Understanding CNC Cutting Speed Calculations
This calculator computes the CNC cutting speed (ft/min or m/min) for milling, turning, or drilling based on spindle speed (RPM), tool diameter, and material type, with imperial or metric units.
Cutting speed, or surface speed, is critical for optimizing tool life, surface finish, and machining efficiency. The formula is (RPM × Diameter × π) / 12 for ft/min or / 1000 for m/min. Material type affects speed selection.
Example CNC Cutting Speeds
| Material | RPM | Tool Diameter | Cutting Speed | Scenario |
|---|---|---|---|---|
| Aluminum | 1000 | 0.5 in. | 131 ft/min | Milling with carbide tool |
| Steel | 800 | 0.25 in. | 52 ft/min | Turning with HSS tool |
| Wood | 1200 | 1.0 in. | 314 ft/min | Routing with carbide tool |
How to Use the CNC Cutting Speed Calculator
- Select the unit system (imperial or metric).
- Enter the spindle speed (RPM) and tool diameter.
- Choose a material type to view suggested cutting speed ranges or select custom.
- Click "Calculate Cutting Speed" to view the cutting speed and suggested speed range.
Cutting Speed vs. Spindle Speed
Cutting speed variation across different spindle speeds for the selected tool diameter.
Frequently Asked Questions
What is cutting speed in CNC machining?
Cutting speed, or surface speed, is the speed at which the cutting tool’s edge moves relative to the workpiece, typically in ft/min or m/min, affecting tool life and surface finish.
Why is cutting speed important?
Correct cutting speed ensures efficient machining, prevents tool wear, and achieves a smooth surface finish, tailored to material and tool specifications.