METRIK MFG
Milling Formulas Reference
Technical reference for CNC milling formulas covering cutting speed, feed, chip load, MRR, cutting power and spindle torque.
Use this page as the canonical formula reference behind Metrik MFG milling calculators. The equations are shown with units, variables and scope notes.
Core relationships
| Formula | Relationship | Scope |
|---|---|---|
| Speed | Vc = πDn/1000 | Metric cutting speed |
| RPM | n = 1000Vc/(πD) | Metric reverse calculation |
| Feed | vf = fz n z | Milling feed |
| Feed/rev | fn = vf/n | Conversion |
| MRR | Q = ae ap vf | Simple engagement model |
| Power | Pc = (ae ap vf kc)/(60×10^6) | Metric model with kc |
| Torque | Mc = 30000Pc/(πn) | Pc in kW |
Variables
D tool diameter; Vc cutting speed; n RPM; fz feed per tooth; z effective teeth; ae radial engagement; ap axial depth; vf feed rate; kc specific cutting force for the selected material/process model.
Important limitation
The formulas connect the variables; they do not choose the correct cutting data for every tool and material. Manufacturer recommendations govern the actual Vc, fz, engagement and other inputs.
Primary references: DATRON and Sandvik Coromant.
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