变薄拉深工艺与模具设计

以某零件的成形为例,探讨了深孔薄壁件变薄拉深成形的基本原理和方法,初步制定了其成形工艺方案,并对深孔薄壁件变薄拉深成形的模具进行了数值分析和研究,提出了较好的模具成形方案,验证了该方案的正确性。     

深杯形件冷挤压工艺分析及变薄拉深模具设计

以典型冷挤压深杯形件为例,通过对零件的形状及材料的性能分析计算后确定出最佳的工艺方案,给出了各成形工序图及润滑与软化处理规范,并对其中的变薄拉深工序进行了模具设计.在设计中,首先通过工艺力计算,选用了合适的成形设备,并根据工艺特点和成形设备特性,选择和设计了变薄拉深模具的主要零件,最后给出了变薄拉深模具的总装图.实践证明,所给出的成形工艺及设计的模具能够实现深杯形件的冷挤压成形,所成形的工件尺寸精度高、强度性能好.     

壁厚变薄直径缩小空心件的变薄拉深

通过薄壁、变壁厚、厚底、大高度的空心零件成形,介绍了变薄拉深工艺的特点,分析了壁厚变薄、直径缩小的变薄拉深变形过程,给出了变形程度的表示方法——加工率,提出了该类变薄拉深的工艺参数计算方法,可为同类型零件变薄拉深工艺计算提供参考。     

深杯形件多道次变薄拉深过程数值模拟

以某典型深杯形件为例,通过零件形状分析确定了最佳的成形方案.然后在Deform3D有限元仿真软件和刚塑性有限元理论基础上,对该深杯形件变薄拉深过程进行了数值模拟.研究了变薄拉深工艺的主要参数(摩擦系数、变形速度)对成形过程的影响.通过分析得到了不同工艺参数与成形载荷和工件损伤之间的关系,这能为深杯形件变薄拉深工艺优化设计提供理论依据.     

薄壁深孔锥形件成形工艺及模具

针对钢质薄壁深孔锥形件成形复杂、难度大的特点，通过优化成形工艺及模具设计，保证了产品质量，提高了生产率。     

某外壳零件成形工艺分析

针对底部带孔的有凸缘圆筒件成形工艺过程,确定了拉深工序的成形工艺参数,结合数值模拟方法模拟验证了拉深的成形过程。对冲孔成形工艺进行了模具设计,从而优化了工艺方案,对同类工件的成形工艺提供一定的借鉴,最终保证了圆筒件拉深成形工序的顺利进行。     

基于Dynaform的点烟器外壳拉深工艺分析

超薄壁带浅锥面阶梯深圆筒件的拉深过程比一般阶梯深圆筒件的拉深更容易发生破裂和起皱。基于多道次拉深系数理论和平均截面法对某超薄壁带浅锥面阶梯深圆筒形点烟器外壳的拉深工艺进行了分析与计算,并利用Dynaform有限元软件对该拉深工艺进行了数值模拟与分析。结果表明,该点烟器外壳的拉深工艺需采用4次拉深成形,拉深的最大变薄率为8%。     

对变薄拉深变形特点的探讨

变薄拉深是制造厚底、薄壁、变壁厚、大高度的带底空心件的冲压方法。变薄拉深件一般要经过多次拉深完成,每拉深一次都要退火和表面处理,这似乎成了一个规定。此规定是否正确尚少论述。另外多模变薄拉深的一次变薄率比单模大一倍以上,具有良好的经济效益。但目前对变形原理及提高变薄率的原因还不清楚。本文将通过对变形特点的研究回答以上两个问题。     

落料拉深侧冲孔复合模设计

通过对侧壁带一小孔无凸缘一次拉深圆筒形件的工艺分析,合理设计了1副完成落料、拉深、侧冲孔3种工序的复合模,提高了产品质量、生产效率和经济效益。这种思路可以推广到侧面有多个孔盒形件的模具设计。     

深孔壁锥形件冷加工工艺研究

通过对锥形件产品的研制，论证了采用复合挤压、变薄拉伸和扩锥挤压相结合的工艺方法是加工深孔薄壁锥形件的可靠工艺方法，得出了变薄拉伸加工中加工率不应处于临界加工率状态的结论。     

缓冲器缸筒成形工艺

针对缓冲器缸筒产品结构特点及性能要求,结合热冲压（挤盂＋热变薄拉深）及冷变薄拉深成形工艺的特点,对缓冲器缸筒成形工艺方案,热冲压（挤盂＋热变薄拉深）毛坯的形状和尺寸,热冲压（挤盂＋热变薄拉深）及冷变薄拉深成形工艺等关键技术问题进行了研究。试验结果表明采用热冲压（挤盂＋热变薄拉深）和冷变薄拉深相结合的工艺方法对缓冲器缸筒进行成形加工高效而经济,比传统热冲压后机械加工的成形工艺原材料利用率提高25％左右,同时所生产的产品尺寸稳定,力学性能一致性好。     

Optimization of ironing processes by means of DOE and FEA

The range of possible applications of ironing processes reaches from the production of cylindrical pressure tanks, shock absorber pipes, battery and beverage cans to the production of flacons for the cosmetics industry. One goal of the finite element analyses of ironing processes is to gain knowledge about process limits regarding maximized forming capacity and optimized surface quality. The ironing process is characterized by parameters like friction, geometry of the ironing ring and anisotropic material behavior. Due to the high complexity of this process, it is complicated to detect these effects on the basis of experimental investigations only. Therefore, one of the aims of this study is to identify relevant process parameters by means of systematic numerical analyses. The design of experiments was utilized to create a model of the ironing process. By means of this model it was possible to reduce the punch load and to minimize the tensile stresses in the first stage of the analyzed ironing process.     

A study of cold ironing as a post-process for net-shape manufacture

Cold forming processes have the potential to enable net-shape components to be made. For net-shape with associated close tolerances to be achieved, a scientific understanding of the elastic distortions arising in the tooling is necessary. To become a useful process, cold ironing as a post-forging operation of warm forged gears needs a clear understanding of form errors due to die-elasticity and springback of component shape. The work described in this paper is aimed at gaining such an understanding. In order to simplify the analysis of cold ironing, a single tooth ironing die, instead of a whole gear die, has been designed and made. The effects of initial interference between die and single tooth in the process were studied experimentally and by FE simulation. The changes in geometrical profile, dimensions, and surface finish in the single tooth were observed. This study reveals the relationship between process variables and demonstrates that predicted dimensions can be achieved and surface finish greatly improved.     

A study on the cold ironing process for the drum clutch with inner gear shapes

This paper describes a 3D FE simulation of the cold ironing process for forming the drum clutch, the main part component of the automatic transmission. The process of the drum clutch with inner gears that was employed in this study consists of 12 steps associated with nine deep drawing processes and three ironing processes to form the inner gear shape. The ironing processes were focused on this study in order to estimate the dimensional accuracy of the inner gear shape according to the process variables such as the punch shape, the approach angle of the punch, and the thickness reduction ratio. A rigid-plastic finite element simulation was applied to analyze the deformation characteristics of the ironing processes and to determine the optimum parameter for selected conditions. Finally, an experiment on the whole drum clutch forming process was carried out to examine the validity of the analytical results and the chosen parameters.     

奥氏体不锈钢变薄拉深过程的数值模拟

利用有限元软件Deform-2D,对奥氏体不锈钢变薄拉深过程进行热力耦合的数值模拟,研究了凸、凹模与坯料间摩擦和变形速度对变薄拉深过程的成形载荷和坯料损伤的影响。模拟结果显示：当凹模与坯料之间的摩擦增大,成形载荷和坯料损伤明显增大;当变形速度增大,坯料损伤增大而成形载荷减小。上述结论为奥氏体不锈钢变薄拉深工艺优化设计提供了可靠的理论依据。     

Development of simulation code for calculating residual stress distribution in D-I cans produced by both-sided ironing process

A code of FEM for an elastic and plastic material has been developed to calculate a residual stress distribution in D-I can by both-sided ironing. It is possible for the code to simulate a forming process of deep drawing from a sheet to a can, an ironing process of both-sided of the can wall, and a deformation of the whole of the can under perfect unloading when the can is removed from an equipment of deep drawing and ironing. From these simulations, quite different and contrary distributions of residual stress are obtained according to mutual positions of dies for the ironing, which are considered to expand the wall of can as an ellipsoidal shape or shrink it to a hyperbolic shape.     

深锥形件拉深模设计

通过对深锥形冲压件成形条件的分析,采用底部依次参与拉深变形以及内径逐渐减小的方法,确定了其变薄拉深工艺路线及变形过程。介绍了其工艺计算方法,对关键冲压工序的模具工作过程进行了说明。为减小摩擦阻力和拉深力,提高变形程度,采用了锥形凹模,同时对变薄拉深时出现的一些常见缺陷给出了解决方法。经生产实践证明,该模具结构合理,经济效益显著。     

浮动凹模在变薄拉深模中的应用

针对传统固定式变薄拉深凹模在拉深时工件的壁厚差往往达不到设计要求的缺陷,分析了工件壁厚超差的原因,提出了采用浮动式变薄拉深凹模的措施,通过使用,工件的壁厚差完全达到设计要求。介绍了变薄拉深模结构及工作过程,并给出了变薄拉深凹模浮动量的确定方法。