Solid carbide · indexable
End Milling Calculators
Everything for peripheral and end milling: speeds and feeds, metal removal rate, unit-power horsepower, radial chip-thinning compensation for light WOC, and ball nose effective diameter for 3D surfacing.
Cutting speed → RPMChip load → table feedMetal removal rateSpindle & motor powerRadial chip thinningBall nose effective diameterScallop height (3D surfacing)
Cutting speed → RPM
n = Vc·1000 / (π·D)Chip load → table feed
vf = fz · z · nMetal removal rate
Q = ae · ap · vfSpindle & motor power
P = Q × unit powerRadial chip thinning
hex = fz · √(ae/D)Ball nose effective diameter
Deff = 2·√(ap·(D−ap))Scallop height (3D surfacing)
h = R − √(R² − (ae/2)²)Formulas used
Chip thinning: for ae < D/2, hex = fz × √(ae/D). Program fz_adj = fz_target / √(ae/D) to hold chip load.
Ball nose: Deff = 2√(ap·(D−ap)); effective speed = π·Deff·n — at the tip center the cutting speed is zero, so avoid ploughing.
Unit power: P_spindle = Q × p (hp per in³/min); P_motor = P_spindle / efficiency.
Frequently asked questions
What is chip thinning in milling?
When radial engagement is less than half the cutter diameter, the actual chip thickness is smaller than the programmed feed per tooth. hex = fz×√(ae/D) — so at ae = 10% of D the chip is only ~32% of fz, and feed should be increased roughly 3× to maintain productivity.
How do I calculate horsepower for milling?
Multiply metal removal rate by the material's unit power: HP = Q (in³/min) × unit power. Mild steel needs about 1 hp per in³/min; aluminum about 0.33; Inconel about 2. Divide by machine efficiency for motor power.
Why does a ball nose mill cut poorly at the center?
Surface speed scales with radius, so at the exact center it is zero — the tool rubs instead of cutting. Tilt the tool 10–15° or use the effective diameter calculator to keep the contact zone on the flutes.