When sourcing Carbide Ball Nose Cutters, you must prioritize Sub-micron or Micro-grain Carbide substrates (typically with a grain size of 0.4μm to 0.6μm) to ensure a balance between hardness and toughness. The Helix Angle is critical; a 30° to 35° angle is standard for general purpose, while 45° or higher is better for hardened steels to reduce cutting forces. Additionally, verify the Ball Nose Radius Tolerance, which for high-precision molds should be within ±0.005mm to ensure surface finish accuracy.