Category: EndMills
How to Choose the Right CNC End Mill
End mill selection drives surface finish, tool life, and material removal rate. Hooguu stocks end mills from Sandvik, Iscar, Walter, OSG, YG-1, and Kennametal.
Flute Count Selection
- 2-flute — Best chip evacuation. Use for slotting, deep pocket roughing in aluminum and soft materials.
- 3-flute — Aluminum standard. Balances chip evacuation with rigidity. 30-50% higher feed rates than 2-flute.
- 4-flute — Steel and stainless general-purpose. Higher feed rate per revolution; slower chip evacuation requires light radial engagement.
- 5-7 flute — High-speed finishing of steel and superalloys. Trochoidal/peeling tool paths required.
End Mill Materials
- HSS — Cheapest, lowest performance. Light-duty manual mills only.
- HSS-Co (cobalt-alloyed) — Better heat resistance than HSS, good for stainless.
- HSS-PM (powder metallurgy) — Finer grain than HSS-Co, longer tool life.
- Solid carbide — Standard for production CNC. 5-10× HSS tool life, allows 3-5× higher cutting speeds.
- PCD-tipped — Premium for aluminum/composites; lasts 50-100× carbide.
Coating Selection
| Material | Coating |
|---|---|
| Aluminum 6061/7075 | ZrN (gold) or polished uncoated |
| Aluminum (high-Si A380) | DLC or PCD |
| Mild steel | TiAlN |
| Stainless 304/316 | AlTiN |
| Hardened steel (45+ HRC) | nACo nano-composite |
| Inconel/titanium | AlTiN with submicron substrate |
| Cast iron | TiAlN or AlCrN |
Geometry Specs to Match Application
- Helix angle: 30° (general), 38-45° (aluminum, high feed), 50-60° (stainless, vibration-resistant)
- Variable helix: anti-chatter, smoother machining
- Corner radius: stronger than sharp corners, required for HSM
- Length-to-diameter (L:D): keep ≤3 for general work, ≤6 for deep pockets with extra-rigid carbide
HSM (High-Speed Machining) Tips
Modern toolpaths (trochoidal, adaptive clearing in Fusion 360/Mastercam) allow:
- Axial depth: up to 1.5-2× diameter (vs traditional 0.5×)
- Radial engagement: 5-15% diameter (very light)
- Feed: 3-5× traditional rate
- Spindle speed: 80-100% of recommended max
Result: 3-5× tool life and 2-3× cycle time reduction vs conventional contouring.
Browse our complete end mill catalog. See our aluminum-specific end mill selection guide.
How to Choose the Right CNC End Mill
End mill selection drives surface finish, tool life, and material removal rate. Hooguu stocks end mills from Sandvik, Iscar, Walter, OSG, YG-1, and Kennametal.
Flute Count Selection
- 2-flute — Best chip evacuation. Use for slotting, deep pocket roughing in aluminum and soft materials.
- 3-flute — Aluminum standard. Balances chip evacuation with rigidity. 30-50% higher feed rates than 2-flute.
- 4-flute — Steel and stainless general-purpose. Higher feed rate per revolution; slower chip evacuation requires light radial engagement.
- 5-7 flute — High-speed finishing of steel and superalloys. Trochoidal/peeling tool paths required.
End Mill Materials
- HSS — Cheapest, lowest performance. Light-duty manual mills only.
- HSS-Co (cobalt-alloyed) — Better heat resistance than HSS, good for stainless.
- HSS-PM (powder metallurgy) — Finer grain than HSS-Co, longer tool life.
- Solid carbide — Standard for production CNC. 5-10× HSS tool life, allows 3-5× higher cutting speeds.
- PCD-tipped — Premium for aluminum/composites; lasts 50-100× carbide.
Coating Selection
| Material | Coating |
|---|---|
| Aluminum 6061/7075 | ZrN (gold) or polished uncoated |
| Aluminum (high-Si A380) | DLC or PCD |
| Mild steel | TiAlN |
| Stainless 304/316 | AlTiN |
| Hardened steel (45+ HRC) | nACo nano-composite |
| Inconel/titanium | AlTiN with submicron substrate |
| Cast iron | TiAlN or AlCrN |
Geometry Specs to Match Application
- Helix angle: 30° (general), 38-45° (aluminum, high feed), 50-60° (stainless, vibration-resistant)
- Variable helix: anti-chatter, smoother machining
- Corner radius: stronger than sharp corners, required for HSM
- Length-to-diameter (L:D): keep ≤3 for general work, ≤6 for deep pockets with extra-rigid carbide
HSM (High-Speed Machining) Tips
Modern toolpaths (trochoidal, adaptive clearing in Fusion 360/Mastercam) allow:
- Axial depth: up to 1.5-2× diameter (vs traditional 0.5×)
- Radial engagement: 5-15% diameter (very light)
- Feed: 3-5× traditional rate
- Spindle speed: 80-100% of recommended max
Result: 3-5× tool life and 2-3× cycle time reduction vs conventional contouring.
Browse our complete end mill catalog. See our aluminum-specific end mill selection guide.
