are fully melted and low when partially melted. Practical manufacturing layer trends thicker,which affects the dimensional accuracy. Considering the comprehensive effects of surface profile,relative density and dimensional accuracy,optimal parameters are obtained. Special specimen with sharp-angled and overhang features for geometrical performance test is manufactured. The relative density,dimensional accuracy and surface roughness Rz are 89%,96.8% and 25 μm respectively,which show a good result.