Turning Time Formula
Turning Time = Length / (RPM x Feed per Rev)
Use diameter at the cut when RPM is fixed. In CSS mode, calculate from the effective average RPM or from CAM/machine actuals.
What to Add for Cycle Time
- Approach and retract distance for each pass.
- Tool index time, turret unclamp/clamp, and spindle acceleration.
- Chuck open-close, part handling, bar pull, or subspindle transfer time.
- In-process gauging, deburring, and inspection steps.
Worked Example
A shaft turning pass cuts 100 mm at 800 RPM and 0.15 mm/rev. There are four passes, plus 45 seconds of approach, indexing, chucking, and inspection.
Feed rate = 800 x 0.15 = 120 mm/min
One pass = 100 / 120 = 0.83 min
Four passes = 3.33 min
Cycle estimate = 3.33 + 0.75 = 4.08 min
Calculator Handoff
Use this guide for the turning formula and pass logic. Use the machining time calculator when you need cycle time, parts per hour, batch quantity, and quote context in one workflow.