Understanding Cutting Speed Calculations
This calculator computes the cutting speed (ft/min or m/min) for CNC machining based on spindle speed (RPM), tool diameter, and tool material, with imperial or metric units.
Cutting speed is the speed at which the tool’s cutting edge moves relative to the workpiece, critical for tool life and surface finish. The formula is (RPM × Diameter × π) / 12 for ft/min or / 1000 for m/min.
Example Cutting Speeds
| Tool Material | RPM | Tool Diameter | Cutting Speed | Scenario |
|---|---|---|---|---|
| HSS | 1000 | 0.5 in. | 131 ft/min | Milling aluminum |
| Carbide | 800 | 0.25 in. | 52 ft/min | Turning steel |
| Carbide | 1200 | 1.0 in. | 314 ft/min | Routing wood |
How to Use the Cutting Speed Calculator
- Select the unit system (imperial or metric).
- Enter the spindle speed (RPM) and tool diameter.
- Choose the tool material (HSS or carbide) to view suggested cutting speed ranges.
- Click "Calculate Cutting Speed" to view the result and suggested range.
Cutting Speed vs. Suggested Range
Comparison of calculated cutting speed against suggested minimum and maximum speeds for the selected tool material.
Frequently Asked Questions
What is cutting speed in CNC machining?
Cutting speed is the speed at which the tool’s edge moves relative to the workpiece, typically in ft/min or m/min, affecting tool life and surface finish.
How does tool material affect cutting speed?
Carbide tools allow higher cutting speeds than HSS due to better heat resistance and durability, enabling faster machining with proper setup.