多道次无芯模旋压成形方式及其优化研究

发布时间：2018-07-12 16:33

本文选题：无芯模旋压 + 分段成形　；参考：《浙江大学》2017年硕士论文

【摘要】：旋压技术作为塑性成形加工工艺的一种,广泛应用于复杂曲面件高精度、轻量、高稳定性的制造加工。目前应用较为广泛的是普通旋压技术,以有芯模为主,但是复杂曲面件芯模的加工制造成本较贵、周期较长,无芯模旋压作为一种无模连续局部金属塑性成形技术,体现了很多优势,研究表明偏移式分段成形方式可以有效控制旋压件的减薄率,但是此方式在多道次无芯模旋压中较少使用,本文将此成形方式应用于无芯模旋压,探讨其对无芯模旋压成形精度的影响。具体的研究内容包括:指出了本文的研究背景,概述了有芯模旋压以及无芯模旋压成形方式与轨迹形状的研究现状,提出了无芯模旋压不同成形精度问题以及成形方式优化问题,并引出本文有关无芯模旋压成形方式研究及其优化的主要内容。构建了多道次无芯模旋压不同成形方式的几何模型及仿真模型。鉴于普旋多道次已经得出的结论,本文分段成形的正返程曲线均使用对壁厚保持较佳的渐开线轨迹。在此基础上推导了渐开线的生成方程,并详细介绍了分段轨迹的确定方法,设计了不同目标曲线的分段成形轨迹。构建了偏转式渐进成形方式几何模型和偏移式分段成形方式几何模型。利用ANSYS/LS-DYNA显示动力学仿真平台构建了不同成形方式的有限元仿真模型,并进行了模型的有效性验证。实验探讨了不同目标轮廓曲线不同成形方式的成形精度。本文所用的实验平台是项目组自主设计的多功能复合式板料旋压机,在设备以及实验条件准备充分的基础上,详细设计了实验方案并进行了旋压实验,利用超声波测厚仪和轮廓测量仪对成形件的壁厚和形状轮廓进行了测量,对结果进行了分析,并得出了针对不同目标轮廓曲线最佳的成形方式。进行了针对复杂目标曲线的无芯模旋压渐进分段成形方式的研究。对三种渐进分段成形方式进行了轨迹设计,针对目标凸凹凸以及凹凸凹曲线进行了实验方案设计并实验验证,得出了对壁厚效果和形状效果保持最优的渐进分段成形方式。进行了成形方式优化和基于进给比优化的成形质量改善研究。为了改善表面质量,提高成形精度,分别进行了基于终道次渐进与前道次渐进分段组合成形方式,以及基于渐进分段与渐进成形混合成形方式的优化研究。并通过不同恒定进给比、道次间变化进给、道次内变化进给的成形质量研究,进一步借助于变进给比优化方式,提高了成形精度。
[Abstract]:As a kind of plastic forming technology, spinning technology is widely used in the manufacture of complex curved surface parts with high precision, light weight and high stability. At present, the common spinning technology is widely used, with the core die as the main part, but the manufacturing cost of the core die of the complex curved surface is more expensive and the cycle is longer. The coreless die spinning is a kind of continuous local metal plastic forming technology without die. The research shows that the offset piecewise forming method can effectively control the thinning rate of spinning parts, but this method is seldom used in multi-pass coreless die spinning. In this paper, this forming method is applied to coreless die spinning. The effect of this method on the forming accuracy of coreless die spinning is discussed. The specific research contents are as follows: the research background of this paper is pointed out, and the research status of the core die spinning, the coreless die spinning mode and the trajectory shape are summarized. The problems of different forming precision and forming mode optimization of coreless die spinning are put forward, and the main contents of this paper about the research and optimization of coreless die spinning are introduced. The geometric model and simulation model of multi-pass coreless die spinning with different forming methods are constructed. In view of the previous conclusions, the positive return curves in this paper all use involute trajectories with good wall thickness. On this basis, the generating equation of involute is derived, the method of determining segmental trajectory is introduced in detail, and the piecewise forming trajectory of different target curves is designed. The geometric models of deflection progressive forming and offset piecewise forming are constructed. The finite element simulation models of different forming modes are constructed by using ANSYS- LS-DYNA display dynamics simulation platform, and the validity of the model is verified. The forming accuracy of different object profile curves and different forming methods was investigated experimentally. The experimental platform used in this paper is a multifunctional compound sheet spinning machine designed by the project team. On the basis of sufficient preparation of the equipment and experimental conditions, the experimental scheme is designed in detail and the spinning experiment is carried out. The wall thickness and shape profile of forming parts were measured by ultrasonic thickness measuring instrument and contour measuring instrument. The results were analyzed and the best forming method for different target contour curves was obtained. The method of coreless die spinning step-by-step forming for complex target curve was studied. In this paper, three progressive piecewise forming methods are designed, and the experimental schemes are designed and verified for the convex and concave curves of the target. The optimum incremental piecewise forming method for the wall thickness effect and shape effect is obtained. The optimization of forming mode and the improvement of forming quality based on feed ratio optimization were carried out. In order to improve the surface quality and improve the forming accuracy, the optimization research was carried out based on the end-pass progressive and the previous progressive piecewise combination forming, and the hybrid incremental and incremental forming. Through the research on the forming quality of different constant feed ratio, variable feed between passes, and variable feed within the pass, the forming accuracy is improved by means of the optimization of variable feed ratio.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG306

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