Comparative performance analysis of cemented carbide, TiN, TiAlN, and PCD coated inserts in dry machining of Al 2024 alloy

Dry machining of aluminum (Al) 2024 alloy has been performed with four different cutting inserts (cemented carbide, titanium nitride (TiN) coated, titanium aluminum nitride (TiAlN) coated, and polycrystalline diamond (PCD) coated), and their performance is assessed for tool wear and workpiece surface roughness. Design of experiments and response surface methodology (RSM) was performed to optimize the cutting parameters. TiAlN coated inserts presented an average ≈ 21%, ≈ 36%, and ≈ 58% less tool wear than the uncoated cemented carbide, TiN and PCD coated inserts, respectively. While TiN coated inserts exhibited an average ≈ 17%, ≈ 37%, and ≈ 42% less workpiece surface roughness than the uncoated cemented carbide, TiAlN, and PCD coated inserts, respectively. PCD coated inserts have greater mechanical properties, but due to the poor adhesion strength of the coating, it performed worst regarding tool wear and workpiece surface roughness. Energy dispersive X-ray spectroscopy (EDX) analysis of the chips validated our findings that the adhesion of coated tools is also very important for the evaluation of machining performance other than mechanical properties. It is concluded that the mechanical properties and adhesion of the coated tools are both important in assessing the tool wear and workpiece surface roughness. Also, the research community and industry need to consider adhesion strength of the coated tools for better machining performance.