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Detection and Characterization of Defects in Additive Manufacturing by Polarization-Based Imaging System

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Chinese Journal of Mechanical Engineering 2023年第5期36卷 120-140页

作者： Xing Peng lingbao kong Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing School of Information Science and TechnologyFudan UniversityShanghai 200438China College of Intelligent Science and Technology National University of Defense TechnologyChangsha 410003HunanChina

Additive manufacturing (AM) technology such as selective laser melting (SLM) often produces a high refection phenomenon that makes defect detection and information extraction challenging. Meanwhile, it is essential to establish a characterization method for defect analysis to provide sufcient information for process diagnosis and optimization. However, there is still a lack of universal standards for the characterization of defects in SLM parts. In this study, a polarization-based imaging system was proposed, and a set of characterization parameters for SLM defects was established. The contrast, defect contour information, and high refection suppression efect of the SLM part defects were analyzed. Comparative analysis was conducted on defect characterization parameters, including geometric and texture parameters. The experimental results demonstrated the efects of the polarization imaging system and verifed the feasibility of the defect feature extraction and characterization method. The research work provides an efective solution for defect detection and helps to establish a universal standard for defect characterization in additive manufacturing.

关键词： Additive manufacturing Selective laser melting High refection Defect characterization Polarizationbased imaging

Design of a real-time fiber-optic infrared imaging system with wide-angle and large depth of field

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Chinese Optics Letters 2022年第1期20卷 29-36页

作者： Xing Peng lingbao kong Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing School of Information Science and TechnologyFudan UniversityShanghai 200433China

A key limitation in the observation of instruments used in operations and heart sutures during a procedure is the scattering and absorption during optical imaging in the presence of ***,we propose a novel real-time fiber-optic infrared imaging system simultaneously capturing a flexible wide field of view(FOV) and large depth of field infrared image in real *** assessment criteria for imaging quality of the objective and coupling lens have been optimized and ***,the feasibility of manufacturing and assembly has been demonstrated with tolerance sensitivity and the Monte Carlo *** simulated results show that the optical system can achieve a large working distance of 8 to25 mm,a wide FOV of 120°,and the relative illuminance is over 0.98 in the overall *** achieve high imaging quality in the proposed system,the modulation transfer function is over 0.661 at 16.7 Ip/mm for a 320×256 short wavelength infrared camera sensor with a pixel size of 30 μm.

关键词： infrared imaging system imaging through blood wide-angle large depth of field optical design telecentric structure

A light field measurement system through PSF estimation by a morphology-based method

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International Journal of Extreme Manufacturing 2021年第4期3卷 113-124页

作者： lingbao kong Panyu Zhou Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing Fudan UniversityShanghai 200433People’s Republic of China

Light field imaging technology can obtain three-dimensional(3D)information of a test surface in a single *** light field reconstruction algorithms not only take a long time to trace back to the original image,but also require the exact parameters of the light field system,such as the position and posture of a microlens array(MLA),which will cause errors in the reconstructed image if these parameters cannot be precisely *** paper proposes a reconstruction algorithm for light field imaging based on the point spread function(PSF),which does not require prior knowledge of the *** accurate PSF derivation process of a light field system is presented,and modeling and simulation were conducted to obtain the relationship between the spatial distribution characteristics and the PSF of the light field system.A morphology-based method is proposed to analyze the overlapping area of the subimages of light field images to identify the accurate spatial location of the MLA used in the system,which is thereafter used to accurately refocus light field imaging.A light field system is built to verify the algorithm’s *** results show that the measurement accuracy is increased over 41.0%compared with the traditional method by measuring a step *** accuracy of parameters is also improved through a microstructure measurement with a peak-to-valley value of 25.4%and root mean square value of 23.5%*** further validates that the algorithm can effectively improve the refocusing efficiency and the accuracy of the light field imaging results with the superiority of refocusing light field imaging without prior knowledge of the *** proposed method provides a new solution for fast and accurate 3D measurement based on a light field.

关键词： light field deconvolution 3D measurement PSF estimation measurement accuracy MLA

Advances in selective laser sintering of polymers

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International Journal of Extreme Manufacturing 2022年第4期4卷 20-56页

作者： Wei Han lingbao kong Min Xu Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing Department of Optical Science and EngineeringFudan UniversityShanghai 200433People’s Republic of China

Polymers are widely used materials in aerospace,automotive,construction,medical devices and *** are being promoted rapidly due to their ease of manufacturing and improved material *** on polymer processing technology should be paid more attention to due to the increasing demand for polymer *** laser sintering(SLS)uses a laser to sinter powdered materials(typical polyamide),and it is one of the critical additive manufacturing(AM)techniques of *** irradiates the laser beam on the defined areas by a computer-aided design three-dimensional(3D)model to bind the material together to create a designed 3D solid *** has many advantages,such as no support structures and excellent mechanical properties resembling injection moulded parts compared with other AM ***,the ability of SLS to process polymers is still affected by some defects,such as the porous structure and limited available types of SLS ***,this article reviews the current state-of-the-art SLS of polymers,including the fundamental principles in this technique,the SLS developments of typical polymers,and the essential process parameters in ***,the applications of SLS are focused,and the conclusions and perspectives are discussed.

关键词： selective laser sintering additive manufacturing laser powder bed fusion 3D printing polymer

Multi-sensor measurement and data fusion technology for manufacturing process monitoring:a literature review

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International Journal of Extreme Manufacturing 2020年第2期2卷 1-27页

作者： lingbao kong Xing Peng Yao Chen Ping Wang Min Xu Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing Department of Optical Science and EngineeringFudan UniversityShanghai 200433People’s Republic of China

Due to the rapid development of precision manufacturing technology,much research has been conducted in the field of multisensor measurement and data fusion technology with a goal of enhancing monitoring capabilities in terms of measurement accuracy and information richness,thereby improving the efficiency and precision of *** a multisensor system,each sensor independently measures certain ***,the system uses a relevant signalprocessing algorithm to combine all of the independent measurements into a comprehensive set of measurement *** purpose of this paper is to describe multisensor measurement and data fusion technology and its applications in precision monitoring *** architecture of multisensor measurement systems is reviewed,and some implementations in manufacturing systems are *** addition to the multisensor measurement system,related data fusion methods and algorithms are *** perspectives on multisensor monitoring and data fusion technology are included at the end of this paper.

关键词： multi-sensor data fusion process monitoring additive manufacturing laser melting

Defect inspection technologies for additive manufacturing

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International Journal of Extreme Manufacturing 2021年第2期3卷 23-43页

作者： Yao Chen Xing Peng lingbao kong Guangxi Dong Afaf Remani Richard Leach Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing Department of Optical Science and EngineeringFudan UniversityShanghaiPeople’s Republic of China Manufacturing Metrology Team University of NottinghamNottinghamUnited Kingdom

Additive manufacturing(AM) technology is considered one of the most promising manufacturing technologies in the aerospace and defense industries. However, AM components are known to have various internal defects, such as powder agglomeration, balling, porosity,internal cracks and thermal/internal stress, which can significantly affect the quality, mechanical properties and safety of final parts. Therefore, defect inspection methods are important for reducing manufactured defects and improving the surface quality and mechanical properties of AM components. This paper describes defect inspection technologies and their applications in AM processes. The architecture of defects in AM processes is reviewed. Traditional defect detection technology and the surface defect detection methods based on deep learning are summarized, and future aspects are suggested.

关键词： additive manufacturing defect inspection machine learning deep learning neural network

Design of a Multi-sensor Monitoring System for Additive Manufacturing Process

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Nanomanufacturing and Metrology 2020年第2期3卷 142-150页

作者： Xing Peng lingbao kong Yao Chen Zhenyong Shan Lizhe Qi Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing Fudan UniversityShanghai 200433China ASAGE ROBOTS(Zhuhai)Co. LtdZhuhai 519085GuangdongChina Academy for Engineering and Technology Fudan UniversityShanghai 200433China

Additive manufacturing(AM)technology is becoming increasingly feasible in industrial *** AM systems continue to improve,the lack of repeatability and stability of these technologies remains an obstacle to industrial ***,AM process monitoring equipment has to be set up to supervise product quality and detect *** study first reviews the various categories of defects,relevant AM process signatures,and optical monitoring methods of powder bed fusion processes proposed so ***,according to the detection requirements,an optical process monitoring system based on multiple sensors is proposed,which is equipped with a white light imaging channel,an infrared imaging channel,and a polarization imaging *** aberrations can be optimized using Zemax software by appropriately selecting the optimization function ***,the design requirements for the multi-sensor monitoring system for the AM process can be achieved.

关键词： Optical design Process monitoring Additive manufacturing Multi-sensor Zemax

胫骨后外侧平台骨折手术治疗中植入物选择与入路对支撑作用的影响

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中国组织工程研究 2021年第6期25卷 942-947页

作者：孔令宝吕欣山西医科大学第二医院骨科山西省太原市030001

背景:胫骨后外侧平台骨折是一种特殊的胫骨平台骨折类型。由于其特殊的解剖位置,在治疗时,国内外采用的手术入路及内植物种类较多,但尚未达成共识。目的:对胫骨后外侧平台局部解剖结构、骨折类型进行分析,对各种手术入路及内植物进行归... 详细信息

背景:胫骨后外侧平台骨折是一种特殊的胫骨平台骨折类型。由于其特殊的解剖位置,在治疗时,国内外采用的手术入路及内植物种类较多,但尚未达成共识。目的:对胫骨后外侧平台局部解剖结构、骨折类型进行分析,对各种手术入路及内植物进行归纳总结。方法:通过计算机检索万方医学网、中国知网、PubMed数据库,中文检索词为“胫骨平台骨折;胫骨后外侧平台骨折;内固定;手术入路”,英文检索词为“tibial plateau fractures;posterolateral tibial plateau fractures;internal fixation;surgical approach”。通过纳入标准与排除标准,最终纳入相关文献54篇进行归纳总结。结果与结论:胫骨后外侧平台局部有腓总神经、胫前动脉、腓骨头等结构,均会对手术产生影响。常用的骨折分型有Schatzker分型、AO/ATO分型、三柱分型、后柱4分区,后柱4分区对胫骨后外侧平台骨折有了更明确的指导作用。治疗胫骨平台后外侧骨折的手术入路及内植物种类较多,需根据骨折特性进行最优选择,对于单纯胫骨后外侧平台骨折,后外侧入路相对其他入路有一定优势;后外侧支撑钢板对胫骨平台后外侧剪切力骨折具有更好的支撑作用。

关键词：骨植入物胫骨后外侧平台胫骨平台骨折手术入路内植物内固定

AQR is a novel type 2 diabetes-associated gene that regulates signaling pathways critical for glucose metabolism

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Journal of Genetics and Genomics 2018年第2期45卷 111-120页

作者： Chun Song Han Yan Hanming Wang Yan Zhang Huiqing Cao Yiqi Wan lingbao kong Shenghan Chen Hong Xu Bingxing Pan Jin Zhang Guohuang Fan Hongbo Xin Zicai Liang Weiping Jia Xiao-Li Tian Laboratory of Human Population Genetics Institute of Molecular Medicine Peking University Beijing 100871 China State Key Laboratory of Membrane Biology Institute of Molecular Medicine Peking University Beijing 100871 China Beijing Key Laboratory of Cardiometabolic Molecular Medicine Peking University Beijing 100871 China Laboratory of Nucleic Acid Technology Institute of Molecular Medicine Peking University Beijing 100871 China Human Population Genetics Human Aging Research Institute and School of Life Sciences Nanchang University Nanchang 330006 China Institute of Life Science and School of Life Science Nanchang University Nanchang 330031 China School of Basic Medical Sciences Nanchang University Nanchang 330006 China Institute of Translational Medicine Nanchang University Nanchang 330031 China Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai 200233 China

Type 2 diabetes mellitus（T2 DM） is a common metabolic disease influenced by both genetic and environmental factors. In this study, we performed an in-house genotyping and meta-analysis study using three independent GWAS datasets of T2 DM and found that rs3743121, located 1 kb downstream of AQR,was a novel susceptibility SNP associated with T2 DM. The risk allele C of rs3743121 was correlated with the increased expression of AQR in white blood cells, similar to that observed in T2 DM models. The knockdown of AQR in HepG2 facilitated the glucose uptake, decreased the expression level of PCK2,increased the phosphorylation of GSK-3β, and restored the insulin sensitivity. Furthermore, the suppression of AQR inhibited the mTOR pathway and the protein ubiquitination process. Our study suggests that AQR is a novel type 2 diabetes-associated gene that regulates signaling pathways critical for glucose metabolism.

关键词： Type 2 diabetes AQR Glucose metabolism Ubiquitination