Milling spindle speed, feed and removal rate
Convert tool-supplier cutting data into machine settings while preserving its material and tool context. Speed and feed equations are geometric/kinematic relationships; they do not determine a safe cutting speed or chip load by themselves.
Worked numbers are illustrative. Use your own operating conditions and documented material/process data.
Required inputs
- Effective cutting diameter D, supplied cutting speed Vc, feed per tooth fz and effective teeth z.
- Radial engagement ae, axial depth ap and explicit cutting travel L.
- Machine speed/feed limits and any valid specific cutting-force coefficient for power work.
Governing equations
n = 1000Vc/(πD)
Vf = fz z n
MRR(cm³/min) = ae ap Vf/1000
tcut(s) = 60L/Vf
Variables and units
- D, ae, ap, L: mm; Vc: m/min; fz: mm/tooth; Vf: mm/min; n: rpm.
- z: effective teeth for feed calculation, dimensionless count.
Assumptions
- Constant entered diameter and feed during the cutting path.
- Example cutting data are illustrative, not recommended for every material or cutter.
Calculation workflow
- Confirm that cutting diameter corresponds to the actual cutting depth/tool geometry.
- Calculate rpm and feed, then compare both with machine limits.
- Use explicit cutting travel for basic time; add non-cutting cycle elements separately.
Worked example
- D = 63 mm; Vc = 180 m/min; fz = 0.10 mm/tooth; z = 6; ae = 40 mm; ap = 2 mm; L = 200 mm.
- n = 909.456818 rpm; Vf = 545.674091 mm/min.
- MRR = 43.653927 cm³/min; cutting time = 21.991149 s; removed volume = 16000 mm³.
Limitations
- Power and torque remain NOT EVALUATED without a valid coefficient basis.
- Tool life, finish, chip evacuation, chatter and manufacturer suitability are not approved by the arithmetic.
Common mistakes
- Using feed per revolution as feed per tooth.
- Using nominal diameter instead of effective cutting diameter.
- Reporting traverse-only cutting time as a complete production cycle.
Practical interpretation
The result reproduces the workspace’s illustrative face-milling case. Increasing teeth raises feed at the same fz/rpm, but practical cutting engagement and chip thickness still depend on the tool geometry. Basic cutting time is not complete machine cycle time.
Related formulas
The governing equations, units and calculation steps above provide the formula basis for this guide. The related workspace also shows its calculation trace.
Rotation and unit bases →Related workspace
Open Manufacturing & Machining →Sources and reference basis
Equations and worked examples are independently explained here. References reviewed 2026-10-17; no copyrighted standard tables are reproduced.