Cross-scale chip removal process analysis and optimization using hybrid CFD-DEM simulation

Abstract

Drilling is a critical process in the manufacturing of aerospace components, and the quality of drilled connection holes directly determines the service reliability of high-end equipment. During drilling, different materials produce chips of varying sizes (ranging from micrometers to millimeters), leading to issues such as high temperature and tool wear. Efficient removal of these multi-scale chips is essential for improving drilling quality. However, the narrow and complex internal structure of enclosed or semi-enclosed chip removal systems often result in inefficient chip evacuation. In addition, experimental observation of airflow and chip velocity within such system is challenging, hence numerical simulation of the chip removal process become a practical alternative. This study utilizes a hybrid approach combining CFD and DEM simulation (CFD-DEM) to systematically investigate the characteristics of cross-scale chip removal processes. Simulation results show that the diffused airflow and low/negative velocity flow regions of the existing system are unfavorable for chip removal. To address this issue, different eccentric designs and diversion holes were introduced, and their impacts on the chip removal performance have been evaluated. The results were then used to guide the optimization of the chip removal system. Through combined/optimized eccentric design and diversion hole design, the overall chip removal performance of the system shows a significant improvement (48.27%)