激光选区熔化区域连续能量调控扫描方法研究

Study on Regional Continuous Energy Control Scanning Method for Selective Laser Melting

针对激光选区熔化(Selective laser melting,SLM)成形悬垂结构件中存在的翘曲、挂渣等成形质量问题,基于局部区域传热差异性和层间热量传递性研究成形过程中已凝固实体与粉末分布对温度分布的影响,从而对悬垂件的成形进行优化。建立了基于零件几何信息驱动的能量调控优化模型,通过识别模型的几何特征,根据局部区域内的凝固实体和材料粉末的比例计算能量影响因子,实现基于软件自适应调节的变工艺参数的定域定量扫描,最终实现区域能量连续调控与工艺优化。选取典型悬垂件进行316L材料的打印实验作为验证,结果表明相较于未优化的普通扫描方案,基于软件自动能量调控的优化扫描方案可以提高小于45°倾角的悬垂结构件的成形质量,成形40°悬垂结构件时,变参数成形的悬垂面面平均粗糙度Sa(Surface average roughness)达24.03μm,相比定参数成形的Sa为46.32μm,表面光洁度明显提高;同时可无支撑成形8 mm跨度的水平悬垂件。

Aiming at the forming quality problems such as warpage and dross in the overhanging structural parts formed by selective laser melting(SLM),the solidified solid and powder in the forming process are studied based on the heat transfer difference in local area and the heat transfer between layers.The effect of the distribution on the temperature distribution to optimize the forming of the drape.An energy regulation optimization model driven by part geometric information is established.By identifying the geometric features of the model,the energy impact factor is calculated according to the proportion of solidified solids and material powder in the local area,and the localization of variable process parameters based on software adaptive adjustment is realized.Quantitative scanning,and finally realize the continuous regulation of regional energy and process optimization.A typical overhanging part is selected for 316L material printing experiment as a verification.The results show that compared with the unoptimized ordinary scanning scheme,the optimized scanning scheme based on software automatic energy regulation can improve the forming quality of overhanging structural parts with an inclination angle of less than 45°,and the forming quality of 40°When suspending structural parts,the Sa(Surface Average Roughness)of the suspending surface formed with variable parameters reaches 24.03μm,which is 46.32μm compared with the Sa formed with fixed parameters,and the surface finish is significantly improved;at the same time,it can be formed with a span of 8 mm horizontal overhang without support.