Material removal rate calculator
Calculate the material removal rate (volume removed per minute) from depth of cut, width of cut and feed rate. A key value for the material removal rate — useful for comparing different cutting strategies.
Material removal rate
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Note: All values are non-binding reference figures. Actual values depend on machine, tool, material and conditions. Start conservatively. No liability is accepted for tool breakage, machine damage or machining results.
What the Machining Volume Calculator Calculates
From depth of cut, width of cut and feed rate, the calculator determines the material removal rate Q (how much material is removed per minute). Q is a purely geometric parameter and is suitable for directly comparing different cutting strategies (e.g. “deep and slow” vs. “shallow and fast”).
The Formula
Q = ap × ae × vf / 1000
Here, Q is the material removal rate in cm³/min, ap is the depth of cut (axial engagement) in mm, ae is the width of cut (radial engagement) in mm and vf is the feed rate in mm/min. The result is divided by 1000 because it is converted from mm³ to cm³. Example: ap = 5 mm, ae = 6 mm, vf = 3000 mm/min give Q = 5 × 6 × 3000 / 1000 = 90 cm³/min.
What Q Is Useful For and What It Is Not
- Comparing strategies: Two infeed combinations with the same Q remove the same amount of material per minute, even if the individual values for depth, width and feed rate differ.
- Not a power rating: Q says nothing about the required spindle power. That also depends on the specific cutting force of the material (aluminium, for example, needs considerably less power per cm³ than steel). This material value is deliberately not part of the calculator because it depends heavily on tool geometry and tool condition.
- Not a statement on tool load: A high Q can load the tool and machine more heavily, even if the spindle power is sufficient. Vibration, tool deflection and tool life also play a role.
Practical Guidance
As a rough guide: for aluminium roughing on rigid CNC gantry milling machines, material removal rates of 20–100+ cm³/min are usual, depending on machine power, tool diameter and workpiece clamping. For steel, the practicable values are considerably lower. The calculator itself makes no material recommendation; it only supplies the pure parameter calculated from your inputs.
Frequently Asked Questions
What is the difference between material removal rate and removed material volume?
Material removal rate (Q) is the removal rate per minute (cm³/min), the value this calculator provides. Removed material volume without a time reference, on the other hand, means the total volume of material removed for a complete machining operation. In practice, both terms are often used synonymously; usually the material removal rate is what is meant.
How does Q relate to the required spindle power?
The power P is calculated approximately from P = Q × kc / 60, where kc is the specific cutting force of the material in N/mm². Because kc varies greatly with the material, tool geometry and cutting conditions, this calculator deliberately provides only Q. For a power estimate, you also need a realistic kc value for your material and tool.
Can I compare different machining strategies using Q?
Yes, Q is well suited for this: if two infeed combinations produce the same Q, they remove the same amount of material in the same time. Whether one strategy is nevertheless gentler on the tool (e.g. a shallow cut with a high feed rate instead of a deep cut with a low feed rate) depends on further factors such as chip thinning and tool deflection.
Why is machining not automatically finished sooner when Q is high?
Q only describes the pure removal rate during the cut. The actual total time also depends on rapid traverses, approach moves, tool changes and setup time. For that, there is the separate machining time calculator.
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