数控渐进成形质量影响因素研究

发布时间：2018-11-22 11:03

【摘要】：目前,对于数控渐进成形质量影响因素的研究大都是从进给参数、层间距、成形工具尺寸等方面进行分析。并且,评价指标也都是从厚度或者表面粗糙度单方面进行考虑的,还没有从成形方式、成形支撑模完整性以及成形轨迹等方面来综合考虑数控渐进成形制件的轮廓精度、表面质量等成形质量指标。本文所研究的数控渐进成形质量影响因素针对成形方式、支撑模完整性和成形轨迹方面,研究了具体的成形方案设计和轨迹规划,通过有限元分析和实际成形实验,探讨了各个因素对板材成形质量的具体影响,给出各因素参数的最优选择,为渐进成形技术的各参数设定与优化提供有力依据,为此技术的研究与实际应用推广提供技术基础。首先,针对异形板材件的成形,进行了成形方式的创新。对于双凸板材件的成形,提出了基于双面挤压的双凸板材件数控渐进反向成形方法,研究了双凸板材件的成形工艺方案;对于单一正向或反向渐进成形不能成形的板材件,提出一种正向成形与反向成形复合的成形方法,研究出了该成形方法中三种成形顺序:反向-正向成形、正向-反向成形、正向/反向并行成形的确定与规划。其次,为解决数控渐进成形时是否采用支撑以及采用何种类型支撑的问题,探讨了支撑模的完整性对成形质量的影响。以典型板材件为研究对象,分别采用整体支撑模、部分支撑模和无底支撑模三种支撑类型进行成形质量分析。再次,通过对比分析数控渐进成形件和数控铣削件的表面残留高度,研究了数控铣削加工模式中残留高度计算方法在数控渐进成形中的可应用性,以及等残留高度轨迹在数控渐进成形中的适用性。第四,为提高数控渐进成形中成形件轮廓的尺寸精度和表面质量,提出了一种通过二次挤压加工来修正由于反弹变形引起的尺寸误差和消除残留痕迹的成形工艺,并给出了通过识别残留痕迹波峰来生成一个能够使挤压工具准确挤压残留痕迹波峰的二次挤压成形轨迹规划和生成方法。最后,应用ANSYS/LS-DYNA有限元分析软件分别对以上所提方法的成形过程进行渐进成形数值模拟,对成形轮廓精度进行了分析。同时,分别进行了成形实验,更进一步对所提出的理论方法进行了验证。
[Abstract]:At present, the research on the influence factors of NC progressive forming quality is mainly from the aspects of feed parameters, layer spacing, forming tool size and so on. Moreover, the evaluation indexes are considered unilaterally from thickness or surface roughness, and the contour accuracy of NC incremental forming parts is not considered synthetically from the aspects of forming mode, forming support die integrity and forming track, etc. Surface quality and other forming quality indicators. In this paper, the influencing factors of NC incremental forming quality are studied, including the forming mode, the integrity of supporting die and the forming track. The specific forming scheme design and trajectory planning are studied. The finite element analysis and the actual forming experiment are carried out. The influence of various factors on the forming quality of sheet metal is discussed, and the optimal selection of each factor parameter is given, which provides a powerful basis for setting and optimizing the parameters of incremental forming technology, and provides the technical basis for the research and practical application of the technology. Firstly, the forming method of special-shaped sheet metal is innovated. For the forming of double convex sheet metal, the NC incremental reverse forming method based on double face extrusion is put forward, and the forming process scheme of double convex sheet metal is studied. For sheet metal which can not be formed by single forward or reverse progressive forming, a compound forming method of forward forming and reverse forming is put forward, and three kinds of forming sequences in this forming method are studied: reverse forward forming, forward reverse forming. The determination and planning of forward / reverse parallel forming. Secondly, in order to solve the problem of whether and what type of brace is used in NC progressive forming, the influence of the integrity of bracing die on forming quality is discussed. Taking the typical sheet metal as the research object, the forming quality analysis was carried out by adopting three kinds of supporting die, I. e., integral supporting die, partial supporting die and unsupported die. Thirdly, by comparing and analyzing the surface residual height of NC incremental forming parts and NC milling parts, the applicability of residual height calculation method in NC progressive forming is studied. And the applicability of equal residual height locus in NC incremental forming. Fourthly, in order to improve the dimension accuracy and surface quality of the profile in NC progressive forming, a new forming process is proposed to correct the dimension error caused by rebound deformation and eliminate the residual trace by secondary extrusion processing. In addition, a method to generate the residual trace wave peak by identifying the residual trace wave peak is presented, which can make the extrusion tool accurately extrude the residual trace wave peak, and the planning and generation method of the secondary extrusion forming trajectory are also given. Finally, the ANSYS/LS-DYNA finite element analysis software is used to simulate the forming process of the above method, and the precision of the profile is analyzed. At the same time, the forming experiments were carried out respectively, and the theoretical method was further verified.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG306

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