Optimization of tool use in sheet metal forming

该研究建议旨在优化金属板成形中的刀具寿命。成形过程中的刀具磨损通常表现出特征性的磨损发展，其中损伤最初线性增加，最后变成指数增加，导致刀具失效。为了优化刀具的使用，有必要尽可能准确地检测这种磨损发展并了解基本机制。工具失效的原因在很大程度上是未知的。在文献中，有一些解释将失效归因于工具粗糙度增加或局部软化。在本研究建议中，应将这些影响分开并进行分析。最后，应确定减少磨损的措施。为了实现这些目标，将进行基于带材拉拔试验的实验磨损试验。第一步包括各种摩擦学系统的磨损发展的分析，以调查的情况下失败的流行机制。为此，将使用现有的在线监测系统记录磨损发展。此外，监测系统将扩展为电阻测量，以检测金属板和工具之间的接触区域的变化。这旨在改善工具故障的检测。在此基础上，还需要进一步的实验研究，分别考察刀具的粗糙度和硬度对磨损的影响。最后，将验证解释性模型，描述故障情况下的因果机制。此外，还应采取措施，以抵消材料去除或硬度下降造成的磨损。

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.