KEVOS® MAKEOS · Manufacturing
Milling Power and Spindle Torque
What power and torque does this milling cut need, and can the spindle deliver it?
Metal removal rate, cutting power, motor power and spindle torque for a milling cut from the specific cutting force, compared with the available spindle power.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Radial width of cut | mm | Width of the cut across the cutter. |
| Axial depth of cut | mm | Depth of the cut along the cutter axis. |
| Table feed | mm/min | Programmed table feed. |
| Cutter diameter | mm | Cutter diameter (for surface speed). |
| Spindle speed | rpm | Spindle speed. |
| Specific cutting force kc | N/mm² | Specific cutting force for the work material at your chip thickness, from the tool supplier’s data (e.g. about 1500–2100 N/mm² for steels, 500–800 N/mm² for aluminium alloys). |
| Machine efficiency | % | Overall machine efficiency from spindle motor to cutting edge (often 70–85%); check the machine manual. |
| Available spindle power | kW | Spindle power available at this speed, from the machine chart. |
Method and formulas
- Removal rate Q = ae × ap × vf ÷ 1000 (cm³/min).
- Cutting power Pc = ae × ap × vf × kc ÷ (60 × 10⁶) (kW); motor power = Pc ÷ η.
- Torque = Pc × 30 000 ÷ (π n) (N·m); cutting speed = π D n ÷ 1000.
- Example: 40 × 3 mm at 800 mm/min removes 96 cm³/min and needs 3.6 kW.
Limitations
- kc must match the mean chip thickness of the cut; light radial engagement thins the chip and raises kc.
- Entry and exit shocks and tool wear raise peak power.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check a face or slot milling cut against spindle power
- Find the feed a spindle can sustain
- Check torque at low spindle speed
Who it is for
- Machinists
- CNC programmers
- Manufacturing engineers
What you get
- Metal removal rate
- Cutting power and motor power
- Spindle torque
- Cutting speed
Interpreting the result
- Use the spindle power and torque curves; torque often limits large cutters at low speed.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1084–1101. Topic reference; no source tables or recommended settings are reproduced.
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