薄壁铝合金封头挡板辅助旋压成形新工艺研究

发布时间：2018-07-21 11:25

【摘要】：旋压是板料连续局部塑性成形方法,具有高质、高效、节能、节材等优点。但成形过程复杂,属于大应变、非线性变形问题,容易出现起皱和开裂问题。薄壁铝合金封头整体刚度较低,旋压过程中更容易产生法兰起皱缺陷,其成形性难以控制。因此如何改进薄壁铝合金封头的旋压工艺,提高成形质量成为研究热点。本文设计了不同径厚比的封头特征零件,研究了封头旋压有限元建模方法,建立了成形质量评价体系,提出了薄壁铝合金封头挡板辅助旋压成形新工艺,对比研究了不同径厚比条件下新工艺的优势,并讨论了尺寸及主要工艺参数对成形质量的影响。本文的主要工作内容包括以下四点:(1)基于ABAQUS/Explicit平台,研究了薄壁铝合金封头旋压有限元建模方法,建立了包含壁厚均匀性和贴膜度的成形质量评价体系;(2)针对传统旋压工艺繁琐、壁厚不均的问题,提出了薄壁铝合金封头挡板辅助旋压成形新工艺,通过在法兰前方设置一刚性挡板,提高法兰支承刚度,可实现特征薄壁封头一道次普旋成形;(3)在此基础上,对挡板辅助旋压和预弯边的先剪后普多道次旋压两种工艺进行了对比研究,发现新工艺得到的构件壁厚均匀性明显优于传统工艺,贴膜度也较传统工艺好。随着径厚比的增大,薄壁结构的弱刚性特征突出,传统工艺需要增加道次数目来克服起皱,但新工艺仍然能够一道次普旋成形,且径厚比越大,新工艺对壁厚均匀性的改善作用越显著;(4)研究了新工艺条件下尺寸参数(板料直径)及主要工艺参数(进给率、旋轮圆角半径和旋轮安装角)对封头成形质量的影响规律,通过合理的参数优化配置,可以在提高壁厚均匀性的同时改善构件贴膜情况,实现零件的优质高效成形;
[Abstract]:Spinning is a continuous local plastic forming method for sheet metal, which has the advantages of high quality, high efficiency, energy saving and material saving. However, the forming process is complex and belongs to the problem of large strain and nonlinear deformation, so it is easy to wrinkle and crack. The integral stiffness of thin-walled aluminum alloy head is low, and the flange wrinkling defect is more easily produced in spinning process, and its formability is difficult to control. Therefore, how to improve the spinning process of thin-walled aluminum alloy head and improve the forming quality has become a research hotspot. In this paper, the characteristic parts of the head with different ratio of diameter to thickness are designed, the finite element modeling method of the head spinning is studied, the evaluation system of forming quality is established, and a new technology of the thin wall aluminum alloy head baffle assisted spinning forming is put forward. The advantages of the new process under different ratio of diameter to thickness are studied, and the influence of the size and main process parameters on the forming quality is discussed. The main work of this paper includes the following four points: (1) based on Abaqus / explicit platform, the finite element modeling method of thin-walled aluminum alloy head spinning is studied, and the forming quality evaluation system including wall thickness uniformity and film adhesion is established. (2) the traditional spinning process is cumbersome. The problem of uneven wall thickness is discussed. A new technology of auxiliary spinning forming for thin-walled aluminum alloy head baffle is put forward. By setting a rigid baffle in front of the flange, the supporting stiffness of the flange can be improved, and the characteristic thin-walled head can be rotated together. (3) on this basis, A comparative study was made between the two processes of baffle assisted spinning and prebending edge cutting and then prebending. It was found that the uniformity of wall thickness of the components obtained by the new technology was obviously better than that of the traditional process, and the film sticking degree was better than the traditional process. With the increase of the ratio of diameter to thickness, the weak rigidity of thin-walled structure is prominent. The traditional process needs to increase the number of passes to overcome the wrinkle, but the new process can still be formed by a secondary rotation, and the larger the ratio of diameter to thickness, the greater the ratio of diameter to thickness. (4) the influence of dimension parameters (sheet diameter) and main process parameters (feed rate, rotary wheel radius and wheel mounting angle) on the forming quality of the head is studied. By optimizing the parameters, we can improve the uniformity of the wall thickness and the case of the component film, and realize the high quality and high efficiency forming of the parts.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306

【参考文献】