Investigation on the machining mechanism and quality of an ice-coated drilling method for thin-walled parts

Abstract

The drilling of thin-walled parts often encounters serious issues, such as low machining dimensional and geometric accuracy, thus compromising the integrity of the hole wall surface and subsurface layer. These issues are major constraints in achieving high-quality and high-precision manufacturing in aerospace and other industries. This study proposes an innovative ice-coated drilling (ICD) method for thin-walled parts and delves into the discussion of its machining mechanism. Four typical aerospace materials with thin-walled parts were selected as the research objects. The influence of different processing methods on machining quality was comprehensively evaluated by comparing and analyzing the performance of traditional drilling (TD) and ICD in terms of the flatness, parallelism, roundness, diameter error, axial force, torque, hole wall, and chip morphology of the hole. Results show that ICD remarkably improves the flatness and parallelism of the four thin-walled parts through the cooling effect and auxiliary support function of the ice layer, and it optimizes the roundness and diameter error of the hole. Moreover, the hole wall is smooth without defects, the height of the outlet burr is greatly reduced, and the overall machining quality is remarkably improved. In addition, the presence of the ice layer not only reduces axial forces and torque but also enhances residual compressive stress. The effects of different machining methods on cutting temperature were further analyzed, and the mechanism of ICD to suppress the heat-affected zone (HAZ) was elucidated. This study provides a novel and efficient solution to the challenges of machining thin-walled parts in manufacturing fields, such as aerospace.