Development of a simulative model for analysis of the effect of cooling lubricants in deep hole drilling with small diameters with respect to chip formation

在DFG的前期研究中，建立了一个流固耦合（FSI）仿真模型来分析螺旋深孔钻削过程中冷却润滑剂的影响。通过耦合有限元（FE）和计算流体动力学（CFD）模拟，可以对刀具、工件和切屑形成之间的相互作用进行建模。在CFD模拟中首次使用了具有特定温度运动中心粘度的深孔钻井油，而不是水。然而，在冷却剂流的CFD模拟中，没有考虑到加工过程中发生的温度变化（取决于待加工的材料和加工时间）的油粘度。为了应用FSI仿真模型来优化工具和工艺，有必要详细考虑冷却润滑剂的粘性特性，这是强烈依赖于温度和压力。因此，该后续项目的重点目标是相应地扩展现有的FSI仿真模型，以包括由于加工过程中的压力和温度变化而导致的冷却液特性变化。利用数学方程，可以定义动态冷却润滑剂特性，并通过FSI仿真模型中的相应变量来实现。采用螺旋深孔钻和工件材料Ti-6Al-4V进行的深孔钻削实验为模拟提供了输入数据。在确定了不同进给量和切削速度下的刀具温度后，对不同冷却压力下的流体流动进行了数值计算。目的是最大化冷却剂流速和冷却剂流动压力，以便在切削刃区域中提供更好的冷却剂供应。通过这些模拟确定的参数组合，将进行实验刀具寿命调查，以确定改进的冷却剂供应对刀具磨损的影响。

In the previous DFG project, a fluid-structure interaction (FSI) simulation model was developed to analyze the influence of the cooling lubricant during spiral deep hole drilling. It was possible, to model the interaction between tool, workpiece and chip formation by coupling the Finite Element (FE) and Computational Fluid Dynamics (CFD) simulation. Instead of water, deep hole drilling oil with a specified, temperature dependent kinematic center viscosity was used for the first time in the CFD simulation. However, the temperature changes that occur during the machin-ing process depending on the material to be machined and the machining time were not taken into account for the viscosity of the oil in the CFD simulation of the coolant flow. In order to apply the FSI simulation model to optimize tools and processes, it is necessary to consider in detail the cool-ing lubricant viscous properties, which are strongly dependent on temperature and pressure. The objective in the focus of this follow-up project is therefore to extend the existing FSI simulation model accordingly, in order to include the changing properties of the coolant due to pressure and temperature changes in the machining process. Using mathematical equations, the dynamic cool-ing lubricant properties, can be defined and implemented by corresponding variables in the FSI simulation model. Deep hole drilling experiments using spiral deep hole drills and the workpiece ma-terial Ti-6Al-4V provide the input data for the simulation. After determining the tool temperature with the simulation for different feeds and cutting speeds, a numerical calculation of the fluid flow at dif-ferent cooling lubricant pressures is performed. The aim is to maximize the coolant flow velocity and the coolant flow pressure in order to provide a better coolant supply in the cutting edge area. With these simulatively determined parameter combinations, experimental tool life investigations will be carried out to determine the influence of the improved coolant supply on tool wear.