Understanding CNC Feed Rate Calculations
This calculator computes the CNC feed rate (in/min or mm/min) for milling or drilling based on spindle speed (RPM), number of flutes, and chip load, with imperial or metric units.
Feed rate is critical for optimizing tool life, surface finish, and machining efficiency. The formula is RPM × Number of Flutes × Chip Load. Material type affects chip load selection.
Example CNC Feed Rates
| Material | RPM | Flutes | Chip Load | Feed Rate |
|---|---|---|---|---|
| Aluminum | 1000 | 2 | 0.006 in. | 12 in/min |
| Steel | 800 | 4 | 0.004 in. | 12.8 in/min |
| Wood | 1200 | 3 | 0.010 in. | 36 in/min |
How to Use the CNC Feed Rate Calculator
- Select the unit system (imperial or metric).
- Enter the spindle speed (RPM) and number of flutes.
- Choose a material type to set a suggested chip load or enter a custom chip load.
- Click "Calculate Feed Rate" to view the feed rate and suggested chip load range.
Feed Rate vs. Spindle Speed
Feed rate variation across different spindle speeds for the selected inputs.
Frequently Asked Questions
What is chip load in CNC machining?
Chip load is the thickness of material removed by each flute per revolution, typically in inches or mm per flute, affecting tool life and surface finish.
Why is feed rate important?
Correct feed rate ensures efficient cutting, prevents tool wear, and achieves a smooth surface finish, tailored to material and tool specifications.