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1.
Investigation into a new hybrid forming process: Incremental sheet forming combined with stretch forming 总被引:3,自引:0,他引:3
B. Taleb Araghi 《CIRP Annals》2009,58(1):225-228
Asymmetric incremental sheet forming (AISF) is a process for the flexible production of sheet metal parts. In AISF, a part is obtained as the sum of localised plastic deformations induced by a simple forming tool that moves under CNC control. Three main problems exist in AISF: material thinning, geometric accuracy and the process duration. These limits restrict the range of applications of AISF. This paper focuses on a new hybrid process, the combination of AISF and stretch forming. First results are presented that show the positive impact of this hybrid process on the process limits. 相似文献
2.
B. Taleb Araghi A. G?ttmann M. Bambach G. Hirt G. Bergweiler J. Diettrich M. Steiners A. Saeed-Akbari 《Production Engineering》2011,5(4):393-404
Asymmetric Incremental Sheet Forming (AISF) has been developed as a flexible process for low-volume production of sheet metal
parts. In AISF, a part is obtained as the sum of localized plastic deformations produced by a simple forming tool that moves
under CNC control. In spite of about 20 years of research and development, AISF has not had much industrial take-up yet. The
main reason for this is that attempts to improve, among other limitations, the accuracy, speed and range of feasible geometries
of the process by adapted process strategies has not brought about general solutions. This paper presents an overview of the
current state of development of hybrid asymmetric incremental sheet forming processes at RWTH Aachen University. The goal
of the development of hybrid ISF processes is to allow for a quantum leap of the capabilities of AISF in order to enable a
broader industrial use of AISF. Two hybrid process variations of AISF are presented: stretch forming combined with ISF and
laser-assisted AISF. It is shown that the combination of stretch forming and AISF can improve the time per part, sheet thickness
distribution and accuracy of the final part. Laser-assisted AISF is shown to enable the flexible forming of non cold-workable
materials such as magnesium and titanium alloys when the forming conditions are adapted to the temperature and strain rate
dependent formability of the sheet metal. In addition, first results of the forming of hybrid aluminum-steel sheet metal are
shown. 相似文献
3.
Tooling concepts to speed up incremental sheet forming 总被引:1,自引:1,他引:0
A major drawback of asymmetric incremental sheet forming (AISF) is the long cycle time. AISF is known in general as forming
of a sheet metal by only one small forming zone. The developed concepts presented in this paper aim at decreasing the main
process time by applying several forming zones on the part through multiple tools working in parallel. By the use of a systematic
design process, four major structural tooling concepts were invented. Those variants were compared to each other by a cost-utility
analysis. As a result, a prototype with two tools was produced to fasten the AISF process. 相似文献
4.
A. G?ttmann J. Diettrich G. Bergweiler M. Bambach G. Hirt P. Loosen R. Poprawe 《Production Engineering》2011,5(3):263-271
Asymmetric Incremental Sheet Forming (AISF) is a relatively new manufacturing process. In AISF, a CNC driven forming tool
imposes a localized plastic deformation as it moves along the contour of the desired part. Thus, the final shape is obtained
by a sequence of localized plastic deformations. AISF is suitable for small series production of sheet metal parts as needed
in aeronautical and medical applications. Two main process limits restrict the range of application of AISF in these fields.
These are the low geometrical accuracy of parts made from titanium alloys or high strength steels and, for titanium alloys,
the limited formability at room temperature. In this paper a new concept for laser-assisted AISF is introduced including the
required components. Furthermore, the CAX tools used for programming the NC path for the forming tool and the laser spot are
illustrated. First experimental results show that the formability of the alloy Ti Grade 5 (TiAl6V4), which is usually used
in aeronautic applications, can be increased. 相似文献
5.
金属板料渐进成形工艺过程有限元模拟 总被引:1,自引:0,他引:1
介绍了金属板料分层渐进成形过程有限元模拟。在金属板料渐进成形过程中,材料的弹塑性变形十分复杂,影响成形过程的因素很多,同时各个工艺参数对成形过程的影响又很难确定。为此,根据金属板料分层渐进成形为多工步成形的技术特点,建立一种有限元模拟方案,对板料渐进成形过程进行了模拟分析。 相似文献
6.
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
7.
1 INTRODUCTIONTheeffectofstressstatesonaxisymmetricsheetformabilityhasbeenstudiedundertheconditionofsolidmetalpunchforming [14 ] ,andtheeffectofblankholderpressure (BHP) ,frictioncoefficientandpunchconfigurationonthestressstateshasbeenob tained .Becauseofthedisadvantagesofsolid punchforming ,newformingtechnologyisneededtoim provethestressstatesofthesheetinformingprocessandtomeettherequirementofforminglow plastici ty ,complexshapeparts .Viscouspressureforming(VPF)isarecentlydevelopedfle… 相似文献
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Technology of sheet hydroforming with a movable female die 总被引:2,自引:0,他引:2
Shi-Hong Zhang Li-Xin Zhou Zhong-Tang Wang Yi Xu 《International Journal of Machine Tools and Manufacture》2003,43(8):781-785
An improved sheet hydroforming process is proposed and investigated experimentally and numerically. A movable female die keeps in contact with the deformed area of the sheet blank so that further deformation of the deformed area is restricted. Under the sealing, the sheet blank under the flange can be drawn in. So the hydroformed part has less thinning than the hydrobulge formed part only, and the limit drawing ratio of the sheet can be remarkably improved. This process is especially suitable for forming of small batch production of sheet metal parts with complicated shapes. The female die can be replaced with other female die of various shapes, and can also be made of very cheap materials such as plaster and hard wood instead of metal when the part number is very small. Thus complex-shaped sheet parts can be formed with less expensive tool systems.In this paper, the hydroforming processes of part A (without a movable die) and part B (with a movable die) were investigated by experiment and by elastoplastic FEM. The effects of various process parameters on the deformation of the sheet blanks were investigated. The forming conditions affecting wrinkling and rupture have been analyzed. The effects of friction and contacting force acting on the experimental results are also discussed. 相似文献
10.
Two-step method of forming complex shapes from sheet metal 总被引:2,自引:0,他引:2
Sergey F. Golovashchenko Nicholas M. BessonovAndrey M. Ilinich 《Journal of Materials Processing Technology》2011,211(5):875-885
A two-step method of forming a part and a method of designing a preform shape are being discussed. The part may be formed from lightweight material to an extent that would normally exceed the forming limits of the material if the part were attempted to be formed in one-step conventional stamping die. Critical areas including deep pockets and sharp radius areas of the final part are formed from a preform or intermediate shape part. The first forming step can be conducted by variety of sheet metal forming methods; the preformed blank is further formed in a fluid pressure forming process to a final part shape wherein broad radius areas and pockets of accumulated metal of the preform are formed into deep pockets and sharp corners of the final shape. Electrohydraulic forming technology is employed for the second forming step. 相似文献
11.
研究了铝合金2024-T3板料在新淬火状态下的成形过程.首先测量了2024-T3板材在新淬火状态下的力学性能,与原始状态性能比较发现,屈服强度和抗拉强度降低,延伸率增大,韧性增加.基于数值模拟方法模拟了橡皮成形过程的回弹规律,对翼肋零件的翻边回弹进行了数值模拟,并通过试验进行了比较.结果表明,数值模拟与试验结果吻合较好,模拟与试验间的偏差足板料发生加工硬化所导致的.因而,通过模拟可以得到考虑了回弹的模具形状,从而修正模具,使回弹后形状达到没计的精度.数值模拟与试验比较表明该方法是可行性的. 相似文献
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采用热力耦合有限元数值模拟方法对铝合金圆锥形零件粘性介质温成形过程进行了模拟分析,研究了成形过程粘性介质和板材的温度分布、不同温度条件下成形零件壁厚分布、成形载荷等.结果表明,圆锥形零件的底部圆角区域为成形危险区域.非等温粘性介质温成形过程中,在粘性介质内部形成的非均匀温度场影响了板材的温度分布.当粘性介质温度略低于板材温度时,坯料中心区域温度较低,有利于延迟底部圆角成形时的破裂,提高了零件壁厚的均匀性.分别进行了室温和加热时铝合金圆锥形零件粘性介质压力成形试验,试验结果与数值模拟具有相同的规律. 相似文献
15.
The occurrence of the shock lines in multi-stage sheet metal forming was investigated to obtain basic knowledge for the prevention of the shock lines. The deformation behaviour for the occurrence of the shock line was observed in detail in both experiment and numerical simulation. For the occurrence of the shock lines, multi-stage forming processes were simplified as a model forming test consisting of deep drawing and unbending. The effects of forming conditions on the occurrence of the shock lines were examined and the prevention of the occurrence was discussed. It was found that the decrease of thickness in the corner formed in previous stages appears as the shock line in the unbending. As an application to actual forming processes, the shock line in a multi-stage forming process of an automobile wheel disk was successfully prevented by increasing the radius of the punch corner in the first stage. 相似文献
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直壁矩形盒渐进成形技术 总被引:2,自引:1,他引:1
介绍了金属板料数控渐进成形的原理、板料变形过程及直壁矩形盒成形的工艺规划。根据正弦定律,直壁矩形盒采用数控渐进成形工艺不能一次成形。经设计平行线形工具路径方法,并进行试验和分析,得出影响直壁矩形盒成形的主要参数是成形半锥角。 相似文献
18.
介绍了一步成形法模拟软件的应用领域、基本原理和方法以及同增量法模拟比较的优点。用一步成形法模拟软件FASTFORM对零件毛坯和成形性进行预测并同增量法模拟结果比较,表明这种方法能够获得正确结果,适用于零件早期设计和工艺参数设计阶段。最后,指出随着一步成形技术的发展以及自身优势,对于中小企业将具有更为广泛的应用前景。 相似文献
19.
在金属板材数控渐进成形中模型姿态决定着成形半锥角,因而对成形件的厚度减薄率和分布具有较大的影响。为了按照能使板材件厚度均匀化的最佳方向或防止某一局部区域板材减薄量过大的方向成形,需要将待成形件CAD模型通过模型变换的方法,按照所希望的成形方向重新定向和定位。提出待成形件CAD模型的三维变换算法和定位算法,使用户能够根据自己所希望的方向进行成形加工。 相似文献
20.
金属薄板成形的有限元仿真技术 总被引:1,自引:0,他引:1
金属薄板成形是一个包括材料非线性、接触非线性和几何非线性等的复杂问题。针对金属薄板的成形特点,探讨金属薄板成形有限元仿真关键技术,即建模、网格划分、算法选择及成形缺陷预测准则的特点及应用中应注意的问题。应用薄板成形专用有限元分析软件Dynaform,对薄板两次拉深成形进行了有限元仿真,仿真结果与实验结果吻合,验证了所论述理论的可行性及有效性。 相似文献