激光粉末床熔融成形件的翘曲变形监测  

Monitoring of Warping Deformation of Laser Powder Bed Fusion Formed parts

作　　者：陈锦堂 张凯[1] 刘婷婷[1] 邹志永 李建森 韦辉亮 廖文和[1] Chen Jintang;Zhang Kai;Liu Tingting;Zou Zhiyong;Li Jiansen;Wei Huiliang;Liao Wenhe(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094

出　　处：《中国激光》2024年第16期211-219,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2022YFB4600800);国家自然科学基金(52005262);江苏省前沿引领技术基础研究重大项目(BK20202007)。

摘　　要：在激光粉末床熔融(LPBF)成形过程中,存在由热应力引起的翘曲变形,严重影响零件精度与性能。为了探究熔池辐射光信号与LPBF工艺中的翘曲变形过程的关联关系,为基于熔池辐射光采集的翘曲缺陷监测提供支持,设置了一组实验,成形了翘曲与非翘曲试样,基于统计学方法分析了翘曲与未翘曲试样成形过程中熔池辐射光信号的特性。结果表明,未翘曲变形试样的光强分布较为均匀,无明显梯度,而翘曲变形试样在翘曲区域出现了明显的光强下降。对于翘曲变形的试样,在悬垂层变形尚未发生时,区域光强均值存在较大极差。翘曲试样与未翘曲试样的光强值层间演化趋势不同。随着成形层数的增加,悬垂结构对光强信号的影响逐渐减小,第5层后光强趋于稳定。Objective Laser powder bed fusion(LPBF)is an additive manufacturing(AM)process that has the advantages of forming complexshaped parts and cutting costs.It is widely used in the aerospace,medical equipment,weapons manufacturing,and other industries.However,in the LPBF process,the material powder is repeatedly heated and melted under the effect of laser energy and then cooled and solidified,which facilitates the formation of a large thermal gradient and thermal stress in the parts,leading to warping deformation.This type of deformation significantly affects the dimensional accuracy and mechanical properties of parts.By combining sensor signal acquisition with data analysis,deformation defects can be detected during AM to reduce production costs and improve the quality of formed parts.The radiant light signal of the molten pool is sensitive to the thickness of the powder layer during the LPBF process,which may reflect the warping deformation that has already occurred.It is also correlated with the temperature of the molten pool,reflecting the peak temperature at that location,and is related to the temperature field of the sample.Therefore,it has the potential to monitor the thermal stress during warping deformation.To study the relationship between thermal stress-induced warping deformation and the radiant light signal of the molten pool,a method for monitoring warping deformation in the LPBF process by acquiring the radiant light signal of the molten pool is explored in this study.In this study,an overhanging sample is formed during the experiment,and the radiation signal of the molten pool is collected and analyzed.The results show that the radiant light signal can not only monitor warping deformation but also reflect formation process of warping deformation to a certain extent.Methods To collect and compare the radiation light signal of the molten pool during the forming process of the warped and normal samples,T-shaped overhanging structure samples are formed(Fig.2),and five samples with three different support

关 键 词：激光技术 激光粉末床熔融 翘曲变形 过程监测 熔池辐射光 

分 类 号：TH16[机械工程—机械制造及自动化] TP277[自动化与计算机技术—检测技术与自动化装置]