镁合金AZ31B板材热拉深成形工艺研究

镁合金(AZ3lB)板材的成形性能可以通过热拉深试验来进行观察评估。成形温度选择在100-400℃之间。以获得适合成形的最佳温度范围。使用有限元方法分析了主要工艺参数对坯料成形质量的影响。试验结果表明。成形温度低于200℃时坯料很脆，高于400℃叶坯料表面易发生氧化而不适合成形。当成形温度选择在300一350℃之间。压边力在6-15kN(单位压边力q为0．7—1．7MPa)之间时镁合金具有较好的成形性能，能成功拉深出质量好的筒形件。数值模拟结果表明，坯料与模具间的摩擦因数对产生破裂的影响较压边力的影响程度大。     

板材拉深成形过程中摩擦条件与压边力设定关系研究

利用“板料拉深成形摩擦系数测试系统”,研究不同种类的润滑剂在不同压边力值设定条件下,拉深过程中的摩擦系数与压边力、拉深力与压边力之间的关系。从两种实验用坯料物理模拟的结果得知：实验用的油基润滑剂其粘度值越大,拉深性能越好,受压边力数值设定的影响也越小;坯料尺寸的增加使拉深成形变得困难,但对摩擦系数的影响很小。该研究结果有助于生产现场中润滑剂的选用和最佳压边力数值的确定。     

研究拉深成形过程中的摩擦系数分布

主要介绍利用探针和传感器测定拉深过程中摩擦系数的实验方法,据此获得变形区的摩擦系数的分布情况。该方法有助于进一步分析板材在拉深成形过程中的摩擦和润滑情况。同时对计算机数值模拟金属板材在拉深成形过程中,如何确定磨擦系数边界条件提供了一种实验方法。     

测定拉深过程中摩擦系数的研究

本文主要介绍采用探针测定拉深过程中的摩擦系数。并与其它常用的方法进行对比。得出的结论是,探针方法可测出变形区域内任意一点的正压力和摩擦系数,且在计算摩擦系数公式中没有任何假设条件,还可测出在压边圈范围内整个金属变形过程中的摩擦系数和平均摩擦系数。试验证明。一旦掌握了利用探针测定拉深过程中的摩擦系数,就可减小测试和计算过程中的人为和其它因素影响。因此可提高测试精度,误差也相对地减小。     

锥形件智能化拉深系统中材料参数和摩擦系数的在线识别

以拉深过程的解析模拟为基础 ,采用非线性最小二乘曲线拟合原理实现了锥形件拉深智能化控制中材料参数和摩擦系数的在线识别。进而给出了材料参数已知时 ,摩擦系数识别非线性问题的一种线性化算法。实验验证结果表明 ,上述识别方法是正确的     

自组织竞争神经网络板材拉深材料参数识别

阐述了自组织竞争人工神经网络模型优化算法的特点，建立了自组织竞争人工神经网络识别模型，给出板材拉深材料性能参数输入输出层设计和样本数据的采集与处理的方法。研究了自组织竞争人工神经网络模型仿真实例，得到了较满意的识别结果，开辟了应用自组织竞争人工神经网络模型优化板材材料性能参数识别诊断研究的新领域。     

大型板材拉深成形的磨擦特征

利用探针法探讨了St14钢板在拉深过程中凸缘处理的摩擦与润滑规律,根据实验结果分析了拉深成形过程中的摩擦特征,结果表明,随着压边力的增加,摩擦系数基本保持恒定：拉深坯料尺寸增加,拉深力将增加,加入粘度较小的润滑油可以在较小拉深力和压边力的工艺条件下完成拉深成形。     

板材拉深成形性能智能化预测系统

对板料成形性能智能化技术的特点及其开发和应用的意义进行简要的介绍，并详细阐述了板料成形性能智能化系统的整体结构和功能，详细论述了该系统开发的关键技术部分：用户信息输入部分、推理和评定部分的设计思路和具体内容。     

摩擦系数对DP780钢拉深成形极限的影响

首先对DP780试样进行圆杯拉深试验,获得DP780试样的极限拉深深度。然后建立圆杯拉深试验的有限元模型,定量分析摩擦系数变化对DP780钢拉深成形应力应变演化的影响规律。最后将拉深试验和有限元仿真相结合,利用CockcroftLatham准则对不同摩擦系数下的DP780钢拉深成形极限进行预测和比较,定量获得摩擦系数对极限拉深深度和极限应变的影响规律。结果表明,极限应变不能用于评价拉深成形极限,应采用极限拉深深度。板料与凹模和压边圈间的摩擦系数越大,DP780钢的极限拉深深度越小,板料与凸模间的摩擦系数对极限拉深深度影响较小。为了提高DP780钢的拉深成形极限,应尽量减少板料与模具间的摩擦系数,且重点关注板料与凹模和压边圈间的摩擦系数。     

圆锥形零件拉深过程分析及工艺参数的影响

建立了包括板料、凸凹模和压边圈在内的整体分析模型,对锥形件拉深成形过程进行了数值模拟。还将分析结果同实验数据进行比较,揭示了锥形件成形的机理。根据多组工艺参数的对比和分析,得出了板料破裂和起皱的原因,这对于拉深过程的智能控制具有重要的意义。     

利用神经网络技术对板料成形摩擦系数进行预测

针对板料拉深成形过程中摩擦系数较难确定的客观情况,结合人工神经网络所表现出来的良好特性,提出了一种将神经网络技术、数值模拟技术相结合,通过建立摩擦系数与板料成形厚度的非线性映射关系来反求摩擦系数的方法。实践证明,该方法是可行的。     

Friction aided deep drawing of sheet metals using polyurethane ring and auxiliary metal punch. Part 1: experimental observations on the deep drawing of aluminium thin sheets and foils

Friction aided deep drawing based on the Maslennikov process is investigated as a method to facilitate the deep drawing of sheet metals with poor drawability. Aluminium foils and thin sheets of 0.1–0.4 mm in thickness are used as a model for the material with poor drawability. An auxiliary metal punch is used together with a polyurethane ring to increase the drawing efficiency and to improve the dimensional accuracy of the drawn cup. The effect of drawing conditions such as thickness, hole diameter and the hardness of the polyurethane ring on the cup height are mainly investigated. Also, the optimum number of drawing operations required to achieve a given drawing ratio is examined by repeating compression and unloading the polyurethane ring. The experimental results show that even for foil and thin sheets, deep cups with drawing ratios of 2.25 and with good shape and dimensional accuracy can be obtained by repeating the drawing operation about ten times. The achievable drawing ratio is appreciably larger when compared with that obtained by the conventional deep drawing process.     

Friction aided deep drawing of sheet metals using polyurethane ring and auxiliary metal punch. Part 2: analysis of the drawing mechanism and process parameters

Friction aided deep drawing using a polyurethane ring as a pressure medium has been analyzed by the slab and the energy methods to understand the main features of the process and to find the optimum conditions to achieve successful drawing. The effect of an auxiliary metal punch on the stress distribution of the deformed blank and the increase in height of the drawn cup is also discussed. From these studies, the reason why the unusual circumferential crack occurs at the flange of the deformed blank has been clarified, based on the radial stress distribution of the deformed blank. A process parameter, which denotes the drawing characteristics of the friction aided deep drawing, has been proposed. In addition, the drawing region diagram has been presented to facilitate the drawing pressure control with the progress of the drawing process. It is shown that the successful drawing region is narrow at the early stage of drawing, although it becomes wide as the drawing proceeds. Therefore, in the early stage of drawing, special care should be paid to the drawing pressure control to avoid the flange crack.     

板料拉深成形过程中的变压边力技术

压边力是板料成形过程中的重要参数之一。在概述压边力在生产中的主要用途和意义的基础上，从压边力的加载模式、理论模型、实验研究变压边力技术与拉延筋、人工智能技术的交叉应用等方面，比较全面的综述了压边力技术的研究现状及存在问题，并探讨压边力技术的研究方向。     

板料拉延中的润滑

论述了板料拉延成形时的摩擦、磨损特征和润滑机理 ,探讨了拉延时润滑油的使用问题 ,为生产实际中润滑油的选择提供了理论根据和实用参考。     

多道次拉深中间构型对成形影响的研究

钣金件多道次拉深中间构型的确定是塑性成形领域的一个难题.针对中间构型对多道次成形的影响,以轴对称盒形件为成形对象,采用试验方法进行了研究.试验设计了两种不同的中间构型,通过网格法研究在第1道次和第2道次中应变的分布规律;通过成形极限图研究两种中间构型第1道次和第2道次的成形性.试验结果表明,轴对称零件多道次成形在第2道次的成形中,底部成形近似为局部成形,容易在底部产生较大的拉伸应变,造成破裂缺陷,设计中间构型的底部应尽量与零件近似;第1道次和第2道次中沿母线方向的应变均为拉伸应变,自零件口部向零件底部周向的应变由压应变逐渐过渡到拉伸应变,以压应变为主,破裂一般发生在拉伸应变区.     

On the acting pressure in laser deep drawing

Through the continuing trend of miniaturization new cost efficient and fast methods for processing of small parts are required. In this paper a non-mechanical process for the forming process of micro deep drawing is presented. This new pulsed laser based deep drawing process utilizes an initiated plasma shock wave at the target, which forms the sheet. Several pulses can be applied at one point and therefore high forming degrees can be reached without increasing the energy density. In this article the pressure of the shock wave is measured and optimized. Furthermore laser deep drawing of samples made out of pure aluminum, copper and stainless steel sheet metal with thicknesses of 20 and 50 μm are shown. Finally the forming behavior after single pulses is presented.     

杯形件的单道次拉深旋压成形工艺研究

研究了杯形件单道次拉深旋压成形工艺的变形特点，试图替代传统的拉深成形工艺和多道次旋压成形工艺，以达到减少产品的加工工序、降低产品的生产成本。研究结果表明，在旋压成形的初期，轴向旋压分力大于径向旋压分力，而在旋压后期，轴向旋压分力则小于径向旋压分力。除了工件口部之外，其它部分的名义厚度应变ε的变化规律与普通拉深的情况相似。本文还给出了不同工艺参数条件下的成形极限图和使旋压顺利进行的成形工艺参数范围。     

Tribological behaviour of DLC-films and their application in micro deep drawing

In this work, the tribological behaviour of DLC-coated as well as uncoated tools was characterized by tests on a tribometer. Special attention was paid to assess how the failure mechanisms of the films proceed, for example, whether the so-called “eggshell effect” plays a role in the failure of the films. Compared to the uncoated tools, the DLC-coated tools showed a significantly lower friction coefficient to the work piece material stainless steel X5CrNi18-10. As the contact pressure was varied from 215 to 330 N/mm², which is comparable to the maximum contact pressure in deep drawing, no damages in form of cracks or flaking were observed. Furthermore, lubricant-free micro deep drawing was performed with DLC-coated tools made of tool steel X153CrMoV12. Though no lubricant was used, the experimentally measured punch force was lower than that from experiments using lubricant with uncoated tools. This indicates that the DLC-coating has a great application potential in micro forming.