Lubricant free forming with tailored tribological conditions

在无润滑剂成形过程中，工件和刀具表面发生强烈的相互作用。该研究项目的目的是通过开发和应用创新的摩擦学系统来实现干成形过程。干式成型的挑战，如摩擦增加和磨损增加，可以通过定制的工具方法进行基于工具的表面修改来解决。在项目的第一阶段，研究了钢板在无润滑油的拉深工艺下的成形。为了测试导出的相关关系对其他工件材料类别的可转移性，还对铝合金进行了测试。在实验室条件下的基础实验中，通过对发生的摩擦学效应的分析和描述，产生了对润滑剂自由成形的基本认识。同时，测试结果作为基于仿真的演示杯制造分段工具设计的输入值。在有限元模拟中，确定了摩擦学相关的刀具区域。随后，每个刀具段所需的表面特性以逆方法推导出来。这些要求代表了定制表面改性开发的目标。为了保证DLC涂层体系的合理耐磨性，对DLC涂层体系进行了无润滑剂深拉深的适用性评估。在某些工具区域，无润滑剂成形要求涂层具有非常高的耐磨性。为此，研究了激光诱导热处理DLC涂层局部增强耐磨性的方法。此外，为了控制材料的流动，基于工具的表面结构将被开发和应用于激光烧蚀。在开发表面涂层和结构的同时，通过在实验室条件下进行模型试验，研究了不同改性类型的摩擦磨损性能。特别是量化了刀具材料、表面结构和涂层等因素对刀具性能的影响。为了确定干成形过程的极限，在实验室试验中研究了工具行为和发生的过程载荷的相互作用。导出的过程载荷、表面变化和刀具行为之间的相关性用于无润滑剂模型过程中摩擦学条件的局部调整。为了验证这些相关性，在所研究的钢和铝等级的深拉深过程中确定了分段刀具的摩擦和磨损行为。该项目第一阶段的结果代表了在无润滑剂成形过程中应用的定制摩擦学系统资格的基础。

Within lubricant free forming an intensive interaction of workpiece and tool surface occurs. The aim of this research project is the realization of dry forming processes by developing and applying innovative tribological systems. The challenges of dry forming such as increased friction accompanied by increased wear are met by tool based surface modifications in a tailored tool approach. In the first period of the project forming of steel sheets is investigated in a lubricant-free deep drawing process. In order to test the transferability of derived correlations to other workpiece material classes also an aluminum alloy is tested. In basic experiments under laboratory conditions the fundamental understanding of lubricant free forming is generated by the analysis and description of the occurring tribological effects. At the same time the test results serve as input values for the simulation based design of the segmented tool for manufacturing the demonstrator cup. In the FE simulation tribological relevant tool areas are identified. Subsequently, required surface properties for each tool segment are derived in an inverse approach. The requirements represent the targets for the development of tailored surface modifications. In order to guarantee reasonable wear resistance the suitability of DLC coating systems for lubricant free deep drawing is assessed. In some tool areas lubricant free forming requires an extraordinary high wear resistance of the coatings. In this regard the laser induced heat treatment of DLC coatings is investigated for the local enhancement of wear resistance. Furthermore, for the purpose of controlling the material flow tool based surface structures will be developed and applied by laser ablation. While developing the surface coatings and structures the frictional and wear behavior of the different modification types are investigated by carrying out model tests under laboratory conditions. In particular, the influences of the factors tool material, surface structure and coating on the tool behavior are quantified. For determination of the limits of dry forming process the interactions of tool behavior and occurring process loads are investigated in the laboratory tests. The derived correlations between the process loads, the surface modifications and the resulting tool behavior are used for the local adjustment of the tribological conditions within the lubricant free model process. In order to validate these correlations the friction and wear behavior of the segmented tool is determined in the deep drawing process for the investigated steel and aluminum grade. The results of the first period of the project represent the basis for qualification of tailored tribological systems for the application in lubricant free forming processes.