Cutting Conditions
Cutting conditions are the three parameters you set on the machine: speed, feed, and depth of cut. They determine everything — tool life, surface finish, power consumption, and cycle time. This page connects the theory to the calculators you'll use every day.
Speed (Cutting Speed Vc)
Cutting speed is the surface velocity of the tool edge relative to the workpiece, in m/min. It is the single most important factor for tool life. Higher speed = more heat = faster tool wear. Lower speed = longer tool life but lower productivity.
Convert between Vc and RPM: Spindle Speed Calculator · Cutting Speed Calculator
Feed
Feed is how far the tool advances per revolution (or per tooth in milling). It directly affects surface finish and chip thickness.
Calculate: Feed Rate Calculator · Chip Load Calculator
Depth and Width of Cut
Depth of cut (ap) in turning is the radial depth. Width of cut (ae) in milling is the radial engagement. Together with feed, they define the chip cross-section and therefore the cutting force and power.
Material Removal Rate (MRR)
MRR is the volume of material removed per minute. It is the direct measure of productivity.
Calculate: MRR Calculator · Power & Torque Estimator
How the Parameters Relate
| If you increase... | Tool life | Surface finish | Power | Productivity |
|---|---|---|---|---|
| Speed (Vc) | ↓↓ drops fast | ↑ better | ↑ | ↑ |
| Feed (f) | ↓ slightly | ↓ rougher | ↑ | ↑↑ |
| Depth (ap) | ↓ minimal | ≈ same | ↑↑ | ↑↑ |
The golden rule: increase depth of cut first (it barely affects tool life), then feed (moderate effect), then speed (biggest effect on tool life). This maximizes MRR while preserving tool life.
Cutting Time
Estimate cycle time: Machining Time Estimator