两厢轿车顶盖尾部冲压工艺优化设计

针对两厢轿车顶盖尾部在拉深、整形后出现起皱的问题,通过Autoform模拟及造型设计分析,对原工艺进行优化,设计了一种上、下模不同造型的工艺方案。该方案能有效增加材料流动性,消除制件起皱的缺陷,对同类制件的冲压工艺设计具有参考意义。     

轿车侧围外板表面起皱现象的工艺改进

针对上海大众汽车普通桑塔纳轿车的侧围外板暴露面起皱的问题，分析其产生起皱的原因，对原模具结构和冲压工艺提出了改进方案及实施措施，应用在生产现场，从而彻底消除侧围外板暴露面起皱现象。     

关于汽车侧围A柱下角起皱的研究

针对汽车侧围A柱下角表面起皱产生的原因及解决起皱缺陷的方法进行了阐述,通过对制件的造型、冲压工艺方案、现场模具调试等3个方面对起皱缺陷进行分析,归纳并制定了相应的解决方案,最终使起皱缺陷得到消除,以便于模具设计和模具调试借鉴与参考。     

Dynaform软件在冲压工艺分析过程中的应用

运用CAE分析软件Dynaform,结合三维建模软件CATIA,对某支架制件进行了工艺分析,对模拟结果进行比对与分析,采用成形工艺时,部分区域有起皱;采用拉伸工艺,无起皱区域,减薄率20.2%,符合制件质量要求,从而确定最佳的工艺方案,缩短生产准备周期,提高制件质量。     

后背门内板成形工艺缺陷分析与优化

以汽车后背门内板为研究对象,根据零件形状起伏变化较大且拉深较深的特点,拟定了4道工序成形工艺方案。利用AutoForm软件对成形工艺方案进行数值模拟,分析拉深过程中零件右上角部位出现的拉裂现象、尾灯附近处存在起皱风险、法兰面有较大回弹量、局部变薄等缺陷,并提出通过加大开裂处R角半径、优化压料面及修改拉延筋减少起皱、在回弹量大的法兰面增加加强筋等措施。结果表明,优化后的后背门内板工艺方案在成形过程中无起皱、开裂缺陷,与数值模拟结果一致,验证了数值模拟分析的正确性。     

汽车侧围外板A柱拐角起皱的分析及解决方案

汽车侧围外板零件是车身重要的冲压件之一,成形过程较复杂,拉深过程中易产生起皱、开裂等缺陷。针对汽车侧围外板A柱拐角部位的起皱、开裂问题,通过分析零件现场冲压工艺、A柱拐角部位变形特征和材料发生起皱的原因,建立有限元仿真模型,使用AUTOFORM模拟软件对原冲压工艺方案进行全程仿真,分析结果表明,在第3工序侧整形时拐角处的流水槽面发生严重起皱缺陷。系统研究了二次拉深工序中增加吸料筋和调整压边力对起皱、开裂的影响规律,并提出在侧围外板A柱拐角处增加吸料筋和调整压边力的整改方案。经现场生产验证了分析结果的准确性和修模方案的有效性。     

浅析行李箱盖内板起皱原因与改进

在行李箱盖内板成形过程中,制件内型面支撑筋两侧材料流动较复杂,制件表面容易起皱,针对此问题,分析制件起皱的原因,并对原模具结构和冲压工艺提出了改进方案及整改措施。     

大型薄壁翼尖深腔整流蒙皮拉深成形技术研究

针对飞机翼尖航行灯深腔整流蒙皮壁薄、尺寸大、拉深过程起皱的问题,以有限元模拟为指导结合模具结构优化展开拉深成形技术研究。在展开毛坯合理、摩擦系数设置较大的情况下,压边间隙控制在1.35～1.45 mm时零件最大减薄率可以控制在10%左右,此时其余拉深成形工艺参数在一定范围内波动对零件成形影响小,可生产高质量合格零件。尖端起皱区抬高不仅可缓解起皱,而且可将严重起皱区转移到工艺补偿区域,通过优化毛坯形状改善压边阻力分布可以达到消除起皱效果。经过对比,工艺方案模拟防起皱与实际拉深防起皱结果吻合,通过模具结构优化与数值模拟技术相结合,可以预测并避免板料成形过程中出现的起皱、开裂现象。     

不等宽不锈钢双层板汽车消声器外壳成形工艺分析

针对不等宽不锈钢双层板汽车消声器外壳成形中出现的起皱和破裂问题,结合零件结构特点,详细分析了问题可能产生的原因,并通过有限元数值仿真提出了合理的成形工艺方案。分析结果表明,对该类零件采用二次拉深工艺方案,能够使零件成形时材料流动均衡,极大地改善零件小端处的破裂、管口处和大端处的起皱和材料层叠问题。     

薄壁深锥形零件的成形工艺及模具设计

采用冷挤压、缩口与扩口相结合的工艺方案,对薄壁深锥形零件的成形工艺者了理论分析和实验验证,说明采用合理的工艺方案和模具结构,能够避免薄壁锥形零件成形时的失稳起皱和开裂现象。     

Analysis of wrinkling limit of rotary-draw bending process for thin-walled rectangular tube

The rotary-draw bending process for thin-walled rectangular tube of aluminum alloy may produce a wrinkling phenomenon if processing parameters are inappropriate, especially for tubes with thin wall and small bending radius. To predict this wrinkling rule rapidly and accurately, here, a wrinkling wave function was proposed and a wrinkling prediction model was developed based on the deformation theory of plasticity combined with the energy method, and then the minimum bending radius without the occurrence of wrinkling in the process was obtained. Furthermore, the effects of geometrical parameters and the material properties of the tube on the minimum bending radius were analyzed. The results show that larger thickness-to-width ratio (t/b) and thickness-to-height ratio (t/h) are beneficial to improve the wrinkling limit of the tube. The minimum bending radius becomes smaller with an increase in strain-hardening exponent of the tube, whereas with the strength coefficient decreasing. And the Young's modulus has little effect on the wrinkling limit. These achievements are helpful to develop the bending technique and provide a guideline in rotary-draw bending process for thin-walled rectangular aluminum alloy tube.     

汽车覆盖件拉伸起皱和开裂现象分析及控制措施

对汽车覆盖件在拉伸过程中的起皱和开裂现象进行了分析 ,并从工艺、设计、调整等几个方面较详细地说明了解决零件拉伸起皱、开裂的方法和控制措施。     

Analysis on critical conditions of sidewall wrinkling for hydroforming of thin-walled Tee-joint

Based on the sidewall wrinkling phenomena in hydroforming of thin-walled Tee-joint, an analytical model for tube wrinkling under double side constraints was proposed to calculate the critical wrinkling stress. The effects of stress ratio, diameter-to-thickness ratio and tube material properties on critical condition of sidewall wrinkling were investigated. It is found that the middle of the main tube side wall is the most dangerous position for wrinkling within hydroforming of thin-walled Tee-joint. At a certain internal pressure, the critical wrinkling stress increases with increasing of ratio of hoop stress to axial stress and material strength coefficients, but decreases with increasing of work-hardening exponent and ratio of diameter to thickness. Through the analytical model combining FEM simulation, the critical wrinkling loading path according to the relation between axial feeding and internal pressure was obtained. Experimental results validates that wrinkle can be avoided if the pressure is above the critical wrinkling loading path, otherwise, wrinkle occurs. It is also verified that the analytical model of critical wrinkling stress is reasonable for the thin-walled Tee-joint hydroforming process.     

Combined Methods for the Prediction of Dynamic Instabilities in Sheet Metal Spinning

A technological and mathematical understanding of the sheet metal spinning process allows to predict dynamic instabilities which lead to wrinkling and other defects in the workpiece depending on the axial feed of the roller tool, the design and the number of the forming passes as well as the angular velocity of the workpiece. The development and combined application of methods of statistical design of experiments, nonlinear time series analysis and finite element analysis yields insight into the dominant effects. The results will allow to predict wrinkling and to design and control the process as to avoid it. Preventing workpiece damage by wrinkling, this methods will help to significantly improve process efficiency.     

无压边多点成形中起皱的分析与控制

起皱是板材无压边多点成形中容易产生的成形缺陷。本文根据对多点成形过程中起皱的数值模拟与力学分析,基于Donnell-Mushtari-Vlasov的浅壳理论,给出了球面多点成形局部起皱的判断准则,计算了起皱的临界应力。利用多点成形的柔性可变的特点,可以抑制甚至完全消除起皱缺陷,有关的成形实验结果说明了变路径多点成形及分段成形技术抑制起皱的有效性。     

A theoretical,numerical, and experimental investigation of plastic wrinkling of circular two-layer sheet metal in the deep drawing

In this paper, the wrinkling of two-layer (aluminum-stainless steel) sheets in the deep drawing process, is investigated through an analytical method, numerical simulations, and experiments. In a deep drawing process, wrinkling can always be eliminated with an increase in the blank holder force (BHF). Thus, the aim of this study is to obtain the minimum required BHF to prevent wrinkling. In the analytical model, energy method is used to predict the wrinkling. Also, FE simulations were performed to study the effect of forming parameters on wrinkling. Experiments have been conducted to verify the analytical model and FE simulations. The effects of parameters such as the material properties of aluminum layer and lay-up on BHF and forming force are investigated. Results demonstrate that the optimum BHF is dependent on the blank geometry, material properties and lay-up. It is shown that BHF is greater when aluminum is in contact with the punch. Results show a good agreement between analytical, FE, and experimental results.     

125摩托车油底壳拉深起皱现象分析与解决

拉深起皱是125摩托车油箱底壳在试模期间经常遇到的问题。以ETA/DynaForm软件为平台,模拟125摩托车油箱底壳拉深起皱现象,并从应力、应变状态着手,分析起皱原因,提出解决方案。经分析结果得到起皱的主要原因为板料在成形过程中应力分量不均衡,采用一模两件的方案有效平衡了制件开口处的应力分布,同时通过加大压边力、改变摩擦系数、增设拉深筋和改变坯料尺寸,基本上消除了制件拉深试模过程中的起皱等缺陷。     

后背门内板密封面起皱问题的改善

对后背门内板拉伸过程出现的起皱问题进行了分析,并结合CAE分析制定整改方案,通过现场模具维修,消除了该处起皱问题,对类似制件的开发和模具维修有一定的借鉴作用。