SpecCalcsReference calculators for the shop floor

Material Removal Rate Calculator

Milling with a 10 mm width of cut, 3 mm depth and 500 mm/min table feed removes 15000 mm³/min (15 cm³/min, 0.9154 in³/min).

MRR calculator
MRR (mm³/min)15000
MRR (cm³/min)15
MRR (in³/min)0.9154

The formulas

Milling
MRR=ae×ap×vf\text{MRR} = a_e \times a_p \times v_f
Turning
MRR=vc×1000×ap×f\text{MRR} = v_c \times 1000 \times a_p \times f
ae radial depth of cut · ap axial depth of cut · vf table feed (mm/min) · vc cutting speed (m/min) · f feed/rev (mm)

What is MRR

Material removal rate measures the volume of material removed per unit time. It is the single most important productivity metric in machining — higher MRR means shorter cycle times and lower cost per part, provided the machine, tooling, and fixture can handle the cutting forces and heat.

Roughing vs. finishing

Roughing passes maximise MRR: large depths of cut, wide radial engagement, and aggressive feeds. Typical roughing MRR for mild steel on a 40-taper VMC is 50–150 cm³/min; aluminium on the same machine can exceed 500 cm³/min. Finishing passes drop MRR by an order of magnitude to achieve surface finish and dimensional accuracy — often below 5 cm³/min.

Power and MRR

Spindle power limits MRR in practice. The specific cutting energy (kc) for a material gives the power draw per unit MRR: P = kc×MRR. For steel kc ≈ 2.5 W·min/cm³; for aluminium ≈ 0.8. Exceeding the available spindle power stalls the cut or triggers a feed override.