Greybox models for in-situ quantification of probabilistic tool life of CVD coated cemented carbide gear hobs

本项目提案的总体目标是通过使用确定性模型，结合现场获取的过程数据和机器学习模型，详细描述滚齿过程中热机械刀具的载荷以及cvd涂层硬质合金刀具的刀具磨损，从而实现对过程的使用寿命优化调节。滚齿是齿轮制造的既定工艺。滚齿机加工过程中的载荷谱会导致磨料刀具的磨损，当载荷谱增大时，会对工件的尺寸精度和刀具刃口的稳定性产生负面影响。硬材料涂层和基体微观结构的局部不均匀性以及涂层微观结构参数的变化导致了概率分布的使用寿命，这些寿命会根据实际复杂的操作条件而发生原位变化。通过根据材料强度和加工过程中的应力预测刀具的剩余使用寿命，通过闭环控制可以显著提高涂层刀具的总使用寿命。迄今为止，无论是通过建模还是实验，都无法充分确定或预测故障的发生、磨损过程和剩余使用寿命。为了更深入地了解工艺-微观结构-使用寿命的关系，因此，在本项目建议中，考虑到材料系统和制造相关的残余应力，对摩擦学系统进行了全面的研究。重点研究了采用气相沉积法制备TiCN基材和α-Al2O3顶层的硬质合金滚齿刀具。这些首先在类比测试中表征。在此基础上，建立了涂层-基体微观结构的微观力学模型，一方面可以确定与制造相关的残余应力，另一方面可以模拟磨具的磨损。从用于预测滚刀应力和强度的确定性白盒模型，以及现场工艺数据和黑盒模型，开发了灰盒模型，允许在工艺时间内对材料敏感的（剩余）刀具寿命预测。

The overall objective of the present project proposal is the detailed description of the thermomechanical tool loading during gear hobbing and the resulting tool wear of CVD-coated cemented carbide tools by using deterministic models coupled with in-situ acquired process data and machine learning models to enable service life optimized regulation of the process. Gear hobbing is an established process for gear manufacturing. The load spectrum in gear hobbing leads to abrasive tool wear, which, when increased, negatively affects the dimensional accuracy of the workpiece as well as the stability of the tool cutting edge. Local inhomogeneities in the microstructure of the hard material coating and substrate as well as varying parameters in the coating microstructure result in probabilistically distributed service lives, which change in-situ depending on the real, complex operating conditions. By predicting the remaining service life of a tool depending on the material strength and the stress during machining, the total service life of coated tools can be significantly increased by closed-loop control. To date, the onset of failure, wear progress and remaining service life cannot be identified or predicted with sufficient certainty either by modeling or experimentally. In order to gain a deeper understanding of the process-microstructure-service life relationship, the tribological system is therefore being comprehensively investigated in the present project proposal, taking into account the material system and the manufacturing-related residual stresses. The focus is on gear hobbing tools made of cemented carbide, which are coated with a TiCN base layer and an α-Al2O3 top layer by CVD. These are first characterized in an analogy test. Based on this, a micromechanical model of the coating-substrate microstructure is built up, which enables the determination of the manufacturing-related residual stresses on the one hand and the simulation of the abrasive tool wear on the other hand. From deterministic white-box models for the prediction of stress and strength of the hob as well as by in-situ process data and black-box models, grey-box models are developed, which allow a material-sensitive prediction of the (remaining) tool life within the process time.