Plunge roughing
Z-Axis Milling Calculators
Z-axis (plunge) milling removes metal axially with the end face of the tool — ideal for deep cavities, poor rigidity and long overhangs. Size plunge feed and metal removal rate here.
Plunge metal removal rate
Q = (π/4)·D²·vfChip load → plunge feed
vf = fz · z · nFormulas used
Plunge MRR: Q = plunge cross-section × axial feed = (π/4)·D²·vf. For stepped linear moves use D × stepover × vf.
Why plunge: axial cutting forces go into the spindle (stiffest direction), so long-reach tools tolerate far higher MRR than radial milling.
Frequently asked questions
When should I use plunge milling?
For deep pockets, thin walls, weak workholding and long tool overhangs — anywhere radial forces cause deflection or chatter. Plunging directs force axially into the spindle.
What feed per tooth for plunge milling?
Typically 0.05–0.15 mm/tooth with indexable plunge cutters; the limiting factor is usually insert geometry and chip evacuation from the hole bottom rather than power.