Tool and Process Optimization for efficient Ejector Deep-Hole Drilling-Processes using Smoothed Particle Hydrodynamics (SPH)

喷射器深孔钻孔可以利用深孔钻孔的典型工艺优势，例如高金属去除率以及低直线度偏差，在工业应用的传统加工中心上，成本相对较低，因为该工艺不需要昂贵的特殊机器，其冷却润滑剂供应不需要复杂的密封。与常规钻井方法相比，喷射器深孔钻井的另一个优点是可以获得优异的表面质量和孔质量。钻头上的导向垫通过井壁的塑性变形使井壁表面的粗糙度峰平滑，因此通常不需要重新加工井壁，例如通过扩孔。此外，通过工具的内管去除切屑可以防止产生的孔壁损坏。在冷却、润滑和输送芯片的主要功能方面，喷射式深孔钻井为冷却润滑剂（冷却剂）的使用提供了巨大的潜力，从而提高了能源和资源效率，从而有助于提高效率并缩短生产过程链。在研究项目的第一阶段，采用平滑粒子流体动力学（SPH）的无网格模拟方法，结合现有的实验和测量分析方法，深入了解流动条件的相互作用，并在物理模拟模型中实现。各研究机构跨学科合作的成功成果已发表在各种科学出版物上。本项目第二阶段的主要目标是通过并行不可压缩光滑粒子流体动力学（ISPH）算法扩展仿真模型，以实现与热工具和工件载荷的耦合。借助仿真模型和基于钻井过程中实验确定的工具负载的静态负载分析，调整了钻头的设计，以改善切削刃的冷却剂供应，并在较低冷却剂体积流量下产生喷射器效应，同时改善切屑的去除。最后，采用增材制造和使用了流量优化的喷射器。

Ejector deep hole drilling allows to exploit the process-typical advantages of deep hole drilling, such as high metal removal rates as well as low straightness deviations, on conventional machining centers for industrial applications at relatively low cost, because no expensive special machines with complex sealing for the cooling lubricant supply are required for the process. Another advantages of ejector deep hole drilling lie in the excellent surface qualities and bore quality that can be achieved compared to conventional drilling methods. The guide pads on the drill head generate a smoothing of the roughness peaks on the bore surface by plastic deformation of the bore wall, so that typically no reworking of the bores, e.g. by reaming, is required. In addition, the removal of chips through the inner tube of the tool prevents damage to the bore wall produced. Ejector deep hole drilling offers great potential for making the use of cooling lubricant (coolant) more energy- and resource-efficient with regard to the main functions of cooling, lubricating, and transporting chips, thus contributing to an increase in efficiency and a shortening of the process chain in production. In the first stage of the research project, the grid-free simulation approach of Smoothed Particle Hydrodynamics (SPH) in combination with current experimental and measurement analysis methods was used to develop an in-depth understanding of the interactions of the flow conditions and to implement it in a physical simulation model. The results of the successful interdisciplinary collaboration of the research institutes have already been published in various scientific publications. An essential goal of the second phase of this project is to extend the simulation model by a parallel Incompressible Smoothed Particle Hydrodynamics (ISPH) algorithm in order to realize a coupling with the thermal tool and workpiece loads. With the aid of the simulation model and a static load analysis based on the tool load determined experimentally during the drilling process, the design of the drill head is adapted to allow an improved coolant supply to the cutting edge and the occurrence of the ejector effect at lower coolant volume flows, as well as to improve chip removal. Finally, the flow-optimized ejector tools are additively manufactured and used.