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

• Applicants: Professor Dr.-Ing. Dirk Biermann; Professor Dr.-Ing. Peter Eberhard
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering ; Mechanics
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 439917965

As a result of rapidly rising energy costs, it is becoming more and more important to improve the efficiency and optimization of tools in machining production. As the total energy consumption of machining operations is significantly influenced by the cooling lubricant supply due to the energy-intensive process requirements, such as high volume flows, this area offers great potential for optimization in order to carry out cutting processes in a resource-efficient manner. Ejector deep hole drilling in particular makes it possible to use high-precision deep hole drilling processes with high cutting performance and excellent surface qualities on conventional machining centers. Due to insufficient process knowledge of the physical processes occurring during ejector deep hole drilling, the current use in the industry is associated with an inefficient use of resources, as the coolant volume flow is often set significantly higher than required, resulting in higher process costs with greatly increased energy consumption. This leads to the overall objective of this cooperative research project, which is to develop tools and processes for efficient ejector deep drilling processes. In the first funding phase of the research project, the mesh-free simulation approach of Smoothed Particle Hydrodynamics (SPH) in combination with current experimental and measuring analysis methods was used to develop a deeper understanding of the interactions of the flow conditions and to implement them in a physical simulation model. In the second funding phase, the thermomechanical load was characterized and the chip formation during ejector deep hole drilling was analysed. These were used as input and validation data for the structure and flow simulation. With the help of the SPH simulation, the flow characteristics at the drill head were modelled and the influence of the design optimization measures with regard to improved cooling lubricant supply to the cutting edges and guide pads as well as improved chip removal was validated. Based on the results, two prototype versions were additively manufactured using the powder bed process and their usability is being tested in current test series. The third funding phase pursues the final main objective of fully capturing the ejector deep hole drilling process and developing additively manufactured modular ejector nozzle adapters based on the modeling results and integrating them into the coolant supply area of the tool system. Finally, an energy efficiency analysis is performed, which takes all the research results into account and compares the flow-optimized ejector drill heads in combination with the modular ejector nozzle adapter and the optimum working regime with the reference tool with standard parameters.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2231: Efficient cooling, lubrication and transportation – coupled mechanical and fluid-dynamical simulation methods for efficient production processes (FLUSIMPRO)