Optimization of tool use in sheet metal forming

该研究方案旨在优化板料成形中刀具寿命的使用。刀具在成形过程中的磨损通常表现为典型的磨损发展过程，在此过程中，刀具的磨损最初呈线性增长，最后转变为指数增长，最终导致刀具失效。为了优化工具的使用，有必要尽可能准确地检测这种磨损发展并了解基本机制。工具失败的原因在很大程度上是未知的。在文献中，有将失效归因于刀具粗糙度增加或局部软化的解释。在本研究方案中，这些影响应该被分离和分析。最后，应确定减少磨损的措施。为了实现这些目标，将在拉拔试验的基础上进行试验性磨损试验。第一步包括分析各种摩擦学系统的磨损发展，以便研究失效情况下的主要机制。为此，将使用现有的在线监测系统来记录磨损的发展情况。此外，监控系统还将扩展电阻测量，以检测金属板材和工具之间接触区的变化。这旨在提高对刀具故障的检测。在此基础上，应进行进一步的实验研究，单独考察刀具的粗糙度和硬度对磨损的影响。最后将验证一个解释性模型，描述故障情况下的因果机制。此外，应采取措施抵消材料去除或硬度降低造成的磨损。

The research proposal aims at optimizing the use of tool life in sheet metal forming. Tool wear in a forming process usually shows a characteristic wear development, where the damage initially increases linearly and finally changes into an exponential increase leading to failure of the tool. For an optimized tool use, it is necessary to detect this wear development as accurately as possible and to understand basic mechanisms. The reasons for tool failure are a largely unknown. In literature there are explanations that attribute failure to an increased tool roughness or a local softening. In this research proposal, these effects should be separated and analyzed. Finally, measures for wear reduction should to be determined.In order to achieve these objectives, experimental wear tests based on a strip drawing test will be carried out. The first step includes an analysis of wear development of various tribological systems in order to investigate the prevailing mechanisms in case of failure. For this purpose, an existing online monitoring system will be used to document the wear development. Additionally, the monitoring system will be extended with a resistance measurement to detect changes in the contact zone between sheet metal and tool. This aims to improve the detection of tool failure. Based on these results, further experimental studies should be carried out, investigating the influence of roughness and hardness of the tools on the wear independently. Finally an explanatory model will be validated, describing the causal mechanisms in case of failure. In addition, measures should be derived that counteract wear caused by material removal or decreased hardness.