When sourcing CNMG inserts, you must prioritize the substrate material (typically tungsten carbide) and the coating technology. For steel machining, look for CVD (Chemical Vapor Deposition) coatings like TiCN or Al2O3 for heat resistance. For stainless steel or superalloys, PVD (Physical Vapor Deposition) coatings are preferred due to their thinner, sharper edges. Additionally, verify the chipbreaker geometry (e.g., -MS, -MA, or -GH) to ensure it matches your specific application—whether it is finishing, semi-finishing, or heavy roughing.