Coupled Eulerian-Lagrangian (CEL) simulation of the chip breaking in a single lip deep hole drilling process (SLD)

In single lip deep hole drilling (SLD), the shape and size of the chips are of particular importance. To ensure reliable chip removal, the chips should be in a suitable shape for transportation through the narrow chip space in the drilling tool. With the help of pulsations along the main axis of the spindle, the chip breakage can be improved in a controlled manner to achieve a more favorable chip shape. In this work, chip formation is optimized with Coupled Eulerian-Lagrangian (CEL) simulation starting with developed helical workpiece. Chip formations of different materials (42CrMo4 – 1.7225; EN AW 6082 T6 – 3.2315; OFHC Copper – CW009A) are investigated. A sinusoidal movement of the tool is defined in the simulation to influence chip breaking varying the amplitude. The chips generated in the simulation are compared with the chip shapes from experimental deep hole drilling. The article presents the model structure for the SLD process using CEL simulation with the defined boundary conditions during pre-processing. The results of the simulations document the drilling process based on the angle of rotation and the simulation time. The chip formation on the inner and outer cutting edge of the drilling tool is shown in 3D using the comparative von Mises stress. Chip breaking with and without pulsation as well as simulations with different pulsation amplitudes, are compared. Diagrams of the feed force and the drilling torque with the different pulsation amplitudes and comparisons between the different simulation parameters summarize the results presented in this article.