Abstract: In order to solve the poor forming quality of 316L porous structure produced by SLM， the influences of technological parameters on the density， different values of porosity and surface roughness of the formed samples were studied， and a multivariate nonlinear prediction model was established by combining with gray relation analysis. The results show that the fitting degree of the model may reach 96.85%， the optimal technological parameters are 250 W laser power， 800 mm/s scanning speed， 0.08 mm hatching distance， the optimized grey relation grade may reach 0.9195， the density， different values of porosity and surface roughness of the samples are 99.25%， 0.60% and 4.39 μm respectively. There is a positive correlation between the relative density and laser power， and the scanning speed and scanning distance show a trend of first increasing and then decreasing with the density increasing， while the porosity difference value， mean value of surface roughness and laser power， scanning speed， hatching distance maintain a trend of first decreasing and then increasing. Combined with the concept of laser  energy density， the reason of influencing the forming quality by technological parameters is revealed. The melting state of powder is the best when the energy density is 109.65～145.83 J/mm3. 

Key words: selective laser melting（SLM）, technological optimization, gray relation analysis, porous structure, forming quality

摘要： 为解决选区激光熔化技术成形医用多孔结构成形质量较差的问题，研究了工艺参数对316L成形样件致密度、孔隙率差值和表面粗糙度的影响，结合灰色关联分析方法建立了多元非线性预测模型。结果表明，预测模型的拟合度可达96.85%，最优工艺参数分别为激光功率250 W、扫描速度800 mm/s、扫描间距0.08 mm。优化后的灰色关联度达0.9195，得到样件的致密度为99.25%，孔隙率差值为0.60%，表面粗糙度均值为4.39 μm。致密度与激光功率正相关，随着致密度的增大，扫描速度和扫描间距呈现先增大再减小的趋势，孔隙率差值和表面粗糙度与激光功率、扫描速度、扫描间距均保持先减小再增大的趋势。结合激光体能量密度概念，揭示了工艺参数影响成形质量的原因，体能量密度为109.65～145.83 J/mm3时粉末的熔化状态最好。

关键词: 选区激光熔化, 工艺优化, 灰色关联分析, 多孔结构, 成形质量