AiVibeCutting Speed (Surface Speed, Vc)
Cutting speed is the relative speed between the cutting edge and the workpiece surface at the point of cutting, usually given in metres per minute. It is the main factor governing heat at the cutting edge and tool life.
Cutting speed Vc is the circumferential speed at the cutting diameter: Vc = pi D n / 1000, with D in millimetres and n in rev/min, giving metres per minute. Imperial practice uses surface feet per minute. Tool suppliers publish recommended cutting speeds for combinations of workpiece material group, tool material, coating and operation, and the CNC program converts the chosen speed into a spindle speed.
Cutting speed is chosen together with feed and depth of cut when planning an operation. Higher speeds shorten cycle times and can improve surface finish in some materials, but they raise cutting temperature and accelerate tool wear, so the economic speed balances machining time against tool cost and tool-change time. Taylor's tool life equation describes this trade-off.
Recommended values are starting points that are adjusted for machine rigidity, workholding, coolant, tool overhang and observed wear. For ball-end mills at shallow axial depths, the effective cutting diameter is smaller than the nominal diameter, so the effective cutting speed is lower than the nominal calculation suggests. Heat-resistant alloys and titanium generally require much lower cutting speeds than aluminium alloys.
Key points
- Vc = pi D n / 1000, expressed in metres per minute
- The main driver of cutting-edge temperature and tool wear
- Tool suppliers publish starting values by material and tool grade
- Ball-end mills cut at a smaller effective diameter at shallow depths
Where AiVibe comes in
AiVibe designs and manufactures the AiAmbA AI Factory: edge devices plus AI agents that let people talk to CNC, PLC and robot controllers in plain language. Agents only propose changes, and a trained operator confirms each one.
Related terms
- Spindle Speed (RPM)CNC & Precision Machining
- Feed RateCNC & Precision Machining
- Tool Life (Taylor's Equation)CNC & Precision Machining
- Cutting Tool MaterialsCNC & Precision Machining
- Material Removal Rate (MRR)CNC & Precision Machining