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A review of low-temperature plasma-assisted machining: from mechanism to application

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0734-y

摘要: Materials with high hardness, strength or plasticity have been widely used in the fields of aviation, aerospace, and military, among others. However, the poor machinability of these materials leads to large cutting forces, high cutting temperatures, serious tool wear, and chip adhesion, which affect machining quality. Low-temperature plasma contains a variety of active particles and can effectively adjust material properties, including hardness, strength, ductility, and wettability, significantly improving material machinability. In this paper, we first discuss the mechanisms and applications of low-temperature plasma-assisted machining. After introducing the characteristics, classifications, and action mechanisms of the low-temperature plasma, we describe the effects of the low-temperature plasma on different machining processes of various difficult-to-cut materials. The low-temperature plasma can be classified as hot plasma and cold plasma according to the different equilibrium states. Hot plasma improves material machinability via the thermal softening effect induced by the high temperature, whereas the main mechanisms of the cold plasma can be summarized as chemical reactions to reduce material hardness, the hydrophilization effect to improve surface wettability, and the Rehbinder effect to promote fracture. In addition, hybrid machining methods combining the merits of the low-temperature plasma and other energy fields like ultrasonic vibration, liquid nitrogen, and minimum quantity lubrication are also described and analyzed. Finally, the promising development trends of low-temperature plasma-assisted machining are presented, which include more precise control of the heat-affected zone in hot plasma-assisted machining, cold plasma-assisted polishing of metal materials, and further investigations on the reaction mechanisms between the cold plasma and other materials.

关键词: low-temperature plasma     difficult-to-cut material     machinability     hydrophilization effect     Rehbinder effect    

难加工材料高速切削力非线性特征规律的最大熵谱分析与小波分析

龙震海,王西彬,王好臣

《中国工程科学》 2004年 第6卷 第10期   页码 28-31

摘要:

在切削速度范围157~1000 m/min内,综合应用析因试验与速度单因素试验,对航空用难加工材料2Cr13马氏体不锈钢进行了高速干式铣削试验。在分析其切削力显著性影响因素的基础上,对切削力随机信号进行了现代谱分析与小波分析。研究结果表明,高速切削马氏体不锈钢材料时,切削速度和每齿进给量之间的交互作用对切削力有显著影响;铣削深度和每齿进给量之间的交互作用在切削力响应信号中表现为低频周期信号;低频周期信号与高频信号叠加后,其波形的振幅将会增大。

关键词: 难加工材料     高速切削     析因设计     Meyer小波变换     Mallat算法    

高性能零件的性能与几何参数一体化精密加工方法与技术

郭东明

《中国工程科学》 2011年 第13卷 第10期   页码 47-57

摘要:

随着高端装备和产品的不断发展,对装备和产品制造的性能要求也越来越多和越来越高,涌现出一大批高性能指标要求的关键零部件,其加工已由以往的单纯几何形状和尺寸精度要求,跃升为以性能要求为主、性能与几何参数一体化的精密加工要求。这些高性能零件多呈精密复杂曲面、超高精度,以及材料超硬、超脆、超黏等难加工特征,其性能受几何、材料等多因素耦合作用,采用传统工艺进行精密加工制造十分困难,存在废品率高、加工效率低,特别是性能指标难以保证等难题。从高端制造装备业的需求出发,提出并阐明了高性能零件的特点、分类以及数字化可控去除加工方式的内涵,在此基础上指出了四类高性能零件精密加工所涉及的关键问题,并着重介绍了这些问题的研究现状、存在的难点和可行的解决方案,为面向高性能要求的性能与几何参数一体化的加工理论、方法和工艺技术体系的建立提供参考,以解决高性能零件的精密制造难题。

关键词: 高性能     性能与几何参数一体化     精密加工     难加工材料     复杂曲面    

Assessing the effects of different dielectrics on environmentally conscious powder-mixed EDM of difficult-to-machinematerial (WC-Co)

Jagdeep SINGH,Rajiv Kumar SHARMA

《机械工程前沿(英文)》 2016年 第11卷 第4期   页码 374-387 doi: 10.1007/s11465-016-0388-8

摘要:

Electrical discharge machining (EDM) is a well-known nontraditional manufacturing process to machine the difficult-to-machine (DTM) materials which have unique hardness properties. Researchers have successfully performed hybridization to improve this process by incorporating powders into the EDM process known as powder-mixed EDM process. This process drastically improves process efficiency by increasing material removal rate, micro-hardness, as well as reducing the tool wear rate and surface roughness. EDM also has some input parameters, including pulse-on time, dielectric levels and its type, current setting, flushing pressure, and so on, which have a significant effect on EDM performance. However, despite their positive influence, investigating the effects of these parameters on environmental conditions is necessary. Most studies demonstrate the use of kerosene oil as dielectric fluid. Nevertheless, in this work, the authors highlight the findings with respect to three different dielectric fluids, including kerosene oil, EDM oil, and distilled water using one-variable-at-a-time approach for machining as well as environmental aspects. The hazard and operability analysis is employed to identify the inherent safety factors associated with powder-mixed EDM of WC-Co.

关键词: WC     hazard and operability analysis (HAZOP)     discharging     aerosol concentration     dielectrics     powders    

A novel approach to minimizing material loss for computer numerical control flank-regrinding of worn

《机械工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0757-z

摘要: Flanks of end mills are prone to wear in a long machining process. Regrinding is widely used in workshops to restore the flank to an original-like state. However, the traditional method involves material waste by trial and error and dramatically decreases the potential regrinding. Moreover, over-cut would happen to the flutes of worn cutters in the regrinding processes because of improper wheel path. This study presented a new approach to planning the wheel path for regrinding worn end mills to minimize material loss and recover the over-cut. In planning, a scaling method was developed to determine the maximum size of the new cutter according to the similarity of cutter shapes before and after regrinding. Then, the wheel path is first generated by envelope theory to regrind the worn area with a four-axis computer numerical control grinder according to the new size of cutters. Moreover, a second regrinding strategy is applied to recover the flute shape over-cut in the first grinding. Finally, the proposed method is verified by an experiment. Results showed that the proposed approach could save 25% of cutter material compared with the traditional method and ensure at least three regrinding times. This work effectively provides a general regrinding solution for the worn flank with maximum material-saving and regrinding period.

关键词: flank-regrinding     worn end mill     wheel position and orientation     material loss     over-cut    

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0744-9

摘要: Energy field-assisted machining technology has the potential to overcome the limitations of machining difficult-to-machine metal materials, such as poor machinability, low cutting efficiency, and high energy consumption. High-speed dry milling has emerged as a typical green processing technology due to its high processing efficiency and avoidance of cutting fluids. However, the lack of necessary cooling and lubrication in high-speed dry milling makes it difficult to meet the continuous milling requirements for difficult-to-machine metal materials. The introduction of advanced energy-field-assisted green processing technology can improve the machinability of such metallic materials and achieve efficient precision manufacturing, making it a focus of academic and industrial research. In this review, the characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials, including titanium alloys, nickel-based alloys, and high-strength steel, are systematically explored. The laser energy field, ultrasonic energy field, and cryogenic minimum quantity lubrication energy fields are introduced. By analyzing the effects of changing the energy field and cutting parameters on tool wear, chip morphology, cutting force, temperature, and surface quality of the workpiece during milling, the superiority of energy-field-assisted milling of difficult-to-machine metal materials is demonstrated. Finally, the shortcomings and technical challenges of energy-field-assisted milling are summarized in detail, providing feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine metal materials in the future.

关键词: difficult-to-machine metal material     green machining     high-speed dry milling     laser energy field-assisted milling     ultrasonic energy field-assisted milling     cryogenic minimum quantity lubrication energy field-assisted milling    

Depth of cut models for multipass abrasive waterjet cutting of alumina ceramics with nozzle oscillation

Jun WANG

《机械工程前沿(英文)》 2010年 第5卷 第1期   页码 19-32 doi: 10.1007/s11465-009-0082-1

摘要: An experimental study of the depth of cut in multipass abrasive waterjet (AWJ) cutting of alumina ceramics with controlled nozzle oscillation is presented. It is found that this cutting technique can significantly increase the depth of cut by an average of 50.8% as compared to single pass cutting without nozzle oscillation under the corresponding cutting conditions and within the same cutting time. Predictive models for the depth of cut are then developed. The modelling process starts with single pass cutting using a dimensional analysis technique and the particle erosion theories applied to alumina ceramics, before progressing to the development of the models for multipass cutting. The models are finally assessed both qualitatively and quantitatively with experimental data. It is shown that the model predictions are in good agreement with the experimental data with the average deviations of about 1%.

关键词: abrasive waterjet     engineering ceramics     depth of cut     cutting performance     nozzle oscillation     machining    

Comparative assessment of force, temperature, and wheel wear in sustainable grinding aerospace alloy using biolubricant

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0719-x

摘要: The substitution of biolubricant for mineral cutting fluids in aerospace material grinding is an inevitable development direction, under the requirements of the worldwide carbon emission strategy. However, serious tool wear and workpiece damage in difficult-to-machine material grinding challenges the availability of using biolubricants via minimum quantity lubrication. The primary cause for this condition is the unknown and complex influencing mechanisms of the biolubricant physicochemical properties on grindability. In this review, a comparative assessment of grindability is performed using titanium alloy, nickel-based alloy, and high-strength steel. Firstly, this work considers the physicochemical properties as the main factors, and the antifriction and heat dissipation behaviours of biolubricant in a high temperature and pressure interface are comprehensively analysed. Secondly, the comparative assessment of force, temperature, wheel wear and workpiece surface for titanium alloy, nickel-based alloy, and high-strength steel confirms that biolubricant is a potential replacement of traditional cutting fluids because of its improved lubrication and cooling performance. High-viscosity biolubricant and nano-enhancers with high thermal conductivity are recommended for titanium alloy to solve the burn puzzle of the workpiece. Biolubricant with high viscosity and high fatty acid saturation characteristics should be used to overcome the bottleneck of wheel wear and nickel-based alloy surface burn. The nano-enhancers with high hardness and spherical characteristics are better choices. Furthermore, a different option is available for high-strength steel grinding, which needs low-viscosity biolubricant to address the debris breaking difficulty and wheel clogging. Finally, the current challenges and potential methods are proposed to promote the application of biolubricant.

关键词: grinding     aerospace     difficult-to-machine material     biolubricant     physicochemical property     grindability    

三峡工程建设的主要科技难题

王家柱

《中国工程科学》 2003年 第5卷 第8期   页码 16-22

摘要:

三峡工程是世界最大的多目标开发的综合利用工程。工程规模巨大,技术复杂,具有防洪、发电、航运等巨大的综合效益。文章论述了工程建设过程中已经和将要解决的一大批重大科学技术难题,并指出其将对水利水电科学技术的发展起到重要的促进作用。

关键词: 三峡工程     科技     难题    

明挖法地下装配式结构接缝防水技术探讨

黄明利,杨泽,谭忠盛,王文正

《中国工程科学》 2017年 第19卷 第6期   页码 131-139 doi: 10.15302/J-SSCAE-2017.06.019

摘要:

装配式结构与传统的现浇结构相比具有节能、环保、节省模具、工期较短等特点,已在地上建筑中获得了飞速发展。由于地下环境复杂,地下装配式结构接头部位的防水处理成为难题,因此,地下装配式结构近几年在我国才刚刚起步。本文在分析地下装配式结构的接头形式和防水技术现状的基础上,提出了应用环氧灌浆料对预制装配式结构接头进行灌封,通过试验研究了环氧灌浆料本身及其黏接混凝土的力学性能。同时还针对明挖法修建的技术特点,介绍了基坑肥槽预拌固化土回填技术,阐述了预拌固化土对地下工程结构防水的作用,研究成果可供类似工程参考。

关键词: 预制装配式结构     地下结构接缝     环氧灌浆料     预拌固化土     防水技术    

liquid addition attained advanced nitrogen removal in low C/N ratio municipal wastewater through short-cut

Shengjie Qiu, Jinjin Liu, Liang Zhang, Qiong Zhang, Yongzhen Peng

《环境科学与工程前沿(英文)》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1318-x

摘要: Abstract • Sludge fermentation liquid addition resulted in a high NAR of 97.4%. • Extra NH4+-N from SFL was removed by anammox in anoxic phase. • Nitrogen removal efficiency of 92.51% was achieved in municipal wastewater. • The novel system could efficiently treat low COD/N municipal wastewater. Biological nitrogen removal of wastewater with low COD/N ratio could be enhanced by the addition of wasted sludge fermentation liquid (SFL), but the performance is usually limited by the introducing ammonium. In this study, the process of using SFL was successfully improved by involving anammox process. Real municipal wastewater with a low C/N ratio of 2.8–3.4 was treated in a sequencing batch reactor (SBR). The SBR was operated under anaerobic-aerobic-anoxic (AOA) mode and excess SFL was added into the anoxic phase. Stable short-cut nitrification was achieved after 46d and then anammox sludge was inoculated. In the stable period, effluent total inorganic nitrogen (TIN) was less than 4.3 mg/L with removal efficiency of 92.3%. Further analysis suggests that anammox bacteria, mainly affiliated with Candidatus_Kuenenia, successfully reduced the external ammonia from the SFL and contributed approximately 28%–43% to TIN removal. Overall, this study suggests anammox could be combined with SFL addition, resulting in a stable enhanced nitrogen biological removal.

关键词: Sludge fermentation liquid     Municipal wastewater     Advanced nitrogen removal     Short-cut nitrification     Partial anammox    

Liquid metal material genome: Initiation of a new research track towards discovery of advanced energy

Lei WANG, Jing LIU

《能源前沿(英文)》 2013年 第7卷 第3期   页码 317-332 doi: 10.1007/s11708-013-0271-9

摘要: As the basis of modern industry, the roles materials play are becoming increasingly vital in this day and age. With many superior physical properties over conventional fluids, the low melting point liquid metal material, especially room-temperature liquid metal, is recently found to be uniquely useful in a wide variety of emerging areas from energy, electronics to medical sciences. However, with the coming enormous utilization of such materials, serious issues also arise which urgently need to be addressed. A biggest concern to impede the large scale application of room-temperature liquid metal technologies is that there is currently a strong shortage of the materials and species available to meet the tough requirements such as cost, melting point, electrical and thermal conductivity, etc. Inspired by the Material Genome Initiative as issued in 2011 by the United States of America, a more specific and focused project initiative was proposed in this paper—the liquid metal material genome aimed to discover advanced new functional alloys with low melting point so as to fulfill various increasing needs. The basic schemes and road map for this new research program, which is expected to have a worldwide significance, were outlined. The theoretical strategies and experimental methods in the research and development of liquid metal material genome were introduced. Particularly, the calculation of phase diagram (CALPHAD) approach as a highly effective way for material design was discussed. Further, the first-principles (FP) calculation was suggested to combine with the statistical thermodynamics to calculate the thermodynamic functions so as to enrich the CALPHAD database of liquid metals. When the experimental data are too scarce to perform a regular treatment, the combination of FP calculation, cluster variation method (CVM) or molecular dynamics (MD), and CALPHAD, referred to as the mixed FP-CVM-CALPHAD method can be a promising way to solve the problem. Except for the theoretical strategies, several parallel processing experimental methods were also analyzed, which can help improve the efficiency of finding new liquid metal materials and reducing the cost. The liquid metal material genome proposal as initiated in this paper will accelerate the process of finding and utilization of new functional materials.

关键词: liquid metal material genome     energy material     material discovery     advanced material     room-temperature liquid alloy     thermodynamics     phase diagram    

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Yu-Chin CHAN, Kohei SHINTANI, Wei CHEN

《机械工程前沿(英文)》 2019年 第14卷 第2期   页码 141-152 doi: 10.1007/s11465-019-0531-4

摘要: Enabled by advancements in multi-material additive manufacturing, lightweight lattice structures consisting of networks of periodic unit cells have gained popularity due to their extraordinary performance and wide array of functions. This work proposes a density-based robust topology optimization method for meso- or macro-scale multi-material lattice structures under any combination of material and load uncertainties. The method utilizes a new generalized material interpolation scheme for an arbitrary number of materials, and employs univariate dimension reduction and Gauss-type quadrature to quantify and propagate uncertainty. By formulating the objective function as a weighted sum of the mean and standard deviation of compliance, the tradeoff between optimality and robustness can be studied and controlled. Examples of a cantilever beam lattice structure under various material and load uncertainty cases exhibit the efficiency and flexibility of the approach. The accuracy of univariate dimension reduction is validated by comparing the results to the Monte Carlo approach.

关键词: robust topology optimization     lattice structures     multi-material     material uncertainty     load uncertainty     univariate dimension reduction    

工程材料研究中科学问题的思考

于翘

《中国工程科学》 1999年 第1卷 第3期   页码 1-4

摘要:

在不少场合下,航天用工程材料处在极端条件下工作,这就对材料提出许多特殊的要求,虽然国内外有一定的研究积累,但对更精确的模型和符合特定材料的损伤的状态方程,有待深一步研究。如高级弹头再入时气动加热和粒子云侵蚀以及两者耦合效应引起弹头防护材料增大后退量的问题;空中垃圾和微流星的高速碰撞对航天器的威胁;特别是核爆和激光武器对材料的损伤和破坏,实质上是辐射引起的热击波层裂破坏,这些都属于超高速碰撞对材料的响应问题。天线罩材料、吸波材料、红外隐身材料、电磁屏蔽材料都是具有不同波长电磁波的电磁功能材料,它们对固体介质的穿透、吸收、反射等会产生响应,不同的电磁功能材料,其宏观性能的物理参量不同,但有几个参量是通用的,如介电常数、磁导率和损耗角正切,搞清这些参量与材料微观结构的关系,可以为材料设计和材料创新提供科学依据。

关键词: 天线罩材料     吸波材料     红外隐身材料     电磁兼容材料    

解决地下通信技术难题的方案及关键设备

司徒梦天

《中国工程科学》 2001年 第3卷 第7期   页码 64-69

摘要:

文章叙述了在地下无线电通信中的两大技术难题——弱信号接收和抗雷电脉冲干扰,提出其解决途径,并介绍解决这些技术难题的关键设备——弱信号抗雷电电报终端机的设计方案,分析该机的性能和给出实验室测试和现场试验的结果。

关键词: 地下无线电通信     弱信号接收     抗雷电脉冲干扰    

标题 作者 时间 类型 操作

A review of low-temperature plasma-assisted machining: from mechanism to application

期刊论文

难加工材料高速切削力非线性特征规律的最大熵谱分析与小波分析

龙震海,王西彬,王好臣

期刊论文

高性能零件的性能与几何参数一体化精密加工方法与技术

郭东明

期刊论文

Assessing the effects of different dielectrics on environmentally conscious powder-mixed EDM of difficult-to-machinematerial (WC-Co)

Jagdeep SINGH,Rajiv Kumar SHARMA

期刊论文

A novel approach to minimizing material loss for computer numerical control flank-regrinding of worn

期刊论文

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

期刊论文

Depth of cut models for multipass abrasive waterjet cutting of alumina ceramics with nozzle oscillation

Jun WANG

期刊论文

Comparative assessment of force, temperature, and wheel wear in sustainable grinding aerospace alloy using biolubricant

期刊论文

三峡工程建设的主要科技难题

王家柱

期刊论文

明挖法地下装配式结构接缝防水技术探讨

黄明利,杨泽,谭忠盛,王文正

期刊论文

liquid addition attained advanced nitrogen removal in low C/N ratio municipal wastewater through short-cut

Shengjie Qiu, Jinjin Liu, Liang Zhang, Qiong Zhang, Yongzhen Peng

期刊论文

Liquid metal material genome: Initiation of a new research track towards discovery of advanced energy

Lei WANG, Jing LIU

期刊论文

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Yu-Chin CHAN, Kohei SHINTANI, Wei CHEN

期刊论文

工程材料研究中科学问题的思考

于翘

期刊论文

解决地下通信技术难题的方案及关键设备

司徒梦天

期刊论文