Milling Force Calculatormechanistic Kienzle model

Scope. Cylindrical, equally spaced, constant-helix tools in steady side milling. No plunging, ramping, ball/taper geometry, runout, variable pitch, chip recutting or tool-motion feedback is included.

Numerical envelope. Diameter 0.1–100 mm, 1–12 flutes, helix 0–65°, axial depth up to 10 diameters, and feed per tooth up to 5% of diameter. Flute length and depth must fit within stickout. These bounds limit the numerical and circular-chip-path approximation; they are not recommended cutting conditions.

Force law. Each axial slice uses dFt = [kc1.1 · h^(1−mc) · wear · (1−rake/100) + Kte] dz, with h = fz · sin(phi). Helix lag is z · tan(helix) / radius. Integration splits at entry/exit events, uses adaptive quadrature, and refines sampled local peaks. The radial component is an assumed constant ratio of tangential force.

Chip thinning. The maximum chip thickness reaches fz at half immersion and above. Below half immersion, it decreases with radial width. At 10% radial engagement, hmax = 0.6 fz. Reducing radial width at fixed feed per tooth makes chips thinner. Any feed compensation must remain within tool and machine limits. Minimum chip thickness depends on the actual edge; no universal rubbing threshold is used.

Material estimates. Family presets are uncalibrated planning scenarios. Lower, typical and higher vary only the force coefficient; the chip-size exponent and radial ratio stay fixed within a family. These are not confidence intervals or machinability ratings. Old shared cuts retain supplied constants as custom values. Editing a constant preserves the base estimate.

Edge contribution. Family estimates add no separate edge term to the power law. Enter a separately calibrated Kte if appropriate. The energy panel reports this term’s share of modelled power; it cannot establish actual ploughing, adhesion or minimum chip thickness.

Power. Net mechanical cutting power comes from mean tangential torque times angular speed. Compare with available shaft power at the current RPM, not electrical input or nameplate power alone. Electrical measurements need an idle baseline and drive-loss accounting.

Static bending. A stepped beam uses δ = F ∫(a−x)²/[E I(x)] dx at the assumed point load, with a = stickout − DOC/2. The headline is the peak in-plane load times this compliance. The revolution-mean vector includes unloaded intervals; RMS is a separate statistic. These are tool-only point-load estimates, not wall error or tool-tip displacement. The actual force distribution along the flute, holder/fixture compliance, and dynamic response are omitted.

Stiffness defaults. Effective bending diameter is 0.70D/0.76D/0.79D/0.82D for 1/2/3/4 flutes and 0.85D for more flutes. These are uncalibrated defaults, not measured core diameters. Because I scales with diameter to the fourth power, a 10% larger effective diameter gives 46% greater section stiffness. Measure the mounted assembly if displacement matters. Imported tool shoulder length is not mounted stickout.

Directions and axial force. Signs of Fx/Fy follow the chosen fixed feed/transverse frame and tooth angle. A sign change is a direction change. The axial curve is an unsigned Ft · tan(helix) proxy; cutting geometry and separate axial coefficients are needed for pullout or fixture design.

Energy is not temperature. Power per removed volume is shown in J/mm³. No chip, tool or workpiece temperature or heat split is predicted. Primary-shear heat-partition relations alone do not determine the whole-process thermal balance or built-up edge.

Screening is not validation. Passing configured power, speed and static-bending checks does not establish chatter stability, tool life, wall tolerance or a safe increase in feed. Static-bending screening thresholds are 0.02 and 0.08 mm, not user-specific tolerances. Chatter needs modal data and regeneration modelling.

Field validation. Record actual geometry, stickout, runout and material condition. Fit coefficients across several chip loads and engagements, then compare with independent cuts. One power measurement cannot identify kc1.1, mc and Kte independently. Numerical agreement with a formula is not agreement with a real cut.