Microstructure and forming mechanism of metals subjected to ultrasonic vibration plastic forming: A mini review

Compared with traditional plastic forming,ultrasonic vibration plastic forming has the advantages of reducing the forming force and improving the surface quality of the workpiece.This technology has a very broad application prospect in industrial manufactur-ing.Researchers have conducted extensive research on the ultrasonic vibration plastic forming of metals and laid a deep foundation for the development of this field.In this review,metals were classified according to their crystal structures.The effects of ultrasonic vibration on the microstructure of face-centered cubic,body-centered cubic,and hexagonal close-packed metals during plastic forming and the mech-anism underlying ultrasonic vibration forming were reviewed.The main challenges and future research direction of the ultrasonic vibra-tion plastic forming of metals were also discussed.

STUDY ON SYNCHRONIZER HUB PLASTIC FORMING

Metal flowing has been numerically simulated for synchronizer hub at different forming conditions. The influences of billet shape, frictional factor,deformation degree and radius of rounded corner on form- ing for been studied and the processing parameters have been optimized. On the basis, a new technol- ogy of refilling multiplicity forming has been put forward and workpiece that meets the requirement of synchronizer hub has been manufactured.

Novel AC Servo Rotating and Linear Composite Driving Device for Plastic Forming Equipment

The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for com- plicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion with- out transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on thedynamic test benches are conducted. The results indicate that the output torque can attain to 420 N-m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive, the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accu- racy direct driving device in plastic forming equipment.

Model-element Analytic Method for Plastic Forming of Material

MEM(model element method) is proposed to resolve the present difficulties and problems in CAE about plastic forming of material.There are four advantages when MEM is integrated with FEM(finite element method) and UBM(upper boundary element method).First,it can make full use of their own advantages and overcome their own disadvantages;second,it can analyse material plastic fluid expediently;third,it can optimize design;finally,it can improve technological content and application effect of CAE software.Based on introducing the principle of MEM briefly,features and applications of MEM are pointed out.In conclusion,a new analysis method for plastic forming comes forth.

Creating Technology and Numerical Analysis of Warm Plastic Forming for Non-symmetrical Axostyle

A creating technology of the part forming was discussed and finite volume method(FVM)was used to simulate the forming process of the non-symmetrical axostyle spring core-bar.The results show that the no-even radial flange on the top part of the eccentric peachy surface can remarkably block the metal flow and the eccentric peachy can be filled contentedly.Increasing the radius of punch near the inner pocket,the head bulge also can be filled contentedly.The temperature distribution in the part and the forming force,which helps to decide the forming temperature and to select the equipment,was also analyzed.The comparison between the simulation and the experiment result shows that they are accordant.

基于Autoform的引擎盖外板冲压成形研究

基于Autoform仿真软件对汽车的引擎盖外板进行了数值模拟和成形仿真研究,通过对引擎盖外板冲压成形的仿真结果进行分析,对部分参数进行优化,使得仿真结果更加符合实际生产应用。主要是针对冲压成形中可能出现的开裂、起皱等问题进行了技术研究,并根据数值模拟结果,及时预测了因拉延过度板料变薄造成拉裂等技术问题的区域,并制定了冲压技术措施,从而提高了引擎盖外板成形模具的利用率,极大地减少了模具修复及操作的时间,使修模变得更为简单。

Towards intelligent design optimization: Progress and challenge of design optimization theories and technologies for plastic forming

Plastic forming is one of enabling and fundamental technologies in advanced manufacturing chains. Design optimization is a critical way to improve the performance of the forming system, exploit the advantages of high productivity, high product quality, low production cost and short time to market and develop precise, accurate, green, and intelligent(smart) plastic forming technology. However, plastic forming is quite complicated, relating to multi-physics field coupling,multi-factor influence, multi-defect constraint, and triple nonlinear, etc., and the design optimization for plastic forming involves multi-objective, multi-parameter, multi-constraint, nonlinear,high-dimensionality, non-continuity, time-varying, and uncertainty, etc. Therefore, how to achieve accurate and efficient design optimization of products, equipment, tools/dies, and processing as well as materials characterization has always been the research frontier and focus in the field of engineering and manufacturing. In recent years, with the rapid development of computing science, data science and internet of things(Io T), the theories and technologies of design optimization have attracted more and more attention, and developed rapidly in forming process. Accordingly, this paper first introduced the framework of design optimization for plastic forming. Then, focusing on the key problems of design optimization, such as numerical model and optimization algorithm,this paper summarized the research progress on the development and application of the theories and technologies about design optimization in forming process, including deterministic and uncertain optimization. Moreover, the applicability of various modeling methods and optimization algorithms was elaborated in solving the design optimization problems of plastic forming. Finally, considering the development trends of forming technology, this paper discusses some challenges of design optimization that may need to be solved and faced in forming process.

Recent research and development on forming for large magnesium alloy components with high mechanical properties

The lightweight of high-end equipment relies on high mechanical properties magnesium(Mg) alloy structural components, because it is the best way to improve equipment service performance and reduce energy consumption. This article summarizes the current progress and characteristics of large-scale high-performance Mg alloy components by analyzing the strengthening-toughening mechanisms, characteristics of plastic forming, and the preparation of large high mechanical properties forging blanks. Due to the lack of breakthroughs in the key technologies for forming large-scale Mg alloy components, their uniformity of mechanical properties and consistency are poor, the forming accuracy of components is low, and the production cost is high, which limit their engineering application and restrict the lightweight level of high-end equipment. In view of the above problems, the forming trends and research directions of large-scale and high mechanical properties Mg alloy components are proposed in this paper. It can provide help for the breakthrough of the key technology of large-scale Mg alloy components with high mechanical properties and expand the application of Mg alloy in high-end products.

Laboratory of Precision Plastic Forming In NWPU

Aiming at the international frontiers of plastic forming fields, under the supports of over 50 important projects such as NSFC, 973, 863 and other National Key Projects, the laboratory focuses on four research topics, viz., local-loading based unequal deformation controlling and integrated precision forming for shape and performance, digitalized precision plastic forming controlling based on through-process, multi-scale modeling ＆ sinmlation and optimization, force-save near-net-shape plastic forming technology for large-scale,

Simulation of bulk metal forming processes using one-step finite element approach based on deformation theory of plasticity

The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/strain distributions.This approach was implemented to minimize the approximated plastic potential energy derived from the total plastic work and the equivalent external work in static equilibrium,for incompressibly rigid-plastic materials,by FE calculation based on the extremum work principle.The one-step forward simulations of compression and rolling processes were presented as examples,and the results were compared with those obtained by classical incremental FE simulation to verify the feasibility and validity of the proposed method.

Research on Extrude-bulge Forming of Tee Tubes with Plastic Medium

ＲｅｓｅａｒｃｈｏｎＥｘｔｒｕｄｅ－ｂｕｌｇｅＦｏｒｍｉｎｇｏｆＴｅＴｕｂｅｓｗｉｔｈＰｌａｓｔｉｃＭｅｄｉｕｍＷＡＮＧＣｈｅｎｌｕＬＵＹａｎ（王成录）（吕炎）（Ｓｃｈ．ｏｆＭａｔｅｒｉａｌＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｒｉｎｇ，ＨａｒｂｉｎＩｎｓ...

GH4169合金塑性加工成形与组织调控方法综述

针对高温合金零部件的精密成形制造由于工艺复杂、成形效率和精度低,其微观组织、力学性能及成形精度难以协同控制的问题,采用组织调控和成形工艺优化作为实现高温合金零部件成形成性一体化制造的有效手段。作为一种高温稳定相,δ相常出现于塑性变形及热处理过程中,其析出量与形貌影响合金的微观组织及力学性能。因为零件结构及服役条件的差异,所要求的组织、性能和采取的制备工艺也不尽相同。介绍了环类、盘类及叶片类3类典型的GH4169合金零件的塑性加工技术,同时引出δ相在其中起到的作用,继而对δ相的析出、球化和溶解等演化行为及其对合金变形行为和力学性能的影响进行了阐述与总结。

微型胶囊机器人外壳的淹没式空化射流成形质量分析

目的针对微型胶囊机器人外壳成形的技术难题,提出了一种基于淹没式空化射流冲击箔材的微型机器人外壳成形方法,分析了微型外壳的成形质量。方法基于微型胶囊机器人外壳的特征尺寸设计模具,利用淹没式空化射流试验装置,完成了对T2铜箔的高能冲击成形试验,分析了淹没式空化射流的成形原理,讨论了微型外壳的成形深度、表面粗糙度、厚度减薄率以及纳米硬度。结果在空化射流冲击成形过程中,微型外壳成形深度的增长率随成形时间的延长而减小,最大成形深度可达291.4μm(模具最大深度为300μm);成形后微型外壳表面粗糙度Ra值由0.7897μm逐渐增加至1.0576μm,厚度减薄率为10%~25%,纳米硬度提高了21.78%~46.64%,最大硬度增长率出现在刃口处。结论在淹没式空化射流成形过程中,微型外壳的成形深度与模具的相当,微型外壳表面存在小幅度粗化现象,成形后减薄率降低,纳米硬度大幅提高,抵抗外界破坏能力提高。

Humanoid Based Intelligence Control Strategy of Plastic Cement Die Press Work-Piece Forming Process for Polymer Plastics

The plastic cement belongs to a sort of polymer material, the chemical composition is very complex, and the plastic cement work-piece is generally manufactured by die press forming. Aimed at being difficult to control in parameters of forming process, the paper explored the humanoid based intelligence control strategy. In the paper, it made the anatomy in control puzzle resulted in uncertainty such as chemical component of plastic cement etc., summarized up the characteristic of cybernetics in forming process, researched on the humanoid based intelligence control strategy, and constructed the control algorithm of forming process in plastic cement work-piece. Taking the process experiment of temperature and pressure control as an example, it validated the good dynamic and static control quality through simulation of control algorithm constructed in this paper. The experimental results show that the control algorithm explored in this paper is reasonably available.

齿轮精密塑性成形理论技术装备研究与应用

齿轮是传动系统的核心基础件,被广泛应用于机械、汽车、航空航天装备等领域。齿轮传统制造技术为切削加工,其材料利用率低、加工周期长,特别是金属流线切断,损害齿轮性能,无法满足高端装备发展需求。齿轮精密塑性成形制造技术具有节能、节材、高效和优质等特点,是高性能齿轮技术发展方向。阐述了齿轮精密塑性成形理论方法,分析了国内外圆锥直齿轮、圆柱直齿轮和圆柱螺旋/斜齿轮精密成形技术特点;介绍了齿轮精密成形典型装备及产线,总结了齿轮无切削摆辗精密成形和锻造精密成形应用情况。此外,展示了圆锥螺旋齿轮多自由度包络成形和非圆齿轮锻造成形新方法,为高性能齿轮无切削成形制造技术装备研究与应用提供了参考。

中国塑性成形技术和装备30年的重大突破与进展

1994以来的30年,在国家重大需求的强劲牵引下,我国塑性成形技术与装备取得举世瞩目的巨大成就,研制出一大批世界第一的成形装备,实现了三大技术跨越,形成了规模最大的研究队伍,我国塑性成形技术总体水平进入世界先进国家行列,多个单项技术和装备达到国际领先水平。选择了其中8项最具代表性成果,并介绍其在塑性工程理论和技术上取得的重大突破以及对国家重大装备研制的突出贡献,分析了我国塑性成形技术与国际领先水平的差距。最后对我国塑性成形技术发展将呈现出的“三超两高”五大发展趋势进行了展望。

金属拉拔工艺中的摩擦与腐蚀交互作用研究进展

综述了金属拉拔成形中的摩擦特点及影响摩擦的主要因素,总结分析了电致塑性和电化学促进金属表面塑化的作用机制,以及电化学冷拉拔中电解液环境下的腐蚀与磨损交互作用对工艺及工件的影响,以期为提高拉拔成形技术中加工金属的表面质量,延长模具使用寿命提供理论基础,为金属塑性成形技术的发展以及关键材料的生产提供重要参考。

基于PLC的可降解塑料片材成型自动化生产线设计

塑料片材是塑料制品中的重要组成部分,然而现有的塑料片材生产线自动化程度较低,原料主要成分为聚乙烯,难以降解。据此,采用一种新型的可降解塑料作为原料,但此原料是粉状料,无法适用于传统的粒状送料装置;由于其特点是通过挤出后离模发泡的方式成型为片材,并且原料对温度要求较高,传统挤出机无法使用此料生产。因而根据此原料特性和加工工艺设计由送料系统、挤出成型系统、牵引滚压系统、分切冲孔系统及夹取码垛系统组成的可降解塑料片材成型生产线,使用PLC和触摸屏对控制系统的硬软件进行设计。以平均生产节拍作为参考指标,此自动化产线生产效率提高了26.5%,为可降解塑料产品的规模应用提供了技术支撑。

基于DEFORM的半轴套管复合鐓挤模拟分析

汽车半轴套管一般采用优质碳素结构钢和合金结构钢热轧,无缝钢管由机加工制造。对于形状简单凸缘直径不大的套管,机加工难度不大,但是对于形状复杂,内孔异形的套管采用机加工成形浪费材料或者根本无法加工。采用挤压成形有诸多优点,如节省材料,提高效率,工件性能由于塑性强化而提高等。设计了一种半轴套管的复合鐓挤成形工艺,模拟仿真的结果很理想,工件尺寸达到要求,凸凹模应力也远低于许用应力。

Three Dimension Rigid-plastic Finite Element Simulation for Two-Roll Cross-wedge Rolling Process

Cross-wedge rolling (CWR) is a metal process of ro ta ry forming. To produce a part, one cylindrical billet should be placed between t wo counterrotating and wedge-shape dies, which move tangentially relative each other. The billet suffers plastic deformation (essentially, localized compressio n) during its rotation between the rotating dies. Compared to other numerical si mulation methods, the finite element method (FEM) has advantages in solving gene ral problems with complex shapes of the formed parts. In cross-wedge rolling, t here are four stages in the workpiece deformation process, namely knifing, guidi ng, stretching and sizing stage. It is time-consuming and expensive to design t he CWR process by trial and error method. The application of numerical simul ation for the CWR process will help engineers to efficiently improve the process development. Tselikov, Hayama, Jain and Kobayashi, and Higashimo applied the sl ip-line theory in study of CWR process analysis. Zb.pater studied CWR process i ncluding upsetting by upper-bound method. The above numerical simulation were b ased on the two-dimensional plain-strain assumption ignored the metal flow in workpiece axial direction. Therefore, the complex three-dimensional stress and deformation involved in CWR processes were not presented. Compared to other nume rical simulation methods, the finite element method (FEM) has advantages in solv ing general problems with complex shapes of the formed parts. As yet, a few 3-D finite element simulation studies on CWR process have been reported in literatu res. In this paper, the process of cross wedge rolling (CWR) has been simulated and analyzed by 3D rigid-plastic finite element method. Considering the charact eristic of CWR, the static implicit FEM program is selected. The models proposed in this study uses the commercial code DEFORM 3D to simulate the CWR process. T his is an implicit Lagrangian finite element code, which includes many new enhan cements functions. A new method of utilizing multiple processors using the MPI s tandard has been implemented. Automatic switching between the two different defo rmation solvers (Sparse Solver and Conjugate Gradient Solver) has also been impl emented in order to increase the speed of simulations. In this paper, all stages in CWR process are simulated to be able to closely understand and analyze the a ctual CWR process. For simulating all forming stages in CWR process, the dynam ic adaptive remeshing technology for tetrahedral solid elements was applied. T he stress distributions in cross section of forming workpiece are analyzed to in terpret fracture or rarefaction in the center of workpiece. Authors also analyze d the time-torque curve and the laws of load changing.