Turning & Cycle Time
Machining time for OD turning (rpm, feed rate, passes from stock and depth of cut) or facing at constant surface speed with an rpm cap, plus non-cutting time.
Spindle speed, feed rate, time per pass and pass count, cutting time, the cycle time per part with your non-cutting minutes, batch minutes and parts per hour.
Example: Ø50 at 200 m/min and 0.25 mm/rev over 100 + 3 mm: 1,273 rpm, 0.324 min per pass; 6 mm off the diameter at 1.5 deep plus a finish pass is 3 passes, 0.97 min cutting, 1.47 min with loading.
Feed motion,
counted in minutes.
How cutting time is built up from speed, feed and passes, and what the facing rule adds.
OD turning
Spindle speed n = 1000·vc ÷ (π·D); feed rate = f × n in mm/min; time per pass = (length + approach and overrun) ÷ feed rate. Roughing passes = ⌈(stock on diameter ÷ 2) ÷ depth of cut⌉ — the stock is removed from the radius — plus the finishing passes you add. Cutting time = passes × time per pass; with constant surface speed the later, smaller passes actually run a little faster than this.
Facing
Facing at constant surface speed (G96) sweeps the annulus from D to d at a constant vc, so the time is the swept area ÷ (vc × f): π(D² − d²)/4 ÷ (vc × f). Near the centre the spindle hits its rpm limit; from the diameter where vc × 1000 ÷ (π·n_max) is reached inward the page switches to constant rpm and adds that time separately.
Cycle time
Cycle time per part = cutting + rapids + tool changes + load/unload — the non-cutting minutes are yours, as are the chip-breaking, inspection and warm-up the arithmetic leaves out. Parts per hour and batch time follow from it. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- n = 1000·vc/(π·D); t = (L + approach) ÷ (f × n); passes = ⌈(stock/2) ÷ ap⌉ + finishing; facing at constant vc: t = π(D² − d²)/4 ÷ (vc × f), constant rpm below the cap diameter
Last reviewed 20 September 2026. How results are checked: How we verify.