齿形无声链链板复合冲裁

对齿形无声链链板外形加工的工艺方法进行分析,介绍一种用冲裁拉削模、可在普通压力机上对链板进行复合冲裁的工艺方法,对冲裁拉削复合模拉削凹模的设计制造进行阐述,实验验证采用这种加工方法所获得的工件质量高、成本低.     

蒙皮拉形机快速换模系统力学安全性分析

拉伸成形是飞机钣金的基本成形方法。由于飞机蒙皮种类繁琐、生产批量小,在拉形的过程中需要频繁的更换模具,而现有国内蒙皮拉形机换模仍为传统换模方式,换模时间长,换模过程繁琐。针对这一情况,研发出了一套蒙皮拉形机快速换模系统,能从根本上提高蒙皮拉形机的换模效率,进而提高蒙皮拉形机的生产效率。采用有限元方法,对所提出的蒙皮拉形机快速换模系统进行力学安全性分析,研究了该系统内部重要零部件在极限工况下的应力分布,对整个换模系统的完善与再优化具有重要的意义。分析结果显示:该蒙皮拉形机快速换系统是结构安全的。     

齿形无声链链板的加工

对齿形无声链链板外形加工的工艺方法进行了分析,介绍了一种用冲裁拉削模、可在普通压力机上对链板进行复合冲裁的加工方法,对这种冲裁拉削复合模的拉削模的设计制造进行了阐述,实验验证了采用这种加工方法所获工件质量高、成本低。     

大直径锥形折边封头制造工艺

本文阐述了广泛应用于化工、食品行业的液态物料常压贮罐的大直径(φ1000～φ1000mm)锥形折边封头制造工艺,此工艺中在应用不锈钢板表面保护、焊缝压磨两项新工艺的同时,采用了拉形和旋压技术。文中介绍了新型工艺专机——锥形封头拉形机。应用实践表明,此工艺较惯例的制造工艺提高了锥形折边封头的制造质量和工效。     

快速装夹冲模通用模柄

对于批量小而品种多的冲压件生产,可根据冲床的情况,制造一种或几种规格的通用模柄,然后按零件情况制出凸、凹模。对一般冲孔、落料、弯曲、简单的拉深、校形等,均可采用此种方法。 下面介绍一种快速裝夹冲模的通用模柄,结构     

高强度石膏仿形模

仿形模是汽车缸盖件模具加工中不可缺少的工艺手段和重要的加工基准,它直接影响模具的加工质量和生产周期。因此,仿形模的制作是汽车复盖件模具制造的关键。 传统的制作仿形模是采用环氧树脂作为面型材料,环氧树脂制模工艺存在制作成本高、生产周期长、操作复杂、模型表面精度低等缺点。而石膏     

U形件通过凹模圆角时不产生表面塑性压痕的方法研究

分析了U形件变形时板料通过凹模圆角的变形机理,通过设计一套实验设备来获得压痕,最后按照实验分析结果来进行弯曲凸模和凹模镶块的设计与制造,给出了详细的设计和制造工艺流程。     

可重构柔性多点模具蒙皮拉形工艺设计系统

针对可重构柔性多点模具蒙皮数字化拉形中的钉柱高度计算和工艺设计问题,开发了可重构柔性多点模具蒙皮拉形工艺设计系统.给出了系统的功能模块和体系结构,研究了曲面空间定位、模面补充、钉柱调形高度计算、毛料尺寸及拉形轨迹计算等关键技术和相关算法.在CATIA环境下,采用组件应用架构二次开发技术,实现了系统的开发.通过对实际蒙皮零件的分析和计算,验证了系统的实用性和有效性.     

飞机蒙皮拉形模拓扑优化设计

将拓扑优化技术应用于大型飞机蒙皮拉形模的轻量化问题,可以解决传统拉形模设计中刚度与重量之间的矛盾。应用ABAQUS软件进行蒙皮拉形的非线性数值模拟,可以获取拉形模工作面的载荷数据。根据载荷数据选取的典型工况及给定的材料属性、约束条件等进行拓扑优化,将得到的拓扑优化结果进行模型重构,再对重构后的模型进行蒙皮拉形仿真,以验证模具的各项设计指标是否符合要求。以某型拉形模为例进行拓扑优化,并与传统设计的模具相比较,结果证明在同体分比的情况下,拓扑优化设计显著减小了模具的最大变形值和应力值。     

飞机蒙皮数字化制造技术应用研究

随着科学技术的迅猛发展,以数字化为核心的制造技术给航空工业带来了史无前例的变革和飞跃。在飞机蒙皮制造领域,逐步形成了以数字量传递为核心,基于可重构柔性多点模具的蒙皮数控拉形技术、基于离线测量闭环形状控制的柔性模具数控拉形工艺优化技术以及可重构柔性夹持数控切边技术的飞机蒙皮数字化制造技术体系,成功实现了从蒙皮零件三维数模设计、工艺仿真和优化、数控成形、数字化检测到最终零件的柔性化、数字化和精确化制造。     

Development of an automated progressive design system with multiple processes (piercing, bending, and deep drawing) for manufacturing products

This paper describes the research work involved in developing an automated progressive design system with multiple processes such as piercing, bending, and deep drawing for manufacturing products. This approach to make a progressive, flexible working system is based on knowledge-based rules. The knowledge required for this system is formulated from plasticity theories, experimental results, and the empirical knowledge of field experts. The system consists of three main modules: shape treatment, strip layout, and die layout modules. The system is founded on knowledge-based rules and is designed in consideration of several factors, such as the material and thickness of a product, the piercing, bending and deep drawing sequence, and the complexities of blank geometry and punch profiles. The system then generates the strip layout drawing for an automobile product. The die layout module carries out the die design for each process from the results of the strip layout module. The results obtained using the modules enable the designers of manufacturing products with multiple processes to be more efficient in this field.     

房车转向节整体模锻关键技术与模具装置研发

房车转向节轮廊尺寸大、结构极其复杂,目前采用的分体制造技术存在材料利用率和生产效率低、产品性能差的问题。为此,提出了转向节整体模锻成形的工艺方案,着重研究了其关键工序弯曲成形的工艺优化并进行了专用模具装置开发。采用经典塑性成形理论、有限元数值模拟和试验相结合的方法,分析了弯曲过程的应力应变状态、金属流动和损伤分布。工艺试验结果表明,所提出方案合理,实现了以整体模锻取代分体制造,材料利用率由约45%提高至70%以上,生产效率提高4~5倍。     

考虑弯曲回弹的拉弯模外形设计方法

拉弯是型材弯曲成形的重要方法,可以有效减少回弹、提高成形精度,在飞机、汽车弯曲件成形中得到广泛应用。采用弯曲回弹理论分析,结合拉弯零件数字化模型,修正拉弯模模具轮廓;采用圆弧样条表示模具轮廓,给出了拉弯模合理外形的计算方法。在理论分析基础上,通过有限元分析方法计算拉弯型材的回弹量,评估拉弯模型面的回弹修正量及拉弯件校形余量的减少情况。为提高汽车和飞机拉弯件的质量和促进工装的数字化设计提供了合理有效的方法。     

弯曲模结构设计中减小回弹的技巧

如何减小弯曲件的回弹，以控制制件精度，提高制件质量，一直是弯曲件生产中要解决的关键问题。从弯曲模结构设计角度，阐述了生产中常用减小回弹的方法和技巧。     

Sheet metal bending optimisation using response surface method, numerical simulation and design of experiments

Bending is one of the processes frequently applied during manufacturing of automotive safety parts that are obtained by successive sequences of blanking and bending. This paper describes a 3D finite element model used for the prediction of punch load and the stress distribution during the wiping-die bending process. The numerical simulation has been modelled by means of elastic plastic theory coupled with Lemaître's damage approach. Numerical simulations were carried out by using the ABAQUS/Standard FE code, for a sufficient number of process parameters combinations, particularly the die radius and the gap between the punch and die. An algorithmic loop, programmed in the Script Language of ABAQUS, was developed in order to investigate the mechanical response of parts bent on a mechanical press for each combination of process parameters. The punch load and stress distribution can be predicted in view of optimising the values of the main parameters involved in the process. Finally, a response surface methodology (RSM) based on design of experiments (DOE) was used in order to minimise the maximum punch load during the bending operation. Numerical results showed the suitability of the proposed model for analysing the bending process. Associated plots are shown to be very efficient for a quick choice of the optimum values of the bending process parameters.     

导管数字化制造集成框架研究

针对传统经验弯管无法满足航天技术日益提高的需求问题,研究导管数字化制造技术。在分析导管数字化制造需求分析的基础上,建立了导管数字化制造集成系统功能结构与集成框架,并研究了基于知识的工艺性分析、基于数值建模与仿真的质量预测以及弯管过程快速仿真建模技术等关键技术。根据该集成框架,开发了基于导管弯曲工艺库且集导管工艺设计、质量预测及加工过程仿真等功能于一体的导管数字化制造系统,该系统已经应用于某航天部门多个型号产品上,效果明显。     

内撑板件多工位级进模设计

分析了内撑板件的冲裁、弯曲生产工艺,介绍了其特殊级进模总体结构。为保证孔同轴度,采用提高导正销送进精度的方法解决。下模卸料结构,采用在弯曲凹模板上设置托块,相当于套式浮顶器,起浮顶托料的作用。论证了其排样方案选择的正确性,制件的冲裁工序采用分步进行,降低了复杂凸模制造难度,提高了模具寿命。采用侧刃加导正销形式定位,精度较高。采用双侧载体连接桥方式连接,稳定性好。采用补偿法达到了控制制件弯曲回弹的目的。实践证明:该模具结构详细、清晰、可靠,加工质量好,生产效率高,对此类零件的级进模设计有重要参考价值。     

新型汽车玻璃滑槽拉弯成形工艺

针对汽车玻璃滑槽的拉弯成形工艺,设计开发了一种基于张臂式拉弯机上安装的一次拉弯工装和非标二次拉弯设备相结合的新型加工工艺。该工艺通过二次拉弯工序,利用机械、电气和液压相结合的控制技术,实现了汽车玻璃滑槽的拉弯成形工艺。采用该工艺来加工汽车玻璃滑槽,具有调试简单和产品状态稳定等优点。     

Comparison between three optimization methods for the minimization of maximum bending load and springback in wiping die bending obtained by an experimental approach

The sheet metal bending process is widely used in the automotive industries, and it is actually one of the most important manufacturing processes. The robustness and the reliability of the bending operation, like many other forming operations, depend of several parameters (geometry, material, and process). In this paper, the die radius and the clearance between the punch and the sheet are optimised in order to reduce the maximum bending load and the springback. Two optimization problems are formulated, and three optimization procedures based on the response surface method are proposed and used to find the optimum solutions. Global and local approximations are used to replace the initial optimization problem, which is implicit by an explicit problem, and the optimum is localised using two algorithms: a sequential quadratic programming and an evolution strategies. The objective functions are evaluated experimentally into a limited points number, which are defined using a design of experiments technique. Good results are obtained from the three optimization procedures. The ability of each technique to find the optimal solution is evaluated, and the results show a good agreement between those three methods.     

Sectional finite element analysis of forming processes for aluminum-alloy sheet metals

The sectional finite element analysis of the forming processes for the aluminum-alloy sheet metal known to be planar anisotropic was performed. The two-dimensional rigid-viscoplastic FEM formulation based on the bending augmented membrane theory as well as the anisotropic yield criteria was introduced. For modeling the anomalous behavior of aluminum-alloy sheet metals, Barlat's strain rate potential and Hill's (Journal of the Mechanics and Physics of Solids 1990;38:405–17) non-quadratic yield theory with an isotropic hardening rule were employed. Furthermore, a new method to determine anisotropic coefficients of Barlat's strain rate potential was proposed. For evaluating bending effects in the forming process of aluminum-alloy sheet metals, the bending equivalent forces were calculated in terms of the changes in the interior angle at a node between two linear finite elements and were augmented to the membrane stretch forces. In order to verify the validity of sectional finite element formulation based on the bending augmented membrane theory, the plane strain stretch/draw forming processes of a square cup test were simulated and simulation results are compared with experimental measurements. Friction coefficient was obtained from drawbead friction test. The properties of selected material were obtained from uniaxial tensile tests. Simulation shows good agreement with measurements. For the application of the sectional finite element formulation introduced in this research, the drawing process of a rear seat back upper bracket of passenger cars is simulated assuming plane strain condition. The thinning distribution of the simulation agreed well with that of the measurement, so that the sectional analysis is acceptable in the design and analysis of aluminum-alloy sheet stamping dies.