AiVibeMaterial Removal Rate (MRR)
Material removal rate is the volume of material removed per unit of time, commonly in cubic centimetres per minute. It is the main measure of roughing productivity and is used to estimate required spindle power.
For milling, MRR Q in cubic centimetres per minute equals axial depth ap times radial depth ae times table feed vf, divided by 1000, with depths in millimetres and feed in millimetres per minute. For turning, Q equals cutting speed in metres per minute times depth of cut in millimetres times feed in millimetres per revolution. Required cutting power can be estimated from MRR and the specific cutting force of the workpiece material.
MRR is used to compare roughing strategies, tools and machines, and to check whether a planned cut is within the spindle's power and torque at the chosen speed. Process engineers raise MRR to cut cycle time on roughing operations, where most of the material is removed.
A higher MRR is only useful if tool life, chip evacuation, workpiece distortion, machine rigidity and chatter stability remain acceptable. Finishing operations are governed by accuracy and surface finish rather than MRR. Specific cutting force varies with material, chip thickness and tool geometry, so power estimates are approximations, and tool supplier data or measured spindle load should confirm them.
Key points
- Milling Q = ap x ae x vf / 1000 in cm3/min
- Turning Q = Vc x ap x fn in cm3/min
- Used with specific cutting force to estimate spindle power
- Relevant to roughing; finishing is governed by accuracy and finish
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.