Micro-structuring and macro-structuring of deep drawing tools for dry forming condition

成形过程中的大摩擦力降低了工艺极限。因此，通常使用润滑剂来减少摩擦并扩大工艺窗口。然而，润滑剂的技术优势伴随着负面的经济和生态影响。因此，在该项目中，通过保护涂层和工具的微观和宏观结构的综合概念，研究和分析了深冲过程中的润滑剂消除。在第一阶段，从根本上分析了不同的综合方法的技术和工具结构的深冲过程进行了实验验证。对于轴对称零件，证明了一般的可行性。在第二个供资期，程序原则得到进一步完善。对于一个时间效率的过程设计的分析模型已被开发描述的输入参数的影响的风险，起皱和底部裂纹。此外，一项关于高强度钢的可行性研究表明，宏观结构深冲工艺比标准工艺具有更多的优势。通过研究涂层技术和工具的微观结构来降低摩擦力，并研究了涂层和结构化表面的磨损行为以及与坯料和工具表面的相互作用。所有技术都转移到非轴对称零件的模块化工具的设计中。基于这些结果，第三阶段的研究目标是为复杂零件和高强度材料实施工业相关的无润滑剂拉深工艺。主要的方法仍然是在宏观结构化，涂层和微观结构化领域的不同工艺的综合应用。将宏观结构增强为三维几何形状是一个关键因素，因为它允许直接控制切向和径向方向的材料流，因此可以系统地调整应力以及弯曲和伸直，以特定地设置零件特性。调整后的半解析模型用于设计宏观结构和选择工艺参数。相应的高要求的成型工艺有关的摩擦和磨损的工具将解决与涂层和微结构的组合方法。目标是通过调整涂层和结构化工艺来改善以前的结果。具体而言，将实施具有氟改性ta-C层的新涂层，并且铬结合层将由硝化工艺取代。此外，DLIP工艺将通过缩短脉冲时间和均匀化激光束来调整，以提高微结构的质量，同时最大限度地减少对衬底的负面影响。所有技术都将使用第二阶段资助的模块化深拉工具进行集成和验证。

Large friction forces in forming processes reduce the process limits. Generally, lubricants are therefore used to reduce friction and enlarge the process window. However, the technological advantages of lubricants are accompanied by negative economic and ecological effects. Therefore, the elimination of lubricants from deep drawing processes by means of an integrated concept of a protective coating and micro- and macro structuring of the tool is studied and analysed during this project. Within the first phase, the different technologies of the integrative approach were fundamentally analysed and the deep-drawing process with tool structuring was experimentally verified. The general feasibility was demonstrated for axially symmetric parts. In the second funding period, the process principle has been further improved. For a time efficient process design an analytical model has been developed describing the influence of input parameters on the risk of wrinkling and bottom cracks. Furthermore, a feasibility study regarding high-strength steels indicated additional advantages of a macro-structured deep drawing process over standard processes. The reduction of friction forces was pursued by investigating coating technology and micro-structuring of tools and the wear behaviour of coated and structured surfaces and the interaction with blank and tool surface were investigated. All technologies were transferred to the design of a modular tool for non axially symmetric parts. Based on these results, the third research phase has the goal to implement an industrially relevant lubricant free deep drawing process for complex parts and high strength materials. The main approach remains an integrative application of different processes in the areas of macro-structuring, coating and micro-structuring. The enhancement of the macro-structuring into three-dimensional geometries is a key factor, because it allows the direct control of the material flow in tangential and radial direction, and therefore the systematic adjustment of stresses as well as bending and unbending to specifically set part characteristics. An adjusted semi-analytical model is used for designing the macro-structures and choosing process parameters. The corresponding high requirements of the forming process regarding friction and wear of the tools will be addressed with a combined approach of coating and micro-structuring. The goal is to improve on previous results by adjusting the coating and structuring processes. Specifically, a new coating with a fluor modified ta-C layer will be implemented and the chromium bonding layer will be substituted by a nitration process. Additionally, the DLIP process will adjusted by shortening pulse times and homogenising the laser beam in order to improve the quality of the micro-structure while minimising negative effects on the substrate. All technologies will be integrated and verified using the modular deep drawing tool from the second funding phase.