为了进一步提高调相机缺陷识别能力,设计了一种基于TCN网络的调相机局部放电智能检测方法。在调相机设备上开展了干扰测试,构建能够满足现场调相机内局部放电检测系统。研究结果表明:设计相位反馈控制能够对低于1.8 k Hz低频噪声造成相...为了进一步提高调相机缺陷识别能力,设计了一种基于TCN网络的调相机局部放电智能检测方法。在调相机设备上开展了干扰测试,构建能够满足现场调相机内局部放电检测系统。研究结果表明:设计相位反馈控制能够对低于1.8 k Hz低频噪声造成相位衰落起到明显抑制效果。调相机局部放电检测试验结果显示,10 s时间内,Michelson光纤干涉系统对内部缺陷信号达到了精确检测的效果,PZT传感器则没有检测出内部缺陷的信号。展开更多
Selective laser melting(SLM)is a 3D printing technology with a high near-net-shape ability and forming accuracy.However,the inevitable internal defects significantly hinder its development.Therefore,it is essential to...Selective laser melting(SLM)is a 3D printing technology with a high near-net-shape ability and forming accuracy.However,the inevitable internal defects significantly hinder its development.Therefore,it is essential to fully understand the causes of internal defects in SLM processing and minimize the defects to achieve quality control accordingly.This work reviews the recent studies on internal defects in SLM,presenting the main internal defects of SLM as impurities,lack of fusion,gas pores,and micro-crack.These internal defects occur on the various phenomena in the laser-powder-melt pool(LPMP)stage.The formation of SLM internal defects is mainly affected by oxidation,denudation,balling,spatter,and keyholes;here,balling,spattering,and the keyhole phenomenon are the main factors causing internal defects in LPMP.Hence,this paper focuses on reviewing the balling effect,spatter behavior,and keyhole phenomenon,introducing the action mechanism of the above three phenomena under different process conditions.Additionally,the spatter behavior when forming internal defects is proposed.This review also considers the correlation between the spatter behavior and keyhole phenomenon and makes an important contribution to understanding and reducing SLM internal defects.It presents a reliable opinion on real-time monitoring and machine intelligent learning for SLM processing in the future,as well as supporting a systematic thinking for the suppression of defect formation in SLM.展开更多
文摘为了进一步提高调相机缺陷识别能力,设计了一种基于TCN网络的调相机局部放电智能检测方法。在调相机设备上开展了干扰测试,构建能够满足现场调相机内局部放电检测系统。研究结果表明:设计相位反馈控制能够对低于1.8 k Hz低频噪声造成相位衰落起到明显抑制效果。调相机局部放电检测试验结果显示,10 s时间内,Michelson光纤干涉系统对内部缺陷信号达到了精确检测的效果,PZT传感器则没有检测出内部缺陷的信号。
基金National Natural Science Foundation of China(Grant No.51975387).
文摘Selective laser melting(SLM)is a 3D printing technology with a high near-net-shape ability and forming accuracy.However,the inevitable internal defects significantly hinder its development.Therefore,it is essential to fully understand the causes of internal defects in SLM processing and minimize the defects to achieve quality control accordingly.This work reviews the recent studies on internal defects in SLM,presenting the main internal defects of SLM as impurities,lack of fusion,gas pores,and micro-crack.These internal defects occur on the various phenomena in the laser-powder-melt pool(LPMP)stage.The formation of SLM internal defects is mainly affected by oxidation,denudation,balling,spatter,and keyholes;here,balling,spattering,and the keyhole phenomenon are the main factors causing internal defects in LPMP.Hence,this paper focuses on reviewing the balling effect,spatter behavior,and keyhole phenomenon,introducing the action mechanism of the above three phenomena under different process conditions.Additionally,the spatter behavior when forming internal defects is proposed.This review also considers the correlation between the spatter behavior and keyhole phenomenon and makes an important contribution to understanding and reducing SLM internal defects.It presents a reliable opinion on real-time monitoring and machine intelligent learning for SLM processing in the future,as well as supporting a systematic thinking for the suppression of defect formation in SLM.
