Investigation of Surface Quality and Hole Integrity in Drilling AISI 430 with Coated and Uncoated HSS Tools

This study investigates the influence of tool coating and cutting parameters on the surface integrity and dimensional accuracy during drilling of ferritic stainless steel AISI 430. Using both Al-Ti-N coated and uncoated HSS drill bits, experiments were performed under dry conditions with varying spindle speeds (800–1200 rpm) and feed rates (0.1–0.2 mm/rev). Results show that coated tools consistently yielded lower surface roughness (Ra), reduced diameter error, improved hole roundness (ovality), and better perpendicularity. The Al-Ti-N coating significantly mitigated tool wear and thermal effects, enhancing process stability and microhardness near the drilled surface. Optimal drilling performance was observed at lower feed rates and moderate spindle speeds when using coated tools. These findings highlight the critical role of tool coatings and parameter optimization in machining ferritic stainless steels for high-precision applications.