共查询到19条相似文献,搜索用时 125 毫秒
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针对镁合金板材室温拉深性能差的问题,通过分析拉深变形过程中坯料不同部位的应力及摩擦状况,提出采用差温拉深工艺和不同的模具工作表面粗糙度。设计了镁合金差温拉深成形模具。实践表明,与坯料变形区接触的压边圈和凹模部位设置加热系统使其温度控制在(200~235)℃、用循环水冷却凹模筒壁及凸模使传力区保持室温状态,模具凸模表面粗糙度数值为Ra1.6um、凹模和压边圈表面的表面粗糙度数值为Ra0.4um,AZ31B镁合金薄板极限拉深比从2.09提高到3.05。 相似文献
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板材充液拉深(hydromechanical deep drawing,HDD)是在拉深凹模中以一定压力液体作为传力介质代替刚性凹模传递载荷,使坯料在液体压力作用下贴靠凸模拟实现金属板材零件的成形。与传统拉深工艺相比,板料成形性显著提高,成形表面质量好,模具寿命长。随着成形设备和相关技术的发展,充液拉深工艺被广泛应用于汽车、飞机制造业。 相似文献
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应用正交试验方法,采用Dynaform对精密级进模多步拉深成形进行有限元数值模拟。结合能量转换原理,研究各步拉深中凹、凸模圆角半径、拉深高度以及压边力等工艺参数对成形件厚度和回弹的影响,并找出各因素影响的主次顺序。以射频(RF)连接器的壳件为例,通过上述方法优化各步成形参数,用以指导模具设计。 相似文献
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介绍了轿车引擎盖零件冲压成形仿真的研究背景,详细论述了板料冲压成形数值模拟的理论和主要步骤.以典型轿车引擎覆盖件为研究对象,以三维成形分析软件Autoform为平台,研究了板科与凸模、凹模的摩擦、压边力、拉深筋等因素对成形性能的影响.通过Autoform的成形仿真预测板料成形过程中减薄、拉裂、起皱等缺陷,分析产生缺陷的原因,进而优化板料成形工艺参数. 相似文献
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薄壁抛物线形壳体成形过程为拉深和胀形两种变形模式的复合,极易发生起皱和破裂。固体颗粒介质成形是采用固体颗粒代替刚性凸模或凹模(或弹性体、液体)对板料进行成形的工艺。板材在颗粒介质内压的作用下成形,可以有效防止抛物线形件拉深成形过程中侧壁的起皱;由于颗粒内压是非均匀分布的,故可以有效控制抛物线形件成形过程中的破裂,提高板材的成形极限。根据固体颗粒介质成形工艺的特点,提出了两次成形薄壁深壳体零件的工艺,建立了数值分析模型,通过数值模拟和试验对该成形过程和工艺参数进行了分析。结果表明,采用固体颗粒介质成形工艺过程简单、成形工件壁厚分布均匀、表面质量好、回弹小。 相似文献
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Deep drawing process is very useful in industrial field because of its efficiency. The deep drawing is affected by many process variables, such as blank shapes, profile radii of punch and die, formability of materials and so on. Especially, in order to obtain the optimal products in deep drawing process, blank shape is very important formability factor. In this paper, the finite element method is used to investigate the cup height of the square cup drawing process. In order to verify the prediction of FEM simulation of the product’s height and forming load in the square cup drawing process, the experimental data are compared with the results of the current simulation. A finite element analysis is also utilized to acquire the designed profile of the drawn products, a reverse forming method for obtaining the initial blank’s shape according to the forward square cup drawing simulation is proposed. The design of initial blank’s shape is also certified to obtain the designed profile of drawn cups by experiment. The influences of the blank’s shape on the height of product, the forming load, the maximum effective stress and the maximum effective strain are also examined. 相似文献
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混合压边液体内向流动动态充液拉深 总被引:1,自引:1,他引:1
为抑制液体内向流动动态充液拉深中凸缘增厚而造成的拉深阻力急剧增长,提出混合压边液体内向流动动态充液拉深新方法。对定间隙下设定恒定压边力的混合压边充液拉深压边形式实质进行分析,采用有限元研究混合压边方式下压边间隙、压边力以及径向压力的变化对成形过程的影响。研究结果表明:定间隙下设定恒定压边力的混合压边充液拉深压边形式的实质是设定压边间隙和设定压边力压边方式的混合;采用混合压边方式可以降低实际最大压边力,降低凸缘区的摩擦阻力,减少第二个谷底点的减薄率;压边力影响零件直壁部分壁厚分布,较大的压边力得到的零件直壁壁厚较薄;压边间隙的变化影响成形零件直壁壁厚分布,较小的压边间隙成形零件直壁较薄,第二个谷底点越接近零件底部。 相似文献
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采用圆锥形凹模拉深工艺可以提高成形极限,但需要用压边圈将板坯先压成与凹模面吻合的形状,当变形程度较大时,板坯很容易起皱。为了克服这一缺点,提出了将圆锥形凹模与径向分块压边方法结合的工艺,该工艺可有效改善压边圈与板坯的约束状态,从而达到抑制起皱的目的。对圆筒形件的拉深成形,采用了刚柔复合的径向分块压边圈结构,设计了圆锥形凹模径向分块多压边圈拉深模,取不同凹模半锥角的圆锥形凹模进行了圆筒形件的拉深成形实验。实验表明,新的压边方法能有效克服初始成形过程的起皱,可与锥度较小的凹模一起使用。采用凹模半锥角为45°的凹模,得到AA5754、AA6061和08Al三种板材的极限拉深系数分别为0.410、0.431、0.373,显著提高了成形极限。对圆锥形凹模的拉深成形,给出了理论计算成形极限的方法,理论与实验结果非常接近。 相似文献
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Optimization of the design parameters of modified die in hydro-mechanical deep drawing using LS-DYNA 总被引:1,自引:1,他引:0
Swadesh Kumar Singh Amrit Dixit D. Ravi Kumar 《The International Journal of Advanced Manufacturing Technology》2008,38(1-2):32-37
The use of a modified die enhances the limiting draw ratio compared to that obtainable in a conventional deep drawing operation. Application of these dies, in conventional deep drawing, eliminated the use of blank holder but enhances the tendency of wrinkling in drawn products. In hydro-mechanical deep drawing process, the punch deforms the blank to its final shape by moving against a controlled pressurized fluid. In this paper, a new concept of the application of modified dies in hydro-mechanical deep drawing is presented. The finite element (FE) simulations of a deep-drawing process using modified dies are performed using the 2-D explicit finite element code LS-DYNA, with the aim of optimization of design parameters and the results are compared with the experimental values. The initial design steps in the design of modified die in finite element simulation were taken from the concept of Tractrix die. The use of Tractrix die enhances the draw ratio but simultaneously increases the tendency of wrinkling. In this paper the design parameters of modified Tractrix die for hydro-mechanical deep drawing are optimized for the successful drawing of cups. It is also experimentally verified that by using such modified dies in hydro-mechanical deep drawing, deeper cups are drawn without wrinkling. 相似文献
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The deep drawing process, one of the sheet metal forming methods, is very useful in the industrial field because of its efficiency.
The limiting drawing ratio (LDR) is affected by many material and process parameters, such as the strain-hardening exponent,
the plastic strain ratio, friction and lubrication, the blank holder force, the presence of drawbeads, the profile radius
of the die and punch, etc. In order to verify the finite element method (FEM) simulation results of the LDR, the experimental
data are compared with the results of the current simulation. The influences of the process parameters such as the blank holder
force, the profile radius of the die, the clearance between the punch and the die, and the friction coefficient on the LDR
are also examined. The abductive network was then applied to synthesize the data sets obtained from the numerical simulation.
The predicted results of the LDR from the prediction model are in good agreement with the results obtained from the FEM simulation.
By employing the predictive model, it can provide valuable references to the prediction of the LDR under a suitable range
of process parameters. 相似文献
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建立了汽车横梁拉深的有限元三维模型,对其拉深成形过程进行了数值模拟,并与实验结果对比分析,说明数值模拟方法的可行性。在此基础上讨论了摩擦润滑条件、压边力和凸模的虚拟冲压速度对板料拉深过程的影响。通过有限元模拟分析方法得到最佳压边力数值,然后通过综合分析数值模拟结果和拉深实验结果确定了实际拉深过程中的最佳压边力。结果表明,在实际拉深过程中要尽量减小模具和板料的摩擦;在模拟拉深成形时,当虚拟冲压速度大于一定值时,会使模拟结果严重失真,因此,汽车横梁拉深数值模拟时最大虚拟冲压速度不要大于2000mm/s。 相似文献
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D. H. Park S. S. Kang S. B. Park 《The International Journal of Advanced Manufacturing Technology》2002,20(1):31-38
In this paper a surface area calculation for non-axisymmetric deep drawing products of elliptical shape was constructed for
the design of blank shapes of deep drawing products by using an AutoLISP function in AutoCAD software. A computer-aided process
planning (CAPP) system for rotationally symmetric deep drawing products has been developed. In this study, a CAPP system for
non-axisymmetric deep drawing products of elliptical shape was constructed using process sequence design. The system developed
consists of four modules. The first is the recognition of shape module for recognising non-axisymmetric products. The second
is a 3D modelling module for calculating the surface area for non-axisymmetric products. The third is a blank design module
for creating an oval-shaped blank with an identical surface area. The fourth is a process planning module based on production
rules that play the most important role in an expert system for manufacturing. The production rules are generated and upgraded
by interviewing field engineers. The drawing coefficient, the punch and die radii for elliptical shape products are considered
as the main design parameters. The suitability of this system was verified by applying it to a real deep drawing product.
This surface area calculation and CAPP system should be very useful for reducing the lead-time for manufacturing and for improving
the accuracy of products. 相似文献
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Dong Hwan Park Prasad K. D. V. Yarlagadda 《The International Journal of Advanced Manufacturing Technology》2008,35(7-8):814-820
Deep drawing process, one of sheet metal forming methods, is very useful in industrial field because of its efficiency. The
production of optimal products using this process is dependent on the process variables such as blank shapes, profile radii
of punch and die, and formability of materials. Of the variables, the blank shape is very important since it controls the
formability factor. This paper reports the investigations on three kinds of blank shapes and the scribed circle test on three
deformation modes. The punch load distribution for elliptical forming processes were measured under different conditions of
profile radii of punch and die and discussed here. These experiments clarified the influence of the profile radii of the punch
and die and the blank shape on the punch-load distribution for the elliptical deep drawing product of automobile parts. The
aim of this study is to investigate the effect that the process variables have on drawability in a non-axisymmetric elliptical
deep-drawing process and to obtain useful data from the industrial field. 相似文献