模锻件的无毛刺冲连皮

将负间隙无毛刺冲裁工艺应用于带孔模锻件,可获得无毛刺冲连皮剪口,极大地增加了冲裁断面光洁剪切带的长度,这不仅省去了清理毛刺的附加工序,而且还提高了模锻件的质量,具有明显的经济和技术效益。     

曲轴锻件的生产与模锻线设计

以曲轴锻件为主 ,介绍了在模锻线设计、制造和锻件生产中需考虑的有关问题、国内外情况和资料。可供发展我国汽车工业的曲轴锻件生产参考。     

Superplastic process modeling of plane strain components with complex shapes

Computational process models using membrane element method are developed in this paper for the superplastic forming of plane strain boxes with complex cross-sectional details. Many practical superplastic components manufactured in industry have sloping sidewalk with die bottoms either corrugated and/or at angles to the sides. The new method is used to develop process models for such configurations and the resulting software can be used interactively in a computer. The method is useful to a designer in the parametric study of die geometry, die wall friction, initial thickness, and material property, or to determine if a specific geometry is suitable for superplastic forming. The kinematics of deformation are illustrated, and the numerical results of the model are compared with continuum finite element solutions and also with experimental data.     

基于灵敏度分析的预锻模具形状优化设计

以最终锻件的形状为目标,采用塑性有限元、灵敏度分析和工程优化算法相结合的方法,对预锻模具形状进行了设计。针对下模速度为零时,下查形状不能优化有的情况,提出了一种处理速度灵敏度边界条件的方法,该方法可同时对上下模具形状进行优化。针对程度耗时较问题,提出了贮存灵敏度刚度矩阵,减少优化设计变量的方法,大大提高了程序的运行速度。最后,给出了优化设计实例,验证了该方法的可靠性。     

基于中间构形的级进模条料分步展开算法研究

级进模条料设计过程中的主要难点在于中间构形的设计。针对级进模成形以弯曲变形为主的特点,提出了一种基于旋转变形的中间构形快速生成算法,该算法通过设置最终构形的旋转轴、固定区、变形区、非变形区、固定约束、形状约束、等长线以及旋转角度等求解条件,通过曲面网格快速求解出中间构形,并以生成的中间构形网格作为参考构形,采用有限元逆算法,将最终构形展开到中间构形上以精确地获取中间构形的修边线。介绍了中间构形生成算法的实现流程,并在SolidWorks平台下采用二次开发技术,开发了一套完全无缝集成的级进模条料分步展开系统SW-CUX。以复杂连续折弯件的中间构形设计为例验证了该算法的可行性。     

Simulating convective die heating for forgings and pressure casting

A comparison is made of die temperature uniformity for two heating configurations: electric air heating and flame heating. The temperature uniformity with electric air heating is noted to be substantially superior to flame heating of large dies. The simulation results are compared with experimentally obtained numbers and found to be in agreement.     

模具形状设计优化新方法-无网格方法

简要介绍了无网格方法，给出了一种常用的无网格方法——重构核粒子法形函数的表达形式；对基于无网格方法的有限变形弹塑性体的设计灵敏度分析和摩擦接触问题的模具设计灵敏度分析加以论述。     

A practical computer-aided approach to mould design for axisymmetric forging die cavities

This paper reviews existing guidelines for the design of mould impressions and discusses previous computer-aided approaches. A critical assessment shows these proposals to be inadequate for design by numerical methods and two new mould design rules are suggested. These are implemented in a computer program based on a Tektronix 4052 microcomputer and designs obtained from the computer are compared with those obtained by previous methods and also shapes collected from industry. Built inside the program are interactive routines which enable the user to modify the designs produced by the program alone, if they are not suitable for a particular purpose.     

A study on die wear model of warm and hot forgings

Factors influencing service lives of tools in warm and hot forging processes are wear, mechanical fatigue, plastic deformation and thermal fatigue, etc. Wear is the predominant factor for tool failure among these. To predict tool life by wear, Archard’s model where hardness is considered as constant or function of temperature is generally applied. Usually hardness of die is a function of not only temperature but operating time of die. To consider softening of die by repeated operation it is necessary to express hardness of die by a function of temperature and time. In this study wear coefficients were measured for various temperatures and heat treatment for H13 tool steel. Also by experiment of reheating of die, die softening curves were obtained. From experimental results, relationships between tempering parameters and hardness were established to investigate effects of hardness decrease by the effect of temperatures and time. Finally modified Archard’s wear model in which hardness is considered to be a function of main tempering curve was proposed. And finite element analyses were conducted by adopting suggested wear model. By comparisons of simulations and real profiles of worn die, proposed wear model was verified.     

A die forging design approach for controlling metal flow way and its application in practice

In this paper a novel idea about die forging process design in relation to metal flow is presented. The purpose is to almost completely fill a die cavity before flash starts to form. The paper shows that preform design is the way to realize this situation. The paper describes a method in which metal flow is simulated using UBET in reverse sequence to that occurring in practice. The successful application of the method in production is shown.     

An innovative extrusion die layout design approach for single-hole dies

To avoid distortion of complex extrudate profiles, it is essential that the exit velocity of the metal is uniform. The most important design parameter that controls the exit velocity is bearing length. However, this factor is not sufficient to achieve optimal design settings. This paper proposes an innovative layout design approach using a geometry based bearing length design methodology to minimise variations in exit velocity. This paper focuses on single hole extrusion dies and develops an optimisation algorithm suitable for any die profile. Since the optimised die design produces less bearing length difference, more uniform exit velocity and higher design quality would be achieved using the proposed approach.     

铝合金模锻件粗晶缺陷浅析

从锻件的材质、锻造工艺参数、锻模温度、热处理工艺参数四个方面,阐述了铝合金模锻件粗晶缺陷的产生原因及消除措施。     

A simple approach to plane strain extrusion with dead metal zone using upper-bound theorem

This paper treats the upper-bound approach to the problem of rigid-plastic deformation in case where the configuration of the deformation zone is previously unknown. The plane strain forward extrusion process with the so-called dead metal zone is analysed by assuming a simple velocity field. The calculations are carried out for the material with or without strain hardening or strain rate sensitivity and for various reduction ratios. The numerical results show that the region of the dead metal zone becomes smaller with the increase in the reduction ratio. The calculated punch forces agree with the experimental ones fairly well. Furthermore, it is found that the dead metal zone becomes larger with increasing the strain hardening as well as the strain rate sensitivity of the material.     

扳手切边模具设计

分析了某扳手零件的成形工艺特点,制定了冲压成形工艺方案,设计了一套切边模去除零件成形后的工艺余料,解决了钳工手工修边所带来的诸多问题,并介绍了切边模模具结构及设计要点。结果表明：该模具结构简单实用,提高了工作效率及零件质量。     

圆筒复合模设计

对圆筒复合模进行了研究和设计,介绍了圆筒复合模加工工艺由落料、拉深、反拉深和切边4道工序复合而成。详细分析了带凸缘圆筒零件加工的工艺性和模具的结构。通过对模具结构的分析,在模具中提出了反拉深和凸缘切边工艺,实现了落料、拉深、反拉深和切边4道工序的复合,使得复合模在加工中取得了成功。     

PA 66中空异型材挤出模设计

通过对异型材截面形状及原材料挤出成型性能分析,设计了正确的口模形状及合理的流线形流道;针对25%玻璃纤维增强的PA66原材料,模具设计了塑化、分流性能较强的滤网式装置,模具结构紧凑合理、易于装配,能够生产出符合尺寸精度要求的型材。     

离心铸管机管模锻件拔长成形工艺研究

管模锻件属薄壁长套类锻件,存在长度长、壁薄、锻造难度大的问题,提出采用多次分段成形法,实现了利用短芯轴生产超长管模锻件的设想,结合计算机模拟技术对管模拔长过程进行分析,确定了合理的拔长工艺参数。经实际生产证明,以上方法切实有效,成功锻造出了合格的管模锻件,提高锻件的拔长效率。     

锥面锁紧两半凹模双侧枝件闭式挤压模设计

因双侧枝件的形状所致,采用传统的整体凹模结构不能实现无飞边模锻,给出了双侧枝件闭式挤压模结构,该模具纵向对合凹模依靠锥面锁紧。锻件在两半凹模和凸模形成的封闭模腔中挤压成形,生产的锻件无飞边。     

协同设计技术及其在模具设计中的应用探讨

CSCW理念为设计领域带来了全新的设计模式--协同设计.本文在分析了协同设计领域中的信息共享、信息同步和冲突消解3个核心问题及其研究成果之后,分析了模具行业的特点,提出了模具协同设计系统应该重点研究解决的三个关键技术任务管理、群体感知和知识融合,并探讨了相应的实现方法.