Question 1

How is cutting force Fc calculated?

Accepted Answer

Cutting force (main component) is calculated using the specific cutting force model: Fc = kc1 × f^(1-mc) × ap. Here kc1 is the specific cutting force (N/mm²) — a material constant, mc is the slope exponent (typically 0.2–0.3), f is feed rate (mm/rev), and ap is depth of cut (mm). For Al6061 kc1 ≈ 700, for 1045 steel kc1 ≈ 2000 N/mm².

Question 2

What is Taylor's tool life equation?

Accepted Answer

Taylor's V-T relationship is T = (C/V)^(1/n), commonly written as VT^n = C. V is cutting speed (m/min), T is tool life (min), and n and C are constants dependent on the material-tool combination. For carbide tooling on 1045 steel, n ≈ 0.25 and C ≈ 180 are typical. The relationship is linear on a log-log scale.

Question 3

How is theoretical surface roughness calculated?

Accepted Answer

For turning, the theoretical maximum height is Rmax = f²/(8r) and the arithmetic mean roughness Ra ≈ f²/(32r), where f is feed rate (mm/rev) and r is nose radius (mm). Actual roughness is typically 1.5–2× higher due to built-up edge and vibration. Halving the feed rate reduces Ra by approximately 75%.

Question 4

How can this calculator be used with CAM software?

Accepted Answer

Use this calculator to pre-estimate optimal cutting conditions (Vc, f, ap) before entering them into CAM software such as Mastercam or Hypermill. Back-calculate tool life T (min) to plan tool change intervals. The power check verifies that conditions are within your machine's horsepower capacity.

CNC Machining — Cutting Force & Tool Life Calculator

Governing Equations