How to Calculate Speeds and Feeds for Different Materials on CNC

May 16, 2026

Correct speeds and feeds are essential for achieving good surface finish, longer tool life, and efficient machining. Using wrong parameters can damage tools and reduce productivity.

Basic Formula

RPM = (Surface Speed × 3.82) ÷ Tool Diameter

Feed Rate (mm/min) = RPM × Number of Flutes × Chip Load per Tooth

Recommended Surface Speeds (SFM)

• Wood: 300 – 600 SFM
• Acrylic: 200 – 400 SFM
• Aluminium: 200 – 300 SFM
• Brass: 150 – 250 SFM
• Mild Steel: 80 – 120 SFM

Final Thoughts

Start with manufacturer-recommended values and adjust based on your machine, tool, and material. Proper speeds and feeds can significantly improve your machining results.

Akriti Precision Systems recommends using correct cutting parameters to achieve better performance and tool life on its CNC machines.