Development of a greybox model to predict tool wear of PVD coatings for finish turning - GreyProPVD

涂层硬质合金刀具经常用于具有几何定义的刀具的加工。根据工艺条件和材料组合的不同，刀具可能会因磨损、粘着、扩散和摩擦氧化而产生凹坑、后刀面和缺口磨损。此外，粘结衬底失效也可能导致剥落。尽管刀具磨损对切削过程有很大的影响，但根据目前的研究状况，涂层刀具的实际应用行为还不能很好地预测。虽然实验方法需要大量的能量和物质资源，但纯模拟的基于有限元的方法由于计算工作量和时间要求较高而不适用。因此，这两种工具主要用于不考虑投入变量的广泛变化的个别调查。然而，基于模拟的方法与数据驱动的黑盒方法的扩展或组合提供了提高工具开发模型的性能和可用性的可能性。这种结合的方法还提供了将摩擦学和热物理工具性能的变化以及经验数据整合到工具和地层开发的模拟模型中的可能性。性能变化的映射对于PVD涂层刀具用于精加工操作的时间分辨磨损预测特别重要。该研究项目的主要目的是建立一个灰箱模型来描述PVD涂层硬质合金刀具的时间分辨连续磨损和粘结基板失效。通过描述磨损行为，可以适应不同的切割材料组合和工艺参数，从而减少刀具磨损和避免废品，从而减少材料消耗资源。为此，基于数据的黑盒模型与基于模拟的白盒模型相结合。黑盒模型被用来推导与磨损相关的、时间分辨的层性能和磨损常数，以及基于现有的层和基板的残余应力来预测粘结基板的失效。白盒模型用于计算接触条件和热机械载荷，用于局部状态变量的时间相关预测，如法向应力、滑动速度和刀具温度。实验是在连续切削条件下进行的。在第二阶段的准备中，计划将模型扩展到中断的切割条件，作为铣削的中间步骤。

Coated carbide tools are frequently used for machining with geometrically defined cutting edges. Depending on process conditions and material combinations, the tools are subject to crater, flank and notch wear generated by abrasion, adhesion, diffusion and tribooxidation. In addition, spalling can occur due to cohesive substrate failure. Despite the significant influence of tool wear on the cutting process, the real application behavior of coated tools cannot be adequately predicted according to the current state of research. While experimental approaches require a high amount of energy and materials resources, purely simulative, FE-based methods are unsuitable due to their high computational effort and time requirements. Both tools are therefore mainly useful for individual investigations that do not consider a wide variation of input variables. However, the extension or combination of simulation-based methods with data-driven black-box approaches offers the possibility to improve the performance and usability of models for tool development. The combined approaches also offer the possibility of integrating changes in tribological and thermophysical tool properties, as well as empirical data, into simulation models of tool and layer development. The mapping of property change is particularly highly relevant for time-resolved wear prediction of PVD coated cutting tools for finishing operations. Main aim of the proposed research project is the configuration of a greybox model to describe the time-resolved continuous tool wear and cohesive substrate failure of PVD coated carbide tools. By describing the wear behavior, an adaptation of different cutting material combinations and process parameters is possible, which leads to reduced tool wear and the avoidance of reject components and thus enables a reduction of resources in material consumption. For this purpose, data based black box models are combined with a simulation-based white box model. The blackbox models are used to derive wear-dependent, time-resolved layer properties and wear constants as well as the prediction of cohesive substrate failure based on the existing layer and substrate residual stresses. The whitebox model is used to calculate contact conditions and thermomechanical loads for time-dependent prediction of local state variables such as normal stress, sliding velocity and tool temperature. The experiments are carried out in continuous cutting conditions. In preparation for the second phase, an extension of the model to interrupted cutting conditions is planned as an intermediate step for milling.