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Three-dimensional sheet metal continuous forming process based on flexible roll bending: Principle and experiments 总被引:3,自引:0,他引:3
To effectively manufacture three-dimensional sheet metal parts with various curvatures produced in small batch quantities, continuous sheet metal forming, a new flexible forming technology is being developed. This process employs an upper flexible roll and two lower flexible rolls as a forming tool, and the shape of a flexible roll can be changed in vertical direction. With the rotation of flexible rolls, the sheet metal is bent in longitudinal and transverse directions simultaneously and is formed continuously. In the present study, the three-dimensional surface of formed part is described by sweep surface based on the characteristic of the forming process and the arc-length parametric equation for describing continuous forming part is developed. The three-roll bending deformation of sheet metal in longitudinal direction is analyzed and the longitudinal curvature equation of the formed part is derived. The shape of flexible roll axis controlled at a number of points is represented by the cubic spline curve and the transverse curvature of the formed part after springback is then calculated piecewise. Typically experiments for forming concave shape surface and saddle-type surface have been performed, the experiment results are measured and analyzed by a binocular stereo vision measurement system, it is demonstrated that the formed surfaces are in good agreement with the desired shapes and the presented equations are useful for the continuous forming process design. 相似文献
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Development of a Highly Flexible Incremental Roll Forming Process for the Manufacture of a Doubly Curved Sheet Metal 总被引:4,自引:0,他引:4
A flexible incremental roll forming process has been developed by adopting the advantages of the incremental forming process and the roll forming process: i.e., inherent flexibility of the incremental forming process and continuous bending deformation of the roll forming process. It has an adjustable roll set as a forming tool composed of one upper center roll and two pairs of lower support rolls, which plays a key role. Through the experiments, it is shown that the improved forming method of the proposed process is effective in the manufacture of various doubly curved sheet metals, and the proposed relationship of the experimental parameters and the radius of curvature of the formed sheet boundary is useful to control the final shape 相似文献
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《Journal of Materials Processing Technology》2014,214(2):380-389
To realize highly effective and continuous fabrication of three-dimensional (3D) sheet metal parts, a new forming method, surface flexible rolling forming, has been investigated. This method takes only two integral flexible rolls as the forming tool. In the forming process, a non-uniform elongation in the rolling direction and a bending deformation in the thickness direction occur simultaneously, and finally three-dimensional surface parts are formed. In this work, the basic principle and forming mechanism of surface flexible rolling are studied. A method to calculate the transversal curvature radius of the arc-shaped roll is brought forward, while the feasibility is verified by the explicit dynamic finite element analysis. An experimental device has been developed and the forming experiments have been performed. Typical 3D surface parts including the convex and saddle surface parts have been obtained. Finite element model of surface flexible rolling is established and the effect of forming parameters such as reduction, velocity, bending radius and friction on the surface shape is analyzed. The forming effects including shape errors and thickness changes are studied by the deviation analysis. The results indicate that the formed surface is quite close to the criteria one; the thickness of the parts changes gradually and keeps within a narrow range. The experimental formed parts are measured and the forming accuracy is investigated. The results show that the accuracy is high, and are consistent with the simulation. 相似文献
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《CIRP Annals》2022,71(1):245-248
In metal forming processes, the interface between a workpiece and a tool was occasionally observed directly. However, the rolling interface has almost never been observed because of high-speed roll rotation. To achieve the in situ observation, this paper proposes a novel method where one roll is fixed in the space without rotation, while the other roll revolves around the fixed roll with rotation. With passing the gap between the two rolls, a sheet is rolled. A prototype machine with transparent rolls was fabricated, then the interface in solder rolling was successfully observed from the interior of the fixed roll. 相似文献
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S.J. Yoon 《CIRP Annals》2005,54(1):221-224
In order to manufacture a doubly curved sheet metal effectively, a flexible incremental roll forming process has been developed by adopting the advantages of the incremental forming process and the roll forming process by combining inherent flexibility of the incremental forming process and continuous deformation of the roll forming process. In the proposed roll forming system, a newly designed gripper system is attached in order to achieve automation and more precision manufacturing of the required sheet intended double curvature. The forming method has been further enhanced to form general quadrilateral blanks (including a square, a rectangle, a symmetrical trapezoid and an asymmetrical trapezoid, etc.) into doubly curved shapes by controlling the forming schedule developed by various experiments. 相似文献
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为了消除螺旋焊管成型过程中压痕等缺陷,提高焊管质量,延长成型辊寿命,分析了螺旋焊管在成型过程中,三辊与管壁不发生相互滑动的情况下,即在纯滚动的理想工作状态下,三辊工况的共性和特性与辊面形状;探讨最接近理想状况的辊面形状,并就目前生产中存在的问题提出解决方案。 相似文献
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The line array roll set (LARS) rolling process is a new incremental sheet metal rolling process for effective manufacture of doubly curved metal plates. In this study, design equations were developed to predict the curvatures of formed plate shapes with complex curvatures using the experimental data. A series of experiments with various curvatures have been performed. The comparison of the finite element computation results with the design equations has shown that the design equations can be effectively used for process design of forming processes in forming of doubly curved plates over a wide range of input curvatures. 相似文献
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《Journal of Materials Processing Technology》2014,214(2):217-228
Force-fit integration of piezoceramic fibers in micro-formed structures is a new approach for function integration in structural sheet metal parts. In a first step, a micro-structured surface is formed in a planar semi-finished sheet metal part by micro-impact extrusion. Piezoceramic fibers are then assembled into this micro-structured surface with a small assembly clearance. The fibers and the structured surface of the sheet metal are joined by a forming process. In the next step, the sheet metal with piezoceramic fibres within a locally micro-formed substructure is shaped by deep drawing into a 3D-geometry. In this paper, results of the micro-impact extrusion and the joining by forming experiments are presented. Furthermore, the design constraints for assembly and joining due to the dimensional and form deviations of the piezoceramic fibers are discussed. Results of a numerical study of micro-forming, joining by forming and the global loading during a deep drawing process step were in good agreement with the experimental investigations. The direct comparison between experiment and numerical simulation increases the process knowledge and shows further improvement potential. 相似文献
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Matthias Kleiner Manfred Curbach A. Erman Tekkaya Robert Ritter Kerstin Speck Michael Trompeter 《Production Engineering》2008,2(2):201-208
The paper concentrates on investigation results dealing with ultra high performance concrete (UHPC) dies for the use in sheet
metal hydroforming. A special mixture of UHPC for these tools with its mechanical properties and its manufacturing is presented.
The developed UHPC features a compressive strength of approx. 250 MPa and a Young’s modulus of approx. 50 GPa. Applying internal
pressure, the UHPC die (without confinement or reinforcement) failed between 80 and 96 MPa. The forming test proved a good
shape accuracy of the sheet metal parts but revealed critical tribological conditions. Drawing foil and already formed sheet
metal parts were tested successfully as interlayer and led to an appropriate material flow and surface quality of the sheet
metal parts. 相似文献
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智能与控制在塑性加工制备与成形中的应用 总被引:2,自引:0,他引:2
对材料制备与塑性加工方面的智能控制特点进行了介绍与分析。首先对钢铁、铜及铜合金管材连铸连轧过程控制加工特点进行了阐述 ,其次介绍了镁合金的“轧制 等通道角挤压 拉制”连续加工制备技术和镁合金薄板半固态双辊铸轧工艺。对于薄板增量加工成形技术 ,介绍了飞机整体壁板增量压弯技术、薄板单点无模增量成形技术和多点无模增量成形技术。讨论了薄板可动凹模液压成形技术、异型截面管件液压成形技术和细长杆件空间弯扭成形技术原理。最后对于微小件加工技术进行了简要介绍 相似文献
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An assessment of finite element software for application to the roll-forming process 总被引:5,自引:0,他引:5
The roll forming industry has many difficulties in product development and process set-up. The design and development of rolls and processes are mainly based on trial-and-error and past experiences. Recent industrial trends demand products having high quality and tight tolerances. This requires more precise and cost-effective roll-forming processes than the ones employed in the traditional product development methods.
SHAPE is a reliable FE based solution provider, which covers a wide range of roll forming and rotary forming simulations including ring rolling, tube spinning, flow forming, and thread rolling. It also provides powerful analysis tools for heat transfer, roll stress and microstructure analyses. In this chapter the technical capability of SHAPE for roll forming is assessed by studying an industrial problem. The accuracy and robustness of the software is evaluated using machine shop results. 相似文献
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采用冷轧复合工艺制备了用于锂离子电池封装用的层状Al-Ni双金属复合带材。针对轧制复合工艺和热处理退火工艺对Al-Ni双金属复合带材界面化合物种类、结构及其应用特性进行了研究。结果表明:合适的轧制变形量是实现Al层和Ni层复合的关键因素,在本实验中复合轧制的变形量应控制在50%~60%之间。在后续退火工艺中,Al层和Ni层界面上首先形成的是Al3Ni相,该相有利于Al层和Ni层实现牢固的冶金结合。随着退火时间的延长,随后会形成较脆性的Al3Ni2相,该相以层状形式存在两层金属中间,容易造成Al层和Ni层金属的剥离,因此通过退火工艺控制界面化合物形成的类型和结构十分重要。实验发现,在698K~748K温度范围内退火1小时的轧制复合Al-Ni双金属复合带材,具有好的抗折弯效果,稳定的焊接性能和合适的电阻值,可以作为锂电池封装材料来进行使用。 相似文献
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Shichao Ding Paul A. MeehanWilliam J.T. Daniel 《Journal of Materials Processing Technology》2011,211(3):376-381
Millipede forming, a novel sheet metal forming method, has been proposed and developed recently to overcome fundamental limitations in conventional roll forming. For this new method, there are two main aspects: use of an optimal transitional surface and implementation of a method to feed the strip through the transition surface. Achieving the optimal transitional surface involves defining the change of surface shape between a flat strip and a final shaped product conceptualised to the strip's mid-surface, regardless of the strip's thickness.In this paper, one method of implementing a transition surface, Millipede forming, is introduced. A prototype has been built to demonstrate the working principle and can be used to produce some simple profiles, within a short forming length of 200 mm. 相似文献
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《CIRP Annals》2019,68(1):305-308
In metal forming processes, electrical contact resistance between the workpiece and a tool could give useful information on the contact state of the two surfaces. However, measurement during rolling is difficult because rolls rotate at high speed. In this study, two titanium sheets were cold-rolled in parallel. A closed circuit was composed of the two sheets, one roll and a power source. Difference in electrical potentials between the two sheets was measured to estimate the contact resistance. It is found that the contact resistance decreases with reduction in thickness and that it depends on lubrication and surface conditions of the rolls. 相似文献
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Grid sheet is a sandwich material consisting of two metal face sheets and a core of woven wire mesh that are joined by welding. It has been designed to act as an actively cooled heat shield, e.g. for steam turbine casings. For this purpose, cylindrical parts have to be produced from initially flat grid sheet. This paper focuses on four-roll bending of grid sheet. It is shown that springback and the number of failed spot welds after forming can be reduced by stress relief annealing and appropriate forming conditions. A finite element model of roll bending of grid sheet is presented, which has been set up to predict springback and spot weld failure. 相似文献