Material Flow Control and Optimization in High‐Pressure Sheet Metal Forming by Active‐Elastic Tools

High‐pressure forming of metal sheets is an innovative forming technology for the production of complex components and offers high potentials to improve the properties and qualities of sheet metal parts. This report describes investigations of a newly developed active‐elastic tool system referred to as ACTEC system. Unlike the use of a comparable semi‐rigid tool system, the ACTEC system shows improvements with respect to the material flow in the flange area and reduced sheet thinning in critical corner regions of the workpiece. In addition, the clamping forces respectively sealing forces necessary to avoid leakage in the tool system during the forming process can be reduced. Moreover, the specific design of the ACTEC‐system as well as current experimental examinations are presented and discussed.     

Development of a Robot‐Based Sheet Metal Forming Process

This paper describes a new sheet metal forming process for the production of sheet components for prototypes and small lot sizes. The generation of the shape is based on kinematics and is implemented by means of a new forming machine consisting of two industrial robots. Compared to conventional sheet metal forming machines, this newly developed forming process offers a high geometrical form flexibility, and comparatively small deformation forces enable high deformation degrees. The principle of the procedure is based on flexible shaping by means of a freely programmable path‐synchronous movement of the two robots. The final shape is produced by the incremental infeed of the forming tool in depth direction and its movement along the contour in lateral direction at each level of the depth direction. The supporting tool with its simple geometry is used to support the sheet metal and follows the forming tool at the rear side of the sheet metal. The sheet metal components manufactured in first attempts are of simple geometry like frustum and frustum of pyramids as well as spherical cups. Among other things the forming results are improved by an adjustment of the movement strategy, a variation of individual process parameters and geometric modifications of the tools. In addition to a measurement of the form deviations of the sheet with a Coordinate Measurement Machine, screened and deformed sheets are used for deformation analyses. Furthermore, the incremental forming process is analysed with assistance of the finite element method. In total the results show that a robot‐based sheet metal forming with kinematic shape generation is possible and leads to acceptable forming results. In order to be able to use the potential of this process, a goal‐oriented process design is as necessary as specific process knowledge. In order to achieve process stability and safety, the essential process parameters and the process boundaries have to be determined.     

Components with Optimised Properties due to Advanced Thermo‐mechanical Process Strategies in Hot Sheet Metal Forming

The increasing demand for car body structures with optimised energy absorption capacity and the ability to maintain their structural integrity even under the highest dynamic load has stimulated the development of new thermo‐mechanical process routes for the production of pressed and roll‐formed sheet metal parts in order to combine both extreme formability and a highest level of strength for the final product. These process routes offer a high potential for further improvements in the field of strength‐strain correlation and load adapted property distribution of the components, as well as an enhanced process productivity. A new type of thermo‐mechanical tailored processing of sheets and profiles is presented, based on the adequate application of differential heating and cooling strategies. By the control of local microstructural effects, the components develop a property distribution adapted to complex load situations. New tooling concepts complement these developments in order to ensure high process efficiency and reliability.     

Controlled Material Flow in Hydroforming by Multipoint Drawing Technology

Sheet hydroforming, which is based on an active working medium, results in advantages over conventional forming techniques that make this technology interesting for the production of components with a large surface area. In order to expand the range of applications for this method, the current limits must be extended and the obstacles eliminated. One important aspect here is finding a solution to the conflict between a reliable tool sealing and a controlled material flow, particularly in the filling and preforming phases of the hydroforming process. One way of achieving progress in this area is to employ multipoint technology. In order to exploit multipoint cushion technology ‐ the potential of which has been proved in conventional deep‐drawing operations ‐ to extend the limits of sheet hydroforming, this technology has to be developed further, similarly to the multipoint cushion systems used in deep‐drawing, and adapted to the process‐specific conditions of sheet hydroforming.     

Material Flow Control in High Pressure Sheet Metal Forming of Large Area Parts with Complex Geometry Details

Working media based forming processes show advantages compared to the conventional deep drawing in the range of sheet metal parts with complex geometry details. By High Pressure Sheet Metal Forming (HBU), complex parts can be formed with reduced tool costs, fewer process steps, and improved part properties, particularly by the use of high strength steels. In order to use these advantages to full capacity, the material flow into the area of the geometry details needs to be optimised. The key element for the material flow control is a multi‐point blank holder. In combination with flange draw‐in sensors, a closed loop flange draw‐in control can be built up which guarantees a reproducible material flow and, consequently, defined part properties. Furthermore, a favourable pre‐distribution of sheet metal material can be reached which leads to a widening of the process limits. Considering a large area sheet metal part with a complex door handle element as example, strategies for the material flow control will be discussed in this paper. The conclusions are based on FE‐simulations as well as experimental findings.     

钣金折弯成型加工中的缺陷处理策略

本文针对钣金折弯成型加工的特点,从钣金折弯成型的基本原理出发,通过采用大量参考文献的分析法、对比法,分析了钣金折弯成型的基本原理.本文通过结束语的形式总结了该处理策略的应用给钣金折弯成型加工带来的积极影响,希望为相关工作人员提供有效的参考.     

薄板冲压成形中摩擦测定装置伺服控制系统

主要介绍了液压伺服系统在汽车板冲压成形中表面摩擦测定装置上的应用 ,分析了系统各部工作原理及动态过程函数的组成。本系统对生产实际冲模中实现冲压过程自动控制具有一定的研究意义     

Process Modeling for Precision Forming of Discrete Parts – State of the Technology and Critical Issues

This paper presents an overview on the application of FE simulation as a virtual manufacturing tool in designing manufacturing processes for precision parts. The processes discussed include forging, sheet metal forming and hydroforming. Determination of reliable input parameters to simulate a process is a key element in successful application of process simulation for process design in all the mentioned areas. These issues are discussed in detail. Practical examples of application of FE simulation are presented for improvement of the existing metal forming process and/or designing new metal forming process for manufacturing discrete precision parts in forging, sheet metal forming and hydroforming.     

High‐Pressure Sheet Metal Forming of Large Scale Structures from Sheets with Optimised Thickness Distribution

In order to manufacture components optimised in regard to lightweight construction, the use of innovative forming processes like high‐pressure sheet metal forming (HBU) in combination with the use of tailor rolled blanks (TRB) as innovative semi‐finished materials is a promising solution. To realise a sufficient forming process reliability, at first, investigations on the seal system were carried out. Hereby, a non‐adjustable as well as a new adjustable seal system have been investigated and qualified as sufficient solutions for this process depending on thickness ratio and thickness gradient within the TRB. One typical workpiece geometry which offers a promising lightweight potential and which can be manufactured from TRB with the HBU‐process is the class of body structures. Therefore, an idealised large scale structure has been designed and investigated in theoretical (numerical) and experimental research. The research work has shown that this large scale structure can be manufactured sufficiently by the HBU of TRB.     

铁水预处理过程稳定控制实践

针对鞍钢股份有限公司炼钢总厂三分厂低硫钢种铁水预处理硫含量高、喷溅和扒损严重等问题,采取了喷枪定位、优化扒渣方法以及应用工业盐等措施,采取上述措施后,喷溅比例降低了68%,高钒钛铁水扒损降低了58.4%。     

双线性应变路径下St14-T冷轧薄板成形极限研究

在多轴加载试验机上开展了St14-T冷轧薄板单拉和双拉预变形试验,在此基础上采用CAMSYS自动网络分析仪测量了板料的极限应变,分析了预变形对板料成形极限的影响,试验结果表明：加载应变路径的变化会蚊蝇乱形极限曲线的高低。单拉预应变路径将显著提高正应变比区的成形极限,而对负应变比区的成形极限影响不大。等双拉预应变将明显降低正应变比区的成形极限,对负应变比区的成形极限有所提高,随着等双拉预应变量的增加,整条成形极限曲线将降低。     

铍板材深冲压成形异形件探讨

冲压成形是金属板材加工异形件的最基本方式。金属材质不同,冲压成形异形件的难易程度不同,主要影响因素是冲压成形性能和冲压成形极限。文章结合铍板材的冲压成形性能和冲压成形极限,对铍板材冲压成形异形件的难易性作了探讨。     

Properties of Large‐Scale Structure Workpieces in High‐Pressure Sheet Metal Forming of Tailor Rolled Blanks

In order to manufacture components optimised in regard to lightweight construction, the use of innovative forming processes like high‐pressure sheet metal forming (HBU) in combination with the use of tailor rolled blanks (TRB) as innovative semi‐finished material is a promising solution. Fundamental investigations on the HBU of TRB have been carried out in a joint research project at the Institute of Forming Technology and Lightweight Construction (IUL), University of Dortmund, and the Institute of Metal Forming (IBF), RWTH Aachen. The experiments performed with cylindrical parts have provided basic knowledge on the sheet material flow and resulting part properties. To achieve sufficient process reliability, a non‐adjustable as well as an adjustable seal system have been tested and proved to be suitable solutions, depending on thickness ratio and thickness gradient within the TRB. In order to demonstrate the lightweight potential of this process chain, a forming tool for an automotive body structure has been designed and tested. The experiments have shown that this large‐scale structure can well be manufactured in the HBU process from a TRB.     

ABB板形仪的测量和控制系统在冷轧板材中的应用特点

在板带生产中,对汽车钢板、镀锡钢板、硅钢板以及航空铝板等冷轧薄板的平直度有很高的要求.因此,在薄带材生产中,板形控制是一个不可缺少的环节.采用ABB板形仪可为板型控制系统提供精确的测量数据,介绍了该仪器的工作原理,板型控制系统的应用情况.     

Metal Forming of Vibration‐Damping Composite Sheets

Composite materials with vibrations damping qualities can be made of two steel sheets enclosing a viscoelastic plasticcorelayer. These sandwich sheets often need to be formed. Material parameters are determined to describe the forming process. Based on these parameters, pilot studies are carried out in order to develop recommendations for forming this class of material.     

数值模拟在汽车板成形中的应用

在汽车和冶金工业中,板成形数值模拟广泛地应用于零件的选材和模具的设计.文章论述了板成形数值模拟的基本方法及其发挥的重要作用,并采用动力显式有限元软件DYNA3D对轿车顶板的冲压成形过程进行仿真计算,分析了成形安全裕度.     

热镀铝锌产品露钢缺陷治理

热镀铝锌产品（Galvalume）因性能优越而得到越来越广泛的使用,人们对Galvalume产品的镀层质量也提出了更高的要求。露钢缺陷是该产品的主要缺陷之一。文章针对露钢缺陷进行了分析并提出了一些改进建议。     

感应加热温度的模糊-前馈复合控制方法

针对感应加热炉的温度控制，提出一种基于模糊控制为主、前馈控制为辅的复合控制方法，利用MATLAB工具软件仿真以及实验室模拟实验，证明其具有过渡过程短、适应性强、鲁棒性好等特点。     

无控制工质电液调节系统改造背压机组的可行性分析

分析了B25机组控制系统改造的必要性,简要介绍了无控制工质电液调节控制系统的特点,结合无控制工质电液调节控制系统的特点,对B25机组改造的可行性进行了分析,为机组的控制系统改造提供了参考。     

板形控制技术在鞍钢冷连轧机组的应用

介绍了鞍钢冷连轧机组采用的先进板形控制技术,包括冷连轧机组轧机机型、板形控制系统及其主要设备工艺参数等,重点分析了板形控制系统的组成。对进一步提高该冷连轧机组板形质量提出了建议。