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A comprehensive review of extrusion-based additive manufacturing processes for rapid production of metallic and ceramic parts

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Advances in Manufacturing 2019年第2期7卷 155-173页

作者： Kedarnath Rane Matteo Strano Department of Mechanical Engineering Politecnico di Milano Via La Masa 1 Milan Italy

The extrusion-based additive manufacturing (EAM) technique is recently being employed for rapid production of metals and ceramic components. This technique involves extruding the metal or ceramic material in solid powder form mixed with a binder (i.e., an expendable viscous fluid), which is removed from the part after 3D printing. These technologies rely on the large design freedom allowed and the cost efficiency advantage over alternative metal additive manufacturing processes that are based on high energy beams, such as laser or electron beams. The EAM of metals and ceramics is not yet widespread, but published scientific and technical literature on it is rapidly growing. However, this literature is still less extensive than that on the fused deposition modeling (FDM) of plastics or the selective laser melting (SLM) of metals. This paper aims at filling this gap. FDM and powder injection molding are identified as preceding or enabling technologies for EAM. This paper systematically reviews all aspects of the feedstock EAM processes used for production of complex-shaped parts. The unique characteristics and advantages of these processes are also discussed with respect to materials and process steps. In addition, the key process parameters are explained to illustrate the suitability of the EAM process for diverse application domains.

关键词： Feedstock extrusion Rapid production Complex-shaped metallic Ceramic parts

Manufacturing Technology of Refractory Metal parts Based on SLS Rapid Prototyping

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稀有金属材料与工程 2011年第S4期40卷 257-260页

作者： Liu Bin,Bai Peikang,Ding Erming College of Material Science and Engineering,North University of China,Taiyuan 030051,China N Univ China Coll Mat Sci & Engn Taiyuan 030051 Peoples R China

A rapid prototyping process of selective laser sintering (SLS) which can be used to refractory metal parts manufacturing is introduced in this text.SLS material of polymer-coated Mo powder is prepared by coating polymer and freezing grinding methods.The laser sintering process has been experimentally researched,and optimized parameters have been acquired.The post treatment process of prototyping parts has been developed,which is sintering framework-Mo by high temperature combining with Cu impregnation method.At last,refractory metal parts of Mo/Cu composites are gained.SEM graph shows that Mo and Cu are close jointed together,and these phases distribute interlocked Mechanical and thermal properties of the material have been tested,concluding tensile strength(470 MPa),elastic modulus(267.8 GPa),elongation(15%),linear expansion(5.5×10-6/K).The technology can be applied to manufacturing fire-resisting parts of weaponry and aerospace arms,as well as conductance and cooling elements used to electronics industry.

关键词： refractory metal parts polymer-coated Mo powder selective laser sintering post treatment

Initial residual stress experiment and simulation of thin-walled parts for layer removal method

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High Technology Letters 2018年第1期24卷 75-81页

作者：刘宇男 Wang Min Zan Tao Gao Xiangsheng Zhang Yanlin Beijing Key Laboratory of Advanced Manufacturing Technology College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology Beijing 100124 P. R. China Beijing Key Laboratory of Electrical Discharge Machining Technology Beiiing 100191 P. R. China Beijing Xinli Machinery Co. Ltd. Beijing 100039 P. R. China

Thin-walled parts have low stiffness characteristic. Initial residual stress of thin-walled blanks is an important influence factor on machining stability. The present work is to verify the feasibility of an initial residual stress measurement of layer removal method. According to initial residual stress experiment for casting ZL205 A aluminum alloy tapered thin-walled blank by a common method,namely hole-drilling method,three finite element models with initial residual stress are established to simulate the layer removal method in ABAQUS and ANSYS software. By analyzing the results of simulation and experiments,the cutting residual stress inlayer removal process has a significant effect on measurement results. Reducing cutting residual stress is helpful to improve accuracy of layer removal method.

关键词： initial residual stress thin-walled parts layer.removal method finite element

Abel’s lemma on summation by parts and partial q-series transformations

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Science China Mathematics 2009年第4期52卷 720-748页

作者： CHU WenChang WANG ChenYing Department of Applied Mathematics Dalian University of TechnologyDalian 116024China

The partial sums of basic hypergeometric series are investigated by means of the modified Abel lemma on summation by parts. Several transformation and summation formulae for well-poised, quadratic, cubic and quartic q... 详细信息

关键词： Abel’s lemma on summation by parts basic hypergeometric series well-poised series quadratic series cubic series quartic series reciprocal relation

Kenyan Wool Fiber Properties Sampled from Different Sheep Body parts

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Journal of Donghua University(English Edition) 2018年第6期35卷 503-508页

作者：王华 MEMON Samiullah MEMON Hafeezullah College of Textiles Donghua University Donghua University Center for Civil Aviation Composites Donghua University Key Laboratory of Textile Science & Technology Ministry of EducationCollege of TextilesDonghua University

This study provides information on fleece characteristics for stakeholders in a wool trade to make sheep farming more viable and profitable for farmers. Wool fiber samples were taken from four sheep body parts of the 95 sheep. Tests were conducted to analyze the fiber diameter,length,color,and strength. Correspondingly,fiber surface morphology and the medullated fibers were also analyzed and the results were reported. The fiber characteristics from the shoulder and flank were better than those shorn from back and belly/legs. From the results, the values of the measured parameters suggest potential for improvement of economical qualities and in fostering the economic and industrial

关键词： Kenya wool sheep body parts

Research of precise pulse plasma arc powder welding technology of thin-walled inner hole parts

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China Welding 2017年第3期26卷 57-62页

作者：李占明杜晓坤孙晓峰宋巍 Department of Equipment Maintenance and Remanufacturing Engineering Academy of Armored Force Engineering Department of Science Research Academy of Armored Force Engineering

The inner hole parts played an oriented or supporting role in engineering machinery and equipment,which are prone to appear surface damages such as wear,strain and corrosion. The precise pulse plasma arc powder welding method is used for surface damage repairing of inner hole parts in this paper. The working principle and process of the technology are illustrated,and the microstructure and property of repairing layer by precise pulse plasma powder welding and CO2 gas shielded welding are tested and observed by microscope,micro hardness tester and X-ray residual stress tester etc. Results showed that the substrate deformation of thin-walled inner hole parts samples by precise pulse plasma powder welding is relatively small. The repair layer and substrate is metallurgical bonding,the transition zones( including fusion zone and heat affected zone) are relatively narrow and the welding quality is good. It showed that the thin-walled inner hole parts can be repaired by this technology and equipment.

关键词： precise pulse plasma arc powder welding thin walled inner hole parts welding repairing layer

Fatigue Life Prediction of Shaft parts

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Journal of Donghua University(English Edition) 2019年第3期36卷 307-314页

作者：陈旭东孙洪华李庆洋 College of Mechanical Engineering Inner Mongolia University of Technology

Taking high speed rotating shaft parts as the research object,the general fault mode of the parts is analyzed.The analysis process of shaft parts is expounded by means of finite element analysis method.A variety of fatigue life prediction methods for mechanical equipment parts are reviewed in this paper.And the selection and calculation method of parameters in the life prediction model of shaft parts are summarized.Finally,taking a gear shaft of a reducer as an example,the Morrow linear correction of the elastic stress model,Manson-Halford(M-H)correction model and Smith Watson Topper(SWT)correction model are applied to fatigue life assessments.The prediction results of the SWT correction model are relatively conservative.The prediction results of the Morrow linear correction of the elastic stress model and the M-H model are similar,and they are larger than the SWT correction model.

关键词： ANSYS software shaft parts fatigue life model comparison

Stems and leaves of Aconitum carmichaelii Debx.as potential herbal resources for treating rheumatoid arthritis： Chemical analysis,toxicity and activity evaluation

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Chinese Journal of Natural Medicines 2018年第9期16卷 644-652页

作者： HE Ya-Nan OU Shui-Ping XIONG Xi PAN Yuan PEI Jin XU Run-Chun GENG Fu-Neng HAN Li ZHANG Ding-Kun YANG Ming State Key Laboratory Breeding Base of Systematic Research Development and Utilization of Chinese Medicine Resources Chengdu University of Traditional Chinese Medicine Chengdu 611137 China Affiliated Hospital of Zunyi Medical College Zunyi 563000 China Sichuan Good Doctor Panxi Pharmaceutical Co. Ltd. Xiehang 615000 China Jiangxi University of Traditional Chinese Medicine Nanchang 330004 China

According to folk usage of Aconitum carmichaelii Debx., the present study was designed to determine the feasibility of the stems and leaves of Aconitum carmichaelii Debx. as a new medicinal resource. Fourteen alkaloids in mother roots, fibrous roots, stems, and leaves of Aconitum carmichaelii Debx. were measured by HPLC-MS/MS. And multivariate analysis methods, such as clustering analysis and principal component analysis, were applied to analyze the difference among various parts. In addition, the acute toxicity, analgesia, and anti-inflammatory tests were carried out. The results suggested that the contents of alkaloids in mother roots and fibrous roots were approximate, but those of leaves and stems were different from mother roots and fibrous roots. The results of the acute toxicity testing demonstrated the toxicity of fibrous root was strongest, and mother roots were slightly less toxic than fibrous roots. The stems and leaves were far less toxic than mother and fibrous roots. In addition, the analgesia and inflammatory tests showed the effects of the various tissues had no difference each other. These results provided a basis for developing new complementary and alternative treatments for rheumatoid arthritis patients. Simultaneously, the approach may also turn wastes into treasure and promote the development of circular economy.

关键词： Aconitum carmichaelii Debx. New medical parts Alkaloids Toxicity Efficacy

Integrated chemical and transcriptomic analyses unveils synthetic characteristics of different medicinal root parts of Angelica sinensis

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Chinese Herbal Medicines 2020年第1期12卷 19-28页

作者： Ran Xu Jiang Xu Yong-chang Li Yun-tao Dai Shao-peng Zhang Guang Wang Zhi-guo Liu Lin-lin Dong Shi-lin Chen College of Biology and Pharmaceutical Engineering Wuhan Polytechnic UniversityWuhan 430000China Institute of Chinese Materia Medica China Academy of Chinese Medical SciencesBeijing 100700China Kansas City University of Medicine and Biosciences Joplin 64804USA

Objective:Why are different medicinal parts including heads,bodies and tails of Angelicae Sinensis Radix(ASR)distinct in pharmaceutical activities?Here we explored their discrepancy in chemical constituents and transcriptome.Methods:ASR were separated into three medicinal parts:heads(rootstocks with petiole traces of ASR),bodies(taproots of ASR)and tails(lateral roots of ASR),and chemical and transcriptomic analyses were conducted simultaneously.Results:High performance liquid chromatography(HPLC)fingerprint results showed that five widely used active ingredients(ferulic acid,senkyunolide H,senkyunolide A,n-butylphathlide,and ligustilide)were distributed unevenly in the three ASR medicinal parts.Partial least squares-discriminant analysis(PLS-DA)demonstrated that the heads can be differentiated from the two other root parts due to different amounts of the main components.However,the content of ferulic acid(a main quality marker)was significantly higher in tails than in the heads and bodies.The transcriptome analysis found that 25,062,10,148 and 29,504 unigenes were specifically expressed in the heads,bodies and tails,respectively.WGCNA analysis identified 17 co-expression modules,which were constructed from the 19,198 genes in the nine samples of ASR.Additionally,we identified 28 unigenes involved in two phenylpropanoid biosynthesis(PB)pathways about ferulic acid metabolism pathways,of which 17 unigenes(60.7%)in the PB pathway were highly expressed in the tails.The expression levels of PAL,C3 H,and CQT transcripts were significantly higher in the tails than in other root parts.RT-q PCR analysis confirmed that PAL,C3 H,and CQT genes were predominantly expressed in the tail parts,especially PAL,whose expression was more than doubled as compared with that in other root parts.Conclusion:Chemical and transcriptomic analyses revealed the distribution contents and pivotal transcripts of the ferulic acid biosynthesis-related pathways.The spatial gene expression pattern partially explained the discrepancy of integral medi

关键词： Angelicae Sinensis Radix biosynthesis comparative transcriptomics ferulic acid three medicinal root parts