整体壁板成形评述

介绍了整体壁板的概念和分类,总结了传统和现代的整体壁板成形工艺方法,如滚弯成形,增量压弯成形,蠕变时效成形,喷丸成形和激光弯曲成形,比较了它们之间的优、缺点及适应范围,简述了各成形工艺目前的应用状态及发展前景.提出针对不同外形形状和筋条高度的整体壁板的成形,可以采用不同的成形方法,必要时还可将几种成形方法进行复合.     

面向CIMS/ERP的塑性成形生产过程控制

根据塑性成形企业生产过程的特点，提出了一种面向CIMS／ERP的塑性成形生产过程控制系统，介绍了各子系统的相互关系及作用，构建了生产自动监控系统以及质量信息监控系统的理论模型和控制结构，并对其进行了详细论述。在此基础上，建立了整体壁板自适应增量成形生产自动监控系统和铜管加工过程质量控制系统，并在现场进行了实际应用。     

等离子电弧加热弯曲精确成形试验

为了实现等离子电弧加热的精确弯曲成形,采用等离子电弧沿直线对1Cr18Ni9Ti不锈钢板材进行加热弯曲成形试验,并用CMOS1303uc数字相机等硬件和相关软件在等离子电弧加热弯曲成形的过程中对弯曲角度进行实时检测,实现了对成形过程的闭环控制。试验结果表明:当扫描次数较少时,板材弯曲角度随扫描次数增加近似呈线性增大;当扫描次数较多时,由于增厚效应的影响,单次扫描弯曲角度的增量会不断减小,弯曲效率明显降低。为了确保加工过程的可靠性并提高成形效率,根据加工余量的不同将成形过程分为粗、中、精三个加工阶段,各个阶段分别采用不同的工艺参数进行加工,通过弯曲角度分别为20°和30°的不锈钢薄板的成形试验验证了该方法的有效性。     

虚拟快速原型系统的构建与实现

基于Java和VRML,建立了虚拟快速原型系统.该系统能够实现成形仿真和成形过程评估,为用户选择合理的加工参数提供依据.将其反馈结果直接用于改进成形方案和优化工艺参数,从而提高制件质量,缩短试制时间,降低制作成本,并将制件的虚拟原型以VRML格式输出,实现用户间的有效交流.     

飞机壁板展开件CATIA建模技巧研究

CATIAV5是目前飞机制造业中常用的软件,飞机整体壁板的加工首先需要对其展开外形建立三维模型,再进行数控铣削,最后弯曲成形。为了提高飞机壁板展开建模的准确性和效率,研究了应用CATIAV5软件对飞机整体壁板展开外形进行建模的基本方法,通过一个工程实例简单阐述了建立飞机壁板零件数字化模型的具体流程及操作步骤,总结了建模过程中常见问题的处理技巧.实践证明,应用这些方法与技巧对于提升飞机壁板展开件的建模效率、缩短设计加工周期．具有一定的现实意义。     

航天器复杂整体壁板加工精度控制

在分析复杂整体壁板制造工艺的基础上,提出一种准确计算复杂整体壁板中性层位置的工程方法,实现了复杂壁板的近似展开以得到较为准确的壁板工艺展开模型;同时通过增加蠕变时效定形以及修正壁板接口精度等工艺措施,大幅度提高了壁板上设备接口的加工精度,实现了复杂整体壁板类工件的高精度加工。     

管材激光成形的工艺参数优化

建立了管材激光弯曲成形工艺优化模型,采用优化软件iSIGHT与有限元模拟软件MSC.Marc相结合,对管材激光弯曲成形工艺参数进行优化,得到成形一定角度并高效成形的最佳工艺参数组合。     

5/12钢筋靠模式弯箍机构设计与参数计算

为有效提高钢筋自动弯曲成形精度和效率,引入靠模成型设计方法,提出了一种新型的箍筋模钢筋弯箍设计方案.基于弹塑性变形理论,建立了钢筋弯曲过程中弯箍转盘转角与钢筋弯曲成形角度之间的数模方程,推导了钢筋弯曲过程中弯曲力以及弯箍转盘的转矩和功率与钢筋弯曲角度的函数关系式,并详细分析了它们随弯曲角度的变化规律,较为详细的研究分析了系统的各个参数,提出了确定各系统参数的方法.结果表明,该机构设计合理,满足使用要求,便于实现自动控制.     

先进复合材料整体壁板RFI成型工艺探讨

复合材料加筋整体壁板是航空复合材料零组部件的一种典型结构,其成型工艺有多种。针对该类整体壁板结构特点,探讨了一种在先进大型飞机上已经取得成功应用的先进复合材料的整体壁板低成本制造技术—RF(I树脂膜渗透成形)工艺。根据此方案制造的整体壁板结构整体性较好,同时成型工艺性好,模具设计与制造方便,制造成本低的特点。     

铝合金交叉筋壁板激光多道扫描成形研究

本文利用激光诱导热成形技术对5A06铝合金交叉筋壁板进行圆柱面弯曲成型的过程中,根据交叉筋分布位置,对边缘区、筋部及网格区扫描时壁板的多道扫描变形进行实验研究,讨论扫描方式对壁板成形的影响。针对多道扫描过程中非期望变形的累积效应,提出一种扫描纵向加强筋的方法来减小自由端的纵向弯曲程度,并对交叉筋壁板圆柱面弯曲成型的多道扫描流程和扫描策略进行规划,通过成形试验检验策略的有效性。     

Investigation of the dynamic bending moment transmitted to the forging manipulator due to press motion

The bending moment transmitted to the forging manipulator due to press motion during metal forming process is investigated. The dynamic model of the forging manipulator system is established, including the manipulator and the workpiece by using Lagrange equation. The system is modeled as an Euler-Bernoulli beam with spring-mass at the sliding end, which experiences a transient vibration due to displacement excitation. The Winkler foundation model is used to simulate the rotational constraint of the forging dies on the workpiece because of the surface contact. The numerical results are compared with the LS-DYNA simulations, and a good prediction on the bending moment could be obtained with the comparatively simple proposed model. The results indicate that the press position where the forging dies work along the workpiece plays a crucial role for the dynamic bending moment. To further investigate the dynamic effects due to the press motion, the influence of clamp mass of the manipulator is also examined.     

金属线材折弯虚拟仿真系统的设计与实现

针对金属线材产品种类多、结构复杂度高、加工过程动作多且易发生碰撞干涉等特点,研究金属线材产品建模和仿真加工技术,实现线材产品的加工仿真,以检查产品设计和机床加工动作的合理性,优化加工工艺。分析了折弯机械的运动控制和折弯工艺,推导出产品建模参数与样机运动参数的数学关系式。基于OpenGL API,使用分段建模的方法实现线材产品参数化三维建模;使用“嵌套矩阵法”和运动控制函数实现线材的加工仿真。虚拟仿真系统由产品建模模块和仿真加工模块组成,前者用于产品建模和三维模型显示,后者用于加工轨迹规划和加工动画演示。实验表明,仿真系统可以实现金属线材产品在线设计和加工工艺优化,能够加快产品设计和试加工过程。     

Experimental analysis of coating layer behavior of Al–Si-coated boron steel in a hot bending process for IT applications

The utilization of high-strength steel for automotive structural parts has increased since the oil crisis in the 1970s owing to its high strength and potential for weight reduction. Because of the limited formability of high-strength steels, automotive components are increasingly produced through hot press forming. In some instances, high-strength steel sheets are coated with an Al–Si layer in order to prevent scaling of components during hot press forming, and this can increase their reliability with a view to the dimensional accuracy and stress distribution when they are in service. In this contribution, the coating degradation mechanisms of Al–Si-coated boron steel after the hot bending process are reported. The issues related to coating degradation during hot press forming are critically reviewed at different positions on a part that was subject to hot bending. In addition, the hardness and friction coefficient were tested by a nano-indenter at various positions. The relationship between the experimental parameters and coating layer properties is also reported. It is concluded that the bending deformation affected the coating layer behavior the most.     

铁路货车轮对压装质量评价指标及保障方法研究

为了提高铁路货车轮轴压装质量,对压装质量的既有保障方法进行了研究。在综合考虑国内外各种标准的基础上,提出并分析了压装质量的4项评价指标,研究了国内外铁路标准与这4项指标相对应的保障方法。通过仿真,揭示了工艺参数对压装质量的影响规律。研究结果有利于构建新的压装质量保障体系,进一步提高轮轴压装质量。     

旋压件的成形质量及其控制参数

本文着重讨论了旋压件成形质量的影响因素,工艺选择以及控制方法。研究结果表明,为了得到质量良好的旋压件,除了要控制好减薄率、主轴转速、芯模和旋轮之间的间隙,迸给比、旋轮安装角、旋轮圆角半径等关键参数外,还必须要注意旋压湿度、毛坯厚度、旋压道次与热处理等问题。     

电液驱动绳钩成型过程动态模拟及参数匹配分析

绳钩用于集装箱中内部固定，其加工过程需2次折弯、1次加热及锻压等5个工序；目前绳钩制造仍采用人工方法，生产效率低，工作环境恶劣且劳动强度大。为此，设计了一种高精度电液折弯锻压绳钩加工机床，其折弯、锻压工艺由4个液压缸执行。基于显示动力学方法，考虑不同温度场的影响，研究了绳钩加工过程中不同工位折弯力和锻压力随时间的变化规律，并结合液压泵站工作压力，合理选用不同工位液压缸参数。经优化后的机床单件加工周期缩短至8 s,较传统人工加工方法节省时间90%。对优化绳钩加工机床的工艺节拍和提升机床生产效率具有工程指导意义。     

Numerical simulation and experimental investigation to improve the dimensional accuracy in electric hot incremental forming of Ti–6Al–4V titanium sheet

Electric hot incremental forming is feasible and easy to control to form hard-to-form sheet metals, but the limited accuracy is a major deficiency. In order to find methods to improve precision, single-point electric hot incremental of Ti–6Al–4V titanium sheet was numerically simulated using MSC.Marc, and experimental investigations were also carried out in this paper. Through numerical analysis, distributing laws of temperature, thermal strain, stress, and equivalent strain were revealed, and impacts of cold contract and thermal strain on forming were also revealed. Analysis showed that electric hot incremental forming is a complex pyroplastic deformation, and there is a large internal stress in single-point electric hot incremental forming. The incremental sheet forming region can be divided into three parts: bending deformation at the beginning, shear forming at middle, and reverse bending at last; it is important to enhance the accuracy of the bending part and the reverse bending part, and adequate support must be provided in the beginning to reduce the bending part. In order to form a workpiece with small angle, two-point incremental forming was adopted at first because the gravity of clamp can reduce the reverse bending, then single-point electric hot incremental forming was adopted to enhance the accuracy and reduce internal stress of workpiece.     

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.     

Al2O3陶瓷薄片CO2连续激光弯曲试验研究

脆性材料的激光弯曲成形技术是激光快速成形技术的重要应用,有着广阔的应用前景。本文通过改变激光功率、扫描速度等工艺参数,利用CO2连续激光对氧化铝陶瓷薄片进行弯曲试验,同时引入线能量密度来寻求适合弯曲的最佳工艺参数,并结合氧化铝陶瓷的高温性能分析了其激光弯曲特点。试验结果表明：采用CO2连续激光可以对氧化铝陶瓷薄片进行弯曲,弯曲角度可达2°;氧化铝陶瓷的激光弯曲过程具有强烈的温度敏感性,当试样表面温度大于临界温度时,弯曲角度迅速增加;适合弯曲的最佳线能量密度范围为17～24 J/mm 。     

基于数控渐进成形技术的车身装饰件成形工艺

基于数控渐进成形技术进行板科成形工艺研究,提出完整的渐进成形工艺规划,并将其成功应用于车身装饰件成形.对影响成形的主要参数成形工具头直径d和每层进给量△h进行了分析.为今后完善和发展金属板料数控渐进成形技术起到重要作用.