KEVOS® MAKEOS · Manufacturing
Inch Milling Setup Check (Speed, Feed, Removal Rate, Spindle Power)
For a milling cut set up in surface feet and inches per tooth, what spindle speed and table feed do I program, and does the machine have the speed and power for it?
Check of an inch-unit milling setup: spindle speed from surface speed and cutter diameter and table feed from teeth and feed per tooth (as the inch speeds and feeds tool), capped at the machine’s top speed with the surface speed and feed that result, then the metal removal rate from width and depth of cut and the spindle power from a unit power for the material, against the machine’s motor power and efficiency.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Surface speed | ft/min | Surface speed recommended for the cutter and material. |
| Cutter diameter | in | Diameter of the cutter. |
| Number of teeth | teeth | Number of cutting teeth (flutes). |
| Feed per tooth | in | Feed per tooth (chip load). |
| Cut and machine | ||
| Width of cut (radial) | in | Radial width of cut. |
| Depth of cut (axial) | in | Axial depth of cut. |
| Unit power of the material | hp per in³/min | Power to remove one cubic inch per minute of the material (from the tool or machine maker). |
| Spindle speed limit | rpm | Highest spindle speed of the machine. |
| Spindle motor power | hp | Rated spindle motor power. |
| Machine efficiency | % | Share of motor power that reaches the cutter. |
Method and formulas
- Speed = 12 × sfm ÷ (π D); feed = speed × teeth × feed per tooth (as the inch speeds and feeds tool).
- Speed capped at the machine limit; surface speed and feed recalculated at the capped speed.
- Removal rate = width × depth × feed; power = removal rate × unit power ÷ efficiency.
- Example: 3,055.8 rpm and 24.446 in/min remove 3.0558 in³/min, needing 3.8197 hp.
Limitations
- Unit power varies with tool sharpness, rake and chip thickness; dull tools need up to half as much again.
- Tool deflection, chatter and work holding limit the cut separately.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check an end mill setup on a small mill
- See whether a cut needs a bigger machine
- Work out the feed after the spindle speed is capped
Who it is for
- Machinists
- CNC programmers
- Process planners
What you get
- Spindle speed and table feed
- Removal rate
- Spindle power against the machine
Interpreting the result
- When the spindle speed is capped, keep the feed per tooth and accept a lower table feed rather than raising the chip load.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1013–1017, 1084–1101. Topic reference; no source tables or recommended settings are reproduced.
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Open the Inch Milling Setup Check (Speed, Feed, Removal Rate, Spindle Power) calculator
