Ultra-precise finishing of parts with complicated geometry has faced many limitations using traditional methods due to the use of rigid tools. This study aims to introduce a new mechanism by developing a rotational abrasive finishing (RAF) operation, where the simultaneous rotation mechanism of a workpiece and the stirring-chamber is used in the opposite directions. In this paper, the associated velocities and forces in the developed RAF technique, the effects of stirring blades rotary speed, working gap as well as various meshing of abrasive grits on material removal (∆m), surface roughness variation rate (∆R_a) the percentage of surface improvement (%∆R_a), and the surface roughness value (R_a), on one of the most important cutting tools, i.e. drill bit, were examined. The research outcomes demonstrated that with increasing the speed of the stirring-chamber combined with the selecting larger abrasive grits, ∆m and ∆Ra will increase, while an increment in working gap resulted in a decrease in ∆m and ∆R_a. Also, reducing surface roughness from micrometer scale to nanometer (from initial value 547 nm to final value 69 nm) resulted in an 87% enhancement in the surface quality. Therefore, the superiority of RAF technique in ultrafinishing of various work parts can be demonstrated theoretically and experimentally.

Carbon fiber-reinforced polymer (CFRP) structures have been increasingly used in various aerospace sectors due to their outstanding mechanical properties in recent years. However, the poor machinability of CFRP plates, combined with the inhomogeneous behavior of fibers, poses a challenge for manufacturers and researchers to define the critical factors and conditions necessary to ensure the quality of holes in CFRP structures. This study aims to analyze the effect of drilling parameters on CFRP delamination and to predict hole quality using a regression-based approach. The design of the experiment (DOE) was conducted using Taguchi’s L9 3-level orthogonal array. The input drilling variables included the feed rate, spindle speed, and three different drill types. A regression-based model using partial least squares (PLS) was developed to predict delamination defects during the drilling of CFRP plates. The PLS model demonstrated high accuracy in predicting delamination defects, with a Mean Squared Error (MSE) of 0.0045, corresponding to an accuracy of approximately 99.6%, enabling the rapid estimation of delamination. The model’s predictions were closely aligned with the experimental results, although some deviations were observed due to tool inefficiencies, particularly with end mill cutters. These findings offer valuable insights for researchers and practitioners, enhancing the understanding of delamination in CFRPs and identifying areas for further investigation.