Process limits for incremental flanging and hole flanging operations using a CNC controlled forming tool

板料渐进成形（ISF）具有一系列的技术优势和潜力。这些优势包括低零件专用模具、快速升温时间带来的高灵活性以及更高的成形极限。特别是最近开发的工艺组合（例如拉伸成形和ISF的组合）提供了低成本生产复杂金属板件的可能性，以满足低工具需求并减少加工时间。因此，技术进步已经达到了一个需要调查整个过程链的状态。除了主要的成形和修边步骤外，精加工操作，如用于引入功能元件的翻边和孔翻边，也是完整制造工艺的一部分。因此，在这项工作中，对ISF在这些元素形成中的应用进行了系统的研究。该项目的总体目标是探索翻边的基本原理以及ISF的孔翻边操作，并使ISF能够使用这些精加工操作的技术要求。在第一个项目期间，对这一过程有了基本的了解。考虑并分析了单个工艺参数的个体影响。结果表明，渐进成形特性允许（显着）扩展已知的传统成形操作的工艺限制。在拟议的研究期间，汇编的知识是在一个常用的CAM工具访问。在计算机辅助制造（CAM）程序中直接执行后续操作是有效利用所示技术潜力的要求。此外，可实现的孔凸缘性能将相对于所得到的几何精度进行优化。为了充分利用增量孔翻边操作的潜力，必须满足几何精度（90°壁角）。此外，预成型步骤的影响进行了分析。因此，要检查所确定的高成形极限在多大程度上可转移到预成形部件的后续加工中。最后，将获得的结果传输到一个复杂的应用程序组件。

Incremental sheet forming (ISF) offers a set of technological advantages and potentials. These include low part specific tooling, high flexibility due to short ramp up times and increased forming limits. Especially the recently developed process combinations (e.g. the combination of stretch forming and ISF) offer the possibility of low cost production of complex sheet metal parts meeting low tooling demand and reduced process times. Thus, the technological progress has reached a state that requires investigations of the complete process chain. Beside the primary forming and trimming steps finishing operations, such as flanging and hole flanging for the introduction of functional elements, are part of the complete manufacturing process. Therefore systematic studies on the application of ISF for forming of these elements are carried out within this work. The overall objective of the project is to explore the fundamentals of flanging as well as hole flanging operations by ISF and to enable the technological requirements for the use of these finishing operations by ISF. In the first project period a basic understanding of the process has been established. Individual influences of single process parameters was considered and analysed. It was shown that the incremental forming character allows (significant) extension of known process limitations of conventional forming operations. In the proposed research period the compiled knowledge is to be made accessible in a commonly applied CAM tool. A direct implementation of the follow-up operations in the computer aided manufacturing (CAM) routine is a requirement for an efficient use of the shown technology potentials. Furthermore, the achievable hole flange properties are to be optimized with respect to the resulting geometrical accuracy. To fully utilize the demonstrated potential of incremental hole flanging operations it is mandatory to meet the geometrical accuracy (wall angle of 90°). Additionally the influence of pre-forming steps is to be analysed. Therefore it is to be examined to what extent the identified high forming limits are transferable to a subsequent processing of preformed components. Finally, the obtained results are transferred to a complex application component.