Reducing delamination risk with response surface methodology-supported drilling analysis for Nomex® aramid fiber composites

This article presents a comprehensive experimental investigation into the drilling behavior of Nomex®, a type of aramid fiber. The study specifically examines the impact of various cutting parameters and drill bit types on drilling outcomes. While Nomex® offers many advantages, difficult chip evacuation during drilling of aramid fiber composites can lead to surface defects and delamination. The research aims to explore how drilling parameters—such as spindle speed, feed rate—and four distinct drill bit types affect drilling performance. The analysis encompasses factors such as thrust force, torque, and surface roughness, studied under different drilling conditions and with various drill bit types. Moreover, the research assesses peeling and push-out delamination factors to gain insights into drill bit and coating characteristics. An examination of burr and chipping further enhances the comprehension of drilling performance. To determine the most effective drilling conditions, the study employs multi-response optimization. The optimal drilling performance is achieved with a combination of a 0.1 mm/rev feed rate, 1402.82 r/min spindle speed, and HSS-TiN drill type. This configuration successfully integrates responses, resulting in a composite desirability value of 0.95.