Plate forging of tailored blanks having local thickening for deep drawing of square cups

A plate forging process of tailored blanks having local thickening for the deep drawing of square cups was developed to improve the drawability. A sheet having uniform thickness was bent into a hat shape of two inclined portions, and then was compressed with a flat die under restraint of both edges to thicken the two inclined portions. The bending and compression were repeated after a right-angled rotation of the sheet for thickening in the perpendicular direction. The thickness of the rectangular ring portion equivalent to the bottom corner of the square cup was increased, particularly the thickening at the four corners of the rectangular ring undergoing large decrease in wall thickness in the deep drawing of square cups became double. The degree of thickening can be adjusted by controlling the punch stroke in the bending. By using the tailor blanks having local thickening, not only the decrease in wall thickness at the bottom corner of the square cup was prevented, but also the limiting drawing height of the cup without fracture was increased to 28.3 mm, whereas that for the uniform blank was 21.3 mm.     

某轿车C柱内板冲压分析与成形模设计

C柱内板是轿车中重要的结构件,冲压变形复杂。首先,对C柱内板零件进行冲压成形分析,确定其成形方案和成形毛坯。在三维计算模型基础上,采用Autoform软件对零件的成形进行数值模拟,得出零件的成形极限图。根据数值模拟结果,分析零件整体成形性能、材料变薄率,预测C柱内板成形过程中的起皱、拉裂等冲压缺陷,结果表明,零件整体成形到位,材料局部位置变薄超过20%,有拉裂危险。其次,基于UG和CAD软件设计了成形模具的上模、压边圈和下模。最后,通过生产实践压制出合格的C柱内板零件,验证了冲压分析的合理性和模具设计的正确性。     

盒形件增量拉深成形数值模拟及工艺试验

为了探索板料增量拉深成形的特点和规律,设计了增量拉深成形轨迹,用Deform-3D模拟软件,对盒形件增量拉深过程进行了数值模拟,分析了凹模圆角半径和凸模进给速度对成形件质量的影响,获得了成形过程中的等效应力和等效应变;并设计了具有双向调节机构的增量拉深模,在Gleeble1500D热模拟试验机上进行了工艺试验验证.结果...     

End formation of a round tube into a square section having small corner radii

Expansion and reduction are the two common end forming processes for tubes. In the tube end expansion process using a square punch, it is difficult to obtain a small corner radii due to the stretching of the tube around the punch corners. The wall thickness around the corners is small when compared to the side wall. Hence, a tube having a poor square look is formed. In this study, a 2-stage end expansion of a round tube end into a square section having an improved square look i.e. small corner radii and increase in wall thickness around corners is developed. In the 1st stage, the tube end is flared into a cone shape using a 30° conical die by axial compression. In the 2nd stage, the conical end of the tube is drawn through a taper square die using a conical bottom square punch, and a near square section is formed. A 15% ironing ratio is applied during the drawing process to flatten the side wall of the square. Experimental and FEM simulation were performed to evaluate and to verify the forming process. Although the height of the square section increases when the punch stroke at the 1st stage is increased. However, this increase is limited by the buckling of the pipe at the circular section of the thick blank tube. Since the conical end is drawn into a square section having different radial lengths, the bottom of the square section is uneven. The uneven bottom end is trimmed off in the later process. A square section having a maximum height of 32 mm after trimming is successfully obtained from the experiment for the punch stroke, S = 44 mm using an API 5 L tube.     

A review on tailored blanks—Production,applications and evaluation

Tailored Blanks is the collective for semi-finished sheet products which are characterised by a local variation of the sheet thickness, sheet material, coating or material properties. With these adaptions the tailored blanks are optimised for a subsequent forming process or the final application. In principle four different approaches can be distinguished to realise tailored blanks: joining materials with different grade, thickness or coating by a welding process (tailor welded blanks), locally reinforcing the blank by adding a second blank (Patchwork blanks), creating a continuous variation of the sheet thickness via a rolling process (tailor rolled blanks) and adapting the material properties by a local heat treatment (tailor heat treated blanks). The major advantage of products made from tailored blanks in comparison to conventional products is a weight reduction. This paper covers the state of the art in scientific research concerning tailored blanks. The review presents the potentials of the technology and chances for further scientific investigations.     

拼焊板车门内板冲压成形工艺研究

采用数值模拟软件Dynaform 5．5对某拼焊板车门内板的拉深成形工艺进行研究,探讨不同压边力和拉延筋对该复杂曲面零件成形性能以及焊缝移动的影响规律。通过调整压边力和拉延筋等工艺参数得到了成形性能较好且焊缝移动趋势较小的车门内板零件。     

Two-stage cold stamping of magnesium alloy cups having small corner radius

A two-stage cold stamping process for forming magnesium alloy cups having a small corner radius from commercial magnesium alloy sheets was developed. In the 1st stage, a cup having large corner radius was formed by deep drawing using a punch having large corner radius, and the corner radius of the cup was decreased by compressing the side wall in the 2nd stage. In the deep drawing of the 1st stage, fracture was prevented by decreasing the concentration of deformation with the punch having large corner radius. The magnesium alloy sheets were annealed at 500 °C to increase the cold formability. Circular and square cups having small corner radii were formed by the two-stage cold stamping. For the circular cup, the height of the cup was increased by ironing the side wall in the 1st stage. The radii of the bottom and side corners of the square cup were reduced by a rubber punch for applying pressure at these corners in the 2nd stage. It was found that comparatively shallow magnesium alloy square cups used as cases of laptop computers and mobile phones can be satisfactorily formed at room temperature without heating by the two-stage stamping.     

拼焊板盒形件冲压成形失效及应变路径分析

采用自制液压机和分瓣压边圈模具,通过模拟仿真和实冲试验,变化各工艺参数,研究分析拼焊板方盒件冲压成形的应变路径、焊缝移动和成形极限,以提高其成形性能。研究表明,厚/薄侧压边力的大小和分布对破裂危险点的应变路径和成形裕度有很大的影响,合理的压边力分布可调节失效破裂的位置,减少焊缝移动和提高成形极限深度;凹模圆角半径的增大,对薄侧侧壁圆角处破裂危险点应变路径影响较大,拼焊板盒形件成形极限深度逐渐增大;厚度比较小时,破裂出现在薄侧圆角处,而厚度比较大时,焊缝移动量大,破裂易出现在薄侧焊缝处;板料毛坯形状和尺寸对失效破裂的位置和成形性能影响显著。因此,以薄侧侧壁圆角处和薄侧焊缝位置附近为破裂危险点,通过优化压边力、凹模圆角半径、板料厚度比、板料毛坯形状和尺寸等工艺参数,改变危险点的应变路径,调节失效破裂的位置,减小其焊缝移动量,可有效地提高拼焊板方盒件的冲压成形性能。     

变截面板方盒形件成形参数的正交试验分析

以影响变截面板方盒形件成形的板料厚度比、板料形状与尺寸、压边力及凹模圆角半径等为参数,以成形深度和过渡区移动量为考核目标,通过数值模拟和利用正交优化方法对比分析不同方案下成形深度、过渡区移动量,调整危险点应变路径,确定最优方案,可提高变截面板成形性能。     

Optimum design of tailor welded blanks in sheet metal forming processes by inverse finite element analysis

Design of weld line in tailor welded blanks is indispensable for good manufacturing of stamped parts as assigned, since the initial weld line is distorted severely during the forming process. The initial weld line has to be determined such that desired weld line in a formed part can be obtained. The initial weld line can be predicted by inverse finite element analysis from the desired weld line in a formed part. In this paper, the multi-step inverse approach is employed to calculate more accurate initial blank shapes and initial weld line of tailor welded blanks for a cylindrical or square cup drawing. The applications demonstrates that the approach is useful for design of weld line in tailor welded blanks.     

圆锥形件冲压成形过程中毛坯上各变形区域行为的研究

从曲面类零件中较为典型的圆锥形件的拉深成形研究入手,分析了该类零件在冲压成形过程中板料毛坯的的变形情况。采用网格分析法,实测了板料毛坯上各区域内金属质点的3个应变值,并根据各区域的变形程度将毛坯划分为法兰、凹模圆角、悬空锥壁、凸模圆角及锥底等5个部分;着得分析了毛坯主要变形区域（悬空锥壁部分）的变形特点,归纳了圆锥形零件的变形规律;讨论了成形过程中各变形区域的相互作用、相互关系及各自的变化规律;找到了圆锥形零件冲压成形中板材毛坯上最有可能产生起皱、破坏缺陷的危险质点位置;最后分析了毛坯在成形过程中不同拉深阶段中的变形情况,为以圆锥形零件为代表的曲面类零件的深入研究奠定了基础。     

Numerical simulation of aluminum alloy ladder parts with viscous pressure forming

1　INTRODUCTIONTheeffectofstressstatesonaxisymmetricsheetformabilityhasbeenstudiedundertheconditionofsolidmetalpunchforming [14 ] ,andtheeffectofblankholderpressure (BHP) ,frictioncoefficientandpunchconfigurationonthestressstateshasbeenob tained .Becauseofthedisadvantagesofsolid punchforming ,newformingtechnologyisneededtoim provethestressstatesofthesheetinformingprocessandtomeettherequirementofforminglow plastici ty ,complexshapeparts .Viscouspressureforming(VPF)isarecentlydevelopedfle…     

推进剂贮箱零件侧翻孔电磁成形数值模拟

基于ANSYS多物理场耦合模块,采用松散耦合法,建立了推进剂贮箱零件侧翻孔电磁成形的有限元模型,揭示了坯料电磁力、应力、应变和厚度等的分布规律及其随时间变化规律,并优化了放电电压和成形线圈内径等工艺参数。分析结果表明:坯料在圆角区域应力和应变较大,且厚度减薄量较大;坯料圆角处残余应力较大。放电电压增大,坯料变形量增加,但厚度减薄量相应增加;线圈内径增大,坯料与模具最大间隙、最大夹角以及坯料最小厚度均先减小后增大。得到的放电电压和成形线圈内径优化值分别为40 kV和40 mm。     

Increase in limiting drawing ratio by using partially thickened blanks

Deep drawing of a partially thickened blank, the thickness of which is somewhat larger at the punch head portion than at the flange portion, is investigated in an attempt to increase the limiting drawing ratio (LDR). A rigid-plastic finite element simulation is firstly used to predict the effect of the partially thickened blank on the increase in LDR. To confirm the result of the simulation, deep drawing experiments are carried out using partially thickened blanks that are produced by machining. In addition, spot welding and forging process methods are employed to produce partially thickened blanks. The finite elements simulation and experimental results show that when a partially thickened blank is used, the LDR increases appreciably compared with that for a normal blank of uniform thickness.     

激光拼焊板在汽车车门内板上的应用

介绍了激光拼焊板的技术特点及成形工艺,阐述了激光拼焊板应用在车门内板上的模具设计与制造过程。     

Influence of variables in deep drawing of AA 6061 sheet

Deep drawing is one of the most important processes for forming sheet metal parts.It is widely used for mass production of cup shapes in automobile,aerospace and packaging industries.Cup drawing,besides its importance as forming process,also serves as a basic test for the sheet metal formability.The effect of equipment and tooling parameters results in complex deformation mechanism.Existence of thickness variation in the formed part may cause stress concentration and may lead to acceleration of damage.Using TAGUCHI's signal-to-noise ratio,it is determined that the die shoulder radius has major influence followed by blank holder force and punch nose radius on the thickness distribution of the deep drawn cup of AA 6061 sheet.The optimum levels of the above three factors,for the most even wall thickness distribution,are found to be punch nose radius of 3 mm,die shoulder radius of 8 mm and blank holder force of 4 kN.     

磁力泵隔离套充液拉深成形模拟分析

运用板料成形有限元软件,对磁力泵隔离套零件的充液拉深成形过程进行模拟,获得成形后的零件成形极限图(FLD)和侧壁厚度分布图,研究了在确定的压边力、凹凸模圆角半径和摩擦系数下,液室压力、压边间隙对零件成形质量的影响规律。研究表明,当液室压力为40 MPa时,侧壁厚度分布范围在0.932~1.027 mm之间;压边间隙为1.08 mm时,零件的侧壁厚度最大减薄率为8.8%;通过控制液室压力为40 MPa、压边间隙为1.08 mm时,试验件壁厚均匀、减薄率低,获得较佳的成形效果,试验结果也进一步验证了结论的有效性。     

Determination of optimal loading profiles in warm hydroforming of lightweight materials

In this study, a methodology is developed to determine proper profiles of the hydraulic pressure and the blank holder force under warm hydroforming conditions at different punch speeds. First, finite element models (2-D and 3-D) are developed and validated through comparisons with the experimental results from the literature. To determine the optimal hydraulic pressure and blank holder force profiles simultaneously, an adaptive FE analysis with fuzzy control algorithm was developed. Thinning, wrinkling, punch wall contact, die corner floating and conduction were used as criteria in the fuzzy control algorithm. The effects of the determined loading profiles are then presented in terms of thickness, strain and stress, and temperature distributions as well as success/failure of the forming process. The effect of punch speed was also investigated to reveal its impact on part formability. It was found that the optimal process conditions can be rapidly and accurately obtained with the developed adaptive FEA method coupled with fuzzy control algorithm.     

切角板坯对纯铜薄板矩形盒拉深影响的试验及数值分析

在大量纯铜薄板矩形盒拉深试验的基础上,结合有限元计算,分析了矩形盒的拉深特性。指出,矩形切角板坯使法兰曲边变形分布得以改善,非拉深变形抵抗弱化,提高了拉深成形性。有限元模拟结果显示矩形板坯拉深断裂点产生在凸模肩部转角附近,且始终承受两向不等拉伸,应变计算值与实际拉深测定值相符;切角板坯的拉深断裂点则转移至接近凹模口的侧壁处,且始终处于压剪组合变形状态,断裂时板厚应变相当小,认为倾向于剪切断裂。切角板坯断裂点的拉、压应力组合效应使该点板厚几乎不变,是提高拉深极限的重要因素之一。     

AZ31B镁合金板径向推力充液拉深试验

镁合金板冷成形性能差,采用液压成形的方法可提高其冷成形性能。对AZ31B镁合金板进行径向推力充液拉深试验,分析液压力大小、模具尺寸和坯料尺寸对最大拉深高度的影响规律,并对液压拉深件破裂位置、裂纹走向及裂纹形态进行分析。研究结果表明,当凸模圆角半径较大时,随着液压力的增大,得到的最大拉深高度也大;凸模圆角半径较小时,仅有当液压力大小合适时,才能改善其成形性能;板坯直径越大,最大拉深高度就越小。破裂位置一般在拉深试件的底部圆角、凸缘和侧壁处,且裂纹走向、裂纹断面呈现不同的形态。