几种多腔工业铝型材挤压模具的设计

介绍了几种多腔复杂工业铝型材的模具设计方案。对上模采取二次分流的形式来改善均匀流动和充分焊合,从而合理地设计出这类型材的模具。     

FEM simulation of aluminum extrusion process in porthole die with pockets

In order to investigate the effects of pockets in the porthole die on the metal flow, temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in the lower die. Two different multi-hole porthole dies with and without pockets in lower die were designed. And the extrusion process was simulated based on the commercial software DEFORM-3D. The simulation results show that the pockets could be used to effectively adjust the metal flow and especially benefit to the metal flow under the legs. In addition, the maximum temperature at the die bearing and the peak extrusion load decrease, which indicates the possibility of increasing the extrusion speed and productivity.     

Investigation on Effects of Die Orifice Layout on Three-Hole Porthole Extrusion of Aluminum Alloy 6063 Tubes

Currently, with the increasing demand of high production output, much attention is paid to the research and development of multi-hole extrusion die. However, owing to the complexity of multi-hole porthole extrusion technology, it has not been applied widely in practice for the production of aluminum profiles, especially for porthole die with an odd number of die orifices. The purpose of this study is to design a three-hole porthole die for producing an aluminum tube and to optimize the location of die orifices based on computer-aided design and engineering. First, three-hole extrusion dies for different locations of die orifices are designed. Then, extrusion processes with different multi-hole porthole dies are simulated by means of HyperXtrude. Through numerical simulation, metal flow, temperature distribution, welding pressure, extrusion load, and die stress, etc. could be obtained, and the effects of the location of die orifices on extrusion process are investigated. With the increasing distance between die orifice and extrusion center (described as eccentricity ratio), metal flow becomes nonhomogeneous, and twisting or bending deformation of profile occurs, but the welding pressure rises, which improves the welding quality of profiles. However, the required extrusion force, billet and die temperature, die displacement, and stress induce no significant changes. In comparison with the extrusion force during single-hole porthole extrusion, there is 18.5% decrease of extrusion force during three-hole porthole extrusion. Finally, design rules for this kind of multi-hole extrusion dies are summarized.     

铝型材宽展挤压数值模拟及模具参数优化

在Deform-3D分析软件平台上,以卷帘门三扇门片为例,采用有限元法对铝型材宽展挤压过程进行了数值模拟,分析了铝型材宽展挤压金属流动过程及变形规律。通过对不同导流孔尺寸宽展挤压模拟结果进行对比分析,得出导流孔中段宽度L取值为19 mm时,金属流出模孔流速均匀,能够实现平稳挤压。根据数值模拟结果设计出的宽展模具能够顺利挤出合格的型材,说明有限元数值模拟能够为宽展模具设计提供有力的技术支持。     

FE analysis of extrusion defect and optimization of metal flow in porthole die for complex hollow aluminium profile

To solve the defects of bottom concave appearing in the extrusion experiments of complex hollow aluminium profiles, a 3D finite element model for simulating steady-state porthole die extrusion process was established based on HyperXtrude software using Arbitrary Lagrangian–Eulerian (ALE) algorithm. The velocity distribution on the cross-section of the extrudate at the die exit and pressure distribution at different heights in the welding chamber were quantitatively analyzed. To obtain an uniformity of metal flow velocity at the die exit, the porthole die structure was optimized by adding baffle plates. After optimization, maximum displacement in the Y direction at the bottom of profile decreases from 1.1 to 0.15 mm, and the concave defects are remarkably improved. The research method provides an effective guidance for improving extrusion defects and optimizing the metal flow of complex hollow aluminium profiles during porthole die extrusion.     

铜铝双金属管材挤压成形工艺参数分析

通过对双金属管材挤压成形的有限元模拟发现:当挤压模凹模带有锥角而芯棒为圆柱体时挤压铜铝双金属管材时常出现内层金属断裂的现象.为了解决这个缺陷通过反向思考提出了芯棒带有锥角而凹模为直筒的特殊的模具结构,并结合有限元软件Deform-3D分析了不同芯棒锥角下金属的变形情况,确定了合适的锥角大小,同时对双金属管材内外管材的厚度比也有限制要求,成功实现了铜铝双金属管件的挤压成形.通过对挤压过程中的芯棒进行强度校核对此挤压模具的结构进行了设计.     

Extrusion of 7075 aluminium alloy through double-pocket dies to manufacture a complex profile

Low-temperature incipient melting and high deformation resistance of aluminium alloy AA7075 place extraordinary demands on extrusion die design and process optimization, especially when the shape of the extrudate is complex. The present case study was aimed at combining the considerations on die design and process optimization for the alloy to manufacture a complex solid profile with large differences in wall thickness, by means of 3D FEM simulation and experimentation instead of the traditional trial and error approach. The effects of die bearing length and extrusion speed on extrudate temperature and extrusion pressure were predicted. The results of the simulations clearly indicate that for AA7075 extrusion speed has a strong effect on extrudate temperature and the latter largely determines the surface quality of the extruded profile. A longer die bearing allows more heat to dissipate from the extrudate to the colder die and leads to a greater extrudate dimensional accuracy. The effects of die bearing length and extrusion speed on extrusion pressure are however insignificant. Thus, the extrusion throughput is mainly limited by the extrudate temperature rather than extrusion pressure. The case study demonstrates that 3D FEM simulation is a viable predictive tool for both die design and process optimization and the approach is applicable to the extrusion of other alloys for any other extrudate shapes.     

CPU散热片挤压过程的数值模拟及模具优化

采用刚粘塑性有限元法,利用Deform-3D有限元软件实现了铝合金CPU散热片导流模挤压过程的数值模拟。获得了挤压过程中材料的流动规律、挤压力、模具应力以及模具出口处流速的分布。通过数值模拟发现,型材出口流速很不均匀,远离型材中心的散热片齿部流速过慢。通过对导流模结构的调节,使得型材出口流速基本均匀,模具应力降低,提高了模具的使用寿命。模拟结果为导流模优化设计提供了依据。     

铝型材挤压模工作带优化

基于MATLAB平台，将BP神经网络、遗传算法和数值模拟技术应用于铝型材挤压模具参数优化设计。采用三层BP神经网络建立型材挤压模具的数学模型，由正交实验法安排模拟实验组合，采用有限元软件进行挤压过程的数值模拟，并以具有不同工作带尺寸的挤压模具中金属流出模口平面上的Z向质点流速均方差作为模型目标值，将模拟结果作为神经网络的输人样本对训练网络并建立网络知识源，通过遗传算法求得模型的全局优化解；最后通过有限元数值模拟技术验证并比较优化所得工作带与经验法确定的工作带对金属流动均匀性的影响。数值模拟结果表明，本研究对挤压模具工作带的优化是有效的。     

异型铜带连续挤压过程的数值模拟研究

利用DEFORM-3D软件对异型铜带的连续挤压扩展成形过程进行三维有限元数值模拟,分析金属的流动规律、速度、应力、应变分布。模拟结果表明,采用常规连续挤压工装模具结构会在产品横截面上产生很大的速度差,中间流速快,两边流速慢。通过对模腔结构的优化设计,使金属流动趋于均匀。在TLJ400连续挤压机上进行了异型铜带的连续挤压工艺试验,试验结果与数值模拟结果吻合良好。     

FE analysis of metal flow and weld seam formation in a porthole die during the extrusion of a magnesium alloy into a square tube and the effect of ram speed on weld strength

The present communication concerns a detailed analysis of metal flow into a porthole extrusion die to produce a thin-walled square magnesium tube by means of three-dimensional FE simulation in both the transient state and steady state. The research was aimed to get an insight into the longitudinal weld seam formation during extrusion through porthole dies and to evaluate the factors determining the quality of the weld seams. FE simulation revealed distinctive stages at the beginning of an extrusion cycle, corresponding to the changes in extrusion pressure during the process. It showed that the commonly observed defect at the extrudate head was due to entrapped air under the bridges in the upper part of the welding chamber. The dead metal zones existed at the corners between the container and die face and between the bottom and sidewall of the welding chamber. Because of the friction at the die bearing, the metal flow through the die bearing resembled laminar flow. Only the virgin metal from the interior of the billet flowed along the bridges and formed the welding seams. As ram speed increased, the mean stresses and temperatures on the welding plane in the welding chamber increased, which was reflected in the increases in extrusion pressure and extrudate temperature, being beneficial to the solid-state bonding at the weld seams. Tensile tests confirmed that extrusion at a higher ram speed led to enhanced transverse tensile strength and strain of the extruded square tube, as a result of improved bonding at the longitudinal weld seams.     

如何在模具设计中克服挤压型材缺陷的产生

铝型材挤压缺陷的产生很大一部分与模具结构有关,简要介绍几种型材模具的优化设计,以克服挤压型材缺陷的产生。     

DEPOSITION OF TiBN HARD FILMS ON HOT-WORKING-STEEL DIES FOR ALUMINIUM EXTRUSION VIA A DUPLEX PROCESS

1. IntroductiollSlide friction and adhesive wear are resulted in the interaction zone between die bearingface and profiles surface during extrusion. This tribological process haJs significant effectsin several aspects such as surface quality of extruded products, dimensional toIerances anddie lifetime8l1'2J. To improve the die performance and the quality of aluminium products,a duplex process was applied on the extrusion die, which is made of hot-workingsteels.Plasma assisted chemical vapour…     

型材宽展挤压的数值仿真

基于MSCSuperforge软件平台,对宽展挤压中金属材料在模具内的流动进行了数值模拟分析,研究了宽展模参数:模具入口宽度、模具出口宽度、宽展模高度以及工作带基准长度和模孔位置等因素对金属流动的影响,从而为优化模具设计提供了重要的参考依据     

空心铝型材挤压过程计算机仿真系统

试开发了一套基于计算机辅助设计和数值模拟的空心铝型材挤压过程计算机仿真系统,它涵盖了模具工艺设计的全过程,可以集成原有的和新建立的工艺设计知识。该系统包括空心型材挤压模具及坯料的参数化几何造型模块,并能分析分流桥的截面形状、分流孔的布置、焊合室的高度、工作带长度和阻流或者助流结构对金属流速分布的影响,模具的弹性变形对工作带有效长度和模孔尺寸的影响。     

Comparison of extrusion strains produced by cosine and conical dies

Visioplastic analysis is used to compare strain fields produced in cylindrical aluminum billets extruded at elevated temperature through axially symmetric dies that have either a cosine or a conical profile. The visioplastic method consists of computing strain rates from changes experienced in a flow function as a billet passes through the extrusion die. The flow function is constructed using a grid that is stamped on an axial plane of the billet before extrusion. After the partially extruded billet is removed from the die numerical methods are used to determine the strain rates from the deformed grid. The state of strain over the extrusion region is computed using transformation and then integration of the strain rates. Results show that, unlike the conical die, the cosine die does not produce strains of reversed sign in the die entry region. The consequent benefits of using cosine dies for extrusion of powder metals are discussed.     

确定挤压凹模模孔位置的局部挤压比法

本文对复杂断面型材的挤压给出了确定模孔位置的局部挤压比法。该方法假设挤压时金属为稳态流动，按金属的流动规律划分变形区，给出局部挤压比的概念，选择局部挤压比与总挤压比之差作目标函数，优化模孔位置。按此方法设计的挤压模可减小金属流动的不均匀性，并较大可能地得到平直的挤压制品。     

新能源汽车电池架空心铝型材挤压模设计

针对新能源汽车电池架空心铝型材,设计分流挤压模,结合有限元模拟技术获得铝型材挤压过程中铝合金的流动速度分布情况。分析模拟得到的数据,针对铝合金挤出速度的不均匀性,对模具的芯模结构提出改进方案,改进后的模拟结果显示型材出口处金属流速均匀,试模试验与有限元模拟结果相符,为相关型材的模具结构设计和改进提供了指导。     

导流室设计对薄壁铝型材挤压出口速度的影响

采用基于ALE算法的HyperXtrude软件,模拟薄壁铝合金型材挤压模具导流室各种设计的金属流动情况,分析了各设计参数对金属流速的影响规律,并统计挤出型材断面上挤出方向的流速均方差S.D.作为衡量流速均匀程度的指标。分析结果表明,在设计断面不对称、壁厚不等型材模具时,有时需将型材的质心相对于模具的中心做一定距离的调整。型材断面上各处的壁厚差异和局部质心偏离都对流速有影响,但壁厚差异对于流速均匀程度的影响更大。在模具的型腔内添加阻流块结构,流速均匀程度可大为改善。调节阻流块的宽度、高度、形状、位置等参数,能够完全消除流速不均匀,但如果尺寸调整超过最佳点,流速均匀程度将迅速恶化。根据最优模拟结果对应的设计生产模具,并进行挤压实验,所得型材的尺寸质检合格,模具达到"零试模"要求。     

分流组合模挤压的有限元模拟与模具设计评价

为探讨分流组合模挤压成形规律,选择分流孔内斜度、外斜度、焊合室高度和工作带长度为变量设计了9副模具,提出了模具设计的无量纲单指标评价因子和综合评价函数,用DEFORM_3D软件实现了分流组合模挤压铝管材的有限元模拟,获得了挤压材料焊合面上的静水压应力场、等效应变场和模具峰值应力,进而对模具设计评价指标进行了极差分析,得到了最优模具设计,模拟分析结果与试验数据吻合良好。研究表明:分流组合模焊合室高度H与工作带长度L的比值对综合评价函数影响很大,应作为设计变量。