Milling Parameter Reference: Vc, fz, and ap for Face Mills, End Mills, and Slot Mills
Milling parameters are more complex than turning because you must account for feed per tooth (fz), number of cutting edges (z), and radial engagement (ae) in addition to cutting speed and axial depth. This comprehensive reference provides starting parameters for the three most common milling operations — face milling, end milling (shoulder/side), and slot milling — across all major material groups.
Key Milling Formulas
| Parameter | Formula | Units |
|---|---|---|
| Spindle Speed (n) | n = (Vc × 1000) / (π × Dc) | RPM |
| Table Feed (Vf) | Vf = fz × z × n | mm/min |
| Metal Removal Rate (Q) | Q = (ae × ap × Vf) / 1000 | cm³/min |
| Feed per Tooth (fz) | fz = Vf / (z × n) | mm/tooth |
| Effective Cutting Speed (Ve) | Ve = (π × Dc × n) / 1000 | m/min |
Where: Vc = cutting speed (m/min), Dc = cutter diameter (mm), fz = feed per tooth (mm), z = number of teeth/flutes, ap = axial depth of cut (mm), ae = radial width of cut (mm).
Face Milling Parameters — Steel (ISO P)
| Material | ISO Group | Cutter Ø (mm) | Roughing Vc (m/min) | Roughing fz (mm/tooth) | Roughing ap (mm) | Finishing Vc (m/min) | Finishing fz (mm/tooth) | Finishing ap (mm) | Korloy Grade |
|---|---|---|---|---|---|---|---|---|---|
| Low Carbon Steel | P10–P20 | 63–100 | 250–350 | 0.15–0.30 | 3.0–5.0 | 350–450 | 0.10–0.20 | 0.5–1.5 | PC5300 |
| Medium Carbon Steel | P20–P30 | 63–100 | 200–300 | 0.12–0.25 | 2.5–4.5 | 300–400 | 0.08–0.18 | 0.5–1.5 | PC5335 |
| Alloy Steel (4140, 42CrMo4) | P30–P40 | 50–80 | 170–250 | 0.10–0.22 | 2.0–4.0 | 250–350 | 0.08–0.15 | 0.5–1.2 | PC5400 |
| Hardened Steel (38–50 HRC) | P40–P50 | 40–63 | 120–180 | 0.06–0.15 | 1.0–2.5 | 180–250 | 0.05–0.10 | 0.3–0.8 | PC3545 |
End Milling (Shoulder/Side Milling) Parameters — Steel
| Material | ISO | Cutter Ø (mm) | ae / Dc Ratio | Roughing Vc | Roughing fz | Roughing ap | Korloy Grade |
|---|---|---|---|---|---|---|---|
| Low Carbon Steel | P10–P20 | 16–40 | 0.5–1.0 × Dc | 250–350 | 0.08–0.18 | 0.5–1.5 × Dc | PC5300 |
| Medium Carbon Steel | P20–P30 | 16–40 | 0.5–1.0 × Dc | 200–300 | 0.06–0.15 | 0.5–1.2 × Dc | PC5335 |
| Alloy Steel | P30–P40 | 12–32 | 0.5–0.8 × Dc | 160–250 | 0.05–0.12 | 0.4–1.0 × Dc | PC5400 / PC3545 |
Note: For ae/Dc ratios below 0.5 (light radial engagement), you can increase Vc by 20–40% using trochoidal or adaptive milling strategies. For ae/Dc = 1.0 (full slot), reduce fz by 20–30%.
Slot Milling Parameters — Steel & Stainless
| Material | ISO | Slot Width (mm) | Vc (m/min) | fz (mm/tooth) | ap (mm) | Coolant | Korloy Grade |
|---|---|---|---|---|---|---|---|
| Low Carbon Steel | P10–P20 | 8–20 | 200–300 | 0.04–0.10 | 0.3–1.0 × Dc | Through-tool / flood | PC5300 |
| Medium Carbon Steel | P20–P30 | 8–20 | 160–250 | 0.04–0.08 | 0.3–0.8 × Dc | Through-tool / flood | PC5335 |
| Alloy Steel | P30–P40 | 8–16 | 130–200 | 0.03–0.07 | 0.2–0.6 × Dc | Through-tool / MQL | PC3545 |
| Austenitic Stainless (304, 316L) | M20–M30 | 8–20 | 120–180 | 0.03–0.08 | 0.3–0.6 × Dc | Through-tool HP (70+ bar) | PC215K / PC3545 |
| Duplex Stainless (2205) | M30–M40 | 8–16 | 80–140 | 0.03–0.06 | 0.2–0.5 × Dc | Through-tool HP | PC2507 |
Face Milling Parameters — Stainless Steel, Cast Iron, Aluminum
| Material | ISO | Cutter Ø | Roughing Vc | Roughing fz | Roughing ap | Finishing Vc | Finishing fz | Finishing ap | Korloy Grade |
|---|---|---|---|---|---|---|---|---|---|
| Austenitic Stainless (304) | M10–M20 | 50–80 | 150–220 | 0.10–0.22 | 2.0–3.5 | 220–300 | 0.08–0.15 | 0.5–1.0 | PC215K |
| Duplex Stainless (2205) | M30–M40 | 50–80 | 100–160 | 0.08–0.18 | 1.5–3.0 | 160–220 | 0.06–0.12 | 0.3–0.8 | PC2507 |
| Gray Cast Iron (GJL-250) | K10–K20 | 63–125 | 250–380 | 0.15–0.30 | 3.0–5.0 | 380–500 | 0.10–0.20 | 0.5–1.5 | KC5305 |
| Nodular Iron (GJS-500) | K20–K30 | 63–100 | 200–300 | 0.12–0.25 | 2.5–4.0 | 300–400 | 0.08–0.18 | 0.5–1.2 | KC5335 |
| Wrought Aluminum (6061-T6) | N10 | 50–100 | 400–700 | 0.12–0.25 | 3.0–6.0 | 700–1200 | 0.08–0.18 | 0.5–2.0 | NCM325 / Uncoated |
| Cast Aluminum (A380) | N20 | 50–80 | 300–500 | 0.10–0.20 | 2.0–4.0 | 500–800 | 0.08–0.15 | 0.5–1.5 | NCM325 |
Super Alloy Milling Parameters
| Material | ISO | Operation | Cutter Ø | Vc (m/min) | fz (mm/tooth) | ap (mm) | ae/Dc | Korloy Grade |
|---|---|---|---|---|---|---|---|---|
| Titanium Ti-6Al-4V | S10–S20 | Face Mill | 50–80 | 50–80 | 0.06–0.14 | 2.0–4.0 | 0.5–0.8 | PC3545 |
| Titanium Ti-6Al-4V | S10–S20 | End Mill | 16–32 | 40–70 | 0.04–0.10 | 0.5–1.5 × Dc | 0.1–0.3 | PC3545 |
| Inconel 718 | S20–S30 | Face Mill | 50–80 | 30–60 | 0.05–0.12 | 1.5–3.0 | 0.5–0.7 | PC3545 |
| Inconel 718 | S20–S30 | End Mill | 12–25 | 25–50 | 0.03–0.08 | 0.3–1.0 × Dc | 0.05–0.2 | PC3545 |
Super alloy milling tip: Use climb milling exclusively. Maintain ae/Dc ≤ 0.5 for end milling to keep cutting forces manageable. Use high-pressure through-tool coolant to prevent chip re-welding and extend tool life.
Milling Cutter Type Selection Guide
| Cutter Type | Best For | Typical ae/Dc | Typical ap/Dc | Key Parameter Priority |
|---|---|---|---|---|
| Face Mill (indexable) | Large flat surfaces, pocket floors | 0.7–1.2 × Dc | 0.03–0.08 × Dc | Vc first, then fz |
| Shoulder/End Mill | Profiles, shoulders, pockets | 0.1–0.5 × Dc | 0.5–2.0 × Dc | fz first, then ae |
| Slot Mill | Keyways, grooves, full-width slots | 1.0 × Dc (full width) | 0.3–1.0 × Dc | Reduce fz 20–30% |
| Ball Nose End Mill | 3D contours, fillets, molds | 0.05–0.2 × Dc | Variable | Stepover (ae), fine fz |
| Chamfer Mill | Edge breaking, bevels | Variable | Small | Match angle, light ap |
Trochoidal & Adaptive Milling Adjustments
Modern CAM-driven strategies like trochoidal and adaptive milling use small ae (5–15% of Dc) with large ap (1.5–3× Dc). Because the radial load is so low, you can significantly increase cutting speed:
- Vc: Increase by 30–60% vs. conventional values above
- fz: Maintain or slightly increase (+10%)
- ap: 1.5–3.0 × Dc (axial depth replaces radial depth)
- ae: 5–15% of Dc (constant light radial engagement)
This approach dramatically extends tool life in hard materials and super alloys. Korloy PC3545 excels in adaptive milling of titanium and Inconel due to its PVD AlTiN coating toughness.
Looking for milling inserts and end mills? hooguu.com stocks a complete range of Korloy face milling, shoulder milling, and slot milling cutters with indexable carbide inserts. Contact our application engineers for optimized milling parameters for your specific setup.
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