Towards understanding the material removal mechanism in multi-tooth milling of 2.5D C/SiC composites: numerical modeling and experimental study

Multi-tooth cutting is an effective method for materials machining with high quality and efficiency. To lay a foundation for the feasibility in multi-tooth milling of 2.5D C/SiC composites, combining with a new micro-macro scale numerical model and experimental analysis, the interaction mechanism and damage fracture mechanism between different fiber (0 degrees, 90 degrees, and Z-direction needling punched fiber) and multi-tooth scales mill are studied. Two main mechanisms resulting in fiber fracture are found, namely the extruding flexural fracture and micro-crack propagation fracture. The proposed numerical model is in good agreement with the experimental results in terms of fiber removal, chip forming, and surface topography. Specifically, fiber debonding and micro-crack propagation fracture occur in 0 degrees fiber, and lamellar surface is produced. 90 degrees fiber is mainly broken by shearing action and extruding bending. Correspondingly, the pits appear due to the fiber pulling out. Extruding flexural fracture occurs in Z-direction needle punched fiber, and peeling and lamellar surface is formed. Multi-tooth of the scales mill plays a repairing and grinding effect on the machined surface. And arc micro edge can restrain the formation of the fiber delamination and burr damage in particular. The study provides a new sight in low damage milling of 2.5D C/SiC composites.