摆块弯曲模

图1所示零件材质为1Cr18Ni9Ti,厚0.5mm的冷轧带。该零件原先用两道工序成形;先用模具弯曲成图2形状,然后用样板手工弯曲成形。这种成形方法,零件质量差、精度低,劳动强度大,效率低。 现采用图3所示摆块弯曲模,经使用证明,效果很好,既保证了质量,又提高了工效。     

抛物面零件充液拉深工艺参数优化分析及成形装置改进

充液拉深是一种先进的板材成形方法.结合装饰零件的实际需求,通过数值模拟的方法对抛物面灯罩的充液拉深成形过程进行了研究,应用显式有限元分析软件DYNAFORM,分析了变压边力和液体介质压力对零件成形质量的影响,得到了变压边力和液体压力匹配的加载曲线.并对充液拉深成形系统进行了合理改造.分析结果表明,采用优化的变压边力和液...     

成形操作中伺服驱动技术用于优化模具和传输的优点

在固态金属成形中采用伺服驱动技术，可为成形工艺、模具技术和零件传输之间的最优化提供众多新的可能性。伺服驱动技术使得先前驱动方式相关的、固定的时间，行程运动曲线的调节成为可能。这样，对于模具脱开／辅助功能与零件传输的成形程序的循环，就可借助于对运动曲线的修正直接优化。结果表明，采用伺服驱动技术改善了零件质量，使工艺更加可靠，并提高了零件的生产率。     

板材充液拉深动态加载系统开发与应用

液室压力和压边力加载路径是充液拉深工艺中决定零件成形质量的关键工艺参数。针对传统被动加压方式加载路径单一,液室压力较低,不能满足复杂结构零件和高强度材料的成形要求,提出采用闭环控制技术实时调节液室压力和压边力的动态加载方式。设计可控压边和高压增压系统,并应用基于上、下位机的检测控制系统实时调节凸模速度、压边力和液室压力满足设定的工艺参数。在动态加载系统上进行异型结构不锈钢零件的充液拉深试验,动态加载路径下试验件一次整体成形,且表面质量好,贴模精度高。结果表明,充液拉深动态加载系统能够实现复杂加载轨迹和局部高压,适用于复杂结构和高强度材料零件的成形制造。     

计算机辅助薄壁管材卷边成形模具优化设计

本文从成形力的角度来辩识薄壁管圆角模卷边成形最佳参数,综合考虑成形各种影响因素,以成形力最小作为目标函数和成形失稳条件作为约束方程,在成形过程计算机模拟的基础上,提出模具计算机辅助优化设计方法。结果表明,应用经过优化设计的模具不仅使成形力最小,而且提高了零件质量,延长了模具寿命。     

锥形杆件加工模具设计

一般工厂加工如图1所示尖锥形杆,大多采用加热后锻打或在车床上加工成形,工效低,材料浪费大,如能采用成形模具加工,不仅能大大提高工效,节约材料,还能提高零件的质量。成形模具结构如图2所示。 当摸具转动到图示位置时,将工件推入型腔,     

测量环多个缺口冲裁模具的设计

分析了测量环的精冲成形工艺,其中关键工艺为零件圆周上8个缺口的精冲。阐明了多缺口精冲模具的结构及工作原理。实践证明,该多缺口精冲模具结构合理,能保证产品质量,提高生产效率。     

安装座的多工位级进模设计

在对安装座成形工艺分析的基础上,根据制件外形复杂、成形精度和生产要求要求高的特点,提出了该零件采用多工位级进模的冲压方案.详细分析了安装座零件的结构特点和冲压工艺性,重点阐述了排样设计.并通过比较两种排样设计方案,进行了安装座零件模具结构及级进模关键零件的设计,选用对角导柱式模架,并在工序排样中确定了成形侧刃定距方式,简化了模具结构.实践证明:该模具结构合理,对同类零件的级进模设计具有重要参考作用.     

聚氨酯胀形增补模具

<正> 图1所示的零件材料为A3,料厚为1.2mm。此零件以前是采用两半冲压成形后再焊接的工艺,因零件曲面多,焊接和打光都比较费时,效率很低,满足不了生产需要。后来我们改为先把板料卷成圆筒再焊接打光后采用聚氨酯橡胶模冲压成型。起先我们采用的模具结构是中间凸模为聚氨酯橡胶,两端采用钢凸模垫,在成形过程中,零件的中间部位成形比较好,但两端的喇叭口部位成形不好,没有达到尺寸要求。经分析,其主要原因是由于中间凸模体积小变形量不够所     

挤压成形技术在接插件端子模具设计中的应用

详细分析了接插件端子零件冷挤压成形工艺方案，拟定了接插件零件的工艺参数，采用冷挤压成形技术，完成了接插件冷挤压成型机的系统组成、模具结构及其关键技术等设计。采用冷挤压成形技术研制设计的DC型接插件端子自动挤压成形机，不仅能实现送料、成形、切断的连续自动完成，结构小巧、合理，大大提高了接插件的生产效率和材料利用率，降低了制造成本，保证了冷挤压接插件的成型质量，而且使接插件端子的硬度和强度得到加强。     

FMEA for the reliability of hydroformed flanged part for automotive application

Tube hydroforming technology is widely used in the automotive industries due to its advantages such as weight reduction, increased strength, improved quality, and reduced tooling cost compared to conventional manufacturing technology. The hydroformed parts often have to be structurally joined at some point. Therefore, the hydroformed automotive parts which have a localized attachment flange are useful. In many cases, the parts formed by hydroforming process are directly related with structural safety, reliability of hydroformed parts must be considered. In this study, hydroforming process of flanged rectangular parts was designed and process reliability was investigated. Finite element analysis was performed to optimize tool geometry considering process parameters such as die aspect ratio and pressure conditions with Dynaform 5.5. Hydroforming experiments to fabricate a flanged rectangular part were performed with optimized tool geometry. The relationship between process parameters and defect was analyzed by FMEA (failure modes and effects analysis). The result shows that process condition was optimized and reliability of rectangular part was increased.     

Development of automotive engine cradle by hydroforming process

The hydroforming technology may bring many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower springback, improved strength and durability and design flexibility. In this study, the whole process of front sub-frame parts development by tube hydroforming using steel material having tensile strength of 440 MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydroformability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive engine cradle by the hydroforming process were carefully investigated. Overall possibility of hydroformable engine cradle parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydroforming. At the die design stage, all the components of prototyping tool are designed and interference with the press is examined from the point of deformed geometry and local thinning.     

Optimization of loading path in hydroforming T-shape using fuzzy control algorithm

The loading path is crucial to the quality of forming parts in the process of tube hydroforming, and thus the design and optimization of loading path is an important issue for tube hydroforming. Wrinkling is a catastrophic defect for thin-walled tube hydroforming. In order to avoid wrinkling, an adaptive simulation approach integrated with a fuzzy control algorithm is used to optimize the loading path of hydroforming a T-shaped tube. The tubular material used is stainless steel and has an outer diameter of 103 mm and the wall thickness of 1.5 mm. The controlled variables are the axial feeding, the counterpunch displacement, and the internal pressure. A code is developed to make the optimization automatically, which works together with LS-DYNA. Six evaluation functions are adopted for identifying geometrical shape and quality of T-shape. Failure indicators obtained from the simulation results are used as the input of the fuzzy control, and then process parameters are adjusted according to the expert experiences in the fuzzy controller. In this way, a reasonable loading path for producing a sound T-shape is obtained, and also a T-shaped product is successfully hydroformed by experiment. The result shows that the fuzzy control algorithm can provide an adequately reliable loading path for hydroforming T-shaped tubes.     

Simulation of dissimilar tailor-welded tubular hydroforming processes using EAS-based solid finite elements

Developments in the numerical simulation of the hydroforming process of tubular metallic components, tailor-welded before forming, are presented. Both technologies, tailor-welded joining operations and hydroforming processes, are well known in industry, although most commonly separately used. Tailor-welded joining operations are usually encountered in plain sheets, subsequently formed by stamping. Tube hydroforming processing, on the other hand, is frequently associated with parts consisting of uniform thickness, material properties, and dimensions. The present analysis focuses on the influence of process parameters, such as the position of the weld-line and initial thickness values, in the innovative process of combining tailor-welded tubes (with distinct thickness values) and hydroforming. Particular attention is posed on the relation of imposed axial displacement vs. imposed hydraulic pressure into the tube, forming parameters that are not known a-priori in the manufacturing of a new part. Another point of practical interest is the numerical simulation of the weld-line movement, after forming is complete. The finite element method is directly employed in the numerical simulation by means of innovative solid elements suited for incompressibility applications, and included by the authors into the commercial program ABAQUS as user-elements. The obtained results can then lead to a better understanding, along with design tools, for the process of hydroforming of tailor-welded tubular parts, accounting for dissimilar thickness of the basic components.     

The effect of upper sheet on wrinkling and thickness distribution of formed sheet part using double-layer sheet hydroforming

In the hydroforming of curved sheet parts with a small thickness-diameter ratio, qualified parts are difficult to be manufactured when using the traditional hydroforming process. To solve this problem, double-layer sheet hydroforming was proposed and the wrinkle-free sheet parts were obtained in the authors’ previous study, but the inhibition mechanism of forming defects is far from perfection. Therefore, in this paper, the inhibition mechanism of forming defects is investigated by the combination of FE simulations and technological experiments. Different from the previous research, 2198 Al-Li alloy sheet was selected as the lower sheet. Other conditions such as heat treatment status and thickness are the same as before. The principle of wrinkle elimination can be concluded into the following two aspects. On the one hand, the upper sheet cannot be wrinkled during hydroforming, On the other hand, the surface blank holder pressure is applied in the suspending area. In addition, the beneficial friction between this two sheets changes the radial stress state of the lower sheet and makes the radial strain at some specific area (punch contact area and die corner area) decreased. In conclusion, qualified sheet parts can be manufactured by double-layer sheet hydroforming.     

Multi-objective optimization and sensitivity analysis of tube hydroforming

Tube hydroforming is a manufacturing process used to produce structural components in cars and trucks, and the success of this process largely depends on the careful control of parameters such as internal pressure and end-feed force. The objective of this work was to establish a methodology, and demonstrate its effectiveness, to determine the optimal process parameters for a tube hydroformed in a die with a square cross section. The Taguchi method was used to establish a design of virtual hydroforming experiments, and numerical simulations were carried out with the finite element code LS-DYNA®. A sensitivity analysis was also carried out with analysis of variance. Multi-objective functions that consider necking/fracture, wrinkling, and thinning were formulated, and the response surface methodology was used with the most sensitive factors to obtain a defect-free part. An objective function, based on the final corner radius in the part, was also included in the optimization model. The forming severity of virtual hydroformed parts was evaluated using the forming limit stress diagram and the forming limit (strain) diagram. Finally, the normal-boundary intersection method and the L ₂ norm were used to obtain the Pareto-optimal solution set and the optimal solution within this set, respectively. The hydroforming process for this part was also optimized using the commercial optimization software LS-OPT®, with two different single-objective algorithms. However, the optimum load path predicted with the proposed methodology was shown to achieve a smaller corner radius. The proposed optimization technique helped to define a process window that leads to a robust manufacturing process and improved part quality.     

基于Dynaform三通管液压成型分析

提出改进液压成型工艺,并通过Dynaform软件仿真及实际生产验证。该方法舍弃了通常管材液压成形中所需的超高压供给系统以及平衡冲头,进而大大降低设备费用。在验证工艺正确基础上,通过Dynaform软件仿真分析影响三通管液压成型因素。仿真模拟分析为模具设计方案和液压成形工艺方案设计提供了科学的依据,提高了设计效率。     

Study on the crushing and hydroforming processes of tubes in a trapezoid-sectional die

A study on the bulging processes of tubes in a trapezoid-sectional die has been carried out through finite-element (FE) analysis. A FE model of the single-step hydroforming process and several FE models of crushing combined with subsequent hydroforming processes in a trapezoid-sectional die with different die closing seams are proposed. The simulations are performed using the FE code LS-DYNA. For the single-step hydroforming process, the effects of loading paths on the formability of the trapezoid-sectional part are investigated. In the case of the crushing combined with subsequent hydroforming processes, the effects of die closing seams, tube diameters, and preforming loading paths on the forming process and the final parts are analyzed. A comparison between the parts formed through single-step hydroforming process and through crushing combined with subsequent hydroforming processes is performed. Finally, an experiment of tube hydroforming in a trapezoid-sectional die is carried out on the hydroforming machine developed by Shanghai Jiaotong University. The simulation results show good agreement with the experimental results.     

航空铝合金复杂构件充液柔性成形过程及质量控制研究

针对某型号飞机铝合金复杂构件充液成形的失效形式,采用有限元数值模拟和试验的手段,研究了毛坯形状、液室压力等关键工艺参数对成形失效的影响,给出了铝合金复杂构件充液成形质量控制的措施,为此类型航空复杂构件的充液成形提供了技术指导。     

汽车制动器外壳液压深拉成形的数值模拟

液压成形能显著降低成本和提高制件质量,在汽车制造领域中将广泛采用。文中用Dynaform有限元仿真软件对汽车制动器外壳液压深拉成形过程进行了模拟,分析了压边力、液体压力、毛坯形状、压边间间隙对制动器外壳件成形质量的影响。研究结果表明,合适的压边力、液体压力、毛坯形状、压边间间隙能控制制动器外壳件拉深缺陷的发生,可获得好的壁厚分布,能实现一次成形成功的成形区域,为今后此类型的制动器外壳件液压成形生产提供了技术指导。