【作者】 柴海啸；

【导师】 胡树根； 王耘； 宋小文；

【作者基本信息】 浙江大学 ， 机械设计及理论， 2006， 硕士

【摘要】 板料冲压成形作为一种塑性加工方法，广泛应用于汽车、航空航天、电器、造船、仪表等工业领域。起皱、破裂和回弹是板料成形中的三种主要缺陷，其中回弹是最难控制的。回弹问题的存在对零件的尺寸精度和生产效率造成极大的影响，因此对回弹控制进行深入研究有重要意义。 传统的解决方法是采用不断的修模、试模的方法来优化模具型面形状和确定成形工艺，这样既耗时又费钱。如果能在模具制造以前就预先知道如何修改模具型面形状以及制定冲压过程中较优的成形工艺，不但可以大大简化修模、试模的过程，而且节约大量人力、物力。基于有限元计算的板料成形数值模拟技术的出现和发展为解决回弹问题提供了有力的现代手段，因此研究基于数值模拟的模具型面修正方法和成形工艺优化方法，提高冲压件的成形精度，就成了本文的工作重点。 本文首先阐述了回弹对板料冲压件成形精度的影响，以及该研究课题对于降低冲压件制造成本、缩短新产品开发周期的重要意义，然后详细叙述了板料成形回弹分析、控制和回弹预测的国内外研究现状，板料成形回弹有限元模拟的关键技术和理论。在此基础上，本文提出了一种新的基于几何回弹补偿的模具型面修正方法和基于工艺回弹补偿的工艺参数优化方法，并将修正的模具型面作为正交试验法的一个因子，用于降低回弹量的工艺参数优化中。 以类U形件为例，应用商业数值模拟软件Dynaform研究了冲压、回弹过程，开发了一套基于回弹量几何补偿的修正模具型面的程序，并结合CAD软件UG、Surfacer完成模具型面设计过程，最后研究了模具型面、冲压速度、冲程、压边力和摩擦系数对回弹量的影响。数值模拟的结果表明，在研究回弹的试验中，将模具型面作为重要因素加入工艺优化方案，能显著降低冲压成形件的回弹量，为控制和解决回弹问题提供了一种新思路。 本文工作的特色在于利用有限元网格的节点数据作为逆向工程软件Surfacer的点云数据，进行模具型面设计；将模具型面作为一种影响回弹量的重要因素，与冲压速度、冲程、压边力和摩擦系数等多工艺参数进行综合分析，得出各因素对回弹量的影响程度，有益于对冲压件回弹几何和工艺补偿两个方面更深入的探讨；将正交试验法、数值模拟法相结合用于冲压工艺参数的优化，在保证一定的分析精度前提下，显著节省了工艺制定的时间，提高了工艺参数设计的效率。更多还原

【Abstract】 Sheet metal stamping is an important process for manufacture of sheet metal parts and is widely used in automobile, aircraft, electronic instrument, shipbuilding, apparatus and other industries. In sheet metal forming, wrinkling, cracking and springback are the main problems, amongst which springback is the most difficult one to be controlled. The phenomenon of springback greatly affects precision of parts and manufacture efficiency, so it is necessary to do further research to control the springback.Traditional method to eliminate the geometric error is trial-and-error to modify the surfaces of the die and establish the stamping process. It not only wastes time, but also has large expenses in manpower and material resources. The process of trial-and-error is simplified if we could know the exact size of the die and the proper stamping process before the die manufacture. Large manpower and material resources of compensation are saved. The appearance and development of the numerical simulation based on finite element method provide modern means for solving the springback problem. Therefore, research on die design and process parametric optimization method to improve the stamping precision becomes the main task of this paper.In this paper, the stamping-springback issue and the significance of research on this subject to cut down the manufacture cost and shorten new product develop cycle are summarized. Internal and overseas articles related to sheet metal forming and springback analysis, control and prediction are discussed. Then the main technology and theory of sheet metal forming and springback based on numerical simulation are discussed in details. After that, a new method based on geometric compensation of die design and process compensation of parametric optimization is presented, and the modification of die surface is used to process parametric optimization to decrease the springback value with orthogonal test.Taking example for U-shape sheet metal, the paper studies the forming and springback process with Dynaform, develops the die-surface-modification program, and finish die design with CAD software UG & Surfacer. Finally, how much the springback influenced by several factors is studied, including die更多还原