Enter the cutting data for a turning or milling cut and get the metal removal rate Q, the net cutting power at the tool and, with a machine efficiency, the spindle power you need to have available. Metric or inch. Runs entirely in your browser, nothing is sent anywhere.
kc is always entered in N/mm² (the unit catalogs use), in both unit systems. The result is net power at the cutting edge for steady cutting. Check the real limit against your spindle torque curve at the rpm you run, not only against rated kW.
The metal removal rate is the volume of chip produced per minute. Every term is a length per minute or a length, so the formula is a plain product:
The factor 60 × 10³ comes from the units: 1 cm³/min is 1000 mm³/min, which is 1000/60 mm³/s, and N/mm² × mm³/s is N·mm/s, so 1 kW needs 60 × 10³ of the product. In inch units Q is in³/min: for turning 12 × SFM × ap × fn, for milling ap × ae × ipm. We convert with 1 in³ = 16.387 cm³ (from 1 in = 25.4 mm) and 1 hp = 745.7 W.
kc is the specific cutting force: the tangential cutting force per unit chip cross-section for a given material. It falls as the chip gets thicker, which is why catalogs list a base value (often kc1) and a correction exponent. We do not publish a kc table here. Use the value your tool maker gives for the workpiece material and grade, and the result will match the data sheet you cut to.
For turning, Q = vc × ap × fn, with vc in m/min, ap in mm and fn in mm/rev, which gives cm³/min. For milling, Q = ap × ae × vf / 1000, with ap, ae in mm and vf in mm/min, which also gives cm³/min. In inch units the same products are in³/min: for turning 12 × SFM × ap × fn, for milling ap × ae × ipm.
Net cutting power is Pc = Q × kc / (60 × 10³), with Q in cm³/min and kc in N/mm², which gives kW. For example Q = 100 cm³/min at kc = 2000 N/mm² gives 3.33 kW. This is the power at the cutting edge. Dividing by the machine efficiency gives the power the motor has to deliver.
This page does not carry a kc table, because kc depends on the workpiece material, its condition and the chip thickness, and the values that matter are the ones your tool maker publishes. Take kc (often listed as kc1 with a correction exponent) from the catalog of the insert or cutter you run, and enter it in N/mm².
This page tells you what a cut demands from the machine. Which insert grade and starting data hold up at that removal rate is the advisor's job, grounded in catalog data and brand-neutral.
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