Material Removal Rate

Volumetric removal rate

Material removal rate is the solid volume removed from a workpiece per unit time. For milling, multiply width of cut by axial depth and linear feed rate. A width of 10 mm, a depth of 2 mm and feed of 100 mm per minute remove 2000 cubic millimetres per minute, equal to 2 cubic centimetres per minute.

Drilling and turning

For drilling into solid stock, multiply the circular hole area by axial feed. For longitudinal outside diameter turning, the removed section is an annulus. With initial diameter D and radial depth a, the final diameter is D − 2a and the removed area is πa(D − a). This accounts for the diameter change geometrically. The rate applies during steady cutting, not during idle moves. Loose chip volume depends on chip shape and packing and is not calculated.

Follow the annulus removed in turning

Choose an initial diameter of 30 mm, radial depth of cut of 3 mm and feed of 80 mm/min. Final diameter is 30 − 2 × 3 = 24 mm. The removed annular area is π × (30² − 24²) / 4 = 81π mm². Multiplying by feed gives 81π × 80 ≈ 20357.52 mm³/min. Divide by 1000 to convert volume to cubic centimetres, giving approximately 20.36 cm³/min. This example shows that depth of cut is not the total reduction in diameter.

Do not enter feed per revolution directly in the feed rate field, which requires linear speed. If feed per revolution is known, multiply by rotational speed and convert to the appropriate time unit first. Apply the calculated volumetric rate only while the tool actually removes material. Approach, retraction, workholding and tool changes affect average production rate. For multiple passes, initial diameter changes with each pass, so evaluate each removed volume separately. Increasing the result alone does not establish suitable cutting conditions. Machine power, workholding, tool strength and surface requirements need separate checks.

Frequently asked questions

How do you calculate material removal rate in milling?

For example, multiplying depth, width and feed gives a material removal rate of 5.4 cm³ per minute for depth 3 mm, width 12 mm and feed 150 mm per minute. This assumes continuous rectangular engagement, excludes air cutting and entry or exit moves, and does not establish tool life or available machine power.

Calculate with these values