When sourcing CNC carbide, you must prioritize the substrate grade, coating type, and geometry. For high-speed machining, look for PVD (Physical Vapor Deposition) coatings like TiAlN for heat resistance, or CVD (Chemical Vapor Deposition) coatings for heavy-duty turning. Ensure the ISO classification (P, M, K, N, S, H) matches your workpiece material—for instance, K-grade is essential for cast iron, while P-grade is standard for steel. Additionally, verify the edge toughness and chip-breaker design to ensure optimal chip evacuation and surface finish.